Mac only works with smaller model's battery..?
A colleague of mine has a 15" MacBook Pro Early 2011 which I'm in the process of upgrading.
The battery swelled and disfigured the base cover/ casing of the machine. It was fortunate because the battery did not burst, so none of the components were damaged - other than the cracked trackpad.
Anyway, we've bought two Replacement batteries now and neither work. One was a refurbished apple battery, the other a brand new third party battery.
The really strange thing is, when I plug in the battery from our 13" MacBook Pro, it works perfectly. I've been able to start and use the Mac as normal with this smaller battery in place. Only problem is, it doesn't fit in the housing so I can't screw the back on yet.
I was trying to figure out why two 15" batteries both won't work when I spotted a couple of strange metal prongs directly between the battery and the ram. Upon further inspection it looks as though these prongs align with a couple of circular indentations on the base cover/ casing. I'm wondering whether the larger batteries need these prongs to be in contact with the metal of the base cover in order to complete the circuit?
As they're not present in the 13" model I thought maybe it was a safety feature for the larger sized batteries in the 15" model's.
The disfigured base plate doesn't fit properly anymore and I suspect doesn't touch these prongs as I believe it's meant to - does anyone know whether this is a genuine thing? Or if not, what these prongs are actually for and why the 15" batteries wouldn't be working but a 13" battery would?
You'll be able to see these prongs in the link below. They're on the left of the image directly below the RAM.