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Washac
Feb 12, 2011, 08:46 AM
Hi All


My Macbook keeps just doing a hard shutdown when on low battery.

Once the battery indicator gets down to the red with about 15 to 20 mins
left the machine just shuts down no warning indicator.

I want to re calibrate the battery but because of the way the machine shuts
down IE: Not going into sleep mode, how can I recalibrate ?

Battery has about 260 cycles on it, but could this issue be the battery going ?

Just done a PMU reset on it and charging it back up at the moment so I can run it down and see
if the PMU reset has achieved anything.



miles01110
Feb 12, 2011, 09:08 AM
Yes, your battery could have a dead cell or something. I'd probably just get a new one; how old is it?

Washac
Feb 12, 2011, 09:20 AM
Yes, your battery could have a dead cell or something. I'd probably just get a new one; how old is it?

Hi

It is 26 months old with 286 battery loadcycles

GGJstudios
Feb 12, 2011, 02:38 PM
Reset the SMC, then calibrate (instructions for both in the following link). Use Caffeine to keep your MB from sleeping while calibrating.

This should answer most, if not all, of your battery questions:
Apple Notebook Battery FAQ (http://forums.macrumors.com/showpost.php?p=9875442&postcount=23)

Washac
Feb 12, 2011, 05:10 PM
Hi

OK, I did a SMC reset.

Charged it up.

Then left for just over two hours.

It was used to run it down, this time the low battery warning came up.

Programs being used were shut down, machine was then left on.

It stayed on until it did a hard shutdown.

It did not go into sleep mode, but I assume this was because the prefs are set
not to sleep until 1 hour.

Now leaving it for over 5 hours (until morning).

Fingers crossed it looks like it maybe OK now.

Washac
Feb 13, 2011, 09:18 AM
Hi


OK, after leaving it discharged for over 5 hours it is now all charged up.

New battery could be in order I think, 1.20 only showing in battery icon.

Have to check to see if my Applecare is still valid, it should be :)