• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 309 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ40Z50-R1: BMS parameter change issues

Abdullah Zaman
Prodigy 70 points
Part Number: BQ40Z50-R1
Other Parts Discussed in Thread: BQSTUDIO
Hope you guys can help us quick here. We have a battery that has been developed and produced by chinese vendor and now we want to make a new firmware version to reduce failure rate. Our battery LiFePO4 4s2p 12.8V,7.8Ah and has bq40z50-R1 BMS for power and cell management plus a stm8 mcu for indicator led control.
Here are my questions:
1. ROM Mode: Some of the batteries while programming BMS give an error stating "Device not in ROM Mode. Switch to ROM mode manually". How can I switch to this mode ? or is it somehow locked  to prevent reprogramming? 
  
2. Overcurrent protection: We wanted to set the over current protection in discharge to be set to -28A to do this we have set the two flags "OCD1 = -28A and OCD2 = -30A with delay of 1 second" in BMS studio but this seems to have no effect on the overcurrent and the battery still trips at -25A. Are there any other parameters that need to be changed or did I misunderstand what the above mentioned parameters are for? Is there any specific procedure I should follow maybe changes are needed in gas gauging or charge algorithms as well?
3. Sealed Mode:  While trying to reprogram the battery says to unseal first. I tried using the unseal full access but it asks for a key. IS there a way to bypass this?
4. CHG/DCHG FET Disabled: We have seen that some batteries are completely drained and do not output anything. The chg and dchg fets are disabled and we cannot communicate with the BMS using the BMS management studio.This observation is done on the basis that we cannot chg using a charger or discharge the battery. Is there a way we can communicate to BMS in this state?
5. Capacity Degraded:  We have quite some batteries that have FCC low that is  set to 800mA which results in disabling the CHG FET and render the battery useless. Could this trigger capacity degraded flag and thus disable the CHG FET?  The capacity degraded flag is set to 0 mAh. 
  • 0
    TI__Mastermind 24870 points

    Hello Abdullah,

    1. To get out of ROM mode, you will have to send the execute FW command. Are you able to first hook these up to bqStudio via the SMBus lines?

    2. These are HW protections, you will have to modify the Rsns value to make sure you are at the right thresholds.

    3. You cannot program with the gauge in SEAL mode. You need the unseal keys, which you should have.

    4. You will need to check if the device can ack it's own address here.

    5. You will have to let us know more information here. Is this at low temperature or room temperature and do you have a bqStudio log file you can provide to show this behavior?