## Re: [Gumstix-users] 3.3v vs. 4v vs. 5v OH MY!

 Re: [Gumstix-users] 3.3v vs. 4v vs. 5v OH MY! From: Julien Lebot <30579108@st...> - 2007-07-30 18:52:10 ```Quoting Dave Hylands : > Hi Julien, > > On 7/30/07, Julien Lebot <30579108@...> wrote: >> I'm using a single cell Li-Po battery on my design, should I regulate >> the battery voltage to be in the range of 3.6-6V for the Vbatt input ? >> The nominal voltage of Li-Po batteries is 3.7V but it can go as low >> a 3.3V... > > No need to regulate the 3.7v. However, you probably shouldn't use the > battery when the voltage drops below 3.6v. I'm n ot sure how much > lower you can go. Certainly not below 3.45v. > > I think most Li-Po's can go down to 3.0v. > > So in order to get maximum battery usage, you may want to use > something like the AnyVolt from http://www.dimensionengineering.com > > You can set the output to 3.6v and you'll continue to get 3.6v volts > out even as the voltage of your LiPo drops down to 3.0v. You should > have a 3.0v cutoff circuit to protect the LiPo from dropping below > 3.0v > > -- > Dave Hylands > Vancouver, BC, Canada > http://www.DaveHylands.com/ Hi Dave, That's exactly what I was afraid of; I'd like to maximise battery usage. Thanks for the pointer, though I'd prefer something with a smaller form factor which I can solder on the PCB. Also I'd like more current flow, would it be possible to use 2 boost regulators in parallel ? Two 2.5" HDD could be connected on my +5V power rail, consuming 1A, so I need to manage that and the Gumstix + onboard peripherals. I estimated the power consumption to 2A max. (This is why I use LiPo batteries) Julien ```

 [Gumstix-users] batteries and GSM antenna not included? From: Jack Smith - 2007-07-30 03:46:26 Attachments: Message as HTML ```I really hate to bother this list with another newbie question, but I certainly don't want to part with ~\$450 for the verdex, goliath, and LCD without understanding everything. Since the NiMH batteries and GSM antenna apparently aren't included, nor sold by gumstix separately, where are we to buy them? Thank you. ```
 Re: [Gumstix-users] batteries and GSM antenna not included? From: Julien Lebot <30579108@st...> - 2007-07-30 08:56:38 ```Quoting Jack Smith : > I really hate to bother this list with another newbie question, but I > certainly don't want to part with ~\$450 for the verdex, goliath, and LCD > without understanding everything. Since the NiMH batteries and GSM antenna > apparently aren't included, nor sold by gumstix separately, where are we to > buy them? > > Thank you. > You can get some from Sparkfun for example (batteries + antenna), or other online distributor. Have a look through google and you may find what you want. I'll be using a blinking antenna for regular cellphones since I have a couple there and there. Julien ```
 Re: [Gumstix-users] 3.3v vs. 4v vs. 5v OH MY! From: Julien Lebot <30579108@st...> - 2007-07-30 11:08:26 ```I'm using a single cell Li-Po battery on my design, should I regulate the battery voltage to be in the range of 3.6-6V for the Vbatt input ? The nominal voltage of Li-Po batteries is 3.7V but it can go as low a 3.3V... Julien ```
 Re: [Gumstix-users] 3.3v vs. 4v vs. 5v OH MY! From: Dave Hylands - 2007-07-30 14:28:39 ```Hi Julien, On 7/30/07, Julien Lebot <30579108@...> wrote: > I'm using a single cell Li-Po battery on my design, should I regulate > the battery voltage to be in the range of 3.6-6V for the Vbatt input ? > The nominal voltage of Li-Po batteries is 3.7V but it can go as low a 3.3V... No need to regulate the 3.7v. However, you probably shouldn't use the battery when the voltage drops below 3.6v. I'm n ot sure how much lower you can go. Certainly not below 3.45v. I think most Li-Po's can go down to 3.0v. So in order to get maximum battery usage, you may want to use something like the AnyVolt from http://www.dimensionengineering.com You can set the output to 3.6v and you'll continue to get 3.6v volts out even as the voltage of your LiPo drops down to 3.0v. You should have a 3.0v cutoff circuit to protect the LiPo from dropping below 3.0v -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ ```
 Re: [Gumstix-users] 3.3v vs. 4v vs. 5v OH MY! From: Julien Lebot <30579108@st...> - 2007-07-30 18:52:10 ```Quoting Dave Hylands : > Hi Julien, > > On 7/30/07, Julien Lebot <30579108@...> wrote: >> I'm using a single cell Li-Po battery on my design, should I regulate >> the battery voltage to be in the range of 3.6-6V for the Vbatt input ? >> The nominal voltage of Li-Po batteries is 3.7V but it can go as low >> a 3.3V... > > No need to regulate the 3.7v. However, you probably shouldn't use the > battery when the voltage drops below 3.6v. I'm n ot sure how much > lower you can go. Certainly not below 3.45v. > > I think most Li-Po's can go down to 3.0v. > > So in order to get maximum battery usage, you may want to use > something like the AnyVolt from http://www.dimensionengineering.com > > You can set the output to 3.6v and you'll continue to get 3.6v volts > out even as the voltage of your LiPo drops down to 3.0v. You should > have a 3.0v cutoff circuit to protect the LiPo from dropping below > 3.0v > > -- > Dave Hylands > Vancouver, BC, Canada > http://www.DaveHylands.com/ Hi Dave, That's exactly what I was afraid of; I'd like to maximise battery usage. Thanks for the pointer, though I'd prefer something with a smaller form factor which I can solder on the PCB. Also I'd like more current flow, would it be possible to use 2 boost regulators in parallel ? Two 2.5" HDD could be connected on my +5V power rail, consuming 1A, so I need to manage that and the Gumstix + onboard peripherals. I estimated the power consumption to 2A max. (This is why I use LiPo batteries) Julien ```
 [Gumstix-users] USB hub low voltage From: <4837jw@la...> - 2007-07-30 19:45:27 ```Realizing that this post will probably raise a lot of "5V is 5V" responses, I just want to ask if anyone has any experience running a USB hub and attached devices at, say, 4.8V? Perhaps even lower... ```
 Re: [Gumstix-users] USB hub low voltage From: <4837jw@la...> - 2007-07-30 19:56:50 ```The USB 2.0 spec indicates a low power port low voltage of 4.4V. However, I'm interested to know if a USB hub (of specific make and model, if someone has experience) can operate at such a voltage...even given the implication that running one at 4.4V will result in port voltages below 4.4V. > Realizing that this post will probably raise a lot of "5V is 5V" > responses, I just want to ask if anyone has any experience running a USB > hub and attached devices at, say, 4.8V? Perhaps even lower... > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > gumstix-users mailing list > gumstix-users@... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > ```
 Re: [Gumstix-users] USB hub low voltage From: David Snowdon - 2007-07-30 20:00:43 ```Its definitely going to depend on the devices. I was doing some current measurement experiments at one point and needed a voltage drop across a resistor, which was fine for the devices we tried. Some (probably most, since they'll probably all run at 3.3V) devices will have regulators that can deal with the slightly lower voltage, but some might rely on the incoming 5V as a power rail directly. Dave. On 30/07/2007, at 12:45 PM, 4837jw@... wrote: > Realizing that this post will probably raise a lot of "5V is 5V" > responses, I just want to ask if anyone has any experience running > a USB > hub and attached devices at, say, 4.8V? Perhaps even lower... > > ---------------------------------------------------------------------- > --- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a > browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > gumstix-users mailing list > gumstix-users@... > https://lists.sourceforge.net/lists/listinfo/gumstix-users ```
 Re: [Gumstix-users] USB hub low voltage From: Marc Nicholas - 2007-07-30 20:03:38 ```I believe +/- 10% is within spec. -marc On 7/30/07, 4837jw@... <4837jw@...> wrote: > Realizing that this post will probably raise a lot of "5V is 5V" > responses, I just want to ask if anyone has any experience running a USB > hub and attached devices at, say, 4.8V? Perhaps even lower... > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > gumstix-users mailing list > gumstix-users@... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > ```