Some rules for converters.
If running a bank of batteries (not multiple banks) total the Amp Hours (remember if you are putting pairs of 6 volts you add voltage when you put 'em in series not amp hours so 2 6V 220 amp hour batteries in series is one 12V 220 amp hours.
But add up all the 12's multiply by 0.30 (30%) and that's your converter size.
Progressive Dynamics 92xx is my choice.
Now if you are using multiple banks of batteries or swapping them out you need to read about something the name of which I can not recall the spelling of.
But a link to it I can find... The moral of the article is that if one battery runs you 2 hours. and you put two in parallel instead of 4 you get more.
https://www.engineersedge.com/battery/discharge_rate_temperature_effects_battery.htm
