You are looking for the "Holy Grail" of kettles, Jane. If you want one that boils quickly and works using 12v then the amount of water boiled is going to be very small indeed. Better to have two kettles, one ordinary, domestic(not fast boil) which will work off the mains in your van and one with a 12v heating element for hubby. You could also consider using a low wattage 240v kettle and an inverter if mains isn't available.