IMHO it's like have a 10 gallon fuel tank vs a 20 gallon fuel tank. I do plug it into my battery charger/maintainer often and leave it on maintainer over winter here in Ohio
Mine is 36 volt also. I don't use it to play 18 holes of golf. Just back and forth to boat dock and riding around neighborhood.
I went to Rural King and bought 3 large 12v deep cycle batteries. Still equals 36.
My Century does the wander thing too. Trim all the way down will help some. I think it's the nature of V-bottom boats. I changed out the prop to a 4 blade, cut half the chasing effect and improved hole shot.
I've moved my 19 ft Century I/O 140 with my 1998 belt driven 19 hp Ranch King Lawn tractor. Back garage thru gravel then thru yard to front driveway. Just Sayin.
I had to run new wiring from both switch/sender on my 1979 MercCruiser up and thru blower grill. Fixed it right a few years later when doing Bellows repair.
Short Answer ,No