EZGo TXT 2010 model jumps when start

[EZGoRider]

My 2010 TXT Electric 48V (6 x 8V) cart started acting up, lurching on take off, finally smoothing out. Runs normal after speed is attained until next stop and take off, then lurches again. Repeats the above

I was told by the dealer that it was probably the cables. I took all the cables off, cleaned terminals and cable ends and replaced a bad end. Cart still lurches. The cart is 7 year old but is it time for new batteries? How do I test the batteries to determine if they need replacing? Could it be the controller or some other problem? I would like to replace all the cables with 4ga DC wire and proper connectors but can't find the wire any where. One place said it would take 15 feet and costs would be about $75 for fine strand 4ga wire. Any ideas?

[EZGoRider]

Although I thought that I had plenty of water in the batteries, I checked them yesterday and they were almost dry. It took 3 gallons of distilled water to fill them, that is 1/2 gallon per battery. I put the charger back on and am letting it charge fully to see if that is what the problem is.