Heating water takes a lot of energy, and batteries don't have much energy in them.
If you have shore power or a generator, no problem, use your electric boiler.
If you are off grid, these things are almost magical to boil a liter of water fast.
They will boil water faster than a home microwave; they use butane/propane camping fuel.
Backpackers consider them essential gear. My favorite brand is Jetboil.
Since they are backpacking gear, they are ultra light and highly compact.
All the parts stow inside the big cup, including the can of fuel.
Mine is the one shown and has a built in french press to make coffee.
They are not cheap, but good gear never is.
I use mine even when I have a stove set up. It's faster and easier than boiling a pan of water on the stove.
