OP, your 10amp charger at 14+ is your best option. You also have the Honda's 8amp to 16v if you have the cable set for it, but since you can't use that and run anything else from the Honda at the same time and that will take a long time too, suggest forget that. When the Honda is running take advantage of it being on to run things instead of waiting till you have to do the same things on battery where possible.
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If you have an extra pair of batteries, you get Way More AH value if you put them in parallel with the other pair while camping and they are drawing down. Peukert rules! Doesn't matter if they are different batteries and all that--it is just for a few days.
Instead of using each pair one at a time like that, park the truck close to the trailer and use jumper cables to parallel the two sets of batteries. Or better still if you are using the truck a lot, just put the extra pair on the ground by the tongue.
When recharging by generator if available, leave them in parallel and both pairs will do the 50-90 or 50-80 whatever you do. Once back home of course you will recharge each pair separately to 100% and then go to Float.
