BQ27220: SoH Update

when does Qmax and Ra tables update? 

Also where is the cycle count data saved in FG? Are there any events that could reset the count to? How is battery health calculated by FG?

 So Cycle count is lost, since after every power event, ROM gets wiped out. Is there a way, to preserve that cycle count, maybe not save it in ROM?

Also, from the explanation, even if we lose cycle count, SOH information is never lost and SOH values we collect are still reliable, right?

I just have one more question, since the gauge is ROM which is read only non-volatile memory, how is cycle count getting saved to read only memory, and how is that information getting wiped out from a non-volatile memory after a power reset? Did you mean, cycle count information is saved into flash memory?

Also, is ROM same as OTP (one time programmable) memory present in the gauge?

Yes. I meant to say that the updated cycle count value is saved in flash memory. Regarding the question about ROM and OTP I will get back to you next week with an answer.

Regards,

Nick Richards

Can you clarify one more thing, to get information out of OTP of the gauge, does FW need to just unseal the battery or bring it in full access mode?

does BQ27220 require the factory to do any golden image learning cycle?