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Old 01-08-2019, 11:35 PM
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Big Sur Big Sur is offline
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Join Date: Nov 2016
Location: The great PNW
Posts: 560

HPS is not the bulb to compare LED to any more. CMH uses less power for the same results as MH and HPS, so ceramic Metal Halide is the one to compare LED to now. And of those, the Phillips CMH bulb is the best. LED ads also seem to be mis-informative. I have yet to test an LED system that had the output as claimed. Most are inferior Chicom produced though. I know that in Europe HPS was more popular, but here in the states, MH was more popular for growing indoors.

By the way, as an electrical engineer, I have to correct you on your statement. Watts are not a measure of current. Current is in amps, power is in watts. In simple terms, watts = amps x volts.

From your LED ad they claim that you can get an 8' x 7.8' growing area at 24" height with 615 watts. That is simply not the case. Light falls off in energy at the inverse square of the distance from the source. If you want an even 2' maximum distance with a 20" x 11" light box, you are only going to get a grow area of 5'-8" by 4'-11". Which is similar to a 630 watt CMH bulb grow area at 3 feet with similar power use. And 2 x 315 CMH bulbs are even better 2 feet above the canopy. A comparison is here:
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