battery loses charge

a friend has a 2000 (?) neon and he has made sure that the alt is good, but when he charges the battery it is weak the next morning. any suggestions???
aaron

How old is the battery. It could be sulfated out. If it is the original one, it is a few years past its time.

Make sure nothing is left on. I had a Pontiac that the radio would stay on, even with the key out, if you shut the car off with the a/c on.