Agree with what chscag mentioned.
I recently replaced the battery in my 2011 17" MacBook Pro. I of course knew that buying a low cost replacement battery via eBay or Amazon had it's risks...but since like many people I like to save money...thus I had to try anyway!
I ended up messing around with THREE replacement battery's purchased via eBay or Amazon:
- The first battery didn't fit properly...and I returned it.
- The 2nd battery & 3rd batteries didn't seem to be "seen" by the computer...since the MacBook Pro was only running at about 20% of it's normal performance (which is what they normally do if you remove the battery completely).
Since these eBay and Amazon purchased replacement battery's had the issues mentioned...I never even got to the point to test them to see if they actually gave close to the normal runtime as the OEM battery. The crazy thing was...these batteries were supposed to be OEM batteries...they had EXACTLY all the same external labeling that my original Apple battery had.
The $30 price of the eBay and Amazon battery's is always very tempting...and that's why I gave it a shot. But in the end I just wasted a lot of time removing & installing the batteries...and all the time wasted shipping & receiving the various batteries purchased.
I finally gave up messing around...paid the $100...and got the replacement battery from macsales.com (which I knew would work). I received it...installed it. It fit perfectly...and has run perfectly.
- Nick