Lighting question

My golf cart has front and rear lights the previous owner had wired into a single battery.

I know from the forum, the lights should be wired into 2 batteries or 12 volts. And better yet, to put in a voltage reducer from 36v down to 12v...

Questions

1) my lights were not very bright... Could this be because they were wired into 1 battery?

2) the wiring to the lights look like a big mess...seems the wiring is real small that runs from the battery to the actual lights...not sure what that gauge is. Could this wiring cause a lot of heat on the terminal and cause a terminal melt down? Don't know if I want to hook the lights back up to my new battery pack without knowing if this can generate a lot of heat or problems?

Thx

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