The Case of the Swollen MacBook Pro Battery [UPDATED]

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.]