Backup battery discharged -> GTA01 and GTA02 dead

Ben Wilson ben at
Sun Jul 20 09:10:03 CEST 2008

Interesting   :)

Werner Almesberger wrote:
> Ben Wilson wrote:
>> but some battery packs have electronics inside and you can?t just charge  
>> them like you would a normal battery.
> Ours have two types of internal electronics: a protection circuit that
> can deny access to the battery, and a Coulomb counter that keeps track
> of the battery status, but does not interfere with its use.
> GTA01 batteries only have the protection circuit, GTA02 batteries have
> both types of circuit.
> The protection circuit cuts the battery off if it is discharged to too
> low a voltage. When sufficient energy is applied at the battery
> terminals, the protection circuit opens the access to the battery
> again, and allows it to charge.
> At this level, whatever the Coulomb counter thinks the battery is
> doing is of no relevance. The Coulomb counter only comes into play
> when we want to know the exact charge status and similar parameters,
> but no such knowledge is needed for the charger logic of the PMU to
> charge a battery.
> - Werner

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