Overly-modest TiBook battery

[Bob Jacobsen]

I have a TiBook 400MHz and three batteries.  The original battery 
recently developed a problem with its idea of how much charge it 
contains.  When charged, it shows 100%.  That drops to zero in about 
20 minutes, giving the usual low-battery warning, etc.  But I can run 
at 0% for an hour or more!

It seems that the battery is holding energy just fine, but that the 
estimation  of how much is left is really off.

I'd like to get this fixed because once the battery is showing zero, 
the computer won't wake from sleep.

The other two batteries, which are significantly younger, are working fine.

I've tried Apple's recommendation for "recalibrating" the battery by 
letting it run down until the computer goes to sleep automatically. 
(I acutally do this pretty often).  That seems to have no effect.

Does anybody have any ideas for resetting the self-esteem of this battery?

Thanks in advance.

Bob
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Bob Jacobsen (Bob_Jacobsen at lbl.gov, 510-486-7355, fax 510-495-2957)