Q: MacBook Air turns off randomly when unplugged
Hi all,
I have a 2011 13" MacBook Air running Mac OS 10.10.2. I have upgraded the SSD to a Transcend JetDrive 500 240GB, and recently replaced the battery with a genuine Apple MacBook Air 13" battery bought on eBay. I will include a screenshot of coconutBattery with battery stats.
Until yesterday evening/this morning, my laptop was running fine. I first noticed the problem when one of my family members was using the laptop, the battery charge was about 40% and the laptop just turned off unexpectedly. I thought originally the battery may have been dead or nearly, but I plugged it in and the charge was ~39%. The whole time the laptop was plugged in, there were no issues. I unplugged the laptop and put it in my bag to go to University, and I didn't know at this time if it had turned off or not.
Fast forward to this morning, went to use my laptop, and sure enough the laptop turned off within 5 minutes, keeping in mind the battery was no where near dead. Now this is where it gets strange. I tried turning my laptop on and this time it wouldn't boot, it got to the Apple logo, the loading bar appeared and after 30 - 40 seconds (way longer than an SSD should take to boot), I was presented with the grey circle with a line. So I thought I'd try safe mode, a
nd it booted fine, albeit very, very laggy. Noticed nothing strange, shut down the computer and tried booting again, no luck. Tried resetting SMC and PRAM (3 times to be sure for PRAM), but it made no difference. Tried booting into recovery and repairing disk permissions. Everything was fine, even the SMART check said the OS X partition was fine. I thought I would try Single-User Mode, but when it loaded, I couldn't try to run fsck, no input of text was allowed, and eventually the colours on the screen became washed and the circle with a line through it appeared.
I then thought perhaps it was Trim Enabler causing the issue with the new kext signing Apple has introduced with Yosemite, so I booted into recovery, and ran the disabling command through Terminal. At this point I don't know if the laptop was plugged in or not, because sure enough when I quit Terminal and rebooted, the computer booted! I have since disabled the kext signing and the computer booted no problem. Since then, I have unplugged the laptop once, and within 10 seconds it had switched off, even though the battery was at 100%! So, I've established the computer only wants to remain on if I have it plugged in to the mains. The battery in the laptop is very new, only about 50 cycles, and my previous battery had over 600 and just didn't hold the same charge any more. Also, ignore the manufacture date coconutBattery states, as I purchased it less than 3 months ago.
So I wonder, does anyone have any ideas as to why the laptop dies instantly, and what may have caused the seemingly endless kernel panics.
Thank you,
Chris.
MacBook Air, OS X Yosemite (10.10.2)
Posted on Mar 10, 2015 11:47 AM



