I have a boat that has two house batteries connected together. Am I able to charge both batteries off of one connection? Which battery charger would you recommend?

Could you please confirm the voltage of each battery and let us know if the two batteries are connected in series or parallel?

Once we have this information, we can recommend the most suitable solar charger for your setup.

How do I choose lithium charging mode or does it detect a Li battery automatically and switch? Will it charge a lithium battery fully?

This solar charger is fully compatible with LiFePO4 (lithium) batteries and does not require any manual mode selection.

Simply connect it directly to the lithium battery, and the charging will automatically starts once the built-in smart controller detect the battery.

Once the battery reaches full charge, the controller will automatically switch to maintenance mode to help keep the battery at an optimal state without overcharging.

I do not see the product dimensions on any of your products. I must be missing them, please advise.

The solar panel dimension is 13.8x9.2x0.7 inch