Substitute batteries

Joel Newkirk freerunner at
Thu Aug 21 07:58:58 CEST 2008

On Wed, 20 Aug 2008 22:49:05 -0700, Michael Shiloh <michael at>
> Joel Newkirk wrote:
>> My guess is that it incorporates some constants that depend on the
> actual
>> battery pack.  Note that I don't actually KNOW that it's in the battery,
>> but previous ML posts by folks at Openmoko refer to it as 'in the
> battery',
>> and with a bl-5c installed almost all battery-related entries in sysfs
> are
>> unpopulated.
> This is to confirm that the coulomb counter is in the battery pack. Why?
> Because it stores the count, and if you swap batteries, you need to know
> the count for the battery in the device, not for the one you removed.

Makes perfect sense. Is it a custom IC, something off-the-shelf, or what? 
Could it be cheaply retrofitted by a hobbyist into a BL-5c clone battery? 
I'm quite happy to crack one open, just not my Openmoko battery... ;)  

Barring the workability of that idea, I'm hoping we can adapt the battery
management/monitoring software to fallback to the 'dumb cellphone' approach
and let us safely charge, and have some idea of remaining capacity of,
non-Openmoko batteries if it detects a battery present without the coulomb
counter circuit.

>> j
>> On Thu, 21 Aug 2008 00:13:00 -0400, "Charles Pax"
> <charles.pax at>
>> wrote:
>>> On Wed, Aug 20, 2008 at 11:29 PM, <freerunner at> wrote:
>>>> OK, I have a few Nokia batteries laying around, BL-5c and BL-6c, and
>>>> desktop chargers.  They power the Freerunner fine, and seem to charge
>>> when
>>>> they're in the FR plugged in.  But the Freerunner doesn't know what to
>>> do
>>>> with them apart from that, presumably since they lack the Openmoko
>>> coulomb
>>>> counter circuit.
>>> The coulomb counter circuitry is in the battery? Why isn't this on the
>>> board
>>> itself?
>>> -Charles
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