computer battery drains to 99% when plugged in!?

[askrib]

Hey guys anyone having this problem or know why this would happen?

I come back to my macbook air i7 256ssd that is plug in that was 100% is now at 99% and i never un plugged it! Whats the deal with this??

 

[Mlrollin91]

Mine does it too, really annoying. My 2009MBP did it as well, but it would then drop to 98% and so on until it reached 94% and recharge itself back to 100%. This process took about a week and a half being plugged in 24/7. My MBA drops to 99% within an hour of reaching 100% and stays there..Doesn't go any lower.

 

[GadgetGeek407]

I got my i7 13 tonight haven't charged the battery yet came 88% out the box now have like 26% should i plug it in or don't plug it until totally dead?

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btw out of box my cycle count was 0 and now it says 1 and i never plugged it in SMH

 

[benhollberg]

My MacBook Pro does this all the time. I have it plugged in 99% of the time and it is always running, sometimes it'll go down to like 93% even. I don't think it is that big of deal, well maybe for me because I use it as a desktop pretty much.

Note though, I have pretty much killed the battery doing this, I can only get about two or 2.5 hours out of it. Sometimes I just let the battery drain while use then plug in to cycle it.

 

[askrib]

Thanks. Its good to know I'm not the only one with this.
But I'm wondering why this happens or if its an OSX bug?

 

[ZBoater]

Thanks. Its good to know I'm not the only one with this.
But I'm wondering why this happens or if its an OSX bug?

No, this is by design. Keeping the battery at 100% all the time kills it. The system kinda lets it drain a little bit before charging it again to prevent overcharging.

http://support.apple.com/kb/ts1909

 

[askrib]

No, this is by design. Keeping the battery at 100% all the time kills it. The system kinda lets it drain a little bit before charging it again to prevent overcharging.

Oh really? Interesting......Thanks for the data! That makes some sense.