Time: 3 MONTHS
A motorcycle battery stores energy gathered by a 50-watt solar panel on the caravan’s roof. A modified plug-in car inverter transforms the battery’s DC output into AC, and a charge controller conditions power for common electronics. Chambers and Reinish say their system collects enough juice to run three devices—e.g., LED lights, a portable fan, and a laptop—for at least three hours.
Borrowing the travel-light tricks of pioneers, such as rounded caravan walls, helped the couple trim their home’s weight and cost. Corrugated steel gave structural support without the heft of wood planks, and waterproof canvas made for a suitable ceiling. They also skipped insulation, built a mattress out of straw, and dual-purposed couch cushions as dirty laundry sacks.
A sink in the caravan drains through a hose in the wall and into a five-gallon jug for disposal. A four-gallon solar shower, essentially a black plastic bag with a hose and perforated nozzle at one end, soaks up solar rays in the morning to provide hot showers and dishwashing water. Coming soon: a composting toilet.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.