Answer
There is a 32 percent increase in power at the higher voltage.
Work Step by Step
Use equation 18–6b, $P=\frac{V^2}{R}$.
$$\frac{P_{13.8V}}{P_{12V}}=\frac{(13.8V)^2}{(12V)^2}=1.3225$$
The power increases by about 32 percent.
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