1999 48 volt Club Car slow after battery change

[Ken Kroll]

My 1999 48 volt club car quit on me. I had 2 bad batteries so I installed 6 new duracell 8 volt batteries. The cart works but is a lot slower than before. It goes faster at 1/2 throttle than full throttle. Seem to speed up and slow down withou me adjusting the throttle. I wired the batteries just like I took them out. I have 52 volts from positive to negitive. Could I have had another problem that I didn't observe because I had two bad batteries? Any help to get my speed back would be appreciated.

Thanks

Ken