What’s the biggest mistake people make when sizing generators?

Incorrect Sizing Assumptions

When sizing generators, many individuals rely on general guidelines or rule-of-thumb calculations, such as “one kilowatt per appliance” or “one horsepower per tool.” However, these assumptions are often overly simplistic and fail to account for the unique demands of specific equipment. For instance, a 5-horsepower impact wrench may require as much as 15 amps of power, while a 1-horsepower drill may only need 8 amps.

Calculating True Power Requirements

To accurately size a generator, it’s essential to calculate the true power requirements of each appliance or tool. This involves consulting the device’s specifications, taking into account factors such as starting current, running current, and voltage requirements. A commonly used formula for calculating the power requirements of a device is: Power (in watts) = Voltage (in volts) x Current (in amps). For example, a 120-volt drill that draws 10 amps would require 1,200 watts of power. When selecting a generator, it’s best to choose one that can deliver at least 20-25% more power than the calculated requirement to account for any inefficiencies or fluctuations in the system.

Considering Load Cycles and Duty Cycles

Another critical factor to consider when sizing a generator is the load cycle and duty cycle of the equipment. Load cycle refers to the duration of time that the equipment is operating, while duty cycle refers to the percentage of time that the equipment is actually working. For example, a generator that will be used to power a workshop for 8 hours a day, 5 days a week, will have a different load cycle and duty cycle than a generator that will be used to power a remote cabin for 24/7. When selecting a generator, it’s essential to consider the load cycle and duty cycle of the equipment to ensure that the generator is properly sized to handle the demands of the load.