I thought of a way to use this monitor on a car that shouldn’t cause any trouble with the warranty. Modify just the battery. Is there a gadget like a battery cutoff switch that fits on a battery post and provides another post to hook up to the car’s battery cable? And it must have room for the Hall Effect sensor loop to go around the conductor from one part to the other. I have a friend who can Silver solder; maybe I could cut a standard cutoff switch in half and get him to solder a copper rod an inch or two long between the two halves.