An ECE110 student decides to "go off the grid" and powers his house by batteries. On the first day, the electric power usage for the household was 29 kW-h. He must recharge his batteries using a bicycle-powered generator with 92 % efficiency. For how many hours must he now pedal the bicycle at a peak power of 560 W in order to recharge to the batteries?

Question

Engineering

China

1 March, 14:43

An ECE110 student decides to "go off the grid" and powers his house by batteries. On the first day, the electric power usage for the household was 29 kW-h. He must recharge his batteries using a bicycle-powered generator with 92 % efficiency. For how many hours must he now pedal the bicycle at a peak power of 560 W in order to recharge to the batteries?

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Answers (1)

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Kadence Giles · Answer 1

47.6 hours

Explanation:

Efficiency = energy output/energy input

Efficiency = 92% = 0.92

Energy output = power * time = 560/1000 kW * t = 0.56t kW-h

Energy input = 29 kW-h

0.92 = 0.56t/29

0.56t = 0.92*29

0.56t = 26.68

t = 26.68/0.56 = 47.6 hours