Strange ‘battery discharge’ behavior when closing in on 0%

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Level 1

21 points

Strange ‘battery discharge’ behavior when closing in on 0%

I primarily use my laptop on A/C (rather than battery) power, so I try to follow Apple’s recommendations for running the battery through a full discharge from time to time.

During the latest run, however, I experienced some odd behavior I don’t recall seeing before:

Normally, my MacBook turns off at approximately 3% battery power (remaining). This time, however, after hitting 3% the battery briefly went back up to 4% before heading downward again. It then went all the way down to 0% (i.e., stepping first through 3%, 2%, 1%). But instead of shutting down when it got to 0%, the battery meter then shot back up to 7%. From there, it gradually declined again, and this time the computer finally shut off at 2%.

Is there anything to take note of from this unusual discharge behavior -- or is it just one of those 'meaningless quirks'?

Thanks.

MacBook, Mac OS X (10.6.8), 1.83 MHz

Posted on Sep 15, 2013 10:45 PM

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Answer 1

Sep 16, 2013 12:40 AM in response to dymar

Check the battery cycle count > Mac notebooks: Determining battery cycle count

Might be time for a new battery.

BTW, better to recharge the battery before it falls below a minimum of 10% power remaining.

Apple - Batteries - Notebooks

Apple - Batteries - Battery Replacement

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Answer 2

Sep 16, 2013 1:23 AM in response to dymar

Go to the Apple in the upper left corner and select About This Mac, then click on More Info then select Power from the left hand column of the System Profiler. Copy and paste the Battery Information from the top of the page back here.

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Answer 3

dymar Author

Level 1

21 points

Sep 16, 2013 8:49 AM in response to Carolyn Samit

Carolyn Samit wrote:

BTW, better to recharge the battery before it falls below a minimum of 10% power remaining.

Thanks. That may be true of general usage, but Apple's article about calibrating the battery says to run it all the way down, until the computer shuts off, and to then leave the computer off (or in 'sleep') for at least five hours:

Disconnect the power adapter while the computer still on and start running the computer off battery power. You may use your computer during this time. When your battery gets low, the low battery warning dialog appears on the screen.
At this point, save your work. Continue to use your computer; when the battery gets very low, the computer will automatically go to sleep.
Turn off the computer or allow it to sleep for five hours or more.

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Answer 4

dymar Author

Level 1

21 points

Sep 16, 2013 8:52 AM in response to frederic1943

frederic1943 wrote:

Go to the Apple in the upper left corner and select About This Mac, then click on More Info then select Power from the left hand column of the System Profiler. Copy and paste the Battery Information from the top of the page back here.

Thanks.

Battery Information:

Model Information:

Manufacturer: DP

Device name: ASMB016

Pack Lot Code: 0002

PCB Lot Code: 0000

Firmware Version: 0110

Hardware Revision: 0500

Cell Revision: 0102

Charge Information:

Charge remaining (mAh): 4511

Fully charged: Yes

Charging: No

Full charge capacity (mAh): 4540

Health Information:

Cycle count: 17

Condition: Normal

Battery Installed: Yes

Amperage (mA): 0

Voltage (mV): 12510

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