My Macbook pro has to charge overnight to get an even usable charge (usually 50%), and when I unplug the charger from it drops to around 1-6%. I just replaced the battery and coconut app says its fine, charging with enough watts, etc. Have no idea what is going on.
Edit: should note, it only charges when off. When its on it claims its not charging. Unplugging the charger while its on causes it to drop or completely turn off.
Logically, there are three possibilities:
a) the charger is faulty
b) the power management unit is faulty
c) the battery is faulty
The charger is the easiest to test: see if you can find another Magsafe 2 charger.
Realistically, the other two need to be tested by an Apple Store or other authorised/qualified technician.
Apple don't sell replacement parts to the public, so any battery you bought will be a third-party attempt to match the specification (within costs). Printed text saying "Designed by Apple" etc is unlikely to be a guarantee of anything.
