How can you determine the length of time that equipment can be powered from a battery?
Divide the watt-hour rating of the battery by the peak power consumption of the equipment
Divide the battery ampere-hour rating by the average current draw of the equipment✓Correct answer
Multiply the watts per hour consumed by the equipment by the battery power rating
Multiply the square of the current rating of the battery by the input resistance of the equipment
Explanation
A battery's ampere-hour rating states how many amperes it can supply for how many hours, so dividing that rating by the average current the equipment draws gives the approximate running time. Using peak power instead of average current would badly underestimate the time.