Generator Power Understanding Guide Australia. Start with a clear picture of what you need to power. Consider:
- Total load (kW/kVA)
- Startup/surge currents
- Duty cycle and daily run times
- Future expansion or additional equipment
Correct sizing prevents equipment strain, downtime, and unnecessary fuel or energy costs.
The size of generator will depend on the total load of the equipment that you want to run on the generator at the same time. If the generator is to be used for back up only, then we recommend you select only essential services to run off the generator – such as security systems, refrigerators, freezers, essential lights, TV’s and computers. This will provide a more cost-effective investment by utilising the smallest generator necessary.
A generator’s size is indicated in watts. To decide what size portable generator to purchase, determine your power needs.
Most electrical products have a tag indicating the amps and volts required to operate or may list their wattage. Amps multiplied by volts equals watts.
- For light bulbs, hot plates, toasters, and space heaters, figure the wattage by multiplying amps and volts. Do this for each item and add those figures for the total wattage needed.
- For example, the wattage of 3 light bulbs at 100 watts each totals 300 watts. Add a 1,000-watt coffee maker, and the total is 1,300 watts. Each additional item adds more wattage until you determine your total load in watts.
- When a motor is required to start an appliance, it will require more wattage, such as refrigerators, freezers, water pumps, Air conditioners, etc. They may need 3 times the rated power required to start up. To determine the appropriate wattage needed for 1 of these appliances, multiply amps x volts x 3.
Total all the wattage to calculate the size of the generator needed.
When you shop to purchase your generator, you'll see a surge wattage shown on the side (2,500W, 3,000W, 5,500W). It's important to note the difference between surge wattage and rated wattage.
- Rated wattage is the amount of watts available for continuous running; surge wattage is the amount of watts available for a short time to start up an appliance with a motor.
- A generator’s rated wattage is less than the surge wattage.
- For instance, a 5,000W generator will deliver about 4,500 continuous watts.
* This sizing information is intended for estimating purposes only. Actual power requirements of high-demand appliances vary widely by brand, model, and capacity. Please have an authorized dealer or qualified electrician analyze your specific needs before making a purchase or decision.