Battery ID chip - help needed

Christian Gagneraud cgagneraud at
Wed Jun 10 23:55:22 CEST 2009

Laszlo KREKACS wrote:
> On Wed, Jun 10, 2009 at 11:04 PM, Christian
> Gagneraud<cgagneraud at> wrote:
>> According to the schematics of the FR, the ID line of the battery is
>> not connected to anything (R1769 is marked NC). I checked my FR rev A6
>> (from your shop Christoph!;)), and this resistor is not populated.
>> So it means the ID line of the battery is definitely not used.
>> Now I'm not saying it is safe to use whatever battery, i'm just saying
>> that the power management chip (the PCF 50633) is not able to read any
>> information out of the battery you fit in your FR (like battery ID,
>> serial number, etc...).
> I dont think it is true. Openmoko's battery is "special", it includes a coulumb
> counter. And the battery indicator relies on it.
> So inserting a nokia BL-5C battery is not complete solution. (because it lacks
> the coulomb counter), and freerunner cant charge it (currently) and cant
> display the remaining capacity.
> The best person to ask are jOERG or Werner. They usually hangs on
> #openmoko-cdevel and are very helpful people.
>> The FR is designed/programmed to charge at 500mA max. It should be
> It is not true either.
> 1. Freerunner identifies the charger with a "magic" 47kOhm resistance
> between D+ and D- line.
> If the resistance is present it charges with 1000mA.
> 2. If the usb enumeration was successful it charges with 500mA (so
> connecting to a computer charges with 500mA).
> 3. If none of the above happens, it defaults to 100mA.

Hi Laszlo,

You right, i was not sure if it was 500mA or 1A max. that's why i did 
enclose my comments in between "not-really-sure" tags.

Anyway, 1A being the best-case charging current, it will still take 
longer to charge a 2100mAh battery than a 1200mAh. (roughly 2 times 
longer i guess)


> Laszlo
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