Nokia BL-5C (was: Re: Broken battery protection circuit) problems?)

Tobias Diedrich ranma+openmoko at
Mon Jul 7 19:13:41 CEST 2008

Tobias Diedrich wrote:
> Looking at the battery circuit schematics I now think that the
> battery protection circuit on this battery is probably broken.
> Discharging is still possible (now at 2.8V at the terminals), but it
> does not accept any charge (I tried current-limited 4.2V/200mA at the
> battery terminals and there is (almost, a few uA) no current flow).

Since I read about the Nokia BL-5C/BL-6C batteries having the same
formfactor and being basically compatible (but without a coulomb
counter), I tried two mobile phone shops today and the second one
had one, which I bought (for 15 EUR).

With this battery I could now switch the Freerunner on again.
Apparently it is also being charged by the pcf50633 power
management controller:
After switching it on, the battery volate according to
was 3.867V, chgmode is 'fast' (usb powered, 500mA).
Now battvolt is 3.972V (still charging).

Looking at dump_regs and the pcf50633 manual, use of the temperature
sensor is disabled, battery float voltage is 4.2V.
MBCC1 says "charger enabled, automatic charge termination, automatic
charge resume, max 60min. precharge, max. 6 hours charge"

Also, as expected without the coulomb counter,
/sys/devices/platform/bq27000-battery.0/power_supply/bat/status says
"cat: read error: Timer expired".


Tobias						PGP:

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