Notebook Battery

[Graham]

I have a Compaq Armada 100s with a Ni MH battery. As I use it mostly on power I am worried that the battery may be damaged by overcharging. Is this likely or does the computer prevent this ? Is there any point in removing the battery when using on power for long periods ?
Thanks for ant ideas
Graham

[hiredgoonz]

According to compaq you should remove the battery if the computer will be plugged in for long periods...I had a laptop which I did not remove the battery from when plugged in and it did not last nearly as long as it should have...

It got to the point where it would not hold enough of a charge to boot the system (after a year and a half) so I would recommend taking it out...

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When all else fails, read the instructions.

[kenja]

About overcharging: I'd hope that Compaq's charging circuit would be sophisticated enough not to do this (unlike the NiMH charger for my phone). A problem with NiMH (and NiCad) batteries is the "memory" effect.

This is an electro-chemical phenomenon. If these batteries are not completely discharged before being recharged, they can become "stuck" at whatever charge level they are most often recharged at. In other words, if a NiMH is recharged repeatedly when only discharged 50%, it will likely lose half of its capacity.

IBM has a utility for NiMH ThinkPads that performs a complete discharge for this reason. Lithium ion batteries supposedly don't suffer from the "memory" effect, but I treat them the same; the battery is most often removed from my notebook. (And, no, lithium batteries are not interchangable with NiMH, the circuits are different.)