BQ40Z50: FCC error

Sung Patrick70

Prodigy 40 points

Part Number: BQ40Z50

Hello TI members

Currently our device which utilize BQ40z50(FW version R3) has an FCC error greater than 2% criteria.

Our pack supplier is working on Rb tweak to fix the issue.

My question is, will the slight FCC error (2~3%) impact the Available Battery Life calculation?

ABL is define as the time it takes for system to consume battery capacity from 100% to 5% RSOC, considering RSOC accuracy test passed.

Thank you for the support

Best Regard, Patrick

over 5 years ago

0 Wyatt Keller over 5 years ago

TI__Guru** 105760 points

Hello Patrick,

Could you clarify how you calculate the FCC error? FCC is dynamic and will update over time to track the battery better. FCC is used in the SOC and other battery calculations, if it has an error it will impact other values. SOC = RemCap/FCC.

If you want to see more in depth of the IT algorithm to see what parameters are connected you can review this app note: https://www.ti.com/lit/an/slua450/slua450.pdf

Sincerely,

Wyatt Keller

0 Sung Patrick70 over 5 years ago in reply to Wyatt Keller

Prodigy 40 points

Hello Wyatt,

The pack vendor follow the instruction provided by TI.

Do you mean FCC accuracy will improve as more charge/discharge cycles were completed? TI_GGAccuracy.pdf

0 Wyatt Keller over 5 years ago in reply to Sung Patrick70

TI__Guru** 105760 points

Hello Patrick,

The gauge will learn the pack during the learning cycle, after the learning cycle the gauge should have all the parameters it needs to accurately gauge. Over time the gauge will periodically update the Qmax and Ra tables to keep the gauging accuracy high.

Sincerely,

Wyatt Keller

Power management

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BQ40Z50: FCC error