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celebrian23

macrumors 65816
Original poster
Mar 12, 2006
1,186
0
Under the sun
Whenever I unplug the magsafe the first battery reading is always some weird number like 477:43 or 102:22 or 9:53. No matter how long I wait before looking at it (I have it to only show the icon) it's always some super high number and if I click on it a seconcd later it goes to a normal low 3 hour range time. It's never done this before today actually. It usually spends a lot of time calculating. Why's it doing this?
 

Star Destroyer

macrumors 6502
Jun 15, 2006
376
4
yeah i get that on my macbook sometimes, usually it will say like 8 or 9 hours of battery life... then goes back down to like 3-4.. its cool hahaahaha seems normal.
 

slooksterPSV

macrumors 68040
Apr 17, 2004
3,545
309
Nowheresville
The batteries actually have a processor in them that calculates the amount of time and energy you have left, this hands it off to OS X and OS X gives you a read out, I think the processors on the batteries are slow though or it takes a min. to convert the energy to time and all that. Ahh, I can't explain it, there is a core on the processor that tells how much there is, OS X just reads that and gives you the readout.
 

balamw

Moderator emeritus
Aug 16, 2005
19,365
979
New England
slooksterPSV said:
The batteries actually have a processor in them that calculates the amount of time and energy you have left, this hands it off to OS X and OS X gives you a read out, I think the processors on the batteries are slow though or it takes a min. to convert the energy to time and all that. Ahh, I can't explain it, there is a core on the processor that tells how much there is, OS X just reads that and gives you the readout.
I don't think the battery reports time, only the total estimated charge in the battery and perhaps some estimate of the current usage, which is where it gets confused. When switching from charging to not, the net drain on the battery goes from zero to the real value. so when it first tries to calculate the time, it divides by a small number and gets an unrealistically large number. (While charging, the net drain on the battery is very low since it's constantly being topped off).

B
 

slooksterPSV

macrumors 68040
Apr 17, 2004
3,545
309
Nowheresville
balamw said:
I don't think the battery reports time, only the total estimated charge in the battery and perhaps some estimate of the current usage, which is where it gets confused. When switching from charging to not, the net drain on the battery goes from zero to the real value. so when it first tries to calculate the time, it divides by a small number and gets an unrealistically large number. (While charging, the net drain on the battery is very low since it's constantly being topped off).

B
You're right, see I knew I couldn't explain it perfect.
 

generik

macrumors 601
Aug 5, 2005
4,116
1
Minitrue
Maybe the battery was overcharged and for a moment the voltmeter read a higher than normal value, and hence concluded that your battery life remaining must be "super good"? ;)
 

Josias

macrumors 68000
Mar 10, 2006
1,908
1
My MB always said 400-900 hours left, then went down to around 5 hours.

Now it's just calculating, and goes to 5 hours. It's no issue.:D
 
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