G’day Peter,
I run my observatory off solar power, I have 2 6v200ah (fell of the back of a truck)to run the mount, cameras dew heaters lighting and whatever else and 1 12v deep cycle battery to run my laptop and can be used as a back up to the other batteries. I have 1 80 watt 4 amp solar panel to charge the 2 6 v batteries and a 40 watt 2 amp panel to charge the 12 v battery .I have it set up so I can charge both batteries at the same time if need to, but most time when I get in the morning both batteries are charging that is the good thing of solar panels
Ian