It charges its internal battery from whatever supply you have over the course of a day, then when you are cooking it can operate off the battery alone. So it doesn’t really matter how good your supply is because most home users won’t be cooking all day, so it will charge its battery slowly.

It has a 3kwh battery, I’m not sure how powerful the inverter is and it depends on supply but it might take an hour or two to charge from flat.

But it probably couldn’t maintain 700F for an extended period of time. I guess most people won’t need that heat for a long time.