What if instead of an incandescent bulb he had a resistive load like for am electric hot water heater.
Let's use 240 volts to make the math easy.
If the heating element is rated at 1500 watts at 240v currnet draw would be 6.25 a.
Now if he ran this off his car battery which is 24 volts current draw would be 62.5 a.
Would you agree?
With a resitive load, like in a hot water heater, would the thing heat according to 1500 watts following ohms law? In otherwords at a lower voltage will current increase to still draw 1500 watts? Or are there some other properties which come into play?