Battery discharging while plugged in

Dale Maggee antisol at
Fri Sep 5 08:45:25 CEST 2008

Edgar D' Souza wrote:
> On Fri, Sep 5, 2008 at 8:59 AM, Dale Maggee <antisol at> wrote:
>> Hi,
>> currently when I have my freerunner plugged into USB, it will charge to
>> 100% and then start (slowly) discharging. If I unplug the USB cable and
>> plug it back in, it charges back up to 100 percent, then starts
>> discharging again.
>> any Ideas?
> ONLY an idea, no factual knowledge :) but:
> Perhaps the charging circuitry is flipped off when the battery reaches
> 100% reported charge level, and then the phone is running off of
> battery, causing the slow discharge you see? When you unplug and
> replug, since the battery is below 100%, the charging circuit is
> turned back on till battery level once again reaches 100%? Think this
> is the explanation? Have you tried unplugging the phone when it hits
> 100% batt charge, and leaving it unplugged, and seeing if it maintains
> the same rate of discharge?
> Are you in a good signal coverage area, or does the phone have to
> 'shout' to talk with the tower (presuming your GSM is on)? When I'm in
> low-signal areas, the battery discharges faster. Been that way for my
> Nokia (past) and Motorola (present) phones too.
> What about other chipsets - Bluetooth, GPS, WiFi? Are they powered
> off, or are they on? Might be contributing to battery drain...
> Ed.

Yes, this sounds like the correct explanation - it stops charging once 
it hits 100%.

When I have it unplugged, it SEEMS to discharge faster, but this may be 
due to usage [i.e, when it's plugged in, the screen is turned off most 
of the time ( I use the 'dim only, don't lock' option), as I tend to do 
everything via ssh. When it's unplugged it tends to either be in use or 
in my pocket (where the screen tends to get bumped and therefore powers 
back on briefly). I'll do some more testing by unplugging it and putting 
it on the desk while i'm not using it, and report back ]

I'm in a good coverage area, and usually have "full bars" or close to it.

I usually have GPS, bluetooth, and wifi turned on, although sometimes I 
turn them off to conserve battery life when I'm not going to be near a 
charger for a while.

It used to just stay at 100% when left plugged in, so I'm guessing that 
one of the updates (probably the kernel? possibly around the time we 
started using the 'aux' led to indicate charging) has changed this.


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