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I have a 17" Macbook Pro (5,2 mid 2009, MC226LL/A) that has a battery that is in need of being replaced.

I'm looking for the correct battery for it and have found various batteries that say they are compatible. The odd thing is that some of the batteries that are said to be compatible have a voltage that is higher than the original.

My battery is model A1309 with a voltage of 7.3V and 95Wh. But batteries that I've seen listed as compatible with model MC226LL/A have a voltage of 10.95V and 95Wh. Does this difference in voltage matter?

  • Every single person that I have known to replace their batteries with aftermarket replacements have all seen either a) markedly lower battery life and b) quick degradation leading to requiring a new battery far sooner than if they had purchased one through Apple. Apple doesn't make their batteries (often outsourcing to company's like Sony), but they do provide excellent ones and do stand behind them quite rigidly. Some complain Apple overprices their components, but I wholeheartedly disagree with respect to their batteries. – user10355 Jan 21 '14 at 1:03
  • So the recommendation would be to just bring it into the apple store and spend the $180 to replace it? I was thinking that might be my best option but it's such a steep price to pay. Why does it seem totally impossible to find and purchase the same battery that apple would put in if I brought it to them? – Sean Lynch Jan 21 '14 at 1:07
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Batteries are the one thing in a laptop you shouldn't mess with -- I'm fairly sure they're the only component in your computer that is in a constantly controlled risk of overheating, catching fire or quite literally exploding. When they are not made to the utmost standards of quality, you could be, again quite literally, putting your life at risk. I'm not saying this is the case with you, and fortunately not with me, but if I were unable to afford a new manufacturer-supplied battery to replace a dying one in my laptop, I would rather sell it and buy a cheaper laptop whose battery I could afford.

I agree Apple's markup on batteries -- and quite generally most of the accessories they sell -- is excessive, but batteries and chargers (due to the risk of electric shock) are two things I would never buy from anyone but Apple. If you search around you will find teardowns of original Apple chargers and cheap Chinese knockoffs, and even if you have zero knowledge of electronics, you can tell the Apple chargers are much higher quality than the Chinese knockoffs. This is quite hard to tell with batteries, but do you believe for a moment the lowest bidder won't cut costs exactly as they do with chargers?

And just to stay on topic, yes the battery is quite important. 7.3 V sounds like a two cell Li-ion configuration while 10.95 V would be a three cell Li-ion battery. Using a two-cell battery in place of a three-cell battery or vice-versa is a sure-fire recipe for disaster -- even if the electronics could take the different voltage, over-charging a two cell battery with enough voltage for a three cell battery would immediately damage it. In case of a high quality battery, only the protection circuit would be damaged, but in case of a low-quality knockoff with no protection circuits, the battery would be immediately and irreversibly damaged, with a symptom of either swelling, fire or an explosion.

  • In the end I decided to go to the apple store and have them change it out for me. No cheap but quick, easy, and lots of piece of mind. – Sean Lynch Jan 23 '14 at 1:20

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