New batteries and only goes 10' then stops

I’m trying to help an elderly man next door. He owns a 2002 Think Neighbor. I’ve replaced the gel batteries with wet acid ones. Can anyone tell me what to do next?
It has a DeltaQ charger and indicates it has an electrical leak. I tried to re-program the instrument cluster. I followed the instructions, but it did not respond as it should; therefore not able to re-program the charger.
I live in Georgia and don’t know where to take it for service…please help.