BQ40Z60: How to set taper current, so can improve the cell imbalance?

Harry Zhang13

Intellectual 495 points

Part Number: BQ40Z60

we met one cell imbalance issue when charge terminate.

Cell 0 voltage: 3.34

Cell 1 voltage: 3.37 V

Cell 2 voltage: 3.84 V

State of charge: 94.00 %

SOC can't reach 100% in this case.

After check our config, our taper current is 800mA, but default value is 150mA. How to define this taper current? smaller taper current or bigger taper current could be better for cell balance?

over 5 years ago

0 Harry Zhang13 over 5 years ago

Intellectual 495 points

And what will BQ do if it finds one cell is OV while SOC not reach 100% due to cell imbalance? thanks.

0 Harry Zhang13 over 5 years ago

Intellectual 495 points

and our Min Rsoc for Balancing is 96%, do we need to reduce it?

0 Harry Zhang13 over 5 years ago

Intellectual 495 points

attach more setting

Cell Balancing Config	Bal Time/mAh Cell 1	9	s/mAh
Cell Balancing Config	Bal Time/mAh Cell 2-4	12	s/mAh
Cell Balancing Config	Min Start Balance Delta	10	mV
Cell Balancing Config	Relax Balance Interval	18000	s
Cell Balancing Config	Min Rsoc for Balancing	96	%

0 Wyatt Keller over 5 years ago in reply to Harry Zhang13

TI__Guru** 105760 points

Hello Harry,

Can you provide the log file of this?

A taper current of 800mA is very high, it would be best to lower this so your batteries can charge closer to 100%.

The cell balancing wont be anabled until you have a Qmax update, this could lead to your cells difference in voltage.

Sincerely,

Wyatt Keller

Power management

Power management forum

BQ40Z60: How to set taper current, so can improve the cell imbalance?