My two batteries are Optima 12-volt, 75 Ah, deep-cycle, and zero-maintenance!
The Optima batteries may be purchased through Amazon.
Optima Batteries 8040-218 D35 YellowTop Dual Purpose Battery
Charge Controller by Morningstar:
Remote Meter by Morningstar:
A reader asked . . .
. . . for the size of the wire leading from the charge controller in the Perfect Tow Vehicle to the Anderson plug at the bumper and then leading to the Best Little Trailer.