Question

Suppose that each headlight of a car uses 3 A and that the driver accidentally left the headlights on. How long will it take for a 12 V battery rated 80 Ah to be fully discharged?

Answer 1

I assume there are 4 headlights. Since each one consume 3A, the total consumtion is 12A. Thus, the time of discharge is:

$$t = \dfrac{80A\cdot h}{12A} \approx 6.7h$$

Answer. 6.7h.