BQ27Z561EVM-011: Voltage dropped issue found on BQ27z561EVM-011.

Darshan Goswami

Part Number: BQ27Z561EVM-011
Other Parts Discussed in Thread: BQSTUDIO

Hi,

I am using BQ27Z561EVM-011, 1s6p battery cell, and 1.5A load.

1. I have triggered the learning cycle. At the stage of discharge, when I connect 1.5A load to BQ27z561EVM-011, my battery pack directly dropped 0.4V voltage.(3.37 V dropped to 2.98 V) So I can't able to complete the learning cycle. What is the reason behind that? I can negate +/- 25mV dropped but here more than 100 mv. When I have connected load directly to the battery it will dropped only 10mA. Is there any configuration needed in BQStudio?

2. Also, I have noticed that when I connect the battery pack to the BQ27z561EVM-011 kit and got 3638 mV voltage on BqStudio instead of 3370 mV (actual battery pack voltage). What is the reason behind that? I wasn't able to understand this behaviour.

Please help me. Onyx Ahiakwo Andy Liu (BMS)

over 3 years ago

0 Andy Liu (BMS) over 3 years ago

TI__Guru 52115 points

Can you share your gg file?

Andy

0 Darshan Goswami over 3 years ago in reply to Andy Liu (BMS)

Prodigy 190 points

Please find as an attachment.

2506.gg.csv

0 Andy Liu (BMS) over 3 years ago in reply to Darshan Goswami

TI__Guru 52115 points

See my comments below.

a) No. The gauge will not control the current. I would suggest you connect your load to BAT+ and PACK-.

b) Do you do the voltage and current calibration?

Andy

0 Darshan Goswami over 3 years ago in reply to Andy Liu (BMS)

Prodigy 190 points

Thanks for the quick reply.

A) Okay. I have connected load to BAT+ and PACK- terminal already. I have found an issue in connection wire resistance. I have resolved it.

B) Yes, I have done voltage and current calibration earlier. Should I need to calibrate for each stage of the learning cycle? Means at full charge (4.2 V) and full discharge (3.3 V) in my application.

0 Andy Liu (BMS) over 3 years ago in reply to Darshan Goswami

TI__Guru 52115 points

I don't think so. I would suggest you connect a 1k ohm resistor to BAT+ and PACK- and also connect a good bench power supply (e.g. 3.5V or 4V) to this resistor. In the bqStudio, check the voltage readings and you should be to see accurate readings if your voltage calibration is good.

Andy

0 Darshan Goswami over 3 years ago in reply to Andy Liu (BMS)

Prodigy 190 points

Thanks for the help. I have done voltage calibration and error was minimized.

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BQ27Z561EVM-011: Voltage dropped issue found on BQ27z561EVM-011.