Question about charging

Helge Hafting helge.hafting at
Wed Jan 28 18:02:27 CET 2009

Werner Almesberger wrote:

> The PMU may be able to keep up with this, but I'm not sure the
> battery will like it. If you google for "short charge cycles", you
> find claims that this kills Li-Ion batteries.
> In particular, if you look at page 84 of
> you see that dropping below the USB detection threshold (~4V) will
> reset the charger state machine and thus defeat the mechanism that
> avoids trickle-charging the battery when it's full.
> Harald posted a while ago that such trickle-charging changes the
> battery's chemistry and damages it.

I see. A homemade charger should stay between 4V and 5V then. Cutting 
below 4V shouldn't be hard to do.

Helge Hafting

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