A powerful F-16-1800 30 Watt Flexible solar panel. Includes the Morningstar charge controller so your batteries will not be boiled off by over-charging. Has a female 12 V socket adaptor to connect any 12 Volt goodie that can hook up to a car, like USB chargers, inverters, whatever. Also has a long lead with eye connectors to install to your battery installation. All this would run you over $400 on Amazon. $300 shipped or trade for Nikon Pro lenses. Shipped via FedEx Ground with shipping, Paypal gift accepted.
It is my spare unit for the truck in Mexico, but never brought it down, determined it would grow tiny feet and walk away. There is a huge variety of adaptors and splitters and so on available for this series of chargers. Folds flat and weighs next to nothing. You can put it up with bungies. A lot more useful than rigid panels.