Power-2-Light Challenge: Generator Sizing

Sizing a portable generator for a lighting load can be very complicated. When you use lights sources like HMIs, Kinos, CLF lamp banks, & even LEDs, on generators it matters not only what type of generator you use but also what type of ballasts the lights use. That is because the poor Power Factor and Harmonic Noise that magnetic and non-Power Factor Corrected electronic ballasts (HMI, Kino, CFL, & LED included) kick back into the power stream can have a severe adverse effect on the power waveform of some generators, but not others.

For example, what size generator is required to power a small lighting package consisting of a 800W Joker Buglite and two 40W 1x1 Litepanels? You would think that you could operate this lighting package on a conventional 1000W generator (800W+40W+40W= 880W.) However, when your lighting package consists predominantly HMIs, Kinos, CLF lamp banks, & even LEDs, you must consider the Power Factor of the lights when calculating the load that you will put on the generator. A careful analysis of the Power Factor of the Joker 800 and 1x1 Litepanel indicates that our lighting package would in fact overload a conventional 1000W generator.

If we look at the technical specifications for the Joker 800 Buglite, we see that it uses a non-Power Factor Corrected ballast with a Power Factor of .58. According to the K5600 website, the Joker 800 ballast draws 12.5 Amps rather than the 7 Amps you would think using Ohm's Law (800W/110V=7.2A.) What that means is that it has an Apparent Power of 1375W (110V x 12.5A = 1375W) or draws nearly twice the power to generate 800W of light output than a quartz instrument of the same wattage. Used on wall outlets, this relatively inefficient use of power is negligible because the power draw of the Joker 800 fits easily in a standard wall circuit. However, the greater Apparent Power of the Joker 800 must be factored when using portable generators because the generator must be sized to supply the Apparent Power (1375W), even though only the True Power (800W) provides light.

The same is true when it comes to the 1x1 Litepanels. According to the manufacturer, the AC-to-DC power supply that Litepanel uses for their 1x1 fixtures has a Power Factor of .54 and so draws nearly twice the power (an Apparent Power of 75W) for it's true power output of 40W. If you were to use this lighting package on a 1000W conventional generator, the total Apparent Power of 1525W (1375W + 75W + 75W = 1525W), would overload the generator because the "continuous load" rating of 1000W conventional generators are usually only 850W. Even though it's power is cleaner and more stable, you would not be able to run this package on a Honda EU1000is Inverter Generator either because, with a continuous load rating of 900W, the accumulative load of 1525W would also overload a 1000W inverter generator.

Could you operate this lighting package on a 2000W conventional generator? Again, the answer is "no" because the greater Apparent Power of lights with a poor Power Factor is not the only consideration when operating them on conventional generators. Of equal importance, is the Harmonic Noise that ballasts with poor Power Factor kick back into the power stream that severely limits the total amount of Leading Power Factor loads, as compared to Unity Power Factor loads, that can be reliably operated on conventional generators.