kind of off topic but maybe not when i was young my dad used to have problems with alternators on his tractor we had a white tractor with a 3208 engine pretty big unit pulling a big john deer pull type combine . we would combine all night once i was old enough , i had rigged up 4 - 3 wide banks of 7 inch halogen automotive (12 lights) headlights. 2 sets on the tracor and 2 on the combine this plus the factory lights lit up the county as i would run the high and low beams at the same time for more flood light action.
to get a idea what this would draw i had to use light welder cable and jumpers onto the battery to run this monster. hook them up when it gets good and dark and instant sun this semed to be ok for a while we had already one of the huge dodge style 120 amp alternators on the tractor . it actually held out pretty good till poof up it went.
we got another alternator hooked up and i took a another older gm alternator and instead of running it off a regulator i ran it direct as when i hooked up the lights it activated the alternator and away we went . they burnt out too but it would still last a pretty long time as only using at night . had lots of the old style gm alternators as could get them for 10.00 apiece .
i think the dual battery idea and a big alternator would work better in this application as it is perodic high amp usage as opposed to putting a huge draw on a system and leaving it there.
already had 2 huge batteries on a tractor anyways.