Proper use of rechargeable batteries

Like many other people, I have a bunch of electronic devices that run off rechargeable batteries - a cell phone, digital camera, laptop, MP3player…

I have been wondering about how to use these for maximum battery life. Should I be totally draining the batteries before hooking them back up to recharge? Sometimes this is inconvenient, like when I’m planning to go out with my camera and want it to be fully charged - I’ll plug it back in even if it is 3/4 full already.

But I was reading in my cell phone manual, (Motorola v66) and it says to avoid charging the phone when it’s still has power remaining. My laptop says something like “totally drain and recharge at least once a week”. I think both my camera and laptop use the Sony lithium batteries. Can any one shed some insight on how to use these things and recharge for max battery life?

Completely discharging before charging is conventional wisdom for Nickel Cadmium (NiCd) batteries but isn’t needed for newer types like Lithium Ion and Nickel metal hydride. Not everyone agrees that it’e even needed for NiCd batteries to avoid the memory effect but fully chagring and discharging a few times does seem to give my batteries maximum life. I don’t own anything that used NiCd anymore so I don’t worry about it but it’s usually best to follow the manufacturer’s directions.

There’s some info on NiCds and a little on NiMHs here but it’s a bit out of date.

Note: do not “completely” drain rechargables. I think what people really mean here is to run them down until the appliance is barely working. Not needed so much with NiMH. Running a pack of rechargables down quite low will probably ruin the weakest cell in the pack, which is bad for the whole bunch.

The main abuse rechargables suffer is from over-charging. People let them trickle charge way too much. (Esp. on things like laptops.) Either: run off the batteries, run off the AC or be charging up the batteries.

The “memory effect” is rarely if ever a problem. And the deeper you discharge a NiCAD, and the more often you do it, the worse it is on the battery. So it goes without saying that you should never purposely deep-discharge NiCADs.