Chosen Solution
Hello, I just installed a new battery from iFixit in my mid-2010 17” unibody MacBook Pro. It seemed to charge okay and reached 100%, but twice now it will quickly go from approx. 65% to less than 10%. What’s going on?
Either battery was defective from factory, or it has gotten hot on it’s initial charge. One fix that seems to work half the time for me come out of a Popular Science issue yeas ago: Remove battery from machine. Place in freezer for at least two full days. Plug back into charging system right after removal. (Moisture will be coming off the battery for a bit—-keep the battery out of the machine so no moisture damage’s it). Monitor the battery temperature by touch while it is charging. If it starts to feel unnaturally warm, unplug the charger for an hour or so or until the battery returns to room temp. Restore charge and monitor temperature again. Repeated heating up would suggest a detective battery. Be sure battery is wiped completely dry before re-installing it into your machine.
