Another Club Car Ds charging question.

[sand dune coon]

I search and searched but couldn't come up with anything, so here goes,,,,,

I just acquired 1999 golf cart. cart has been recently refurbished, very clean cart that came from a knowledgeable owner.

I bought new batteries but didn't check pack voltage before my initial charge. after the first charge which seemed quick did and i got 51.1 total pack voltage and all individual batteries were 8.51 or 8.52.

no matter how many times i put this cart on the charger it turns off so i cant get it above 51.6 = 80%.

when i pug in the charger there is a click then a pause then it starts charging at 15 amps but quickly goes down to 10 amps then 5 amps and turns off. that whole process take probably 20 - 30 minute at this point. i did put my meter on the pack when is was charging at 10 amps and pack voltage was 60 volts.

The charger I'm using is the club car power drive, pretty sure its the first generation.

Any help would be greatly appreciated.