Lights use almost double the wattage!!!

[extinctx11]

This threw me into a loop,

MY 250W HPS uses about 450Actual watts (about 4Amps @ 120volts) fully warmed up

And my 400W HPS uses about 700Actual watts warmed up.


This is killing me beause I designated 1 15Amp breaker (only use 70-80% of a breakers rated amp) for 2x 400W Lights, but now I can see that just one will almost max it out! With the fans and the one 400W HPS Im around 8.5Amps total.

extinctx11 Reviewed by extinctx11 on 07-10-2007. Lights use almost double the wattage!!! This threw me into a loop, MY 250W HPS uses about 450Actual watts (about 4Amps @ 120volts) fully warmed up And my 400W HPS uses about 700Actual watts warmed up. This is killing me beause I designated 1 15Amp breaker (only use 70-80% of a breakers rated amp) for 2x 400W Lights, but now I can see that just one will almost max it out! With the fans and the one 400W HPS Im around 8.5Amps total. Rating: 5

[johneg]

How do you know??I hope ur wrong!!

[extinctx11]

I know because my Clamp meter tells me so.

I measured more things tonight. Amps, just multiply by 120 to get watts.
A/C system: 10amps
Oven: 15amps
stovetop: 8amps per top, 11amps for the big one
100W CFL: .1amp
40w incandecent: .35amps
computer + LCD: 1.2~amps
40Watt hot glue gun: .35amps
4x cfls + one fan: 1amp
hot water heater: 15amps
250W HPS: 3.5Amps

so me running my a/c system is like using almost 3x 250W HPS lights.
Too bad you cant cycle the HPS Like the A/C....

[thoughtwriter]

geeezeee....im soooo gonna stop cooking on my stove!!!! strickly grilling for me.....plus i have an eye on my grill, so that should help. I'm down to using 1 window unit for my grow room...i keep the rest of the house .....hot, lol. I will suffer for my plants.

[princedapimp4]

how old is your ballast? After a certain length of use the ballast will actually starting using more wattage than noted and will produce less light. Maybe it is time for a upgrade?

[synergist]

"Less-expensive clamp meters use an average-detecting rectifier circuit that is then calibrated to read in RMS units; it is assumed in their design that the current is a sine wave of the local mains frequency, that is, either 50 or 60 Hz. If either of these assumptions are violated, incorrect readings may be obtained so when such meters are used with non-sinusoidal loads such as the ballasts used with fluorescent lamps or high-intensity discharge lamps or most modern computer and electronic equipment, the readings produced by such meters can be quite inaccurate."

Clamp meter - Wikipedia, the free encyclopedia

I'm not suggesting your clamp meter is one of the less expensive ones but it would explain your high readings if it was.

S :weedpoke: