how to fully decharge your battery

Discussion in 'Macintosh Computers' started by shorty116, Aug 8, 2005.

  1. shorty116 macrumors member

    Dec 8, 2004
    hi, i got the old ibook battery problem - percentage goes down to about 85% and then the ibook turns off. tried resetting the pmu and recalibrating the battery, nothing did work. i think i remembered i read somewhere it could be helpful if you fully decharge your battery with a lightbulb or something, cause if its in normal use there will always be some energy left in the battery. does anybody know if this could help me, has anybody tried this yet? any help appreciated
  2. gammamonk macrumors 6502a


    Jun 4, 2004
    Madison, WI
    A multi-cell lithium battery can't be fully discharged. At least by design. It would ruin it, and possibly give NEGATIVE charge! I'm not kidding, google for it. They have built in electronics to prevent it. Now, discharging to 5% or something, sure. But I don't see how it would help.

    If your battery quits at 85%, you probably need a new one or your ibook is hosed... That's what I would think...

    How old is the battery? My friend's iBook battery was useless-- 10 minutes of run time or so. but he refused to buy a new one. I don't know why.
  3. shorty116 thread starter macrumors member

    Dec 8, 2004
    the battery runs just fine, i don't know 2 or 3 hours. it's just that the status indicator in the menubar can't calculate the remaining time and counts from 100 - 85 like a normal battery would from 100 - 0. so it's not that big of a problem, but it's kinda annoying. i read lots about this problem at the discussion, but they must have deleted the old threads, anyway this is not a software problem, a new battery would do the trick but i ain't gonna spend 70 bucks just for knowing how much time is left so i thought i'd go the cheap way

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