BQ40Z50-R1: RSoC Stuck at 0 after charge but then jumps to 100

Brian Heston

Part Number: BQ40Z50-R1
Other Parts Discussed in Thread: BQSTUDIO

We have one battery pack that is showing RSoC being 0 after charging and sitting for 24 hours. When checking the BattStat, we get 0x03C0. This seems to indicate the charging chip gauge is still in initialization. If we briefly connect to a power supply, the BattStat changes to 0x0080. That seems to indicate the gauge initialization is complete. We noticed that battery current is -8 but jumps to 580 when the the BattStat changes to 0x0080. As soon as BattStat changes to 0x0080, the RSoC jumps to 100 (we expect it to be at 100 the entire time). We believe it charged so it's unclear why we are seeing RSoC at 0. We have 3 other packs and they are not having this issue. Is there an error happening? Am I missing something?

over 5 years ago

0 Onyx Ahiakwo over 5 years ago

TI__Guru* 76230 points

Hi Brian

Your description is not sufficient enough to have a hypothesis as to what is going on. To be able to debug, you need to attach log and gg files. A snap shot of the register screen of bqstudio would be helpful in addition. Did that pack experience a drastic temperature change? Was the battery discharge at cold temperature? It might be a case of negative rem cap where the gauging is thinking the battery is overdischarged. severely.

thanks
Onyx

0 Brian Heston over 5 years ago

Prodigy 70 points

Hello - thank you for the help. Attached is the bqstudio image of the battery pack at 0 RSoC and then minutes later as it jumps to 100 RSoC. Hope this provides some clues!

0 Onyx Ahiakwo over 5 years ago in reply to Brian Heston

TI__Guru* 76230 points

The first screen shot is showing an unreasonable firmware version on the device. It appears your device might be loosing communication or there your i2c signals are having false readings. Is this test being done on an EVM? can you capture a scope shot of the comm signals?
I had requested log and gg files as well. Pls address all questions here

thanks
Onyx

0 Brian Heston over 4 years ago in reply to Onyx Ahiakwo

Prodigy 70 points

Here is the GG file information:

GG_Data_22April2019.pdf

0 Onyx Ahiakwo over 4 years ago in reply to Brian Heston

TI__Guru* 76230 points

Brian
pls you need to follow instructions for me to be able to help you.
thanks
Onyx

0 Brian Heston over 4 years ago in reply to Onyx Ahiakwo

Prodigy 70 points

Hi Onyx - this is not being done on an evaluation module. This is a production circuit board. See attached for the clock and data of one of our good battery packs and the suspect battery pack.

Battery_Clock_Data_24April2019.pdf

0 Onyx Ahiakwo over 4 years ago in reply to Brian Heston

TI__Guru* 76230 points

Hi Brian
Can you try reprogramming the device with the golden srec to see if it resolves the issue? Disconnect the battery pack, reattach, apply a charge current to wake the device and then try reprogramming .

Thanks
Onyx

0 Brian Heston over 4 years ago in reply to Onyx Ahiakwo

Prodigy 70 points

We discovered the programming pins on the BMS had been exposed to moisture and shorted. The internal pack was showing some dampness.
This seems to be the root cause for this specific issue.

0 Onyx Ahiakwo over 4 years ago in reply to Brian Heston

TI__Guru* 76230 points

thanks for letting us know.
regards
Onyx

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BQ40Z50-R1: RSoC Stuck at 0 after charge but then jumps to 100