I have 6 solar panels on the roof of the tree house I made for my boys. ( 2 sets of cheapie Harbor Freight panels)
The panels are connected to a charge controller and then to a 12 volt yellow top optima car battery.
Everything in the tree house is powered by the 12 volt battery.
I made light strips by camo painting pvc pipe, and sticking 12 volt self adhesive LED strips to the pipe, and then covering the pipe with clear heat shrink tubing.
There are a variety of 12volt accessories in the tree house (fans, air mattress pumps, security cameras, etc...) and most barely draw any current.
It does have a remote controlled ATV winch that raises and lowers the stairs, and it draws a lot, but I tell them not to constantly raise and lower it, and it works out pretty well.