Lipo Charging and Power Left Measurement
When charging a Lipo on the expansion board I'd like to see how many percent the Lipo is charged and during normal usage I'd like to see how many percent of power is left, just like with a mobile phone. How can I achieve this?
My suggestion? Don't bother with ADC measurement. Get a "gas gauge" breakout, like the one from SparkFun: https://www.sparkfun.com/products/10617
I've created a thread with feature suggestions for the various expansion boards. One thing I'd like to see is the gas gauge IC integrated to all boards; preferably the MAX17048 (which is a newer, more power-efficient version of the IC on the previously-mentioned breakout). Forum thread here: https://forum.pycom.io/topic/2476/expansion-board-suggestions
The charging chip (BQ24040) doesn't provide this information, you'd need one with a so called "fuel gauge" or a coulomb counter.
The best you can do with the expansion board is track the battery voltage via G3 (which comes from a voltage divider) - see this topic https://forum.pycom.io/topic/226/lopy-adcs/12 - but for LiPo batteries this will be a VERY rough approximation.