BQ34Z100-G1: SOC jump from 10% to 0%

user4880411

Part Number: BQ34Z100-G1

Hi TI experts,

My pack is 10S4P(36V/13Ah) which is using BQ34Z100-G1 gas gauge. Recently I met a problem that has been bothering me for a long time. I need your team's help. Below is the problem details.

The pack discharging to 10% SOC with 14.2A,stop discharging, then rest about 30 seconds. SOC will jump from 10% to 0% although I disable the RELAX_JUMP_OK. the jump only occurs when the SOC ≤10%. sometimes occur jump, not always.

Does TI have any suggestions for RELAX_JUMP_OK? Should we disable it?

attach the gg file and logging datas.SOC jump from 10 to 0.zip

Best regards

James

over 5 years ago

0 Andy Liu (BMS) over 5 years ago

TI__Guru 52115 points

Hi James,

Let me first take a look at your files. I might ask for more details if necessary.

Andy

0 user4880411 over 5 years ago in reply to Andy Liu (BMS)

Prodigy 50 points

Hi Andy,

Thank you, If you have any questions, please let me know.

Best regards

James

0 Andy Liu (BMS) over 5 years ago in reply to user4880411

TI__Guru 52115 points

Hi James,

I took a quick look. The direct reason is that the remaining capacity was updated. I guess a simulation occurred after the batteries rested for 30s and it changed the remaining capacity to 0, which eventually led to the 0% RSOC.

I am trying to figure out why the simulation was triggered.

Andy

0 Andy Liu (BMS) over 5 years ago in reply to Andy Liu (BMS)

TI__Guru 52115 points

Hi James,

It seems like the temperate change from the last situation triggers a run of the simulation. I'm trying to confirm that now.

0 user4880411 over 5 years ago in reply to Andy Liu (BMS)

Prodigy 50 points

Hi Andy,

Thank you for showing the SOC curve, I am looking forward to find the SOC jump root cause. thank you for your hard work.

Best regards

James

0 Kang Kang over 5 years ago in reply to user4880411

TI__Mastermind 24870 points

Hello James,

Can you attach an srec file as well. We would like to run some simulations.

0 user4880411 over 5 years ago in reply to Kang Kang

Prodigy 50 points

Hi Kang,

Thank you for your support, Attach the srec file, please review it. I need to clarify the srec which the RELAX_JUMP_OK=1. I found the RELAX_JUMP_OK default is enable. I though it is the reason lead to jump. so , I disable the RELAX_JUMP_OK. and I can sure I reset the chip after disable the RELAX_JUMP_OK.

Best regards

bq34z100G1-SDI35E-V1.1-191104-GOLDEN.zip

0 Andy Liu (BMS) over 5 years ago in reply to user4880411

TI__Guru 52115 points

I will try to set up a simulation and see if we are able to duplicate this. Will let you know if I need more details from you.

Andy

0 Kang Kang over 5 years ago in reply to Andy Liu (BMS)

TI__Mastermind 24870 points

Hello User,

This jump looks normal. It is the avg I last run updated and we ran a simulation with the latest current prediction. You could try changing the load mode and select to 0/6 with a less aggressive current prediction such as C/5 to see if the jump goes away.

Does this always occur or only sometimes? If it is only sometimes, it is most likely due to temperature.

0 user4880411 over 5 years ago in reply to Kang Kang

Prodigy 50 points

Hi Kang,

Sorry for delaying reply, it not always occur when disable the RELAX_JUMP_OK. i have a question about the register. what the advantage when enable it ( RELAX_JUMP_OK=1)? OR, is there any disadvantage when disable it (RELAX_JUMP_OK=0)? it seems we should disable it.

Best regards

James

0 Kang Kang over 5 years ago in reply to user4880411

TI__Mastermind 24870 points

Hello James,

It depends on what you want to display to the end user.

1. RELAX_JUMP_OK just allows the SOC to jump. This will help adjust the capacity based on temperature on top of smoothing algorithm.

2. If you set this to 0, you may not see jumps in relaxation due to temperature change, but the soc accuracy may not be correct.

0 Kang Kang over 5 years ago in reply to Kang Kang

TI__Mastermind 24870 points

Hello James,

In other words, if you really do not like SOC adjustments in relaxation mode due to temperature, you can disable the RELAX_JUMP_OK bit. However, here is a situation.

You reach 0% at low temperature conditions, enter relaxation, then the battery goes to room temperature. There is actual capacity, but we will remain at 0%.

Power management

Power management forum

BQ34Z100-G1: SOC jump from 10% to 0%