We have a 12v system installed and working.
The battery runs the water system and lights, when they arrive.
We also have a 12v power point for the shower system.
The solar panel is keeping the battery charged and managed and it works inside the window so no need to set it up outside when it only needs a small top-up.
I have also put in another mains power socket ready for extended trips when we need more time inside the van.