"More energy than can possibly be stored." For it to be a real test you'd have to exceed the total energy output of any plausible chemical system. Calculate th

"More energy than can possibly be stored." For it to be a real test you'd have to exceed the total energy output of any plausible chemical system. Calculate the total amount of energy of a stoichiometric mixture of, say, liquid oxygen and kerosene, and then draw power until you have exceeded that. At that point you can be pretty damn sure it's not a chemical battery.