My kettle is a boiler wired under the sink. But a normal 2400w kettle in countries with 240v outlets plugs into the wall. It's not really the kind of appliance

My kettle is a boiler wired under the sink. But a normal 2400w kettle in countries with 240v outlets plugs into the wall. It's not really the kind of appliance you want battery operated either. My toothbrush is already USB charged. I think for those small / battery charged applications you mentioned we'll get there pretty soon.