Electrical – How to implement coulomb counter method for battery capacity using any micro-controller?


I trying to implement coulomb counter method in any micro-controller.
suggest me, any circuit ?
Or Any give idea how to implement?

Best Answer

To implement energy counter for a battery, you need to measure its voltage (easy part) and the instantaneous flowing current. That's where a little problem is. You need to take DIFFERENTIAL measurements across a shunt resistor which should be kept small, and thus the differential voltage will be small too.

Without amplification of the shunt voltage you will need to have two channels of a very high-resolution ADC (say, 16+ bits) to get reasonable accuracy in current measurements. High-resolution ADC are not a part of "any microcontroller", so an upscale MCU will cost you.

Alternatively you can use a simple $1 dedicated (bi-polar) shunt converter into plain voltage, something like INA199, and use an ordinary ADC channel to take current measurements.

Better you can use a dedicated autonomous IC that does all measurements for you and reports results over I2C bus, something like INA219 IC, which can take voltage and current measurements simultaneously, and even multiply them for you.