Substitute batteries

robin paulson robin.paulson at
Sun Aug 24 01:40:49 CEST 2008

Harald Welte wrote:
> On Thu, Aug 21, 2008 at 12:13:00AM -0400, Charles Pax 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?
> because the charging state is a property that is inherent to the battery, not your device.
> imagine you remove a 50% charged battery and insert a 90% charged battery.  if
> the coulomb counter was on the mainboard, it would still think 50% after you
> put in the 90% battery.

do batteries have serial numbers? is this something readable via the 
data terminals (i'm assuming they have a data terminal, most certainly 
have more than +ve and -ve connectors)?

new serial number -> battery meter in phone starts new calculations as 
to charge state of battery. it wouldn't take too many charge/discharge 
cycles to work out the characteristics of the battery. in fact, do we 
even need the serial number-reading part? as soon as the phone charging 
circuit detects any different characteristics, it could start the 
calculations afresh

More information about the community mailing list