[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