Generators

How to calculate your backup power needs

This guide to diesel engine generators and backup power generator sizing will help you decide what the minimal and/or maximal power needs are for your individual situation. You will need to choose if you want full, uniterrupted operation of all electrical appliances with some power to spare. This will mean a large emergency generator. Or you can choose the slightly less convenient, but much more economical option: An emergy operating modus where you will switch off some appliances and power users when running on generator power. This online info for sizing your needs should help to decide which diesel engine and backup power generator is best suited.

The indicated values are for your guidance only, some appliances may have a higher or lower power consuption, check the individual operating instructions or labels on the appliance to calculate the exact power consumed.

If you don't need an automatic power back-up that switches over immediately when mains power is lost, you can significantly reduce the size of your generator, by first switching off the appliances that consume a lot of power at start-up, then starting the emergency generator, and after it runs smoothly, adding one appliance after the other, leaving enough time between starting them, so that the power consumption for the newly switched on appliance is at the nominal running value.

If you are calculation your power needs for a permanent generator set up, allow for generous additional capacity. Power needs usually increase over time, and to have your generator run at about 60 to 70% of nominal maximal output will let it run more economically and with less stress on all parts.