1. Multiply the number of watts by the number of hours to calculate watthours. As an example, if you know your laptop computer uses 30 watts of power and you want a battery to power
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Divide the watts by the voltage of the circuit.
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1 Familiarize yourself with the quantities involved. To understand the relationship between watts and amps, you will need to understand 3 different units: watts, amps, and volts.
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Amps = Wattage / Voltage Thank you for using ChaCha!
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