How much horse power does an 80 amp alternator require?

The amount of horsepower required by an alternator is determined by its output capacity in terms of electrical power, not its amperage rating alone. The relationship between horsepower, electrical power, and amperage is as follows:

Horsepower = (Electrical Power in Watts) / 746

Electrical Power (Watts) = Voltage (Volts) x Current (Amps)

In the case of an 80 amp alternator, the voltage output is typically around 14 volts (V). So, to calculate the electrical power in watts:

Electrical Power (Watts) = 14 V x 80 A

Electrical Power (Watts) = 1,120 W

Now, we can calculate the horsepower required using the formula above:

Horsepower = 1,120 W / 746

Horsepower ≈ 1.5 hp

Therefore, an 80 amp alternator requires approximately 1.5 horsepower to operate effectively.