next topic »

[on:]

I was wondering if anyone has any interest in shields, chargers or just standalone fuel gauges for Li-poly/Li-Ion batteries.  I came across a chip that uses minimal components and no external sense resistors and gives a very accurate state of charge for single cell batteries.  I prototyped it and tested it and it appears to be very accurate.  

I see a lot of people use Lipo batteries for projects and rely solely on the Arduino ADC to monitor battery life (which isn't very accurate).  

Again if anyone thinks there may be an interest let me know.  I also forgot to mention it uses I2C for communication and has a programmable setting to generate an external interrupt when the SOC falls below a certain level.

[Reply #1 on:]

I'm sure a lot of us would be interested. So, what chip is it?  

[Reply #2 on:]

Oops forgot to add the link to the datasheet. It's a MAX17043
http://www.maxim-ic.com/datasheet/index.mvp/id/6546

[Reply #3 on:]

Looks good but I'm afraid its above my soldering skill level.

[Reply #4 on:]

Finally finished the first revision on the fuel gauge pcb.  If anyone is interested please have a look http://www.dsscircuits.com/li-poly/max17043.html

[Reply #5 on:]

I see a lot of people use Lipo batteries for projects and rely solely on the Arduino ADC to monitor battery life (which isn't very accurate).  

You might want to check out the below thread. Coding Badly helped me to come up with a method where one can accurately measure the voltage powering the Vcc pins on the processor chip. It utilizes the internal bandgap reference and does not require any external wiring or voltage dividers. Should be good for measuring the state of charge based on a li-po 4.2 to 3 volt discharge ramp.

 By using this correct Vcc voltage value one can remap the A/D conversion such that A/D will maintain constant calibration even with a slowly falling battery voltage.

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1294478456

While not as sophisticated as the method used with that I2C chip, it is simple and cost effective in just determining when the li-po voltage is getting too low and take action like auto shut off, alarm, etc.

Lefty

[Reply #6 on:]

That's an interesting little set up, I'll have to play around with that tonight.