Released June 2012, Model A1278. Intel processor with Turbo Boost, Up to 512 MB DDR5 Video RAM

688 Questions View all

MacBook turns off when charger is disconnected


Around two days ago I was about to move my workhorse to the kitchen, to do some culinary research (read: how to boil potatoes) when my MacBook just turned off when I disconnected the charger. I've had this problem before, which went away after a short while by itself. I just pinned it down to magnets or magic. After a while of being mildly annoyed by it shutting down, I began testing the battery in TechTool, which gave me virtually no information save for the fact that the battery is just maintaining its charge, but not actually getting any.

The battery indicator shows a 100% charge, as does Coconut Battery, which should mean that it's not the SMC. I did an SMC and PRAM reset, though it's unclear if it did anything at all. I'll try an SMC bypass and see if that does anything at all and update on this.

Logic tells me that it's the I/O board which is fooling around, but given my current financial situation, I don't want it to be. So, bottom line, is there any way to be completely sure that it's due to the I/O board, and/or any good way to fix it? Any help will be very appreciated and will hopefully help others in the future too.

Update (11/23/2016)

For the sake of clarity, I'll enclose two Coconut Battery screenshots for future reference.

Block Image

Block Image

Answered! View the answer I have this problem too

Is this a good question?

Score 0


Hello @henchr,

Thanks for using the forum. I under stand this problem and would like to share.

Sometimes the battery of many laptops fail. There is also a possibility that the battery got disconnected from the logic board. I would bring it into a PC repair shop and get them to diagnose the problems. And then follow that diagnosis.


Keegan Bourque


It's certainly not the battery, that's for sure. It's a NewerTech battery, still with 103% health, and all tests show it's in good condition. The fact that it shows up in TechTool and Coconut Battery is a good indication that it isn't disconnected. I'll pry open the computer now and see if that'll teach me something, but experience tells me I'll just blankly stare at its insides and wonder what I'm looking at. And as we all know, the difference between me and a PC repair shop is mainly that they charge me for doing the same thing I do; staring blankly at it. I appreciate your answer, and I'll have a look inside to see if something is looking awry.


Add a comment

2 Answers

Chosen Solution

I bet you leave your system plugged in most of the time.

What is happening here is SMC thinks the power level is below the set threshold so it needs to power down the system into deep sleep mode.

So how to fix? It's quite simple you need to do a SMC reset and cycle the battery a few times by fully discharging it and recharging it. That way the setpoint is memorized correctly.

Here's the Apple TN you'll need to reference: Reset the System Management Controller (SMC) on your Mac

Was this answer helpful?

Score 1


I bet you didn't read my post in which I said I reset the SMC. As far as my battery goes, I try my best to not have it plugged in most of the time and give it a chance to fully empty out before plopping the charger back in. However, I did just open the MacBook up and tinkered with a few wires, which seemingly did nothing. Then I did an SMC bypass (unplugging the laptop, holding the power button for 10 secs, plugging the computer back in while holding the power button for an additional 10 secs and then releasing and pressing it again to get it to boot) which got it up and running without a charger plugged. From there, I just did yet another SMC reset, booted in safe mode, checked TechTool and everything looked positive - this time with a 0% charge (as opposed to the 100% charge reported earlier). No clue what caused the Mac to report a faulty battery/I/O board, but we're back to normal. Again we can nail this down to magnets and magic.


Did you pull the battery connection? Often I find I end up needing to do it that way to be effective. Pull the battery internally, press and hold the power button a good 2 minutes then plug the battery back in and restart.

No magic here and it's not magnets either :-) I confess I did skim your Q. It's a problem I've seen a few times so I had a strong idea what was up here.


You may want to clean the MagSafe connector pins and pads. The middle pin is how the charger and the system communicate. If the cord pins or the DC inboard contact pads are dirty or corroded you can have some charging issues. But given your coconut battery info I don't see this as your issue.


Add a comment

Problems related to unexpected system sleep, shutdown, lights or fans call for an SMC reset:

Resetting the System Management Controller (SMC)

Resetting the SMC on Mac portables with a battery you can remove

Shut down the computer.

Disconnect the MagSafe power adapter from the computer, if it's connected.

Remove the battery (to remove the battery - click here: MacBook or MacBook Pro).

Press and hold the power button for 5 seconds.

Release the power button.

Reconnect the battery and MagSafe power adapter.

Press the power button to turn on the computer.

Resetting the SMC on portables with a battery you should not remove on your own

Shut down the computer.

Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.

On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.

Release all the keys and the power button at the same time.

Press the power button to turn on the computer.

Was this answer helpful?

Score 0
Add a comment

Add your answer

Henning Klepp Christensen will be eternally grateful.
View Statistics:

Past 24 Hours: 43

Past 7 Days: 363

Past 30 Days: 1,484

All Time: 3,085