The Case of the Swollen MacBook Pro Battery [UPDATED]

| Analysis

About six weeks ago, I noticed that the cover plate on my 15-inch MacBook Pro (Unibody, 1G) was bulging. It got steadily worse to the point where the cover plate would no longer close properly. I was introduced, for the first time, to the swollen MacBook battery syndrome.

My TMO workstation has my MacBook Pro connected to some external hard disks (Time Machine) and an older 23-inch Cinema display - with a DisplayPort to DVI connector. In place, the power cord tends to stay connected all the time. From time to time, I unplug all the connectors and take the MBP to another room to write in a comfortable recliner.

About six weeks ago, I noticed that the 2-inch wide cover plate over the battery was slightly ajar. I didn’t recall that defect before, but I didn’t have time to worry about it very much. Last week, when I moved the MBP, I noticed that the cover plate was ajar and couldn’t be closed properly — one of the latches just couldn’t catch. This was serious, even though the battery continued to function.

MBP battery

MBP, Unibody G1, replaceable battery, $129 (Credit: Apple, Inc)

I called AppleCare. (I never buy a Mac without AppleCare. That policy has paid off handsomely for me.) After I explained the situation, the Apple rep said, matter-of-factly, that I had a “swollen battery” and asked me for the location of my closest Apple store. (Park Meadows Mall, Lone Tree, Colorado) Even before we hung up, I had received an e-mail, reserving me a time with an Apple genius to replace the battery.

Saturday morning, the battery replacement went smoothly. I found it interesting, however, that even though I had a reservation, AppleCare in Austin had no visibility into the Apple retail store inventory — so I could have arrived and there’d be no replacement battery on hand. Fortunately, the store had two. Once the battery was replaced, the cover plate fit perfectly. Good as new.

I asked the Apple genius about why the battery swells. She said she thought it was a safety feature, but couldn’t offer any additional details.

Over the weekend, I did some research. It turns out that this has been an occasional problem in the past, and Apple had an official battery replacement program — but the program was terminated in 2008. Consumer reports had some helpful comments in July, 2009. A brief perusal of the Internet suggests that Apple has, without much fuss, replaced swollen MacBook batteries, even when out of warranty, at their discretion. However, there’s no guarantee it’ll happen that way, and AppleCare is strongly recommended. My problem occurred 18 months from the date of purchase with about 30+ recharge cycles.

Fortunately, there was no physical damage to the cover plate, but I’ve seen some ugly photos of warped MBP cases as the battery swells. So if you start to see this effect, my suggestion is to get the battery replaced right away — even if you have to pay for one. I’ve asked Apple about all this, and will update the article if I hear anything.

[UPDATE: Apple did respond and said that if you have a swollen battery, in or out of warranty, they want to know about it. Contact AppleCare at 1-800-275-2273. Also, Apple reminds us that one can OPTION + Click on the battery icon in the Menu bar to see the state of the battery.]

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Mike Weasner

My two year old MacBook Pro 17” has not (knock on wood) experienced this swollen battery problem.  I leave the computer plugged in almost all the time although I do swap the battery with another one about every six months. The only things connected are an Apple Studio Display 17” (as a 2nd display), iPhone 3GS, powered external speakers, Gigabit ethernet, and occasionally a Firewire 800 hard disk, a DV camcorder via Firewire 400, and a midi keyboard.


It would be interesting to see if there’s any correlation between this failure and system temperature. For example systems that run in warmer environments have a higher failure rate, or systems with lap stands that raise them up to aid cooling had a lower failure rate.


When the battery of my Core Duo MBP 15? died (apparently, I fried it by always leaving it plugged in and never cycling it) and I bought a replacement, I started leaving my bad battery always plugged in; swapping it for my new one only when I wanted to take my computer somewhere.  That has worked very well for about 2 years now.

I, too, wonder about any correlation between battery failure and system temperature and how much does faithful regular cycling protect charge life,

Lee Dronick

A few years ago I needed to replace the battery in my cell phone. The new one wouldn’t fit, it was swollen. No problem they gave me a different one that did fit properly. From what I understand, I may be incorrect, is these types of batteries can swell from being overcharged.


On my previous cell phone I bought a backup battery and left it in the charger.  It was thin battery not unlike a CompactFlash card.  After about two months it had swollen to almost twice it’s original width.  Needless to say, it was never going to fit in the cell phone I bought it fore.


I had an issue with my MBP where the trackpad began failing to register clicks.  After going thru Apple support and heading to the closest store 50 miles away, it occured to me that I had a heck of a time getting the battery cover back in place after an Apple rep had me pop the battery to do a PRAM reset (or whatever its called on Intel Macs).  While sitting at the Genius Bar I told them about it and they checked and low and behold the battery rocked on the counter top instead of sitting flat.  They poped a new battery in and trackpad was like new.  Live and learn!


my macbook pro went thru 3 swollen batteries in 4 years.  Apple replaced the 1st 2.  I bought the last replacement, about a month ago.  The 1st swollen one had lots to do with defective design or manufacturing, according to Apple.  When the last one got swollen up, I suspected it might have something to do with me leaving my macbook pro ON all the time in my tight, well-cushioned laptop bag after work.  I rarely shut down my macbook pro, maybe once every few weeks, even months.  Perhaps, it might get real hot in there.  grin


might have something to do with me leaving my macbook pro ON all the time in my tight, well-cushioned laptop bag after work.

Which might support the theory that it has to do with overheating.

Samuel Rizzo

I’m very frustrated. I’m in a very similar case. A 1.6 years old 13’’ MacBook, with a 30+ recharge cycles battery. But the Brazilian Apple WON’T replace it. They say the official replacement program was closed, and I will have to buy a new one. Don’t know what to do. Those are very expensive here.

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