CMOS Battery

Question

Level 1

1 points

CMOS Battery

So last night I let my MacBook run some unities on Drive Genius overnight, I woke up this morning to find out that somehow it stopped charging at some point, and the battery died completely. Once I finally got the computer back on, had to use a different power socket, I found out that the clock had been reset back to December 31, 2000. Does anyone know if the computer has a CMOS battery in it? Or is this a normal thing if the battery dies completely? What concerns me is that the Mac is only 7 months old. The Model Identifier is MacBookPro 8,2 and the model number is A1286.

Thanks!

MacBook Pro, Mac OS X (10.6.8), 15", Core i7, 500GB, 8GB Ram

Posted on Mar 29, 2012 6:59 PM

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Answer 1

Kappy

Level 10

362,007 points

Mar 29, 2012 7:04 PM in response to wrighta379

The computer has a lithium cell used to maintain the PRAM for a short period of time when the user is changing batteries. However, if the main battery goes completely dead then the computer will drain all the power from the lithium cell in just a few seconds to a minute.

Unless you wish to disassemble the computer in order to replace the lithium cell you will need to take the computer in for servicing.

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Answer 2

ds store

Level 7

30,855 points

Mar 29, 2012 7:02 PM in response to wrighta379

No CMOS battery, it uses the main battery and yes that's to be expected if you run it dry.

https://discussions.apple.com/community/notebooks/macbook_pro?view=documents

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Answer 3

wrighta379 Author

Level 1

1 points

Mar 29, 2012 7:08 PM in response to wrighta379

Sounds good, I've never actually drained the battery all the way before like that, so I just wanted to make sure there wasn't something running amuck he

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Answer 4

ds store

Level 7

30,855 points

Mar 29, 2012 7:08 PM in response to Kappy

Kappy, is this also for the new machines without the user replaceable battery?

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Answer 5

Kappy

Level 10

362,007 points

Mar 29, 2012 7:10 PM in response to ds store

I don't know about those with non-replaceable batteries, but wouldn't seem necessary if the user can't swap batteries. I didn't think about that.

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