Possible battery issues or charger issues

[parcarnick]

Hi
I was wondering if anyone could help me.
When i charge my 1989 par car for 12 hours, i only get like an hour or 2 at most out of the charge. Is that normal? I believe the charger is pretty old, it maybe the orignal not sure. When its charging it hums and the needle goes to between half way and 3/4. I think my batteries are around 4 years old, so i think that may be the problem. Any help is appreciated.