Battery discharging while plugged in

Angus Ainslie angus.ainslie at
Fri Sep 5 18:04:20 CEST 2008

On Fri, Sep 5, 2008 at 9:37 AM, Mike Montour <mail at> wrote:

> That might be normal - the charger in the PCF50633 shuts off the charge
> current once the battery is full, and turns it on again when the voltage
> falls below a threshold. It seems that it can discharge quite a bit
> before charging switches back on - in one test my battery got down to
> around 75% before it started to charge again.

It doesn't completely turn off charging. It drops to a 100mA trickle charge
which is insufficient to keep the battery topped up with the GSM radio
turned on. That's why the batteries state of discharge is slower when its
plugged into the charger ( even the wall charger )

What should happen is when the battery reachs 100% charge the kernel should
check to see if the GSM radio/WLAN/Bluetooth/GSP is turned on and set the
trickle charge to the base 100mA plus whatever each of the powered
components requires. As the amount that each of these radios uses varies
depending on signal strength and Rx/Tx mode its not an exact science.

Even just putting the charge mode to ~250mA would probably keep the battery
charged up and the GSM radio happy.

Is there a dbus signal for a full battery that a script could hook to setup
this trickle charge state ?

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