Battery life fluctuating

hohohong

macrumors 6502a
Original poster
Jun 1, 2007
519
3
I normally have my battery in percentage. When i change it to time left (96%), it fluctuate from 1:40 to 2:06 -> 1:20 -> 1:58,... But shouldn't battery be 5hr (3 hr to be reality)?

I have my slingbox, Firefox, skype, yahoo messenger running. Brightness is on level 9 (max at level 16). I have the new SR MBP.

Is there something wrong?
 

hohohong

macrumors 6502a
Original poster
Jun 1, 2007
519
3
What is your battery life? I'm concerned I have defective battery that might explode.
 

plinden

macrumors 68040
Apr 8, 2004
3,968
3
The OS will estimate the battery life based on the charge level and the current draw. So say you have a charge level of 4800mAh and you're drawing 1200mA, it will estimate about 4 hours left. But if you do something that causes the current to change, to say 1500mAh, the OS will lower the estimated time to 3h20m. That's likely what's happening here.
 

CalBoy

macrumors 604
May 21, 2007
7,849
36
The OS will estimate the battery life based on the charge level and the current draw. So say you have a charge level of 4800mAh and you're drawing 1200mA, it will estimate about 4 hours left. But if you do something that causes the current to change, to say 1500mAh, the OS will lower the estimated time to 3h20m. That's likely what's happening here.
Yeah, battery life estimates are always based on present power usage. The computer can only estimate for you; it doesn't have precognition. Have you calibrated the battery yet? You should probably do that if you haven't. It does help a lot.