Other Parts Discussed in Thread: BQ24172,
Low Batteries shutting down the system even with AC installed. With AC power plugged in, it is not recharging to a normal state. System is a 2S1P, 3150mAh, 7.6V nominal, 3V/Cell.
We've discovered batteries that are getting shipped that are at ~5.7V pack voltage (rather than the 7.6v), which may be a battery manufacturer problem, however these packs do not seem to charge back to normal.
Also uses a BQ24172 battery charger, set to precharge the pack to a defined low voltage. When plugged into the unit, the gas gauge appears to disconnect the cells from the pack inputs as no voltage can be read on our isolated battery power rail. This happens with the AC power plugged in and unplugged.
Looking at the BQ28Z610 registers, I see that XCHG and XDSG is active. XDSG makes sense as the cells are critically undervoltaged as confirmed by the FD register being flagged. However I’m not 100% sure why XCHG is flagged. The only flagged register I can see is CTO, which would flag XCHG, but CTO is supposed to clear when battery capacity drops 5mAh. I’ve seen the battery capacity drop below this while unplugged entirely and the register remains flagged. Unfortunately despite unsealing with full access there’s something wrong with the data memory and I can’t write to the device, otherwise I would set the CTO recovery capacity to 0 and see if that clears it.
