Solar panel mounted on my truck, but I still need to run the wires and hook up the fuse. I estimate it will do about 4 amps in bright sun or about 50% output due to lack of a perfect angle. The panel is 100 watt or 8.5 amp but we don’t have that kind of sunshine outside of laboratory.

Unless it’s a bright sunny day, parked in the sun all I probably won’t be able to get the accessory battery to full charge this way, but combined with the alternator running while driving, I should easily be able to get close to 100% most days camping after a 15-30 minute drive plus a few hours parked in the sun.