[ltp] Battery Cell Replacement
Wed, 15 Mar 2006 15:41:00 -0500
Ron Joffe wrote:
> But looking back, I think I need to understand the battery control circuitry
> better. Booting into windows, the machine almost immediately tried going into
> hibernation mode (since it thinks that the battery has a capacity of all of 5
> minutes). And the battery indicator blinking is quite annoying.
You might be able to convince it that the battery has more capacity than
it used to by taking an old trick from the NiCd battery days -- run a
few complete discharge/charge cycles on the machine. Even though battery
memory isn't a problem anymore with LIon batteries, the control
circuitry seems to have its own "memory" of the battery's state.
Not long after I first got my used, non-brick T22 battery (to replace
the lifeless brick it was sold to me with), I accidentally cycled the
battery a few times. (It was in a room with no power outlet positioned
nearby the only spot where I could get a wireless signal, and kept
forgetting to run and plug it in often enough.) I had all
power-management turned off COMPLETELY in the BIOS and in my Linux configs.
I'd first noticed, while working on the machine, that the new battery
was keeping the machine running quite a while longer than the
battery-life-timer reached the "0:00" mark. Then, at the end of the
night, I discovered that the "Remaining Capacity" indication in
/proc/acpi/battery/<mumble> at 100% charge had actually RISEN from the
point it had been at before I accidentally cycled the thing. In my case
it wasn't much, a few 100 mWh, but the same trick may work for your
battery. Presumably, the control circuitry noticed that it was hitting
the 0 mark on its calibrated battery-life scale WAY before it stopped
spitting out power, and corrected.
My specific 'method' (to madness) was to run the computer with
power-management disabled systemwide, unplugged, until the machine
actually lost power and died. (Might be a good idea to keep the
filesystems relatively quiescent towards the end of the period.) Then,
I'd take the machine over to its power supply and plug it in to charge,
still powered off. Lather, rinse, repeat.