Document with answers to most popular battery-related questions is ready

Paul Fertser fercerpav at
Sun Aug 2 20:02:42 CEST 2009

Wolfgang Spraul <wolfgang at> writes:
> this is an excellent document, obviously I cannot spot anything
> wrong!

Thanks for you kind words. :)

> I didn't know that some external chargers would not charge gta01 or gta02
> batteries because of the thermistor check you are writing about.

I'm not sure i saw any charger like that myself or seen reports
(except on our wiki). But i suspect the probability of that for nokia
brand charges is quite high.

> All the cheap external chargers we bought in Taiwan or China for testing can
> charge both gta01 or gta02 batteries without a problem.

Proves my point :D

> I have a question for all:
> We will ship our first NanoNote with a BL-4C compatible battery, without
> Coulomb counter (middle pin unused) [1].

Hm, can BL-5C fit there? Because it'd be much nicer as modern 5Cs have
quite some capacity.

> How are people really using the Coulomb counter in gta02?
> Theoretically I would think that it provides far superior power measurement
> options for actual software development, just as you write.
> For example when playing with power saving codes, whether in the kernel,
> middleware or applications, I would think over the course of several hours or
> days the Coulomb counter data is the primary means for efficient
> development.

To me it seems that CC readings are almost unused except for
presenting the user with a bit more accurate capacity data. And when
someone is developing something lowlevel he could as well connect and
external ampmeter, much more reliable and flexible approach.

> So we are considering shipping the next version of the NanoNote with Coulomb
> counter batteries same as the Neo FreeRunner.
> But if nobody is actually using the data from the Coulomb counter, then it's a
> wasted effort.

I'm not sure you'll get much for using CC.

The only problem so far with using a dumb battery on FR is that
there's no way to know the current from inside the device. On gta01
there's a resistor shunt supposed to be used to measure the current
but readings are too noisy to be useable. So if you have a good way to
measure current already i'd not go for CC.

Be free, use free ( software!
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