batteries

Hi
If you use power from them, they will need topping up ie charging.
How ?? depends on if you are bush camping [no power ] or cps with power Also if you will be driving a reasonable distance every few days or so & what you intend to use & for how long each day.

Fully charge them and then disconnect them.

charge with a 300w inverter and 12a 2 stage Jaycar battery charger. Use Redarc to switch inverter on and off automatically. Friend has this setup and has fully charged battery every night. Until traveled for 3 wks with friend did not realise how good this was. Making a back up system the same for when the sun does not shine.

If its a wet cell deep cycle, it will lose more voltage than an AGM deep cycle. But no matter what, charge them before you leave, remove the earth leads from both batteries and recharge when you get back.