[quote=JLATD]Ohm's Law can help us determine how much current we will need.

Current (Amps) = Power (Watts) / Voltage.

This isn't what they told me when they explained Ohm's law

Ohm's law: voltage = current x resistance

Well, we can't use that formula because we don't know current or resistance in this case. That is why we are looking for current.

Voltage = current x resistance

Voltage = SqRt (power x resistance)

Voltage = power / resistance

We already knew Voltage (12.5V) the question was what can the car handle (current).

Current = voltage / resistance

Current = power / voltage

Current = SqRt (power / resistance

Because we only know the amp's power and the available voltage, the formula to use was correctly stated as

Current (amps) = Power (Watts) / Voltage.