Solar Panels & Controllers
In order to keep the second battery in my 4Runner and the dual batteries in my AT Overland Horizon off road trailer charged while camping, I use solar panels and Morningstar controllers. I purchased both panels and accessories from CaliforniaPC.
For the 4 Runner I use a PowerFilm 90W Foldable solar panel and a Morningstar SunSaver SS-6L-12V. This is a 12V PWM charger so it throws away any excess voltage resulting in less efficient use of the solar panel. In the future I will likely upgrade to a MPPT charge controller for my vehicle or future vehicle. The PowerFilm panels use Delphi weather pack connectors and you can get connectors kits to make your own custom cables and connectors.
For the trailer I use a P3Solar 200W EZ Out System. This operates nominally at 24V so you need a controller to handle 24V. I installed a Morningstar Sunsaver MPPT TrakStar SS-MPPT-15L which can use both 12V and 24V panels. The MPPT technology also converts extra voltage to amperage so your battery charges faster. The P3Solar panels use SAE connectors so you have to make sure the polarity of your connections is correct. I made Delphi Weatherpack to SAE converters and vice versa so I can use either panel on my off-road trailer. I also have a parallel cable so I can use both panels at once on the trailer. The P3 Solar 200W Ez-Out system includes a folding aluminum stand that holds the panel at 30°. The stand can be staked down at the two front aluminum bars and two straps attached to the back corner legs and a longer strap to the center top of the panel. As long as it is not windy you can leave the panel unstaked then rotate around as the position of the sun changes.The rollable panel has Velcro on the top corners that hold the panel to the frame. on each side there are two cinch straps to cinch the panel to the frame. There is a fiberglass rod designed to attached to the two front corners of the panel. The rod openings are too small making them difficult to get the rod in and the rod is actually slightly too long to fit anyway. It isn't really needed and I don't see any advantage it gives. The system comes in a bag. The easiest way to pack up is to roll the panel and insert into the bag to expand. Next insert the cardboard tube in the bag so the solar panel is wrapped around it. The folding legs and stakes go inside the cardboard tube. The tube protects the solar panel from abrasion and damage.
The size and weight ratio of the PowerFilm Solar panel can't be beat. However you can't get rollable panels in higher wattages. I chose the P3 Solar for the highest wattage for the same price and the angled stand to optimize the collection of solar energy. Since it is stored and transported in the trailer size is less of an issue but this thing is still big and heavy. Fixed rigid panels are the cheapest per watt but are heavier and also take up space and need protection from breakage. Ideally I would like a folding stand for a larger wattage foldable PowerFilm panel.