I had the same/similar problem. My battery "got pregnant" and was pushing out to the touchpad. So I decided to replace it. Unfortunately I bough battery for newer version of MacBook Pro (15"). I was too lazy to return it and order new one, so I searched for another solution. I came across this thread where pinouts were written. After small research (or I should rather call it experimenting) I found a solution :-)
The above answer where you cut the fatter connector to fit is wrong. If you would look closely you will see that the + and - pins are reversed between these two connectors. On each connector there is a mark for + and -. So cutting it down wont help.
If you have both batteries, you need to disassemble them and exchange connectors between them. The control pins are on both connectors same. So while one connector has pins in this order
[code]
+12
+12
+12
SMBUS_SMC_BSA_SCL
SYS_DETECT_L
SMBUS_SMC_BSA_SDA
GND
GND
GND
[/code]
the other has pins reordered
[code]
GND
GND
GND
SMBUS_SMC_BSA_SCL
SYS_DETECT_L
SMBUS_SMC_BSA_SDA
+12
+12
+12
[/code]
Be aware! Without proper tools (like soldering iron, etc) and at least some technical skills you wont get too far.
I exchanged connectors today. Battery got detected and has no problems with charging it. In case of any complications, I will write here again for more information :-) Good luck everyone!
[code]
Battery Information:
Model Information:
Serial Number: D86138301HGDGDLAJ
Manufacturer: SMP
Device Name: bq20z451
Pack Lot Code: 0
PCB Lot Code: 0
Firmware Version: 406
Hardware Revision: 2
Cell Revision: 158
Charge Information:
Charge Remaining (mAh): 6277
Fully Charged: Yes
Charging: No
Full Charge Capacity (mAh): 6277
Health Information:
Cycle Count: 0
Condition: Normal
Battery Installed: Yes
Amperage (mA): -31
Voltage (mV): 12153
[/code]