TXT Series cart upgrade question

[unknown1]

New guy here. I recently was gifted a 36v EZ-Go Series TXT with a few goodies on it including the rear seats, some kind of lift, 22x11's, a Curtis 350A controller and a few other cosmetic goodies. The cart runs great but seems to die pretty quick. I went ahead and swapped out the #6 cable for some copper 1/0 with soldered lugs although it didn't seem to make much of a difference.

I am guessing it is due for new batteries but is there anything else I should be replacing? I was thinking maybe a heavy duty solenoid since mine gets somewhere between warm and hot after driving around.

Suggestions appreciated!