Other Parts Discussed in Thread: GPCCHEM
I'm using BQ27441-G1 in my medical system to monitor a 300mAh Li Poly battery with voltage range 3.4V - 4.2V. My system active operation current is 150 ~ 240mA (10 - 200 seconds), idle operation current is 15mA (60 ~ 300 seconds) while sleep mode current is 60uA (most time).
I didn't do the learning cycle and Chemical ID so far, but I conducted several round of full charge and discharging to empty on the same BQ and battery pair. Those are the facts I found: 1) Just at the time of full charged from empty battery , the FullChargeCapacity can go ~300mAh sometimes, but not always. 2) During the normal use or stress test by big load 200mA for >200 seconds, FullChargeCapacity is changing very much, from ~300mAh to 216 mAh or 195mA. The more interesting thing is RemainingCapacity is even higher than FullChargeCapacity by 40mAh！？ After a while in idle or sleep mode, the FullChargeCapacity is kind of stable but sometimes could go back to higher between 260 ~ 300mAh again. The temperature for above test is 28 ~ 37C, not a big variation.
Thus my questions are:
1) Is FullChargeCapacity accurately reflecting the real battery capacity? Should I believe that changing FullChargeCapacity? How about the accuracy and confidence level of RemainingCapacity ?
2) Is the heavy load the main factor that change the FullChargeCapacity？If true, how to deal with it if my system working mode is like this?
3) I didn't need a very accurate battery measurement. 5% error or more is acceptable, but can't accept the big change of FullChargeCapacity then SoC as SoC make people confusing about if battery level could support the next medical use. Must I have to do the learning cycle and chemical ID? Is there any other simpler way to solve it?
Highly appreciate your suggestions.
