All the electronic is already in the charger he wants to use. One of the panels I suggested is the only thing he needs whit his charger.

Oh? And what will that charger do when provided 6V from the panel?

 

Those panels are not designed to be used in the dark.

And the charger requires a regulated voltage input, which no panel produces. But fortunately that is a common problem with many solutions developed and available off-the-shelf.

If it were me, I think I'd look for a solar charge controller meant for a 12V system. That would enable including, or not, a 12V battery into the rig. That could come in really handy if the car battery back at camp gets drained. This rig could be plugged into the accessory port and used to add charge to the car battery. Or it would allow the car battery to help charge the smaller batteries. Lots of versatility and a 12V charge controller is a very common item these days. Pretty sure the big box stores even have them.