MacBook battery replacement successful ...but

Mi Problema

MacBook would randomly shutdown even when connected to power and battery life was extremely poor. Battery reported that it needed service.

Mi Solución

The repair went smoothly and only took a few minutes. MacBook worked without a hitch for a week but now it sometimes won't recognize that the power is connected and therefore wont charge the battery. When this happens I have to shutdown the MacBook, open it up again, disconnect the battery and reconnect it. MacBook will then be fine for a day or so but then the same problem.

Mi Consejo

Need advice. I replaced the 60Wh battery with the 63.5Wh which iFixit says is OK. The serial number on the new battery is different to that reported in System Profiler (there was no discrepancy with the old battery). Is his normal? Could the new battery be faulty?