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Old 12-29-2012, 06:42 PM   #7
MaestroPNW
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Joined: Jul 2010
Location: Greater Seattle
Oddometer: 82
Easy - just measure the resistance of both together in parallel. Assuming it's "R" Ohms, plugging them into 12V will produce I = 12 / R amps. The consumed power then will be equial to 12 * I = 12 * ( 12 / R ) = 144 / R Watts
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