Failed battery hack- analysis?

Werner Almesberger werner at
Mon Oct 10 23:22:20 EDT 2011

cenobyte at wrote:
> My guess was
> that I used a bad wire set? or that I should not have had both
> colors of wire connected.

Hence my suggestion to measure ;-) There's nothing inherently
wrong with trying to use a different battery, so you should be
able to find out why it didn't work.

In theory, a battery could refuse to deliver more than some
minimum current before receiving an "unlock" sequence from the
host, but I haven't heard of this sort of contraption in
mobile phone batteries.

Some batteries do have a cut-off state when the charge is too
low, though. E.g., the battery of the Openmoko GTA02 had such
a circuit. This is to protect the battery from "deep"
discharges. In the cut-off state no significant current is
allowed out of the battery, but it can still be charged. In
the case of the GTA02 battery, a few seconds of charging make
the protection circuit exit the cut-off state.

- Werner

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