## Re: [Gumstix-users] Monitoring battery voltage from lipo's

 Re: [Gumstix-users] Monitoring battery voltage from lipo's From: J. L. - 2010-08-19 23:30:06 ```I have a few arduinos already that I am using. Just was not aware of how to properly go about reading the actual voltage of my battery and not the incoming stepped down power I use to power it. I was kind of hoping the balance connectors would just be at the voltage of each pack and I could some how easily tap off that. Your last two posts have given me enough to google more and see what I can come up with. Thanks a million for a huge jump start I really appreciate it and will post back with what I come up with and see if I am headed the right way. On Thu, Aug 19, 2010 at 4:13 PM, Alex Gibson wrote: >  Easiest would be something like an arduino and talk to overo via rs232. > > Arduino (simplified c/java cross for avr's) is very easy to use > > sparkfun sells a lot > http://www.sparkfun.com/commerce/categories.php?c=103 > > See their tutorials and  the arduino tutorials > http://www.sparkfun.com/commerce/tutorials.php > http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=195 > http://www.arduino.cc/en/Tutorial/HomePage > > > You could just use one of the onboard adc's  via a resistor netowrk > to drop the maxium battery output voltage to a level suitable for the > adc to read. > > If the batteries max voltage is 25V > > The adc's max input voltage is 2.5V > > Then you need a resistor network that divides the  voltage by 10. > http://en.wikipedia.org/wiki/Voltage_divider > > > If my heads working correctly this morning > if you pick > R1 = 1k > > R2 = R1 / ((Vin/Vout) - 1) > > R2 should be approx 112ohms to give a max output of 2.5V > > Try this > http://www.raltron.com/cust/tools/voltage_divider.asp > > On 20/08/2010 8:32 AM, Alex Gibson wrote: >>    On 20/08/2010 5:58 AM, vwyodapink wrote: >>> ero running from my lipos. What I would like to know >>> how to do or if its even possible. Would I be able to use a pin on summit to >>> monitor the battery voltage coming from my lipos balancing plug? So that way >>> I could monitor the voltage on each cell from the pack. Also if this is >>> possible, can I monitor multiple lipo's in the same manner from their >>> balance port? I tried doing some searching but not even sure what or where >>> to look for this one. The voltages of my batteries are below. >> >> I2C or spi adcs ? >> >> or use the onbard adc's via resistor network >> >> May make more sense to use a small micro (avr , pic or arm7/arm cortex >> M) to do the monitoring >> then send the data via rs232 or spi/i2c or via can(can to usb - usb on >> overo end) >> >> Alex >> >> -- >> UTS CRICOS Provider Code:  00099F >> DISCLAIMER: This email message and any accompanying attachments may contain >> confidential information.  If you are not the intended recipient, do not >> read, use, disseminate, distribute or copy this message or attachments.  If >> you have received this message in error, please notify the sender >> immediately and delete this message. Any views expressed in this message >> are those of the individual sender, except where the sender expressly, and >> with authority, states them to be the views the University of Technology, >> Sydney. Before opening any attachments, please check them for viruses and >> defects. >> >> ------------------------------------------------------------------------------ >> This SF.net email is sponsored by >> >> Make an app they can't live without >> Enter the BlackBerry Developer Challenge >> http://p.sf.net/sfu/RIM-dev2dev >> _______________________________________________ >> gumstix-users mailing list >> gumstix-users@... >> https://lists.sourceforge.net/lists/listinfo/gumstix-users > > > -- > UTS CRICOS Provider Code:  00099F > DISCLAIMER: This email message and any accompanying attachments may contain > confidential information.  If you are not the intended recipient, do not > read, use, disseminate, distribute or copy this message or attachments.  If > you have received this message in error, please notify the sender > immediately and delete this message. Any views expressed in this message > are those of the individual sender, except where the sender expressly, and > with authority, states them to be the views the University of Technology, > Sydney. Before opening any attachments, please check them for viruses and > defects. > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by > > Make an app they can't live without > Enter the BlackBerry Developer Challenge > http://p.sf.net/sfu/RIM-dev2dev > _______________________________________________ > gumstix-users mailing list > gumstix-users@... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > ```