apcupsd-users — Users forum for Apcupsd related matters. Support questions welcome.

Re: [Apcupsd-users] help with apcupsd message

[Pavel B. <boc...@po...>]

Start with replacing the caps for something decent (Panasonic, Rubycon, 
Nichicon, Chemi-Con), there should be about 8 pcs of small 22uF, one or two 
4.7uF. Most of them are tiny D5×7 mm, use standard D5×11, few of them may 
colide with the chassis so bend them towards the board. These usually go bad
as they are garbage, which results in this kind of strange errors.

Then the input flters could be replaced with 10 uF/400-450 V. Charger output
could be anything between 470 and 1500 uF/16 V. And the last one is 47 uF in
parallel with the relay coil.

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...
+420 739 190 151
http://www.hwworld.cz (elektromontáže silnoproud/slaboproud, kondenzátory, 
aku/baterie, mikrospínače pro myši a klávesnice aj./capacitors etc.)
https://www.hardwareinsights.com (power supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e‑mail ----------
Od: Rich Painter <pai...@gm...>
Komu: Pavel Boček <boc...@po...>
Datum: 19. 2. 2026 9:57:29
Předmět: Re: [Apcupsd-users] help with apcupsd message
" 
P

sorry it took a while to track down where I got it.

I got 2 of these at the same time from newegg...2017-08-29

that makes its age at least 8 1/2 years old.

the other unit has operated for the same time but does not exhibit any 
problems.

thanks

rich


On 2/17/26 1:45 AM, Pavel Boček wrote:

" How old is the unit?

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...(mailto:Be...@ja...)
+420 739 190 151
http://www.hwworld.cz(http://www.hwworld.cz) (elektromontáže silnoproud/
slaboproud, kondenzátory, aku/baterie, mikrospínače pro myši a klávesnice 
aj./capacitors etc.)
https://www.hardwareinsights.com(https://www.hardwareinsights.com) (power 
supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e‑mail ----------
Od: Rich Painter <pai...@gm...>(mailto:pai...@gm...)
Komu: apc...@li...
(mailto:apc...@li...)
Datum: 16. 2. 2026 23:30:36
Předmět: [Apcupsd-users] help with apcupsd message 
" 
I replaced an APC Back-UPS ES 650G1 battery in November. I used a Duracell 
12-9F2 from Batteries Plus. It seems to be an exact replacement. I tested it
with a high-end tester and it reported excellent properties.

I was notified prior to this that the old (original APC battery that came 
with the unit) was in need of replacement. I tested this and found it was 
about half capacity with a pretty high internal impedance.


Recently, I have started to get the following messages from apcupsd:

2026-02-16T03:42:31.494405-07:00 ras2 apcupsd[410]: Battery disconnected.
2026-02-16T03:42:40.495040-07:00 ras2 apcupsd[410]: Battery reattached.

and the log file shows (all of these disconnect messages):

2026-02-16 14:14:36 -0700  Battery reattached.
 
2026-02-16 14:14:27 -0700  Battery disconnected.
 
2026-02-16 14:10:29 -0700  Battery reattached.
 
2026-02-16 14:10:20 -0700  Battery disconnected.
 
2026-02-16 03:42:40 -0700  Battery reattached.
 
2026-02-16 03:42:31 -0700  Battery disconnected.
 
2026-02-15 18:18:51 -0700  Battery reattached.
 
2026-02-15 18:18:42 -0700  Battery disconnected.
 
2026-02-10 23:28:18 -0700  Battery reattached.
 
2026-02-10 23:28:09 -0700  Battery disconnected.
 
Notice the reattached message is always 9 seconds later! Very Strange!!

The current apcupsd status is 


Monitoring: ras2
 UPS Model: Back-UPS ES 650G1 
  UPS Name: BE650G1
   APCUPSD: Version 3.14.14
    Status: ONLINE
Capacity 100%
Runtime 705 minutes           (note this is the typical runtime for the load that has existed for many years)



Does anyone have any ideas on why I'm getting this "battery disconnected" 
message? I've checked the leads...

thanks

rich

_______________________________________________ 
Apcupsd-users mailing list 
Apc...@li...
(mailto:Apc...@li...) 
https://lists.sourceforge.net/lists/listinfo/apcupsd-users
(https://lists.sourceforge.net/lists/listinfo/apcupsd-users) 
" 






_______________________________________________
Apcupsd-users mailing list
<a href='mailto:Apc...@li...' class='-wm-moz-txt-link-abbreviated'>Apc...@li...</a>
<a href='https://lists.sourceforge.net/lists/listinfo/apcupsd-users' class='-wm-moz-txt-link-freetext'>https://lists.sourceforge.net/lists/listinfo/apcupsd-users</a>

" "

Re: [Apcupsd-users] help with apcupsd message

[Pavel B. <boc...@po...>]

How old is the unit?

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...
+420 739 190 151
http://www.hwworld.cz (elektromontáže silnoproud/slaboproud, kondenzátory, 
aku/baterie, mikrospínače pro myši a klávesnice aj./capacitors etc.)
https://www.hardwareinsights.com (power supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e‑mail ----------
Od: Rich Painter <pai...@gm...>
Komu: apc...@li...
Datum: 16. 2. 2026 23:30:36
Předmět: [Apcupsd-users] help with apcupsd message
" 
I replaced an APC Back-UPS ES 650G1 battery in November. I used a Duracell 
12-9F2 from Batteries Plus. It seems to be an exact replacement. I tested it
with a high-end tester and it reported excellent properties.

I was notified prior to this that the old (original APC battery that came 
with the unit) was in need of replacement. I tested this and found it was 
about half capacity with a pretty high internal impedance.


Recently, I have started to get the following messages from apcupsd:

2026-02-16T03:42:31.494405-07:00 ras2 apcupsd[410]: Battery disconnected.
2026-02-16T03:42:40.495040-07:00 ras2 apcupsd[410]: Battery reattached.

and the log file shows (all of these disconnect messages):

2026-02-16 14:14:36 -0700  Battery reattached.
 
2026-02-16 14:14:27 -0700  Battery disconnected.
 
2026-02-16 14:10:29 -0700  Battery reattached.
 
2026-02-16 14:10:20 -0700  Battery disconnected.
 
2026-02-16 03:42:40 -0700  Battery reattached.
 
2026-02-16 03:42:31 -0700  Battery disconnected.
 
2026-02-15 18:18:51 -0700  Battery reattached.
 
2026-02-15 18:18:42 -0700  Battery disconnected.
 
2026-02-10 23:28:18 -0700  Battery reattached.
 
2026-02-10 23:28:09 -0700  Battery disconnected.
 
Notice the reattached message is always 9 seconds later! Very Strange!!

The current apcupsd status is 


Monitoring: ras2
 UPS Model: Back-UPS ES 650G1 
  UPS Name: BE650G1
   APCUPSD: Version 3.14.14
    Status: ONLINE
Capacity 100%
Runtime 705 minutes           (note this is the typical runtime for the load that has existed for many years)



Does anyone have any ideas on why I'm getting this "battery disconnected" 
message? I've checked the leads...

thanks

rich

_______________________________________________ 
Apcupsd-users mailing list 
Apc...@li... 
https://lists.sourceforge.net/lists/listinfo/apcupsd-users 
"

[Apcupsd-users] help with apcupsd message

[Rich P. <pai...@gm...>]

I replaced an APC Back-UPS ES 650G1 battery in November. I used a 
Duracell 12-9F2 from Batteries Plus. It seems to be an exact 
replacement. I tested it with a high-end tester and it reported 
excellent properties.

I was notified prior to this that the old (original APC battery that 
came with the unit) was in need of replacement. I tested this and found 
it was about half capacity with a pretty high internal impedance.

Recently, I have started to get the following messages from apcupsd:

2026-02-16T03:42:31.494405-07:00 ras2 apcupsd[410]: Battery disconnected.
2026-02-16T03:42:40.495040-07:00 ras2 apcupsd[410]: Battery reattached.

and the log file shows (all of these disconnect messages):

2026-02-16 14:14:36 -0700  Battery reattached.

2026-02-16 14:14:27 -0700  Battery disconnected.

2026-02-16 14:10:29 -0700  Battery reattached.

2026-02-16 14:10:20 -0700  Battery disconnected.

2026-02-16 03:42:40 -0700  Battery reattached.

2026-02-16 03:42:31 -0700  Battery disconnected.

2026-02-15 18:18:51 -0700  Battery reattached.

2026-02-15 18:18:42 -0700  Battery disconnected.

2026-02-10 23:28:18 -0700  Battery reattached.

2026-02-10 23:28:09 -0700  Battery disconnected.

Notice the reattached message is always 9 seconds later! Very Strange!!

The current apcupsd status is

Monitoring: ras2
  UPS Model: Back-UPS ES 650G1
   UPS Name: BE650G1
    APCUPSD: Version 3.14.14
     Status: ONLINE
Capacity 100%
Runtime 705 minutes           (note this is the typical runtime for the load that has existed for many years)

Does anyone have any ideas on why I'm getting this "battery 
disconnected" message? I've checked the leads...

thanks

rich

Re: [Apcupsd-users] Wishlist: Absorb apcupsd features and device support that may be still missing in NUT

[Jim K. <jim...@gm...>]

Thanks for the quick replies, this is encouraging!

  I suppose the first part is easy for almost all users: try to deploy both
toolkits side by side, and constructively complain about what is missing :)
e.g. in that https://github.com/networkupstools/nut/issues/3301 ticket.

  I understand the configuration methods may differ and cause some
friction, and that is mostly to be accepted with migration to a different
toolkit - new house, new rules. The more interesting part is about missing
data points, device/protocol/media support, clients, tools (e.g. is there
one to push firmwares to UPSes?) etc.

  I've now posted a starter page on Wiki about this:
https://github.com/networkupstools/nut/wiki/Migrating-from-apcupsd-to-NUT
and would welcome the first explorers to update it with factual suggestions
about the migration ("In apcupsd-land we did this, and for NUT a similar
concept/setup looks like this").

  NOTE: It may be problematic to install both toolkits side-by-side with
packaging on some systems allowing only one of the UPS management
implementations, but it is recommended to build the recent NUT master
branch anyway to try the newest features (and debug-ability ever growing),
e.g. following instructions from
https://github.com/networkupstools/nut/wiki/Building-NUT-for-in%E2%80%90place-upgrades-or-non%E2%80%90disruptive-tests
and
platform-specific prerequisites linked from there.

  I'll be largely offline for a couple of weeks from mid-February, but hope
other NUT community members can help out when questions arise. And we have
a ton of documentation collected over the almost three decades... it might
be a bit hard to dig through all of it, but hopefully most answers are out
there somewhere. One starting point is
https://networkupstools.org/documentation.html and the
https://github.com/networkupstools/ConfigExamples/releases/latest/download/ConfigExamples.pdf
book
:)

Hope this helps,
Jim Klimov

[Apcupsd-users] Wishlist: Absorb apcupsd features and device support that may be still missing in NUT

[Jim K. <jim...@gm...>]

Hello all,

  For those who don't know me (e.g. in the cross-post to apcupsd-users), I
am Jim Klimov, a maintainer of the Network UPS Tools for over 5 years now,
and a user->contributor during about 20 years before that.

  My main focus during the recent years was, and remains, to ensure that
NUT can help all running computers to be protected from outages by graceful
shutdowns with modern UPSes. This includes computers (and their operating
systems) released since roughly 2000: boxes may still be running with
whatever OS and compilers they had at the time, because vendors may be long
gone. While they could be running NUT (or apcupsd) back then, an UPS
replacement might involve a device made in the past few years which the 20+
year old builds of our software running there had no idea about. As a
result we have a large CI build matrix ranging from CentOS 7 and occasional
Solaris 8 to cutting-edge distros (POSIX and Windows), with various
implementations of make, compilers, shells and other tools, with different
CPU architectures and complaining about different nuances, and each NUT
iteration should pass on all of that before getting merged. There's always
a heap of work to clean up the code, but it gets smaller over the years :)

  Over here at NUT we recognize that the apcupsd project delivers some
features and abilities, especially regarding certain device and
media/protocol support, where NUT lacks. Some things like MODBUS USB
support caught up years later, and might still need improvements.

  Sadly, to the best of my knowledge, `apcupsd` source code over at
https://sourceforge.net/p/apcupsd/svn/HEAD/tree/ (copy stashed at
https://github.com/networkupstools/apcupsd) has not seen releases nor even
development for almost 10 years now. And according to chats at the latest
FOSDEM, some distros are considering dropping it as effective abandonware :(

  I would like to propose a friendly merger of the two GPLv2+ codebases
with allegedly shared parentage, so our shared population of end-users do
not miss out on some functionality that apcupsd delivers now when/if the
time comes that it itself is not delivered, and they (have to) migrate to
NUT. And so that the decades of work invested there are not lost to
posterity.

  First of all, able hands are called on board to walk over the code and
run-time usage (with some device in tow) to compare functionality and map
out what NUT is missing, so we might specify concrete issues and file PRs
eventually. Of particular interest might be some tools or clients
introducing concepts that NUT lacks (if any).

  I've defined a GitHub label
https://github.com/networkupstools/nut/issues?q=state%3Aopen%20label%3Aapcupsd
to track related new issues/PRs, and will try to add it over time to
existing records to help cross-referencing and search.

  This matter is also raised as
https://github.com/networkupstools/nut/issues/3301

Thanks in advance,
on behalf of the Network UPS Tools project,
Jim Klimov

[Apcupsd-users] Not sure which device to use

[John O. <jn...@gm...>]

I just installed apcupsd on my Ubunty 24.04.3 laptop.  apcaccess returns
results.  If I stop apcupsd and run apctest, I get

2026-01-23 15:00:57 apctest 3.14.14 (31 May 2016) debian
Checking configuration ...
sharenet.type = Network & ShareUPS Disabled
cable.type = USB Cable
mode.type = USB UPS Driver
Setting up the port ...
apctest FATAL ERROR in apctest.c at line 319
Unable to open UPS device.
  If apcupsd or apctest is already running,
  please stop it and run this program again.
apctest error termination completed


dmesg says:

[109090.765376] usb 3-3.4.3: new full-speed USB device number 14 using
xhci_hcd
[109090.904893] usb 3-3.4.3: New USB device found, idVendor=051d,
idProduct=0002, bcdDevice= 0.90
[109090.904905] usb 3-3.4.3: New USB device strings: Mfr=1, Product=2,
SerialNumber=3
[109090.904909] usb 3-3.4.3: Product: Back-UPS XS 1500M FW:947.d10 .D USB
FW:d10
[109090.904913] usb 3-3.4.3: Manufacturer: American Power Conversion
[109090.904915] usb 3-3.4.3: SerialNumber: 3B2037X70339
[109090.913843] hid-generic 0003:051D:0002.0008: hiddev1,hidraw3: USB HID
v1.00 Device [American Power Conversion Back-UPS XS 1500M FW:947.d10 .D USB
FW:d10     ] on usb-0000:00:14.0-3.4.3/input0

It appears in lsusb:

Bus 003 Device 014: ID 051d:0002 American Power Conversion Uninterruptible
Power Supply


And when apcupsd is running, after a minute communication is lost:

root@magpie:~# systemctl status apcupsd
● apcupsd.service - UPS power management daemon
     Loaded: loaded (/usr/lib/systemd/system/apcupsd.service; enabled;
preset: enabled)
     Active: active (running) since Fri 2026-01-23 15:14:04 MST; 1min 28s
ago
       Docs: man:apcupsd(8)
    Process: 365824 ExecStartPre=/lib/apcupsd/prestart (code=exited,
status=0/SUCCESS)
    Process: 365828 ExecStart=/sbin/apcupsd (code=exited, status=0/SUCCESS)
   Main PID: 365830 (apcupsd)
      Tasks: 4 (limit: 18567)
     Memory: 488.0K (peak: 2.3M)
        CPU: 56ms
     CGroup: /system.slice/apcupsd.service
             └─365830 /sbin/apcupsd

Jan 23 15:14:04 magpie systemd[1]: Starting apcupsd.service - UPS power
management daemon...
Jan 23 15:14:04 magpie systemd[1]: apcupsd.service: Can't open PID file
/run/apcupsd.pid (yet?) >
Jan 23 15:14:04 magpie apcupsd[365830]: apcupsd 3.14.14 (31 May 2016)
debian startup succeeded
Jan 23 15:14:04 magpie apcupsd[365830]: NIS server startup succeeded
Jan 23 15:14:04 magpie systemd[1]: Started apcupsd.service - UPS power
management daemon.
Jan 23 15:15:16 magpie apcupsd[365830]: Communications with UPS lost.

root@magpie:~# ls -lZ /var/run/apcupsd.pid
-rw-r--r-- 1 root root ? 7 Jan 23 15:14 /var/run/apcupsd.pid

There are no recent denials in auditd.log, nor in /var/log/syslog

How do I tell what TTY it wants?

Re: [Apcupsd-users] REPLACEBATT asserted despite normal charge and runtime estimate on Smart-UPS SMC1000C

[Pavel B. <boc...@po...>]

Starting with SMT (which includes all the later like SMC, xxxxxxxxxxxC 
units, etc.), they removed that whole constant and its calibration thingy 
though, so I have no idea how are the units generaly dealing with 
replacement of accumulators with close to zero capacity for new ones. Or 
differently said, those few I had in me hands behaved as would be expected.

Previous models required the "public" part of the constant to be reset if it
drifted too far (there's the whole process in the apcupsd manul), otherwise 
even repeated complete discharging under load could not help it to properly 
store information about actual capacity of the accumulators.

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...
+420 739 190 151
http://www.hwworld.cz (elektromontáže silnoproud/slaboproud, kondenzátory, 
aku/baterie, mikrospínače pro myši a klávesnice aj./capacitors etc.)
https://www.hardwareinsights.com (power supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e-mail ----------
Od: Ted Mittelstaedt <te...@mi...>
Komu: apc...@li...
Datum: 29. 12. 2025 23:01:31
Předmět: Re: [Apcupsd-users] REPLACEBATT asserted despite normal charge and 
runtime estimate on Smart-UPS SMC1000C
"Before writing off the battery pack I'd try running a calibration.

Since you are running an SMC you can't do it from apcupsd. Instead do 
the following:

1) Plug in a load like a resistance heater or something that runs the 
UPS at 60% load

2) Pull the plug on the UPS from the wall

3) Ignore the UPS beeping and wait until the battery pack is drained and 
the UPS shuts the heater off

4) Plug in the UPS and allow it to charge, then plug in your Linux box 
and fire up apcupsd.

Remember that the SmartUPSes do self-tests but those depend on the 
battery constant.  The battery constant changes as the battery ages but 
if there is not enough load on the UPS then the constant in the UPS 
won't get properly updated during self tests.  A common newbie UPS 
mistake is buying the highest capacity UPS you can lay your hands on 
then plugging something ridiculous like a single wall wart into the 
thing - assuming you have this massive battery compared to the load that 
will give hours of uptime to the wall wart and router running on it.

The battery constant is basically a variable related to the internal 
resistance of the battery.  As the battery ages it changes but if the 
UPS doesn't track that change it will get out of wack.

Note that you also need to do this process with a brand new battery.   
You plug the new battery pack in, give it a few hours to get fully good 
and charged, then run a calibration on it.


Ted


On 12/22/2025 8:45 PM, David Roth wrote:
> Hello all,
>
> I am running apcupsd 3.14.14 on Rocky Linux, monitoring an APC 
> Smart-UPS SMC1000C via USB.
>
> Recently, apcupsd began reporting:
>
> STATUS   : ONLINE REPLACEBATT
> BCHARGE  : 98.0 Percent
> TIMELEFT : 21.0 Minutes
> BATTV    : 27.0 Volts
>
> There has not been a recent real power outage, at least not within the 
> last month. Battery voltage appears nominal for a 24V system, and the 
> reported runtime estimate remains relatively high.
>
> The UPS manufacturing date, as reported on the unit label, is 2023. To 
> the best of my knowledge, these are the original batteries that 
> shipped with the UPS, which would make them approximately two years old.
>
> I have been using APC Smart-UPS units for many years and have not seen 
> this alert before. In the past, I typically replaced batteries only 
> after observing a clear history of declining runtime under load.
>
> My questions are:
>
> 1. What exact condition causes apcupsd to assert REPLACEBATT on 
> Smart-UPS models?
> 2. Is this flag driven primarily by internal battery age counters, 
> impedance tests, self-test results, or voltage behavior under load?
> 3. Is it expected for REPLACEBATT to appear even when TIMELEFT remains 
> strong?
> 4. Are there any apcupsd diagnostics beyond the standard status fields 
> that help distinguish an age-based warning from actual capacity 
> degradation?
>
> For reference, I intend to order a genuine APC APCRBC142 replacement 
> battery cartridge, but I wanted to better understand the logic behind 
> this flag and how apcupsd interprets it.
>
> Best regards,
>
> David Roth
>
>
> _______________________________________________
> Apcupsd-users mailing list
> Apc...@li...
> https://lists.sourceforge.net/lists/listinfo/apcupsd-users


_______________________________________________
Apcupsd-users mailing list
Apc...@li...
https://lists.sourceforge.net/lists/listinfo/apcupsd-users
"

Re: [Apcupsd-users] REPLACEBATT asserted despite normal charge and runtime estimate on Smart-UPS SMC1000C

[David R. <dav...@gm...>]

Hi Ted,

Thank you for the detailed explanation. That was very helpful, especially
the discussion of the battery constant and how it depends on having
sufficient load during calibration and self-tests.

Your point about lightly loaded Smart-UPS units not properly updating the
internal battery model makes a lot of sense, and it clarifies why
self-tests alone are not always sufficient to keep the battery state
accurate over time.

I appreciate you taking the time to spell this out so clearly. It is
exactly the kind of practical insight that makes this list valuable.

Best regards,
David

On Mon, Dec 29, 2025 at 5:02 PM Ted Mittelstaedt <te...@mi...>
wrote:

> Before writing off the battery pack I'd try running a calibration.
>
> Since you are running an SMC you can't do it from apcupsd. Instead do
> the following:
>
> 1) Plug in a load like a resistance heater or something that runs the
> UPS at 60% load
>
> 2) Pull the plug on the UPS from the wall
>
> 3) Ignore the UPS beeping and wait until the battery pack is drained and
> the UPS shuts the heater off
>
> 4) Plug in the UPS and allow it to charge, then plug in your Linux box
> and fire up apcupsd.
>
> Remember that the SmartUPSes do self-tests but those depend on the
> battery constant.  The battery constant changes as the battery ages but
> if there is not enough load on the UPS then the constant in the UPS
> won't get properly updated during self tests.  A common newbie UPS
> mistake is buying the highest capacity UPS you can lay your hands on
> then plugging something ridiculous like a single wall wart into the
> thing - assuming you have this massive battery compared to the load that
> will give hours of uptime to the wall wart and router running on it.
>
> The battery constant is basically a variable related to the internal
> resistance of the battery.  As the battery ages it changes but if the
> UPS doesn't track that change it will get out of wack.
>
> Note that you also need to do this process with a brand new battery.
> You plug the new battery pack in, give it a few hours to get fully good
> and charged, then run a calibration on it.
>
>
> Ted
>
>
> On 12/22/2025 8:45 PM, David Roth wrote:
> > Hello all,
> >
> > I am running apcupsd 3.14.14 on Rocky Linux, monitoring an APC
> > Smart-UPS SMC1000C via USB.
> >
> > Recently, apcupsd began reporting:
> >
> > STATUS   : ONLINE REPLACEBATT
> > BCHARGE  : 98.0 Percent
> > TIMELEFT : 21.0 Minutes
> > BATTV    : 27.0 Volts
> >
> > There has not been a recent real power outage, at least not within the
> > last month. Battery voltage appears nominal for a 24V system, and the
> > reported runtime estimate remains relatively high.
> >
> > The UPS manufacturing date, as reported on the unit label, is 2023. To
> > the best of my knowledge, these are the original batteries that
> > shipped with the UPS, which would make them approximately two years old.
> >
> > I have been using APC Smart-UPS units for many years and have not seen
> > this alert before. In the past, I typically replaced batteries only
> > after observing a clear history of declining runtime under load.
> >
> > My questions are:
> >
> > 1. What exact condition causes apcupsd to assert REPLACEBATT on
> > Smart-UPS models?
> > 2. Is this flag driven primarily by internal battery age counters,
> > impedance tests, self-test results, or voltage behavior under load?
> > 3. Is it expected for REPLACEBATT to appear even when TIMELEFT remains
> > strong?
> > 4. Are there any apcupsd diagnostics beyond the standard status fields
> > that help distinguish an age-based warning from actual capacity
> > degradation?
> >
> > For reference, I intend to order a genuine APC APCRBC142 replacement
> > battery cartridge, but I wanted to better understand the logic behind
> > this flag and how apcupsd interprets it.
> >
> > Best regards,
> >
> > David Roth
> >
> >
> > _______________________________________________
> > Apcupsd-users mailing list
> > Apc...@li...
> > https://lists.sourceforge.net/lists/listinfo/apcupsd-users
>
>
> _______________________________________________
> Apcupsd-users mailing list
> Apc...@li...
> https://lists.sourceforge.net/lists/listinfo/apcupsd-users
>

Re: [Apcupsd-users] REPLACEBATT asserted despite normal charge and runtime estimate on Smart-UPS SMC1000C

[Ted M. <te...@mi...>]

Before writing off the battery pack I'd try running a calibration.

Since you are running an SMC you can't do it from apcupsd. Instead do 
the following:

1) Plug in a load like a resistance heater or something that runs the 
UPS at 60% load

2) Pull the plug on the UPS from the wall

3) Ignore the UPS beeping and wait until the battery pack is drained and 
the UPS shuts the heater off

4) Plug in the UPS and allow it to charge, then plug in your Linux box 
and fire up apcupsd.

Remember that the SmartUPSes do self-tests but those depend on the 
battery constant.  The battery constant changes as the battery ages but 
if there is not enough load on the UPS then the constant in the UPS 
won't get properly updated during self tests.  A common newbie UPS 
mistake is buying the highest capacity UPS you can lay your hands on 
then plugging something ridiculous like a single wall wart into the 
thing - assuming you have this massive battery compared to the load that 
will give hours of uptime to the wall wart and router running on it.

The battery constant is basically a variable related to the internal 
resistance of the battery.  As the battery ages it changes but if the 
UPS doesn't track that change it will get out of wack.

Note that you also need to do this process with a brand new battery.   
You plug the new battery pack in, give it a few hours to get fully good 
and charged, then run a calibration on it.


Ted


On 12/22/2025 8:45 PM, David Roth wrote:
> Hello all,
>
> I am running apcupsd 3.14.14 on Rocky Linux, monitoring an APC 
> Smart-UPS SMC1000C via USB.
>
> Recently, apcupsd began reporting:
>
> STATUS   : ONLINE REPLACEBATT
> BCHARGE  : 98.0 Percent
> TIMELEFT : 21.0 Minutes
> BATTV    : 27.0 Volts
>
> There has not been a recent real power outage, at least not within the 
> last month. Battery voltage appears nominal for a 24V system, and the 
> reported runtime estimate remains relatively high.
>
> The UPS manufacturing date, as reported on the unit label, is 2023. To 
> the best of my knowledge, these are the original batteries that 
> shipped with the UPS, which would make them approximately two years old.
>
> I have been using APC Smart-UPS units for many years and have not seen 
> this alert before. In the past, I typically replaced batteries only 
> after observing a clear history of declining runtime under load.
>
> My questions are:
>
> 1. What exact condition causes apcupsd to assert REPLACEBATT on 
> Smart-UPS models?
> 2. Is this flag driven primarily by internal battery age counters, 
> impedance tests, self-test results, or voltage behavior under load?
> 3. Is it expected for REPLACEBATT to appear even when TIMELEFT remains 
> strong?
> 4. Are there any apcupsd diagnostics beyond the standard status fields 
> that help distinguish an age-based warning from actual capacity 
> degradation?
>
> For reference, I intend to order a genuine APC APCRBC142 replacement 
> battery cartridge, but I wanted to better understand the logic behind 
> this flag and how apcupsd interprets it.
>
> Best regards,
>
> David Roth
>
>
> _______________________________________________
> Apcupsd-users mailing list
> Apc...@li...
> https://lists.sourceforge.net/lists/listinfo/apcupsd-users

Re: [Apcupsd-users] Off Topic- Push pin replacement

[Ted M. <te...@mi...>]

plastic bodypanel rivets available at any auto parts store...

Ted

On 12/24/2025 9:03 PM, Ed Warner via Apcupsd-users wrote:
> Hello all,
>
> I have a few SUA750 SmartUPS that have the two white push pins that hold the metal plate in front of the battery to the chassis. I am looking where I can get these or if there is a better yet suitable substitute
> Thanks for your help.
>
> Monte
>
>
> _______________________________________________
> Apcupsd-users mailing list
> Apc...@li...
> https://lists.sourceforge.net/lists/listinfo/apcupsd-users

[Apcupsd-users] Off Topic- Push pin replacement

[Ed W. <edw...@ya...>]

Hello all,

I have a few SUA750 SmartUPS that have the two white push pins that hold the metal plate in front of the battery to the chassis. I am looking where I can get these or if there is a better yet suitable substitute
Thanks for your help. 

Monte

[Apcupsd-users] REPLACEBATT asserted despite normal charge and runtime estimate on Smart-UPS SMC1000C

[David R. <dav...@gm...>]

Hello all,

I am running apcupsd 3.14.14 on Rocky Linux, monitoring an APC Smart-UPS
SMC1000C via USB.

Recently, apcupsd began reporting:

STATUS   : ONLINE REPLACEBATT
BCHARGE  : 98.0 Percent
TIMELEFT : 21.0 Minutes
BATTV    : 27.0 Volts

There has not been a recent real power outage, at least not within the last
month. Battery voltage appears nominal for a 24V system, and the reported
runtime estimate remains relatively high.

The UPS manufacturing date, as reported on the unit label, is 2023. To the
best of my knowledge, these are the original batteries that shipped with
the UPS, which would make them approximately two years old.

I have been using APC Smart-UPS units for many years and have not seen this
alert before. In the past, I typically replaced batteries only after
observing a clear history of declining runtime under load.

My questions are:

1. What exact condition causes apcupsd to assert REPLACEBATT on Smart-UPS
models?
2. Is this flag driven primarily by internal battery age counters,
impedance tests, self-test results, or voltage behavior under load?
3. Is it expected for REPLACEBATT to appear even when TIMELEFT remains
strong?
4. Are there any apcupsd diagnostics beyond the standard status fields that
help distinguish an age-based warning from actual capacity degradation?

For reference, I intend to order a genuine APC APCRBC142 replacement
battery cartridge, but I wanted to better understand the logic behind this
flag and how apcupsd interprets it.

Best regards,

David Roth

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Pavel B. <boc...@po...>]

Dude, yo're totally missing it. Done many many dozens of units, if we talk 
about APC, 98 % of them are small (4.7, 10, 22, 100, 220, 330 uF; majority 
are the 22uF ones). You almost never have to replace the large ones (40 V in
case of Smart-UPS), haven't seen (or read about) single bad one.

Sure, for me it's about going 3 meters since I started ordering whole boxes 
(and reselling OFC, when buying in those numbers at those prices), but 
still. Second-hand Smart-UPS are often few bucks each. Caps won't be much 
more expensive even from those large-resseling thieves (like DK, TME, 
Farnell, etc.). BUT old units could be notoriously unreliable - till you 
replace caps for quality ones. Then you usually have decade++ of continued 
operation again. About 19 of 20 units work great after that. (Sometimes, 
especially in those beige ones, also some resistor drifts too far. That's 
relatively easy to find as well. Also it's a good idea to check film caps in
very old units, too). OFC, not everybody could solder, sure, that may be a 
problem.

The situation is, since APC/Schneider started using constantly worse caps, 
and also because of newer CPUs which run on lower voltage (thus are more 
sensitive to bad/rippled supply power), 20 years old SU unit needs recapping
the same as 10 years old SUA and 5 years old (just ditched of corporate) 
SMT.

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...
+420 739 190 151
http://www.hwworld.cz (elektromontáže silnoproud/slaboproud, kondenzátory, 
aku/baterie, mikrospínače pro myši a klávesnice aj./capacitors etc.)
https://www.hardwareinsights.com (power supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e-mail ----------
Od: Ted Mittelstaedt <te...@mi...>
Komu: apc...@li...
Datum: 8. 12. 2025 13:45:14
Předmět: Re: [Apcupsd-users] apcupsd not showing any UPS load
" 
It takes a long time for electrolytic capacitors to go bad.   Yes your going
to always have a few edge cases but we are looking mainly at 10 years out on
this kind of thing.  It's also known that cap failure is not as quick on 
gear under continuous power because when the cap dries out and is under load
it basically keeps working until it loses power.

The other problem is the cost.  A lot of those electrolytics in UPSes are 
large and more expensive, and there are multiple values.  It's not fun to 
tear apart a UPS and have it sitting chewing up your bench while you 
meticulously read off all the values and make up your order and collect all 
the new parts.

Then there is the labor of unsoldering and resoldering in all the old ones.

I've done re-capping of other lower cost electronics.  Sometimes it works 
sometimes it does not.  Always the time cost is significant.  This kind of 
thing is classified much more in the labor of love department, akin to 
automobile restoration.  Economically it's not worth it - your still most 
well advised to just buy a new UPS in most cases.


It would be much better for the entire apcupsd community for someone to take
the work that has been done on reverse-engineering the Microlink protocol 
with python and add it into apcupsd or at least into NUT.


Ted


On 11/30/2025 11:15 AM, Pavel Boček wrote:

" Majority of "internal problems" are just garbage crapacitors going bad. 
Now some of the newer schneider-tainted models tend to go bad somewhat more 
because of different reasons, but it's is never a bad idea to just replace 
the caps, it's gonna help at least half of the times. Also it seems that 
some SMT models tend to burn through even more accumulators then the old SU/
SUA units.

I go with (properly) refurbished old unit any day of the week, there is no 
problem with SU/SUA units with pretty much nothing you plug into them, 
apcupsd runs notoriously great with them, since they all use only the good 
ol' Smart protocol (UPSlink). No reason to support their stupid product 
development they show to us in the last decade.

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...(mailto:Be...@ja...)
+420 739 190 151
http://www.hwworld.cz(http://www.hwworld.cz) (elektromontáže silnoproud/
slaboproud, kondenzátory, aku/baterie, mikrospínače pro myši a klávesnice 
aj./capacitors etc.)
https://www.hardwareinsights.com(https://www.hardwareinsights.com) (power 
supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e-mail ----------
Od: Jeffery Small <je...@cj...>(mailto:je...@cj...)
Komu: apc...@li...
(mailto:apc...@li...)
Datum: 29. 11. 2025 21:22:35
Předmět: Re: [Apcupsd-users] apcupsd not showing any UPS load 
"Ted: 

Once again, thanks for the detailed history. It's is all making more sense 
now and yes, I do wish I had known about this before purchasing another 
SMC model, but since my old unit was working just fine on my previous 
workstation and only needed a new battery, I really didn't give it any 
thought. 

When I get a moment, I'll look into the MODBUS code and see what's up. 

I may swap out the battery from the new unit into the old one and see 
if that helps. As you said below, my past experience in installing new 
batteries in the UPS has twice been followd by some UPS internal failure 
requiring the unit to be replaced, so I also just replace the entire unit 
rather than update the battery. 

Regards, 
-- 
Jeff 

Ted Mittelstaedt <te...@mi...>(mailto:te...@mi...) writes:


>The main product lines hit are the SMC (and SRT) series.  These were 
>always targeted at the small business market - the 10-15 person company 
>with 1 server, running Windows Server.  The protocol change happened 
>before Schneider purchased APC.  The really small individual market or 
>1-2 person company market was buying BackUPS and didn't care about the 
>self-test stuff. 

>Although APC makes a rack-mounted SMC they mostly sell the standalone 
>UPSes in the SMC model line. 

>I'm pretty positive  that the way things played out is that back in the 
>"olden days" during the reign of the beige-colored UPSes (SmartUPS and 
>BackUPS) that APC had some really sharp in-house talent that designed 
>and built microprocessor-controlled boards and very simple firmware.  
>What I think happened was those people retired or moved on and for a 
>while they were just making a few firmware tweaks but things basically 
>were the same through the reign of the "Black-fronted UPSes with just 
>lights"  But then the Chinese (CyberPower and Goldenmate and so on) 
>started releasing UPSes with big digital readouts on the front and APC 
>had to respond to that - and also very likely they were also facing the 
>end of production of the older microprocessors and support chips used 
>for the UPSLink firmware. 

>I'm pretty sure whoever was in charge of APC farmed out a redesign of 
>the new firmware to a 3rd party and I'm 100% positive that they didn't 
>know what the hell they were doing (the APC person not the 3rd party) 
>and the 3rd party took APC down the yellow brick road.   Without 
>understanding anything APC signed a developer agreement for a 
>PROPRIETARY SDK that required them to not release source code or other 
>documentation for Microlink. When word of this got out the large 
>enterprises (that's me) basically told APC we won't be buying anymore 
>UPSes from APC, we will switch over to Eaton, because your not going to 
>make us pay licensing for PowerChute Business over our dead bodies. 

>That was what triggered the decision to write MODBUS support into the 
>APC firmware.  And as Klaasdc found out 6 years ago, the MODBUS 
>implementation copies the same formatting of parameters from Microlink, 
>so clearly the MODBUS firmware was sort of a quick hack - and I'm also 
>pretty sure that the development group that screwed over APC was not 
>particularly happy about writing it because I'm pretty sure they get a 
>portion every time APC sells a UPS with a copy of PowerChute. 

>But, having 2 independent protocols inside of a UPS chews up more flash 
>than a single protocol, so the cost-reduced SmartUPS line - the SMC - 
>appears to be frozen out. 

>I do hope you try out that KlassDC github python code I posted the link 
>to and report back to us - we get so little info on Microlink because 
>few people using apcupsd buy Microlink-only UPSes. 

>There has, unfortunately, been some bit-rot in the apcupsd code, the 
>primary problem at this time is that apcupsd has problems with running 
>MODBUS over USB now, whereas a few years ago, that worked.  However, the 
>FDDI and ATEN and Prolific USB-to-serial adapters are so ridiculously 
>cheap on Ebay for the Chinese clones, AND they are STILL including 
>honest-to-God serial ports on server-class hardware (HP Proliants and 
>such) that limiting MODBUS to serial port only inside of apcupsd, is 
>really not the limit it appears on the surface.  The SMT models that 
>include MODBUS are all targeted to Enterprises who are using them in 
>cabinets and relay racks with server quality hardware that can plug into 
>the APC serial cable, the low-end BackUPSs that have monitoring ports 
>all support USB-UPSHID and work out of the box with apcupsd. 

>It's actually more significant that NUT finally appropriated the MODBUS 
>code out of apcupsd just like they did when the UPSLink protocol was 
>reverse-engineered.  NUT has a far more wide support for different UPSes 
>as well as they had some financial support from Eaton at one time.  They 
>also are affected by that bug with MODBUS not working on USB but I'm 
>happy to let them try to fix it. 

>It's the folks like yourself - people wanting to buy a cut above the 
>SOHO BackUPSes, but not understanding why it's important to pay an extra 
>$200 for a SMT instead of a SMC, are the ones getting screwed over.  I 
>think the issue with the SMCs is that they only speak Microlink out that 
>USB port, not USB-UPSHID like the lower end BackUPS.  (the lower end 
>BackUPS don't speak Microlink)  But it's really hard to know.  I 
>personally don't have a SMC model UPS in my fleet so I can't test.  It 
>MIGHT be that the USB port merely starts out Microlink but receipt of a 
>magic packet switches it to USB-UPSHID. 

>You also have to keep in mind that once an Enterprise gets large enough, 
>UPS monitoring isn't as important as you would think.  The reason I use 
>UPS monitoring in the Enterprise is because that way my department gets 
>notified when a battery in a UPS is toasted, instead of having to depend 
>on the notoriously unreliable users we have, letting us know "there's 
>this strange beeping coming from the closet"  But not much of what's 
>plugged into most of my UPSes in the Enterprise are setup to shut down 
>on power loss - because in the locations where I have servers that 
>really matter - we have generators.  And in the less critical locations 
>it's all network gear and it makes no difference if the site loses power 
>for the network to stay up because people can't get power for 
>workstations and monitors and such. 

>The truth is that the entrance of Cloud Computing is a much greater 
>threat to the UPS market than any of this arguing over protocols.  APC 
>for sure makes far more money off the sale of BackUPSes than large 
>SmartUPSes, to SOHO.  But, when the 2-10 employee business goes 100% to 
>the cloud - who needs a UPS?  And when the home users go to laptops - 
>which just about all of them have save the hardcore gamers - who needs a 
>UPS? 

>This is why I think that APC's board allowed APC to be acquired in 2007 
>by Schenider.  And it's not lost on anyone that Schneider squashed UPSes 
>into datacenter cooling systems.  They saw the on-premise server market 
>shrinking as SOHO exited it, and the datacenter market growing as SOHO 
>entered it, and they figured they could disguise the revenue drop off in 
>the UPS division by pairing it with revenue increase from the datacenter 
>cooling products. 

>Nowadays when you buy a BackUPS you are basically buying something made 
>on the same assembly lines in China that are making CyberPower UPSs  
>CyberPower has little presence in the US Enterprise market - which is a 
>very conservative purchasing market - and likely never will.  But they 
>use the same protcol that BackUPSes use - and that GoldenMate Pro uses 
>and all of the other no-name Chinese UPSes use - USB-UPSHID. 

>I'm probably an anomaly in Enterprise purchasing anyway since I know a 
>lot of Enterprise IT directors just spec SMT for -everything- including 
>stuff (like switches) that can't even plug into a UPS monitoring port, 
>whereas I'll use BackUPSes for the non-server stuff.  And in the real 
>blue chip companies they don't even bother buying replacement 
>-batteries- they just throw the entire UPS in the garbage 3 years after 
>buying it and buy a new one.  I learned a lot about how these companies 
>operate in a prior life with judicious dumpster diving.... 

>Ted 

>On 11/28/2025 1:31 PM, Jeffery Small wrote: 
>> Ted: 
>> 
>> Thanks you for all of the very useful information. Since you have 
>> explained the change in APC protocol, I can stop banging my head against 

>> this problem. It would be nice if apcupsd was ever modified to deal with 

>> this, but I can expect it would be a difficult problem. 
>> 
>> I'm sad to see another great company like APC taken over by Schneider and

>> made worse for the end user, similar to Oracle purchasing Sun 
Microsystems. 
>> 
>> 
>> Time marches on -- not always for the better. 
>> 
>> Regards, 
>> 
>> 
>> _______________________________________________ 
>> Apcupsd-users mailing list 
>> Apc...@li...
(mailto:Apc...@li...) 
>> https://lists.sourceforge.net/lists/listinfo/apcupsd-users
(https://lists.sourceforge.net/lists/listinfo/apcupsd-users) 

_______________________________________________ 
Apcupsd-users mailing list 
Apc...@li...
(mailto:Apc...@li...) 
https://lists.sourceforge.net/lists/listinfo/apcupsd-users
(https://lists.sourceforge.net/lists/listinfo/apcupsd-users) 
" 






_______________________________________________
Apcupsd-users mailing list
<a href='mailto:Apc...@li...' class='-wm-moz-txt-link-abbreviated'>Apc...@li...</a>
<a href='https://lists.sourceforge.net/lists/listinfo/apcupsd-users' class='-wm-moz-txt-link-freetext'>https://lists.sourceforge.net/lists/listinfo/apcupsd-users</a>

" _______________________________________________ 
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"

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Ted M. <te...@mi...>]

It takes a long time for electrolytic capacitors to go bad.   Yes your 
going to always have a few edge cases but we are looking mainly at 10 
years out on this kind of thing.  It's also known that cap failure is 
not as quick on gear under continuous power because when the cap dries 
out and is under load it basically keeps working until it loses power.

The other problem is the cost.  A lot of those electrolytics in UPSes 
are large and more expensive, and there are multiple values.  It's not 
fun to tear apart a UPS and have it sitting chewing up your bench while 
you meticulously read off all the values and make up your order and 
collect all the new parts.

Then there is the labor of unsoldering and resoldering in all the old ones.

I've done re-capping of other lower cost electronics.  Sometimes it 
works sometimes it does not.  Always the time cost is significant.  This 
kind of thing is classified much more in the labor of love department, 
akin to automobile restoration. Economically it's not worth it - your 
still most well advised to just buy a new UPS in most cases.

It would be much better for the entire apcupsd community for someone to 
take the work that has been done on reverse-engineering the Microlink 
protocol with python and add it into apcupsd or at least into NUT.

Ted

On 11/30/2025 11:15 AM, Pavel Boček wrote:
> Majority of "internal problems" are just garbage crapacitors going 
> bad. Now some of the newer schneider-tainted models tend to go bad 
> somewhat more because of different reasons, but it's is never a bad 
> idea to just replace the caps, it's gonna help at least half of the 
> times. Also it seems that some SMT models tend to burn through even 
> more accumulators then the old SU/SUA units.
>
> I go with (properly) refurbished old unit any day of the week, there 
> is no problem with SU/SUA units with pretty much nothing you plug into 
> them, apcupsd runs notoriously great with them, since they all use 
> only the good ol' Smart protocol (UPSlink). No reason to support their 
> stupid product development they show to us in the last decade.
>
> -- 
> S uctivým pozdravem/best regards,
>
> Pavel Boček
> Jabber: Be...@ja...
> +420 739 190 151
> http://www.hwworld.cz (elektromontáže silnoproud/slaboproud, 
> kondenzátory, aku/baterie, mikrospínače pro myši a klávesnice 
> aj./capacitors etc.)
> https://www.hardwareinsights.com (power supply reviews and more)
> stickers-cz.com (nekonformní samolepky, placky)
>
> ---------- Původní e-mail ----------
> Od: Jeffery Small <je...@cj...>
> Komu: apc...@li...
> Datum: 29. 11. 2025 21:22:35
> Předmět: Re: [Apcupsd-users] apcupsd not showing any UPS load
>
>
>     Ted:
>
>     Once again, thanks for the detailed history. It's is all making
>     more sense
>     now and yes, I do wish I had known about this before purchasing
>     another
>     SMC model, but since my old unit was working just fine on my previous
>     workstation and only needed a new battery, I really didn't give it
>     any
>     thought.
>
>     When I get a moment, I'll look into the MODBUS code and see what's
>     up.
>
>     I may swap out the battery from the new unit into the old one and see
>     if that helps. As you said below, my past experience in installing
>     new
>     batteries in the UPS has twice been followd by some UPS internal
>     failure
>     requiring the unit to be replaced, so I also just replace the
>     entire unit
>     rather than update the battery.
>
>     Regards,
>     -- 
>     Jeff
>
>     Ted Mittelstaedt <te...@mi...> writes:
>
>     >The main product lines hit are the SMC (and SRT) series. These were
>     >always targeted at the small business market - the 10-15 person
>     company
>     >with 1 server, running Windows Server.  The protocol change happened
>     >before Schneider purchased APC.  The really small individual
>     market or
>     >1-2 person company market was buying BackUPS and didn't care
>     about the
>     >self-test stuff.
>
>     >Although APC makes a rack-mounted SMC they mostly sell the
>     standalone
>     >UPSes in the SMC model line.
>
>     >I'm pretty positive  that the way things played out is that back
>     in the
>     >"olden days" during the reign of the beige-colored UPSes
>     (SmartUPS and
>     >BackUPS) that APC had some really sharp in-house talent that
>     designed
>     >and built microprocessor-controlled boards and very simple firmware.
>     >What I think happened was those people retired or moved on and for a
>     >while they were just making a few firmware tweaks but things
>     basically
>     >were the same through the reign of the "Black-fronted UPSes with
>     just
>     >lights"  But then the Chinese (CyberPower and Goldenmate and so on)
>     >started releasing UPSes with big digital readouts on the front
>     and APC
>     >had to respond to that - and also very likely they were also
>     facing the
>     >end of production of the older microprocessors and support chips
>     used
>     >for the UPSLink firmware.
>
>     >I'm pretty sure whoever was in charge of APC farmed out a
>     redesign of
>     >the new firmware to a 3rd party and I'm 100% positive that they
>     didn't
>     >know what the hell they were doing (the APC person not the 3rd
>     party)
>     >and the 3rd party took APC down the yellow brick road. Without
>     >understanding anything APC signed a developer agreement for a
>     >PROPRIETARY SDK that required them to not release source code or
>     other
>     >documentation for Microlink. When word of this got out the large
>     >enterprises (that's me) basically told APC we won't be buying
>     anymore
>     >UPSes from APC, we will switch over to Eaton, because your not
>     going to
>     >make us pay licensing for PowerChute Business over our dead bodies.
>
>     >That was what triggered the decision to write MODBUS support into
>     the
>     >APC firmware.  And as Klaasdc found out 6 years ago, the MODBUS
>     >implementation copies the same formatting of parameters from
>     Microlink,
>     >so clearly the MODBUS firmware was sort of a quick hack - and I'm
>     also
>     >pretty sure that the development group that screwed over APC was not
>     >particularly happy about writing it because I'm pretty sure they
>     get a
>     >portion every time APC sells a UPS with a copy of PowerChute.
>
>     >But, having 2 independent protocols inside of a UPS chews up more
>     flash
>     >than a single protocol, so the cost-reduced SmartUPS line - the
>     SMC -
>     >appears to be frozen out.
>
>     >I do hope you try out that KlassDC github python code I posted
>     the link
>     >to and report back to us - we get so little info on Microlink
>     because
>     >few people using apcupsd buy Microlink-only UPSes.
>
>     >There has, unfortunately, been some bit-rot in the apcupsd code, the
>     >primary problem at this time is that apcupsd has problems with
>     running
>     >MODBUS over USB now, whereas a few years ago, that worked.
>     However, the
>     >FDDI and ATEN and Prolific USB-to-serial adapters are so
>     ridiculously
>     >cheap on Ebay for the Chinese clones, AND they are STILL including
>     >honest-to-God serial ports on server-class hardware (HP Proliants
>     and
>     >such) that limiting MODBUS to serial port only inside of apcupsd, is
>     >really not the limit it appears on the surface.  The SMT models that
>     >include MODBUS are all targeted to Enterprises who are using them in
>     >cabinets and relay racks with server quality hardware that can
>     plug into
>     >the APC serial cable, the low-end BackUPSs that have monitoring
>     ports
>     >all support USB-UPSHID and work out of the box with apcupsd.
>
>     >It's actually more significant that NUT finally appropriated the
>     MODBUS
>     >code out of apcupsd just like they did when the UPSLink protocol was
>     >reverse-engineered.  NUT has a far more wide support for
>     different UPSes
>     >as well as they had some financial support from Eaton at one
>     time.  They
>     >also are affected by that bug with MODBUS not working on USB but I'm
>     >happy to let them try to fix it.
>
>     >It's the folks like yourself - people wanting to buy a cut above the
>     >SOHO BackUPSes, but not understanding why it's important to pay
>     an extra
>     >$200 for a SMT instead of a SMC, are the ones getting screwed
>     over.  I
>     >think the issue with the SMCs is that they only speak Microlink
>     out that
>     >USB port, not USB-UPSHID like the lower end BackUPS.  (the lower end
>     >BackUPS don't speak Microlink)  But it's really hard to know.  I
>     >personally don't have a SMC model UPS in my fleet so I can't
>     test.  It
>     >MIGHT be that the USB port merely starts out Microlink but
>     receipt of a
>     >magic packet switches it to USB-UPSHID.
>
>     >You also have to keep in mind that once an Enterprise gets large
>     enough,
>     >UPS monitoring isn't as important as you would think.  The reason
>     I use
>     >UPS monitoring in the Enterprise is because that way my
>     department gets
>     >notified when a battery in a UPS is toasted, instead of having to
>     depend
>     >on the notoriously unreliable users we have, letting us know
>     "there's
>     >this strange beeping coming from the closet"  But not much of what's
>     >plugged into most of my UPSes in the Enterprise are setup to shut
>     down
>     >on power loss - because in the locations where I have servers that
>     >really matter - we have generators.  And in the less critical
>     locations
>     >it's all network gear and it makes no difference if the site
>     loses power
>     >for the network to stay up because people can't get power for
>     >workstations and monitors and such.
>
>     >The truth is that the entrance of Cloud Computing is a much greater
>     >threat to the UPS market than any of this arguing over
>     protocols.  APC
>     >for sure makes far more money off the sale of BackUPSes than large
>     >SmartUPSes, to SOHO.  But, when the 2-10 employee business goes
>     100% to
>     >the cloud - who needs a UPS?  And when the home users go to
>     laptops -
>     >which just about all of them have save the hardcore gamers - who
>     needs a
>     >UPS?
>
>     >This is why I think that APC's board allowed APC to be acquired
>     in 2007
>     >by Schenider.  And it's not lost on anyone that Schneider
>     squashed UPSes
>     >into datacenter cooling systems.  They saw the on-premise server
>     market
>     >shrinking as SOHO exited it, and the datacenter market growing as
>     SOHO
>     >entered it, and they figured they could disguise the revenue drop
>     off in
>     >the UPS division by pairing it with revenue increase from the
>     datacenter
>     >cooling products.
>
>     >Nowadays when you buy a BackUPS you are basically buying
>     something made
>     >on the same assembly lines in China that are making CyberPower UPSs
>     >CyberPower has little presence in the US Enterprise market -
>     which is a
>     >very conservative purchasing market - and likely never will.  But
>     they
>     >use the same protcol that BackUPSes use - and that GoldenMate Pro
>     uses
>     >and all of the other no-name Chinese UPSes use - USB-UPSHID.
>
>     >I'm probably an anomaly in Enterprise purchasing anyway since I
>     know a
>     >lot of Enterprise IT directors just spec SMT for -everything-
>     including
>     >stuff (like switches) that can't even plug into a UPS monitoring
>     port,
>     >whereas I'll use BackUPSes for the non-server stuff.  And in the
>     real
>     >blue chip companies they don't even bother buying replacement
>     >-batteries- they just throw the entire UPS in the garbage 3 years
>     after
>     >buying it and buy a new one.  I learned a lot about how these
>     companies
>     >operate in a prior life with judicious dumpster diving....
>
>     >Ted
>
>     >On 11/28/2025 1:31 PM, Jeffery Small wrote:
>     >> Ted:
>     >>
>     >> Thanks you for all of the very useful information. Since you have
>     >> explained the change in APC protocol, I can stop banging my
>     head against
>     >> this problem. It would be nice if apcupsd was ever modified to
>     deal with
>     >> this, but I can expect it would be a difficult problem.
>     >>
>     >> I'm sad to see another great company like APC taken over by
>     Schneider and
>     >> made worse for the end user, similar to Oracle purchasing Sun
>     Microsystems.
>     >>
>     >>
>     >> Time marches on -- not always for the better.
>     >>
>     >> Regards,
>     >>
>     >>
>     >> _______________________________________________
>     >> Apcupsd-users mailing list
>     >> Apc...@li...
>     >> https://lists.sourceforge.net/lists/listinfo/apcupsd-users
>
>     _______________________________________________
>     Apcupsd-users mailing list
>     Apc...@li...
>     https://lists.sourceforge.net/lists/listinfo/apcupsd-users
>
>
>
> _______________________________________________
> Apcupsd-users mailing list
> Apc...@li...
> https://lists.sourceforge.net/lists/listinfo/apcupsd-users

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Pavel B. <boc...@po...>]

Majority of "internal problems" are just garbage crapacitors going bad. Now 
some of the newer schneider-tainted models tend to go bad somewhat more 
because of different reasons, but it's is never a bad idea to just replace 
the caps, it's gonna help at least half of the times. Also it seems that 
some SMT models tend to burn through even more accumulators then the old SU/
SUA units.

I go with (properly) refurbished old unit any day of the week, there is no 
problem with SU/SUA units with pretty much nothing you plug into them, 
apcupsd runs notoriously great with them, since they all use only the good 
ol' Smart protocol (UPSlink). No reason to support their stupid product 
development they show to us in the last decade.

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...
+420 739 190 151
http://www.hwworld.cz (elektromontáže silnoproud/slaboproud, kondenzátory, 
aku/baterie, mikrospínače pro myši a klávesnice aj./capacitors etc.)
https://www.hardwareinsights.com (power supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e-mail ----------
Od: Jeffery Small <je...@cj...>
Komu: apc...@li...
Datum: 29. 11. 2025 21:22:35
Předmět: Re: [Apcupsd-users] apcupsd not showing any UPS load
"Ted: 

Once again, thanks for the detailed history. It's is all making more sense 
now and yes, I do wish I had known about this before purchasing another 
SMC model, but since my old unit was working just fine on my previous 
workstation and only needed a new battery, I really didn't give it any 
thought. 

When I get a moment, I'll look into the MODBUS code and see what's up. 

I may swap out the battery from the new unit into the old one and see 
if that helps. As you said below, my past experience in installing new 
batteries in the UPS has twice been followd by some UPS internal failure 
requiring the unit to be replaced, so I also just replace the entire unit 
rather than update the battery. 

Regards, 
-- 
Jeff 

Ted Mittelstaedt <te...@mi...> writes: 

>The main product lines hit are the SMC (and SRT) series.  These were 
>always targeted at the small business market - the 10-15 person company 
>with 1 server, running Windows Server.  The protocol change happened 
>before Schneider purchased APC.  The really small individual market or 
>1-2 person company market was buying BackUPS and didn't care about the 
>self-test stuff. 

>Although APC makes a rack-mounted SMC they mostly sell the standalone 
>UPSes in the SMC model line. 

>I'm pretty positive  that the way things played out is that back in the 
>"olden days" during the reign of the beige-colored UPSes (SmartUPS and 
>BackUPS) that APC had some really sharp in-house talent that designed 
>and built microprocessor-controlled boards and very simple firmware.  
>What I think happened was those people retired or moved on and for a 
>while they were just making a few firmware tweaks but things basically 
>were the same through the reign of the "Black-fronted UPSes with just 
>lights"  But then the Chinese (CyberPower and Goldenmate and so on) 
>started releasing UPSes with big digital readouts on the front and APC 
>had to respond to that - and also very likely they were also facing the 
>end of production of the older microprocessors and support chips used 
>for the UPSLink firmware. 

>I'm pretty sure whoever was in charge of APC farmed out a redesign of 
>the new firmware to a 3rd party and I'm 100% positive that they didn't 
>know what the hell they were doing (the APC person not the 3rd party) 
>and the 3rd party took APC down the yellow brick road.   Without 
>understanding anything APC signed a developer agreement for a 
>PROPRIETARY SDK that required them to not release source code or other 
>documentation for Microlink. When word of this got out the large 
>enterprises (that's me) basically told APC we won't be buying anymore 
>UPSes from APC, we will switch over to Eaton, because your not going to 
>make us pay licensing for PowerChute Business over our dead bodies. 

>That was what triggered the decision to write MODBUS support into the 
>APC firmware.  And as Klaasdc found out 6 years ago, the MODBUS 
>implementation copies the same formatting of parameters from Microlink, 
>so clearly the MODBUS firmware was sort of a quick hack - and I'm also 
>pretty sure that the development group that screwed over APC was not 
>particularly happy about writing it because I'm pretty sure they get a 
>portion every time APC sells a UPS with a copy of PowerChute. 

>But, having 2 independent protocols inside of a UPS chews up more flash 
>than a single protocol, so the cost-reduced SmartUPS line - the SMC - 
>appears to be frozen out. 

>I do hope you try out that KlassDC github python code I posted the link 
>to and report back to us - we get so little info on Microlink because 
>few people using apcupsd buy Microlink-only UPSes. 

>There has, unfortunately, been some bit-rot in the apcupsd code, the 
>primary problem at this time is that apcupsd has problems with running 
>MODBUS over USB now, whereas a few years ago, that worked.  However, the 
>FDDI and ATEN and Prolific USB-to-serial adapters are so ridiculously 
>cheap on Ebay for the Chinese clones, AND they are STILL including 
>honest-to-God serial ports on server-class hardware (HP Proliants and 
>such) that limiting MODBUS to serial port only inside of apcupsd, is 
>really not the limit it appears on the surface.  The SMT models that 
>include MODBUS are all targeted to Enterprises who are using them in 
>cabinets and relay racks with server quality hardware that can plug into 
>the APC serial cable, the low-end BackUPSs that have monitoring ports 
>all support USB-UPSHID and work out of the box with apcupsd. 

>It's actually more significant that NUT finally appropriated the MODBUS 
>code out of apcupsd just like they did when the UPSLink protocol was 
>reverse-engineered.  NUT has a far more wide support for different UPSes 
>as well as they had some financial support from Eaton at one time.  They 
>also are affected by that bug with MODBUS not working on USB but I'm 
>happy to let them try to fix it. 

>It's the folks like yourself - people wanting to buy a cut above the 
>SOHO BackUPSes, but not understanding why it's important to pay an extra 
>$200 for a SMT instead of a SMC, are the ones getting screwed over.  I 
>think the issue with the SMCs is that they only speak Microlink out that 
>USB port, not USB-UPSHID like the lower end BackUPS.  (the lower end 
>BackUPS don't speak Microlink)  But it's really hard to know.  I 
>personally don't have a SMC model UPS in my fleet so I can't test.  It 
>MIGHT be that the USB port merely starts out Microlink but receipt of a 
>magic packet switches it to USB-UPSHID. 

>You also have to keep in mind that once an Enterprise gets large enough, 
>UPS monitoring isn't as important as you would think.  The reason I use 
>UPS monitoring in the Enterprise is because that way my department gets 
>notified when a battery in a UPS is toasted, instead of having to depend 
>on the notoriously unreliable users we have, letting us know "there's 
>this strange beeping coming from the closet"  But not much of what's 
>plugged into most of my UPSes in the Enterprise are setup to shut down 
>on power loss - because in the locations where I have servers that 
>really matter - we have generators.  And in the less critical locations 
>it's all network gear and it makes no difference if the site loses power 
>for the network to stay up because people can't get power for 
>workstations and monitors and such. 

>The truth is that the entrance of Cloud Computing is a much greater 
>threat to the UPS market than any of this arguing over protocols.  APC 
>for sure makes far more money off the sale of BackUPSes than large 
>SmartUPSes, to SOHO.  But, when the 2-10 employee business goes 100% to 
>the cloud - who needs a UPS?  And when the home users go to laptops - 
>which just about all of them have save the hardcore gamers - who needs a 
>UPS? 

>This is why I think that APC's board allowed APC to be acquired in 2007 
>by Schenider.  And it's not lost on anyone that Schneider squashed UPSes 
>into datacenter cooling systems.  They saw the on-premise server market 
>shrinking as SOHO exited it, and the datacenter market growing as SOHO 
>entered it, and they figured they could disguise the revenue drop off in 
>the UPS division by pairing it with revenue increase from the datacenter 
>cooling products. 

>Nowadays when you buy a BackUPS you are basically buying something made 
>on the same assembly lines in China that are making CyberPower UPSs  
>CyberPower has little presence in the US Enterprise market - which is a 
>very conservative purchasing market - and likely never will.  But they 
>use the same protcol that BackUPSes use - and that GoldenMate Pro uses 
>and all of the other no-name Chinese UPSes use - USB-UPSHID. 

>I'm probably an anomaly in Enterprise purchasing anyway since I know a 
>lot of Enterprise IT directors just spec SMT for -everything- including 
>stuff (like switches) that can't even plug into a UPS monitoring port, 
>whereas I'll use BackUPSes for the non-server stuff.  And in the real 
>blue chip companies they don't even bother buying replacement 
>-batteries- they just throw the entire UPS in the garbage 3 years after 
>buying it and buy a new one.  I learned a lot about how these companies 
>operate in a prior life with judicious dumpster diving.... 

>Ted 

>On 11/28/2025 1:31 PM, Jeffery Small wrote: 
>> Ted: 
>> 
>> Thanks you for all of the very useful information. Since you have 
>> explained the change in APC protocol, I can stop banging my head against 
>> this problem. It would be nice if apcupsd was ever modified to deal with 
>> this, but I can expect it would be a difficult problem. 
>> 
>> I'm sad to see another great company like APC taken over by Schneider and

>> made worse for the end user, similar to Oracle purchasing Sun 
Microsystems. 
>> 
>> 
>> Time marches on -- not always for the better. 
>> 
>> Regards, 
>> 
>> 
>> _______________________________________________ 
>> Apcupsd-users mailing list 
>> Apc...@li... 
>> https://lists.sourceforge.net/lists/listinfo/apcupsd-users 

_______________________________________________ 
Apcupsd-users mailing list 
Apc...@li... 
https://lists.sourceforge.net/lists/listinfo/apcupsd-users 
"

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Jeffery S. <je...@cj...>]

Ted:

Once again, thanks for the detailed history.  It's is all making more sense
now and yes, I do wish I had known about this before purchasing another
SMC model, but since my old unit was working just fine on my previous
workstation and only needed a new battery, I really didn't give it any
thought.

When I get a moment, I'll look into the MODBUS code and see what's up.

I may swap out the battery from the new unit into the old one and see
if that helps.  As you said below, my past experience in installing new
batteries in the UPS has twice been followd by some UPS internal failure
requiring the unit to be replaced, so I also just replace the entire unit
rather than update the battery.

Regards,
-- 
Jeff

Ted Mittelstaedt <te...@mi...> writes:

>The main product lines hit are the SMC (and SRT) series.  These were 
>always targeted at the small business market - the 10-15 person company 
>with 1 server, running Windows Server.  The protocol change happened 
>before Schneider purchased APC.  The really small individual market or 
>1-2 person company market was buying BackUPS and didn't care about the 
>self-test stuff.

>Although APC makes a rack-mounted SMC they mostly sell the standalone 
>UPSes in the SMC model line.

>I'm pretty positive  that the way things played out is that back in the 
>"olden days" during the reign of the beige-colored UPSes (SmartUPS and 
>BackUPS) that APC had some really sharp in-house talent that designed 
>and built microprocessor-controlled boards and very simple firmware.  
>What I think happened was those people retired or moved on and for a 
>while they were just making a few firmware tweaks but things basically 
>were the same through the reign of the "Black-fronted UPSes with just 
>lights"  But then the Chinese (CyberPower and Goldenmate and so on) 
>started releasing UPSes with big digital readouts on the front and APC 
>had to respond to that - and also very likely they were also facing the 
>end of production of the older microprocessors and support chips used 
>for the UPSLink firmware.

>I'm pretty sure whoever was in charge of APC farmed out a redesign of 
>the new firmware to a 3rd party and I'm 100% positive that they didn't 
>know what the hell they were doing (the APC person not the 3rd party) 
>and the 3rd party took APC down the yellow brick road.   Without 
>understanding anything APC signed a developer agreement for a 
>PROPRIETARY SDK that required them to not release source code or other 
>documentation for Microlink. When word of this got out the large 
>enterprises (that's me) basically told APC we won't be buying anymore 
>UPSes from APC, we will switch over to Eaton, because your not going to 
>make us pay licensing for PowerChute Business over our dead bodies.

>That was what triggered the decision to write MODBUS support into the 
>APC firmware.  And as Klaasdc found out 6 years ago, the MODBUS 
>implementation copies the same formatting of parameters from Microlink, 
>so clearly the MODBUS firmware was sort of a quick hack - and I'm also 
>pretty sure that the development group that screwed over APC was not 
>particularly happy about writing it because I'm pretty sure they get a 
>portion every time APC sells a UPS with a copy of PowerChute.

>But, having 2 independent protocols inside of a UPS chews up more flash 
>than a single protocol, so the cost-reduced SmartUPS line - the SMC - 
>appears to be frozen out.

>I do hope you try out that KlassDC github python code I posted the link 
>to and report back to us - we get so little info on Microlink because 
>few people using apcupsd buy Microlink-only UPSes.

>There has, unfortunately, been some bit-rot in the apcupsd code, the 
>primary problem at this time is that apcupsd has problems with running 
>MODBUS over USB now, whereas a few years ago, that worked.  However, the 
>FDDI and ATEN and Prolific USB-to-serial adapters are so ridiculously 
>cheap on Ebay for the Chinese clones, AND they are STILL including 
>honest-to-God serial ports on server-class hardware (HP Proliants and 
>such) that limiting MODBUS to serial port only inside of apcupsd, is 
>really not the limit it appears on the surface.  The SMT models that 
>include MODBUS are all targeted to Enterprises who are using them in 
>cabinets and relay racks with server quality hardware that can plug into 
>the APC serial cable, the low-end BackUPSs that have monitoring ports 
>all support USB-UPSHID and work out of the box with apcupsd.

>It's actually more significant that NUT finally appropriated the MODBUS 
>code out of apcupsd just like they did when the UPSLink protocol was 
>reverse-engineered.  NUT has a far more wide support for different UPSes 
>as well as they had some financial support from Eaton at one time.  They 
>also are affected by that bug with MODBUS not working on USB but I'm 
>happy to let them try to fix it.

>It's the folks like yourself - people wanting to buy a cut above the 
>SOHO BackUPSes, but not understanding why it's important to pay an extra 
>$200 for a SMT instead of a SMC, are the ones getting screwed over.  I 
>think the issue with the SMCs is that they only speak Microlink out that 
>USB port, not USB-UPSHID like the lower end BackUPS.  (the lower end 
>BackUPS don't speak Microlink)  But it's really hard to know.  I 
>personally don't have a SMC model UPS in my fleet so I can't test.  It 
>MIGHT be that the USB port merely starts out Microlink but receipt of a 
>magic packet switches it to USB-UPSHID.

>You also have to keep in mind that once an Enterprise gets large enough, 
>UPS monitoring isn't as important as you would think.  The reason I use 
>UPS monitoring in the Enterprise is because that way my department gets 
>notified when a battery in a UPS is toasted, instead of having to depend 
>on the notoriously unreliable users we have, letting us know "there's 
>this strange beeping coming from the closet"  But not much of what's 
>plugged into most of my UPSes in the Enterprise are setup to shut down 
>on power loss - because in the locations where I have servers that 
>really matter - we have generators.  And in the less critical locations 
>it's all network gear and it makes no difference if the site loses power 
>for the network to stay up because people can't get power for 
>workstations and monitors and such.

>The truth is that the entrance of Cloud Computing is a much greater 
>threat to the UPS market than any of this arguing over protocols.  APC 
>for sure makes far more money off the sale of BackUPSes than large 
>SmartUPSes, to SOHO.  But, when the 2-10 employee business goes 100% to 
>the cloud - who needs a UPS?  And when the home users go to laptops - 
>which just about all of them have save the hardcore gamers - who needs a 
>UPS?

>This is why I think that APC's board allowed APC to be acquired in 2007 
>by Schenider.  And it's not lost on anyone that Schneider squashed UPSes 
>into datacenter cooling systems.  They saw the on-premise server market 
>shrinking as SOHO exited it, and the datacenter market growing as SOHO 
>entered it, and they figured they could disguise the revenue drop off in 
>the UPS division by pairing it with revenue increase from the datacenter 
>cooling products.

>Nowadays when you buy a BackUPS you are basically buying something made 
>on the same assembly lines in China that are making CyberPower UPSs  
>CyberPower has little presence in the US Enterprise market - which is a 
>very conservative purchasing market - and likely never will.  But they 
>use the same protcol that BackUPSes use - and that GoldenMate Pro uses 
>and all of the other no-name Chinese UPSes use - USB-UPSHID.

>I'm probably an anomaly in Enterprise purchasing anyway since I know a 
>lot of Enterprise IT directors just spec SMT for -everything- including 
>stuff (like switches) that can't even plug into a UPS monitoring port, 
>whereas I'll use BackUPSes for the non-server stuff.  And in the real 
>blue chip companies they don't even bother buying replacement 
>-batteries- they just throw the entire UPS in the garbage 3 years after 
>buying it and buy a new one.  I learned a lot about how these companies 
>operate in a prior life with judicious dumpster diving....

>Ted

>On 11/28/2025 1:31 PM, Jeffery Small wrote:
>> Ted:
>>
>> Thanks you for all of the very useful information.  Since you have
>> explained the change in APC protocol, I can stop banging my head against
>> this problem.  It would be nice if apcupsd was ever modified to deal with
>> this, but I can expect it would be a difficult problem.
>>
>> I'm sad to see another great company like APC taken over by Schneider and
>> made worse for the end user, similar to Oracle purchasing Sun Microsystems.
>>
>>
>> Time marches on -- not always for the better.
>>
>> Regards,
>>
>>
>> _______________________________________________
>> Apcupsd-users mailing list
>> Apc...@li...
>> https://lists.sourceforge.net/lists/listinfo/apcupsd-users

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Ted M. <te...@mi...>]

The main product lines hit are the SMC (and SRT) series.  These were 
always targeted at the small business market - the 10-15 person company 
with 1 server, running Windows Server.  The protocol change happened 
before Schneider purchased APC.  The really small individual market or 
1-2 person company market was buying BackUPS and didn't care about the 
self-test stuff.

Although APC makes a rack-mounted SMC they mostly sell the standalone 
UPSes in the SMC model line.

I'm pretty positive  that the way things played out is that back in the 
"olden days" during the reign of the beige-colored UPSes (SmartUPS and 
BackUPS) that APC had some really sharp in-house talent that designed 
and built microprocessor-controlled boards and very simple firmware.  
What I think happened was those people retired or moved on and for a 
while they were just making a few firmware tweaks but things basically 
were the same through the reign of the "Black-fronted UPSes with just 
lights"  But then the Chinese (CyberPower and Goldenmate and so on) 
started releasing UPSes with big digital readouts on the front and APC 
had to respond to that - and also very likely they were also facing the 
end of production of the older microprocessors and support chips used 
for the UPSLink firmware.

I'm pretty sure whoever was in charge of APC farmed out a redesign of 
the new firmware to a 3rd party and I'm 100% positive that they didn't 
know what the hell they were doing (the APC person not the 3rd party) 
and the 3rd party took APC down the yellow brick road.   Without 
understanding anything APC signed a developer agreement for a 
PROPRIETARY SDK that required them to not release source code or other 
documentation for Microlink. When word of this got out the large 
enterprises (that's me) basically told APC we won't be buying anymore 
UPSes from APC, we will switch over to Eaton, because your not going to 
make us pay licensing for PowerChute Business over our dead bodies.

That was what triggered the decision to write MODBUS support into the 
APC firmware.  And as Klaasdc found out 6 years ago, the MODBUS 
implementation copies the same formatting of parameters from Microlink, 
so clearly the MODBUS firmware was sort of a quick hack - and I'm also 
pretty sure that the development group that screwed over APC was not 
particularly happy about writing it because I'm pretty sure they get a 
portion every time APC sells a UPS with a copy of PowerChute.

But, having 2 independent protocols inside of a UPS chews up more flash 
than a single protocol, so the cost-reduced SmartUPS line - the SMC - 
appears to be frozen out.

I do hope you try out that KlassDC github python code I posted the link 
to and report back to us - we get so little info on Microlink because 
few people using apcupsd buy Microlink-only UPSes.

There has, unfortunately, been some bit-rot in the apcupsd code, the 
primary problem at this time is that apcupsd has problems with running 
MODBUS over USB now, whereas a few years ago, that worked.  However, the 
FDDI and ATEN and Prolific USB-to-serial adapters are so ridiculously 
cheap on Ebay for the Chinese clones, AND they are STILL including 
honest-to-God serial ports on server-class hardware (HP Proliants and 
such) that limiting MODBUS to serial port only inside of apcupsd, is 
really not the limit it appears on the surface.  The SMT models that 
include MODBUS are all targeted to Enterprises who are using them in 
cabinets and relay racks with server quality hardware that can plug into 
the APC serial cable, the low-end BackUPSs that have monitoring ports 
all support USB-UPSHID and work out of the box with apcupsd.

It's actually more significant that NUT finally appropriated the MODBUS 
code out of apcupsd just like they did when the UPSLink protocol was 
reverse-engineered.  NUT has a far more wide support for different UPSes 
as well as they had some financial support from Eaton at one time.  They 
also are affected by that bug with MODBUS not working on USB but I'm 
happy to let them try to fix it.

It's the folks like yourself - people wanting to buy a cut above the 
SOHO BackUPSes, but not understanding why it's important to pay an extra 
$200 for a SMT instead of a SMC, are the ones getting screwed over.  I 
think the issue with the SMCs is that they only speak Microlink out that 
USB port, not USB-UPSHID like the lower end BackUPS.  (the lower end 
BackUPS don't speak Microlink)  But it's really hard to know.  I 
personally don't have a SMC model UPS in my fleet so I can't test.  It 
MIGHT be that the USB port merely starts out Microlink but receipt of a 
magic packet switches it to USB-UPSHID.

You also have to keep in mind that once an Enterprise gets large enough, 
UPS monitoring isn't as important as you would think.  The reason I use 
UPS monitoring in the Enterprise is because that way my department gets 
notified when a battery in a UPS is toasted, instead of having to depend 
on the notoriously unreliable users we have, letting us know "there's 
this strange beeping coming from the closet"  But not much of what's 
plugged into most of my UPSes in the Enterprise are setup to shut down 
on power loss - because in the locations where I have servers that 
really matter - we have generators.  And in the less critical locations 
it's all network gear and it makes no difference if the site loses power 
for the network to stay up because people can't get power for 
workstations and monitors and such.

The truth is that the entrance of Cloud Computing is a much greater 
threat to the UPS market than any of this arguing over protocols.  APC 
for sure makes far more money off the sale of BackUPSes than large 
SmartUPSes, to SOHO.  But, when the 2-10 employee business goes 100% to 
the cloud - who needs a UPS?  And when the home users go to laptops - 
which just about all of them have save the hardcore gamers - who needs a 
UPS?

This is why I think that APC's board allowed APC to be acquired in 2007 
by Schenider.  And it's not lost on anyone that Schneider squashed UPSes 
into datacenter cooling systems.  They saw the on-premise server market 
shrinking as SOHO exited it, and the datacenter market growing as SOHO 
entered it, and they figured they could disguise the revenue drop off in 
the UPS division by pairing it with revenue increase from the datacenter 
cooling products.

Nowadays when you buy a BackUPS you are basically buying something made 
on the same assembly lines in China that are making CyberPower UPSs  
CyberPower has little presence in the US Enterprise market - which is a 
very conservative purchasing market - and likely never will.  But they 
use the same protcol that BackUPSes use - and that GoldenMate Pro uses 
and all of the other no-name Chinese UPSes use - USB-UPSHID.

I'm probably an anomaly in Enterprise purchasing anyway since I know a 
lot of Enterprise IT directors just spec SMT for -everything- including 
stuff (like switches) that can't even plug into a UPS monitoring port, 
whereas I'll use BackUPSes for the non-server stuff.  And in the real 
blue chip companies they don't even bother buying replacement 
-batteries- they just throw the entire UPS in the garbage 3 years after 
buying it and buy a new one.  I learned a lot about how these companies 
operate in a prior life with judicious dumpster diving....

Ted

On 11/28/2025 1:31 PM, Jeffery Small wrote:
> Ted:
>
> Thanks you for all of the very useful information.  Since you have
> explained the change in APC protocol, I can stop banging my head against
> this problem.  It would be nice if apcupsd was ever modified to deal with
> this, but I can expect it would be a difficult problem.
>
> I'm sad to see another great company like APC taken over by Schneider and
> made worse for the end user, similar to Oracle purchasing Sun Microsystems.
>
>
> Time marches on -- not always for the better.
>
> Regards,
>
>
> _______________________________________________
> Apcupsd-users mailing list
> Apc...@li...
> https://lists.sourceforge.net/lists/listinfo/apcupsd-users

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Jeffery S. <je...@cj...>]

Ted:

Thanks you for all of the very useful information.  Since you have
explained the change in APC protocol, I can stop banging my head against
this problem.  It would be nice if apcupsd was ever modified to deal with
this, but I can expect it would be a difficult problem.

I'm sad to see another great company like APC taken over by Schneider and
made worse for the end user, similar to Oracle purchasing Sun Microsystems.


Time marches on -- not always for the better.

Regards,
-- 
Jeff


Ted Mittelstaedt <te...@mi...> writes:

>This is a multi-part message in MIME format.
>--===============0310786591105536694==
>Content-Type: multipart/alternative;
> boundary="------------G5BBnVjXuS1axEnWf6QErFKm"
>Content-Language: en-US

>This is a multi-part message in MIME format.
>--------------G5BBnVjXuS1axEnWf6QErFKm
>Content-Type: text/plain; charset=UTF-8; format=flowed
>Content-Transfer-Encoding: 8bit

>The older SMC model UPSes used the UPSLink protocol that was compatible 
>with apcupsd

>The newer SMC model UPSes use the Microlink protocol that is not.

>I think a lot of people were hoping that with the reverse-engineering of 
>the microlink protocol that someone would write support into either NUT 
>or apcupsd.

>The NUT project eventually copied the MODBUS driver out of apcupsd and 
>use it with their project now.

>The Smartcard slot in the SMT models allow you to install a web card 
>with an ethernet port that does NOT require access to APC's website

>The green ethernet ports on their newer UPSes require a yearly fee to be 
>paid to their website to "monitor"


> From experience, I can tell you with purchasing for an enterprise today 
>for the US market, these are the models of UPSes that I buy - all are 
>compatible with apcupsd:

>The first 2 are for workstations - we don't often get much call for 
>these and I have pretty strict requirements on a user who wants a UPS - 
>almost always, we will swap out their desktop with a laptop long before 
>we give them a UPS.  Sometimes I will use these for remote switches in 
>cabinets.   These work fine with apcupsd and a USB cable - they use the 
>USB-UPSHID protocol:

>APC UPS Battery Backup, 1050VA UPS with 6 Backup Battery Outlets, Type C 
>USB Charging, BE1050G3 Back-UPS

>APC BACK-UPS 850VA part # BE850G2

>Tjese 3 are for larger server rooms, remote domain controllers and the like

>APC 1500VA Smart UPS with SmartConnect, SMT1500C Sinewave UPS Battery 
>Backup, AVR, 120V, Line Interactive Uninterruptible Power Supply


>APC 2200VA Smart UPS with SmartConnect, SMT2200RM2UC Rack Mount UPS 
>Battery Backup, Sinewave, AVR, 120V, Line Interactive Uninterruptible 
>Power Supply


>APC 1500VA Smart UPS with SmartConnect, SMT1500RM2UC Rack Mount UPS 
>Battery Backup, Sinewave, AVR, 120V, Line Interactive Uninterruptible 
>Power Supply

>In the US new and modern commercial construction dictates 20A 120V.   I 
>have experimented with 30A 125V circuits but ultimately I have found 
>with modern server gear the power requirements are not high enough to 
>justify the extra cost of specialty connectors and so on for 3000VA UPSes.

>I use the 1500VA units in older buildings where the power is 
>questionable - the outlet isn't on a dedicated circuit, or something 
>like that.

>It's imperative to properly size UPSes and NOT to oversize them!!!!   
>You want the load no less than 20%.  Otherwise what happens is when the 
>UPS self-tests, there's not enough load on the batteries to get proper 
>calculation of battery discharge curve and over time the UPS will 
>display inaccurate battery life.  If you don't get 20% load then use a 
>smaller UPS

>Ted

>On 11/27/2025 9:45 AM, Jeffery Small wrote:
>> Trev via Apcupsdusers<apc...@li...>  writes:
>>
>>> Jeffery Small wrote on 27/11/25 10:56 am:
>>>> Xubuntu:    24.04.3
>>>> apcupsd:    3.14.143.1build2  (standard Ubuntu package)
>>>> UPS:	    New APC SMC1500C with USB connection
>>>>
>>>> I just built a new Linux workstation with a new APC UPS.  Everything is
>>>> running fine except that the monitor is showing no load despite all of
>>>> my equipment plugged into the UPS.  Here is a link to a screenshot:
>>>>
>>>> http://cjsa.com/misc/apcupsd_01.png
>>>>
>>>> Any reason that this is happening?  On my previous system with the same UPS
>>>> which was more than five years old, all of this worked fine.  Could this
>>>> be a configuration issue?
>>> It is unclear to me whether you are using the same UPS. You say it's a
>>> new APC UPS and later the same UPS. I'd hazard a  guess that it is a new
>>> UPS and very probably has a different firmware. APC's USB firmware
>>> versions have been notoriously buggy. Is there a firmware update for the
>>> new UPS? If so, apply it and hope.
>>> Alternatively:
>>> 1) try the modbus protocol as someone has already helpfully suggested; or
>>> 2) try a USB->RS232 converter if you have a serial port on your new
>>> computer.
>> It is a new UPS but when I said it was the same, I meant identical model:
>> SMC1500C hooked up the same using USB.
>>
>> Thanks for the suggestions, both from you and other.  I'll report if I
>> have success.  I'll see if there is new firmware and load it.  I have been
>> loath to connect the UPS to the network because it looks like Schneider
>> has go the route of Microsoft and others and wants to own and control your
>> equipment.  I don't want them on my LAN. :-(
>>
>> Do people think that the self-test option should work through the apcupsd,
>> or is this failure to be expected?  I guess I can run self test from the
>> front panel and see if apcupsd then recognizes it.
>>
>> Regards,
>--------------G5BBnVjXuS1axEnWf6QErFKm
>Content-Type: text/html; charset=UTF-8
>Content-Transfer-Encoding: 8bit

><html>
>  <head>
>    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
>  </head>
>  <body>
>    <p>The older SMC model UPSes used the UPSLink protocol that was
>      compatible with apcupsd<br>
>    </p>
>    <p>The newer SMC model UPSes use the Microlink protocol that is not.</p>
>    <p>I think a lot of people were hoping that with the
>      reverse-engineering of the microlink protocol that someone would
>      write support into either NUT or apcupsd.</p>
>    <p>The NUT project eventually copied the MODBUS driver out of
>      apcupsd and use it with their project now.<br>
>    </p>
>    <p>The Smartcard slot in the SMT models allow you to install a web
>      card with an ethernet port that does NOT require access to APC's
>      website</p>
>    <p>The green ethernet ports on their newer UPSes require a yearly
>      fee to be paid to their website to "monitor"</p>
>    <p><br>
>    </p>
>    <p>From experience, I can tell you with purchasing for an enterprise
>      today for the US market, these are the models of UPSes that I buy
>      - all are compatible with apcupsd:</p>
>    <p>The first 2 are for workstations - we don't often get much call
>      for these and I have pretty strict requirements on a user who
>      wants a UPS - almost always, we will swap out their desktop with a
>      laptop long before we give them a UPS.  Sometimes I will use these
>      for remote switches in cabinets.   These work fine with apcupsd
>      and a USB cable - they use the USB-UPSHID protocol:<br>
>    </p>
>    <p id="title" class="a-size-large a-spacing-none" style="box-sizing:
>      border-box; padding: 0px; margin-top: 0px; margin-right: 0px;
>      margin-bottom: 0px !important; margin-left: 0px;
>      padding-block-end: 0px; text-rendering: optimizelegibility;
>      font-weight: 400; font-size: 24px !important; line-height: 32px
>      !important; color: rgb(15, 17, 17); font-style: normal;
>      font-variant-ligatures: normal; font-variant-caps: normal;
>      letter-spacing: normal; text-align: start; text-indent: 0px;
>      text-transform: none; word-spacing: 0px;
>      -webkit-text-stroke-width: 0px; white-space: normal;
>      background-color: rgb(255, 255, 255); text-decoration-thickness:
>      initial; text-decoration-style: initial; text-decoration-color:
>      initial;"><span id="productTitle" class="a-size-large
>        product-title-word-break" style="box-sizing: border-box;
>        font-size: 24px !important; line-height: 32px !important;
>        text-rendering: optimizelegibility; word-break: break-word;">APC
>        UPS Battery Backup, 1050VA UPS with 6 Backup Battery Outlets,
>        Type C USB Charging, BE1050G3 Back-UPS</span></p>
>    <p>APC BACK-UPS 850VA part # BE850G2</p>
>    Tjese 3 are for larger server rooms, remote domain controllers and
>    the like<br>
>    <p><span id="productTitle" class="a-size-large
>        product-title-word-break" style="box-sizing: border-box;
>        font-size: 24px !important; line-height: 32px !important;
>        text-rendering: optimizelegibility; word-break: break-word;">APC
>        1500VA Smart UPS with SmartConnect, SMT1500C Sinewave UPS
>        Battery Backup, AVR, 120V, Line Interactive Uninterruptible
>        Power Supply</span></p>
>    <p><br>
>    </p>
>    <p id="title" class="a-size-large a-spacing-none" style="box-sizing:
>      border-box; padding: 0px; margin-top: 0px; margin-right: 0px;
>      margin-bottom: 0px !important; margin-left: 0px;
>      padding-block-end: 0px; text-rendering: optimizelegibility;
>      font-weight: 400; font-size: 24px !important; line-height: 32px
>      !important; color: rgb(15, 17, 17); font-style: normal;
>      font-variant-ligatures: normal; font-variant-caps: normal;
>      letter-spacing: normal; text-align: start; text-indent: 0px;
>      text-transform: none; word-spacing: 0px;
>      -webkit-text-stroke-width: 0px; white-space: normal;
>      background-color: rgb(255, 255, 255); text-decoration-thickness:
>      initial; text-decoration-style: initial; text-decoration-color:
>      initial;"><span id="productTitle" class="a-size-large
>        product-title-word-break" style="box-sizing: border-box;
>        font-size: 24px !important; line-height: 32px !important;
>        text-rendering: optimizelegibility; word-break: break-word;">APC
>        2200VA Smart UPS with SmartConnect, SMT2200RM2UC Rack Mount UPS
>        Battery Backup, Sinewave, AVR, 120V, Line Interactive
>        Uninterruptible Power Supply</span></p>
>    <p><br>
>    </p>
>    <p id="title" class="a-size-large a-spacing-none" style="box-sizing:
>      border-box; padding: 0px; margin-top: 0px; margin-right: 0px;
>      margin-bottom: 0px !important; margin-left: 0px;
>      padding-block-end: 0px; text-rendering: optimizelegibility;
>      font-weight: 400; font-size: 24px !important; line-height: 32px
>      !important; color: rgb(15, 17, 17); font-style: normal;
>      font-variant-ligatures: normal; font-variant-caps: normal;
>      letter-spacing: normal; text-align: start; text-indent: 0px;
>      text-transform: none; word-spacing: 0px;
>      -webkit-text-stroke-width: 0px; white-space: normal;
>      background-color: rgb(255, 255, 255); text-decoration-thickness:
>      initial; text-decoration-style: initial; text-decoration-color:
>      initial;"><span id="productTitle" class="a-size-large
>        product-title-word-break" style="box-sizing: border-box;
>        font-size: 24px !important; line-height: 32px !important;
>        text-rendering: optimizelegibility; word-break: break-word;">APC
>        1500VA Smart UPS with SmartConnect, SMT1500RM2UC Rack Mount UPS
>        Battery Backup, Sinewave, AVR, 120V, Line Interactive
>        Uninterruptible Power Supply</span></p>
>    <p>In the US new and modern commercial construction dictates 20A
>      120V.   I have experimented with 30A 125V circuits but ultimately
>      I have found with modern server gear the power requirements are
>      not high enough to justify the extra cost of specialty connectors
>      and so on for 3000VA UPSes.</p>
>    <p>I use the 1500VA units in older buildings where the power is
>      questionable - the outlet isn't on a dedicated circuit, or
>      something like that.</p>
>    <p>It's imperative to properly size UPSes and NOT to oversize
>      them!!!!   You want the load no less than 20%.  Otherwise what
>      happens is when the UPS self-tests, there's not enough load on the
>      batteries to get proper calculation of battery discharge curve and
>      over time the UPS will display inaccurate battery life.  If you
>      don't get 20% load then use a smaller UPS</p>
>    <p>Ted<br>
>    </p>
>    On 11/27/2025 9:45 AM, Jeffery Small wrote:<br>
>    <blockquote type="cite" cite="mid:10ga2nc$2ubvu$1...@cu...">
>      <pre class="moz-quote-pre" wrap="">Trev via Apcupsdusers <a class="moz-txt-link-rfc2396E" href="mailto:apc...@li...">&lt;apc...@li...&gt;</a> writes:

></pre>
>      <blockquote type="cite">
>        <pre class="moz-quote-pre" wrap="">Jeffery Small wrote on 27/11/25 10:56 am:
></pre>
>        <blockquote type="cite">
>          <pre class="moz-quote-pre" wrap="">Xubuntu:    24.04.3
>apcupsd:    3.14.143.1build2  (standard Ubuntu package)
>UPS:	    New APC SMC1500C with USB connection

>I just built a new Linux workstation with a new APC UPS.  Everything is
>running fine except that the monitor is showing no load despite all of
>my equipment plugged into the UPS.  Here is a link to a screenshot:

><a class="moz-txt-link-freetext" href="http://cjsa.com/misc/apcupsd_01.png">http://cjsa.com/misc/apcupsd_01.png</a>

>Any reason that this is happening?  On my previous system with the same UPS
>which was more than five years old, all of this worked fine.  Could this
>be a configuration issue? 
></pre>
>        </blockquote>
>      </blockquote>
>      <pre class="moz-quote-pre" wrap="">
></pre>
>      <blockquote type="cite">
>        <pre class="moz-quote-pre" wrap="">It is unclear to me whether you are using the same UPS. You say it's a 
>new APC UPS and later the same UPS. I'd hazard a  guess that it is a new 
>UPS and very probably has a different firmware. APC's USB firmware 
>versions have been notoriously buggy. Is there a firmware update for the 
>new UPS? If so, apply it and hope.
></pre>
>      </blockquote>
>      <pre class="moz-quote-pre" wrap="">
></pre>
>      <blockquote type="cite">
>        <pre class="moz-quote-pre" wrap="">Alternatively:
></pre>
>      </blockquote>
>      <pre class="moz-quote-pre" wrap="">
></pre>
>      <blockquote type="cite">
>        <pre class="moz-quote-pre" wrap="">1) try the modbus protocol as someone has already helpfully suggested; or
>2) try a USB-&gt;RS232 converter if you have a serial port on your new 
>computer.
></pre>
>      </blockquote>
>      <pre class="moz-quote-pre" wrap="">
>It is a new UPS but when I said it was the same, I meant identical model:
>SMC1500C hooked up the same using USB.

>Thanks for the suggestions, both from you and other.  I'll report if I
>have success.  I'll see if there is new firmware and load it.  I have been
>loath to connect the UPS to the network because it looks like Schneider
>has go the route of Microsoft and others and wants to own and control your
>equipment.  I don't want them on my LAN. :-(

>Do people think that the self-test option should work through the apcupsd,
>or is this failure to be expected?  I guess I can run self test from the
>front panel and see if apcupsd then recognizes it.

>Regards,
></pre>
>    </blockquote>
>  </body>
></html>

>--------------G5BBnVjXuS1axEnWf6QErFKm--


>--===============0310786591105536694==
>Content-Type: text/plain; charset="us-ascii"
>MIME-Version: 1.0
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>Content-Disposition: inline


>--===============0310786591105536694==
>Content-Type: text/plain; charset="us-ascii"
>MIME-Version: 1.0
>Content-Transfer-Encoding: 7bit
>Content-Disposition: inline

>_______________________________________________
>Apcupsd-users mailing list
>Apc...@li...
>https://lists.sourceforge.net/lists/listinfo/apcupsd-users

>--===============0310786591105536694==--

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Ted M. <te...@mi...>]

The older SMC model UPSes used the UPSLink protocol that was compatible 
with apcupsd

The newer SMC model UPSes use the Microlink protocol that is not.

I think a lot of people were hoping that with the reverse-engineering of 
the microlink protocol that someone would write support into either NUT 
or apcupsd.

The NUT project eventually copied the MODBUS driver out of apcupsd and 
use it with their project now.

The Smartcard slot in the SMT models allow you to install a web card 
with an ethernet port that does NOT require access to APC's website

The green ethernet ports on their newer UPSes require a yearly fee to be 
paid to their website to "monitor"


 From experience, I can tell you with purchasing for an enterprise today 
for the US market, these are the models of UPSes that I buy - all are 
compatible with apcupsd:

The first 2 are for workstations - we don't often get much call for 
these and I have pretty strict requirements on a user who wants a UPS - 
almost always, we will swap out their desktop with a laptop long before 
we give them a UPS.  Sometimes I will use these for remote switches in 
cabinets.   These work fine with apcupsd and a USB cable - they use the 
USB-UPSHID protocol:

APC UPS Battery Backup, 1050VA UPS with 6 Backup Battery Outlets, Type C 
USB Charging, BE1050G3 Back-UPS

APC BACK-UPS 850VA part # BE850G2

Tjese 3 are for larger server rooms, remote domain controllers and the like

APC 1500VA Smart UPS with SmartConnect, SMT1500C Sinewave UPS Battery 
Backup, AVR, 120V, Line Interactive Uninterruptible Power Supply


APC 2200VA Smart UPS with SmartConnect, SMT2200RM2UC Rack Mount UPS 
Battery Backup, Sinewave, AVR, 120V, Line Interactive Uninterruptible 
Power Supply


APC 1500VA Smart UPS with SmartConnect, SMT1500RM2UC Rack Mount UPS 
Battery Backup, Sinewave, AVR, 120V, Line Interactive Uninterruptible 
Power Supply

In the US new and modern commercial construction dictates 20A 120V.   I 
have experimented with 30A 125V circuits but ultimately I have found 
with modern server gear the power requirements are not high enough to 
justify the extra cost of specialty connectors and so on for 3000VA UPSes.

I use the 1500VA units in older buildings where the power is 
questionable - the outlet isn't on a dedicated circuit, or something 
like that.

It's imperative to properly size UPSes and NOT to oversize them!!!!   
You want the load no less than 20%.  Otherwise what happens is when the 
UPS self-tests, there's not enough load on the batteries to get proper 
calculation of battery discharge curve and over time the UPS will 
display inaccurate battery life.  If you don't get 20% load then use a 
smaller UPS

Ted

On 11/27/2025 9:45 AM, Jeffery Small wrote:
> Trev via Apcupsdusers<apc...@li...>  writes:
>
>> Jeffery Small wrote on 27/11/25 10:56 am:
>>> Xubuntu:    24.04.3
>>> apcupsd:    3.14.143.1build2  (standard Ubuntu package)
>>> UPS:	    New APC SMC1500C with USB connection
>>>
>>> I just built a new Linux workstation with a new APC UPS.  Everything is
>>> running fine except that the monitor is showing no load despite all of
>>> my equipment plugged into the UPS.  Here is a link to a screenshot:
>>>
>>> http://cjsa.com/misc/apcupsd_01.png
>>>
>>> Any reason that this is happening?  On my previous system with the same UPS
>>> which was more than five years old, all of this worked fine.  Could this
>>> be a configuration issue?
>> It is unclear to me whether you are using the same UPS. You say it's a
>> new APC UPS and later the same UPS. I'd hazard a  guess that it is a new
>> UPS and very probably has a different firmware. APC's USB firmware
>> versions have been notoriously buggy. Is there a firmware update for the
>> new UPS? If so, apply it and hope.
>> Alternatively:
>> 1) try the modbus protocol as someone has already helpfully suggested; or
>> 2) try a USB->RS232 converter if you have a serial port on your new
>> computer.
> It is a new UPS but when I said it was the same, I meant identical model:
> SMC1500C hooked up the same using USB.
>
> Thanks for the suggestions, both from you and other.  I'll report if I
> have success.  I'll see if there is new firmware and load it.  I have been
> loath to connect the UPS to the network because it looks like Schneider
> has go the route of Microsoft and others and wants to own and control your
> equipment.  I don't want them on my LAN. :-(
>
> Do people think that the self-test option should work through the apcupsd,
> or is this failure to be expected?  I guess I can run self test from the
> front panel and see if apcupsd then recognizes it.
>
> Regards,

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Jeffery S. <je...@cj...>]

Trev via Apcupsdusers <apc...@li...> writes:

>Jeffery Small wrote on 27/11/25 10:56 am:
>> Xubuntu:    24.04.3
>> apcupsd:    3.14.143.1build2  (standard Ubuntu package)
>> UPS:	    New APC SMC1500C with USB connection
>> 
>> I just built a new Linux workstation with a new APC UPS.  Everything is
>> running fine except that the monitor is showing no load despite all of
>> my equipment plugged into the UPS.  Here is a link to a screenshot:
>> 
>> http://cjsa.com/misc/apcupsd_01.png
>> 
>> Any reason that this is happening?  On my previous system with the same UPS
>> which was more than five years old, all of this worked fine.  Could this
>> be a configuration issue? 

>It is unclear to me whether you are using the same UPS. You say it's a 
>new APC UPS and later the same UPS. I'd hazard a  guess that it is a new 
>UPS and very probably has a different firmware. APC's USB firmware 
>versions have been notoriously buggy. Is there a firmware update for the 
>new UPS? If so, apply it and hope.

>Alternatively:

>1) try the modbus protocol as someone has already helpfully suggested; or
>2) try a USB->RS232 converter if you have a serial port on your new 
>computer.

It is a new UPS but when I said it was the same, I meant identical model:
SMC1500C hooked up the same using USB.

Thanks for the suggestions, both from you and other.  I'll report if I
have success.  I'll see if there is new firmware and load it.  I have been
loath to connect the UPS to the network because it looks like Schneider
has go the route of Microsoft and others and wants to own and control your
equipment.  I don't want them on my LAN. :-(

Do people think that the self-test option should work through the apcupsd,
or is this failure to be expected?  I guess I can run self test from the
front panel and see if apcupsd then recognizes it.

Regards,
-- 
Jeffery Small

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Ted M. <te...@mi...>]

The SMC series has always been problematical.  Among other things it's 
firmware never supported MODBUS.  It also never had a smartcard slot.   
It's a very cost-reduced version of the SMT.  It supports Microlink only 
and POSSIBLY it supports the USB-HID-UPS documented here:

https://www.usb.org/sites/default/files/documents/pdcv10.pdf

You MIGHT get it working with 
https://networkupstools.org/docs/man/usbhid-ups.html

apcupsd also mostly supports this as well BUT it does not always work.

There is some reverse-engineering of that protocol here and you might 
this to work:

https://sites.google.com/site/klaasdc/apc-smartups-decode

The model of UPS that supports MODBUS is the SMT series.  It also 
supports a smartcard slot.

Unfortunately, although many times in the past on this list we have 
advised against the SMC series people don't check and we will get posts 
like this from time to time.  Unfortunately, nobody has ever followed up 
and I strongly suspect people issue returns on this model of UPS the 
minute they find out about the problem.

Ted

On 11/26/2025 3:56 PM, Jeffery Small wrote:

> Xubuntu:    24.04.3
> apcupsd:    3.14.143.1build2  (standard Ubuntu package)
> UPS:	    New APC SMC1500C with USB connection
>
> I just built a new Linux workstation with a new APC UPS.  Everything is
> running fine except that the monitor is showing no load despite all of
> my equipment plugged into the UPS.  Here is a link to a screenshot:
>
> http://cjsa.com/misc/apcupsd_01.png
>
> Any reason that this is happening?  On my previous system with the same UPS
> which was more than five years old, all of this worked fine.  Could this
> be a configuration issue?  I believe I'm using the same configuration as
> the last machine.  Here is my /etc/apcupsd/apcupsd.conf file stripped of
> comments and empty lines:
>
> -----------------------------------------------------------
> UPSNAME CUP_SMC_1500
> UPSCABLE usb
> UPSTYPE usb
> DEVICE
> LOCKFILE /var/lock
> SCRIPTDIR /etc/apcupsd
> PWRFAILDIR /etc/apcupsd
> NOLOGINDIR /etc
> ONBATTERYDELAY 10
> BATTERYLEVEL 10
> MINUTES 5
> TIMEOUT 0
> ANNOY 300
> ANNOYDELAY 480
> NOLOGON disable
> KILLDELAY 0
> NETSERVER on
> NISIP 127.0.0.1
> NISPORT 3551
> EVENTSFILE /var/log/apcupsd.events
> EVENTSFILEMAX 20
> UPSCLASS standalone
> UPSMODE disable
> STATTIME 0
> STATFILE /var/log/apcupsd.status
> LOGSTATS off
> DATATIME 0
> -----------------------------------------------------------
>
> I also find that I cannot run a selftest on the ups which seems very
> strange.  As root, here is what I do:
>
> -----------------------------------------------------------
> # service apcupsd stop
> # apctest
>
> This part of apctest is for testing USB UPSes.
>
> Getting UPS capabilities...SUCCESS
>
> Please select the function you want to perform.
>
> 1)  Test kill UPS power
> 2)  Perform self-test
> 3)  Read last self-test result
> 4)  View/Change battery date
> 5)  View manufacturing date
> 6)  View/Change alarm behavior
> 7)  View/Change sensitivity
> 8)  View/Change low transfer voltage
> 9)  View/Change high transfer voltage
> 10) Perform battery calibration
> 11) Test alarm
> 12) View/Change self-test interval
>   Q) Quit
>
> Select function number: 2
>
>
> This test instructs the UPS to perform a self-test
> operation and reports the result when the test completes.
>
> I don't know how to run a self test on your UPS
> or your UPS does not support self test.
> -----------------------------------------------------------
>
> I would think that this type of unit would be able to perform the
> self test.  Could this also be a config issue?
>
> Any pointers are appreciated.
>
> Regards,

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Pavel B. <boc...@po...>]

In second case, switch to serial cable from the UPS of course. Things appear
to be working OK over good ol' serial as has been confirmed dozens of times 
already.

-- 
S uctivým pozdravem/best regards,

Pavel Boček
Jabber: Be...@ja...
+420 739 190 151
http://www.hwworld.cz (elektromontáže silnoproud/slaboproud, kondenzátory, 
aku/baterie, mikrospínače pro myši a klávesnice aj./capacitors etc.)
https://www.hardwareinsights.com (power supply reviews and more)
stickers-cz.com (nekonformní samolepky, placky)

---------- Původní e-mail ----------
Od: Trev via Apcupsd-users <apc...@li...>
Komu: Apcupsd Discussion List <apc...@li...>
Kopie: Trev <tr...@se...>
Datum: 27. 11. 2025 6:16:26
Předmět: Re: [Apcupsd-users] apcupsd not showing any UPS load
"Jeffery Small wrote on 27/11/25 10:56 am: 
> Xubuntu: 24.04.3 
> apcupsd: 3.14.143.1build2 (standard Ubuntu package) 
> UPS: New APC SMC1500C with USB connection 
> 
> I just built a new Linux workstation with a new APC UPS. Everything is 
> running fine except that the monitor is showing no load despite all of 
> my equipment plugged into the UPS. Here is a link to a screenshot: 
> 
> http://cjsa.com/misc/apcupsd_01.png 
> 
> Any reason that this is happening? On my previous system with the same UPS

> which was more than five years old, all of this worked fine. Could this 
> be a configuration issue? 

It is unclear to me whether you are using the same UPS. You say it's a 
new APC UPS and later the same UPS. I'd hazard a guess that it is a new 
UPS and very probably has a different firmware. APC's USB firmware 
versions have been notoriously buggy. Is there a firmware update for the 
new UPS? If so, apply it and hope. 

Alternatively: 

1) try the modbus protocol as someone has already helpfully suggested; or 
2) try a USB->RS232 converter if you have a serial port on your new 
computer. 


_______________________________________________ 
Apcupsd-users mailing list 
Apc...@li... 
https://lists.sourceforge.net/lists/listinfo/apcupsd-users 
"

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Trev <tr...@se...>]

Jeffery Small wrote on 27/11/25 10:56 am:
> Xubuntu:    24.04.3
> apcupsd:    3.14.143.1build2  (standard Ubuntu package)
> UPS:	    New APC SMC1500C with USB connection
> 
> I just built a new Linux workstation with a new APC UPS.  Everything is
> running fine except that the monitor is showing no load despite all of
> my equipment plugged into the UPS.  Here is a link to a screenshot:
> 
> http://cjsa.com/misc/apcupsd_01.png
> 
> Any reason that this is happening?  On my previous system with the same UPS
> which was more than five years old, all of this worked fine.  Could this
> be a configuration issue? 

It is unclear to me whether you are using the same UPS. You say it's a 
new APC UPS and later the same UPS. I'd hazard a  guess that it is a new 
UPS and very probably has a different firmware. APC's USB firmware 
versions have been notoriously buggy. Is there a firmware update for the 
new UPS? If so, apply it and hope.

Alternatively:

1) try the modbus protocol as someone has already helpfully suggested; or
2) try a USB->RS232 converter if you have a serial port on your new 
computer.

Re: [Apcupsd-users] apcupsd not showing any UPS load

[Šarūnas B. <sa...@ma...>]

On 2025-11-26 18:56, Jeffery Small wrote:
> UPSTYPE usb

You could try using modbus protocol instead: check in UPS control panel 
that modbus is enabled. Then set UPSTYPE to modbus.


-- 
Šarūnas Burdulis
Dartmouth Mathematics
https://math.dartmouth.edu/~sarunas

· https://useplaintext.email ·

[Apcupsd-users] apcupsd not showing any UPS load

[Jeffery S. <je...@cj...>]

Xubuntu:    24.04.3
apcupsd:    3.14.143.1build2  (standard Ubuntu package)
UPS:	    New APC SMC1500C with USB connection

I just built a new Linux workstation with a new APC UPS.  Everything is
running fine except that the monitor is showing no load despite all of
my equipment plugged into the UPS.  Here is a link to a screenshot:

http://cjsa.com/misc/apcupsd_01.png

Any reason that this is happening?  On my previous system with the same UPS
which was more than five years old, all of this worked fine.  Could this
be a configuration issue?  I believe I'm using the same configuration as
the last machine.  Here is my /etc/apcupsd/apcupsd.conf file stripped of
comments and empty lines:

-----------------------------------------------------------
UPSNAME CUP_SMC_1500
UPSCABLE usb
UPSTYPE usb
DEVICE
LOCKFILE /var/lock
SCRIPTDIR /etc/apcupsd
PWRFAILDIR /etc/apcupsd
NOLOGINDIR /etc
ONBATTERYDELAY 10
BATTERYLEVEL 10
MINUTES 5
TIMEOUT 0
ANNOY 300
ANNOYDELAY 480
NOLOGON disable
KILLDELAY 0
NETSERVER on
NISIP 127.0.0.1
NISPORT 3551
EVENTSFILE /var/log/apcupsd.events
EVENTSFILEMAX 20
UPSCLASS standalone
UPSMODE disable
STATTIME 0
STATFILE /var/log/apcupsd.status
LOGSTATS off
DATATIME 0
-----------------------------------------------------------

I also find that I cannot run a selftest on the ups which seems very
strange.  As root, here is what I do:

-----------------------------------------------------------
# service apcupsd stop
# apctest

This part of apctest is for testing USB UPSes.

Getting UPS capabilities...SUCCESS

Please select the function you want to perform.

1)  Test kill UPS power
2)  Perform self-test
3)  Read last self-test result
4)  View/Change battery date
5)  View manufacturing date
6)  View/Change alarm behavior
7)  View/Change sensitivity
8)  View/Change low transfer voltage
9)  View/Change high transfer voltage
10) Perform battery calibration
11) Test alarm
12) View/Change self-test interval
 Q) Quit

Select function number: 2


This test instructs the UPS to perform a self-test
operation and reports the result when the test completes.

I don't know how to run a self test on your UPS
or your UPS does not support self test.
-----------------------------------------------------------

I would think that this type of unit would be able to perform the
self test.  Could this also be a config issue?

Any pointers are appreciated.

Regards,
-- 
Jeffery Small