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Original question:

BQ28Z610-R1: BQ28Z610-R1, low temperature operation inquiry

BQ28Z610-R1: BQ28Z610-R1, low temperature operation inquiry

SEONGMIN KANG
Prodigy 80 points
Part Number: BQ28Z610-R1

Tool/software:

We sloved 'SOC jump down issue at -20°C' by changing register.

Previously we proceeded getting chemistry ID, Cycle learning, Resistance Temperature Compensation Optimizer in order.

But SOC jump down issue was not solved. So we applied hysterisis method by changing register like below

<Register Action>

Action No.

Address

NAME

Below -5°C

0°C or more

1

0x45BE

Term Voltage

3400mV -> 2800mV

2800mV -> 3400mV

2

0x45C3

Term Min Cell V

3000mV -> 3100mV

3100mV -> 3000mV

3

0x464D

IT Gauging Configuration

16ce

14ce

Our system cut-off voltage is 3400mV but our cell is dropped to 3300mV when loading 700mA at -20°C. So SOC was dropped to 0% and powered off as soon as loading current in 1minute.

But when I set Term Voltage enabled, set this to 2800mV, SOC dropped issue was disappeard and possible to load 700mA continuously about 3 hours.

However I wonder whether it is the right workaround that I applied

If you need logs or settings, ask me anything

Thanks

  • 0
    TI__Mastermind 19931 points

    Hello Seongmin,

    One question is does the datasheet of the battery support discharging all the way down to 2800mV? Thus my question is, what is the terminate voltage of the battery based from the data sheet?

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    Prodigy 80 points

    Our cell's cut-off voltage is 3000mV. first time I set term voltage to 3100mV, but It doesn't work much(Just 3 hours only was continued when playing a video) and powerd off at 3343mV. At this point, we guessed It has margin about 200mV between term voltage setting voltage and system power off voltage. So we set term voltage to 2800mV considering the margin and it does work well(more than 8 hours was continued when playing a video)

  • 0 in reply to SEONGMIN KANG
    TI__Mastermind 19931 points

    Hello Seongmin,

    If that's the case, then I think the settings you have is a valid work around.

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    Prodigy 80 points

    Do you think there are no risks? I would like to review the risk points.

  • 0 in reply to SEONGMIN KANG
    TI__Mastermind 19931 points

    Hello Seongmin, 

    Only risk is you are slightly discharging further than the battery datasheet specifies, however, this is not too much lower than the specified terminate voltage in the data sheet. The only risk I can see is that the battery will degrade a little more over time compared to a normal use case.

    Regards,

    Nick Richards