Is there a quick way to discharge a laptop battery in linux? I just got a new battery for my old laptop (Ni-MH) and the directions say I may have to charge/discharge the battery up to 5 times to get optimal results. It discharged itself quickly after the first charge (about 3 minutes) After that it seems to be working fine, but I also read in the instructions that these batteries need to be forcibly discharged to prolong the battery life. They mentioned a DOS utility called dcharge and I was wondering if there was such a utility for linux? If not, how do I go about efficiently and fully discharging this battery. I guess if nothing else, I can take one of my spare hard drives for the thing and just throw DOS on it and use it, but of course I would prefer to stay in linux-land.

-cor-

It's true that you should fully charge and then fully discharge batteries in order to gain maximum performance out of them, but I'm skeptical that there are any programs that would accomplish that. To discharge a battery, the easiest thing to do is to turn off any kind of power-saving options, fire up a few power-draining apps, then walk away or go surfing for a few hours. Example: set the display settings to Never blank out the screen, drop in a CD and play it in Shuffle mode and Repeat All, and/or also log in a go surfing for a few hours. If you've got a DVD player in your machine, that's even better. In no time flat (seemingly) your battery will be totally drained. Repeat as necessary. -- J.W.

I had a problem with this approach, unwillingly discharged the battery completely on a compaq armada laptop and now cannot recharge it (in fact it is NOT recommended to discharge it to 100% but to leave only 3-5% of remaining charge on a battery, well, I didn't and now it doesn't charge again...

I recommend reading some posts on the debian mailing list (one guy there has read some research about battery discharge...:
http://www.mail-archive.com/debian-l.../msg15719.html

daniel ;-)

if you find out how to charge a battery that is completely down, please let me know...

Here's a nice write-up on batteries and why you should never fully discharge them (cell reversal).

http://www.myra-simon.com/bike/charger3.html


As for the question about how to safely discharge them, just let your laptop do its job. Learn patience

As a practical guide, discharging should not exceed 2x of the battery's capacity (according to Panasonic). So for a 3000maH battery, you would not want to exceed 6 amps (6000ma).

Radio control models exceed this rate all the time, so this may just be a Panasonic thing (but by the same token our batteries don't seem to last long either).


Oh, and never, never recharge a hot battery. Wait for it to cool, it harms the battery if you let it overheat.


Here's the Panasonic NIMH design guide (very good, short read)

http://www.panasonic.com/industrial/...recautions.pdf


John