I am getting 13.9 v from the solar panel on a sunny day. It keeps the battery nicely topped up, replacing the drain from the tracker I have installed. I am going to investigate having a portable 100W solar panel that I can connect into the cabling I have installed, so i can use it whilst travelling too. It will mean a different Charge Controller (MPPT), though. I may also/instead go down the route of gluing flat solar panels to the top of the pop up roof and running cabling down through the wardrobe as others have done on here. Makes sense with the current price of electricity!