Slightly off-topic: I found a USB charger for Oral B toothbrushes on Amazon, in case anyone needs one without an inverter availableIMO. No you don’t, we camp for weeks at a time, mostly off site. The only thing we ‘needed’ mains power for is to charge electric toothbrushes. That’s solved by Phillips Ultrasonic which seems to last weeks on one charge. We don’t use gas, just a Wallas XC Duo for cooking and heating.