I posted this elsewhere, but it's more appropriate here...
Solar is awesome!,... Unless you like to park your rig in the forrest; Overland in the winter; Overland when it's raining, or there are clouds in the sky; Need a charge at night.
As sexy as solar is, I can't give up my 2kw Genny (8 hours on 1 gallon) and Schumacher FR01235. I get 12amps of battery charging power (day or night / rain or shine), equal to TWO 100w solar panels (approx 16 square feet), which only get their rated wattage about 4 hours a day, pointed directly at the sun, with no cloud cover. Plus, I get 100amp jump start anytime I need it.
5 Gallons of gas will give you the same charging power as two weeks, with a 100w solar panel, in perfect weather.
Total cost: $600
True: It's not as Eco-friendly, but if we were that "Green" we'd all be backpackers ;-)
Also consider: Running your batteries below 50% is hard on them. With this setup, you can avoid that, regardless of weather, latitude, time of year, or time of day.
ONE FINAL NOTE: Whenever possible, I try to only purchase things that serve more than one purpose. Example: If your power goes out at home, this generator can keep all the food in your fridge/freezer from spoiling. Food for thought ;-)