Electric rigs are more common that many think. EarthRoamers and GXV rigs are all electric. Neither run on propane nor have a generator. For a standard slide-in truck camper to have the same capability, it would require at least four group-27 batteries and a minimum of 400 watts of solar. Most campers don’t have the room for that many batteries, which is one reason why flatbed campers are so popular (flatbed here can mean either a true flatbed camper or a standard slide-in truck camper mounted on a flatbed with storage boxes like those made by SherpTek). Flatbed campers have the room for more batteries, more water, and other goodies sought after by overlanders and those who full-time in their campers.