Years ago, when I was traveling Australia out of my car, my dad gave me a travel inverter. I love this thing so much.
Basically, the car power inverter plugs into your car auxiliary power outlet (aka cigarette lighter) and it has electrical outlets to power your electronics and your kettle.
Not only does it give you electricity on the road, but if you’re traveling internationally, you don’t have to worry about getting a converter for your gear. The inverter will fit plugs and voltage requirements for the country you bought it in.
In Yellowstone, the inverter worked perfectly for making hot meals from any picnic area parking lot.