All kinds of possibilities from solar to multiple batteries.In our case we dry-camped on Gabriola Island,BC for 3 days and nights. No facilities outside the Plateau B. One battery. We were grateful for the genset which I cranked up to charge the house battery and give us some LIGHTS. Sure, running the diesel engine would have charged the battery faster but, there was a NOISE prohibition with NO engines allowed to run but,but, a genset was allowed for short duration use ie charging battery. Would not be without a generator.Period. But to each his/her own!!!