app_battery: MAX17205 isn't calculating the pack capacity correctly

[andrewgreenberg]

On each OreSat battery card, we have two 2S1P battery packs. Each pack has it's own MAX17205 battery IC which measures voltage, current, and calculates the capacity of the pack it's on.

Voltage, current, and temperature are working just fine.

But for some reason, the capacity measurements (in amp-hours (Ah)) are just terribly off. It's mostly just stuck at either 50% or some very low number. The MAX17205 has two ways of calculating the capacity: by measuring current in and out of the battery, and by measuring the open cell voltage on the cells when it can. Neither method seems to be working correctly.

Some possible ideas:

• We power cycle the MAX17205 ICs once a day. This IC was never designed to be power cycled, since it's attached to the battery pack directly. So this might be reseting everything, or there's some kind of issue here?
• We might not be setting up the ICs with the correct values and/or enabling the capacity algorithms in the right way.