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Lion problem, computer now shuts off at 25% battery power (but only sometimes)?

I

iFanboy

Guest
Original poster
This is weird.

About half the time i'm running on battery my macbook pro will just "turn off" when the power level gets to 25%

The rest of the time it will use the power right down to the single digit percentages as normal.

Anyone else getting this particular intermittent battery problem?
 
Possible Solution - resetting the SMC

1. Restart your Mac
2. Hold down the shift, ctrl, and option (cloverleaf/cmd) keys together with the power button
3. Hold for 10 seconds.
4. Turn on your Mac

I haven't had chance to test this yet on a full battery deplete, but i'll report back if issues remain!
 
If it's happening to you a lot, check your battery. Premature shut downs could indicate that the computer is not reading the battery correctly. This happens to me sometimes but I know it's the battery as it has been needed to be replaced for almost half a year..
 
Either you need to calibrate your battery or the battery is almost depleted.

http://www.apple.com/batteries/notebooks.html
http://support.apple.com/kb/ht1490

Most lithium-ion polymer batteries use a fast charge to charge your device to 80% battery capacity, then switch to trickle charging. That’s about two hours of charge time to power an iPod to 80% capacity, then another two hours to fully charge it, if you are not using the iPod while charging. You can charge all lithium-ion batteries a large but finite number of times, as defined by charge cycle.


A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity. As with other rechargeable batteries, you may eventually need to replace your battery.
Click to expand...
 
Ok, so resetting the SMC didn't help.

I just ran my battery down and when it got to 19% the computer just turned itself off and wouldn't turn itself back on.

The weird thing is that my battery was perfect under Snow Leopard, and this literally started happening as soon as I installed Lion.

Could this be a Lion issue or do I need to buy a new battery? :(
 
iFanboy said:
Ok, so resetting the SMC didn't help.

I just ran my battery down and when it got to 19% the computer just turned itself off and wouldn't turn itself back on.

The weird thing is that my battery was perfect under Snow Leopard, and this literally started happening as soon as I installed Lion.

Could this be a Lion issue or do I need to buy a new battery? :(
Click to expand...

In System Information, how many cycles does it say your battery has completed? (Hold option while in the Apple menu, open System Information, and look in" Power" for "Cycle Count".)
 
rorschach said:
In System Information, how many cycles does it say your battery has completed? (Hold option while in the Apple menu, open System Information, and look in" Power" for "Cycle Count".)
Click to expand...

182.

My battery was great before Lion. Now it just won't use the last 25%. It will just abruptly shut off the computer instead :(
 
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