Portable solar panels will work, providing you have enough panels ( I would say 200w minimum, more is better), you can keep them tilted toward the sun all day (difficult without constant attention) and you can keep them from being stolen / broken (most difficult). It took us years and a set of batteries before a slot with 120v shore power came open at our storage yard. Output from one, 100w solar panel is about 5 amps for about 5 hrs/day. Cloudy days you won't see much from the solar. Oh, and use big enough wire (4ga) to keep any voltage drop to a minimum. Or take your batteries home with you and keep them pn a trickle charger (easiest, cheapest).
