250watt HPS V's 250watt CFL?

the hps system actually consumes more energy than the bulb is rated at.

this thread has lots of good information about lighting - specifically cfl vs hps.

let me know if this helps

 

The ballast from a 250w HID adds 30-40w to the total power draw, 250w cfl ballast does not, so any comparison between the two should take that into consideration. I suspect that most large cfls don't actually draw the power they claim, some manufacturers are actually honest about it... CFL Lamp 125W flowering Plug and Grow - Lighting - Growshop - Dutch-Headshop <this 125w bulb draws 90w, lol

^I think that also explains why one large cfl bulb puts out less lumens per watt than several smaller ones, because the large ones aren't actually drawing the full wattage, but few manufacturers will admit it. Isn't it counterintuitive knowing that several smaller bulbs are more efficient than a single large bulb? I think this explains why.

Any experiment should use a power meter to measure the draw of both types of lighting, then figure for the extra wattage the HPS ballast uses. I'm betting that all things being equal, watt for watt they both put out the same amount of heat energy. HID lighting just transfers more energy into a useful spectrum over a much smaller surface area, while cfl (using less watts to begin with) transfers more energy to conductive or convective distribution over a larger surface area, like comparing a match to a radiator. That's why we get more lumens per watt with HID, because more energy is being converted to light.

That's my basic understanding, would love to see a controlled experiment between the two. I did keep my bare 250w hps bulb about 3-4" from my tops with minimal heat damage, 8" fan blowing right on the bulb. Anybody else notice that bare bulbs yield more than air cooled hoods? Another variable to consider in your experiment

 

another thing to consider about the big CFL bulbs is that they're tubular. this means that one side of the tube is blocking the other from shining down onto your plants. i'm not sure if this affects a manufacturers lumen output rating, because i'm not sure where they measure it from! so the 10k lumens from your bulb may have been measured from the inside of the tube, where it was exposed to every side of the bulb. the hps bulbs only have one light radiation point, with nothing to block the light from itself.

and to not sure - i've heard the glass panels in air cooled hoods dampen your lumen output from the fixture. i've heard they use a specific glass to reduce the number of lumens lost, but it still happens.

 

Same exact location, same cainet, same fans. These were two different runs using the same cabinet, only thing i changed were the lights. THe only difference is the MH and HPS were in a 6in cooltube (open ended for sucking out cabinet air). For the T5 grow I removed the Cooltube, but left the exahust in the same exact location. I use several different temp monitors so I know what water temps are, under screen, above screen, canopy and mounted to the roof. All were 2-4 degrees difference (averaging 3 degrees). Ambient intake temp is constantly 70 degrees with 40% humidity.

I was also suprised at the heat the t5s give off. Granted I wasnt using a cooltube sucking air directly off the t-5 bulbs, but noticed an average of 2 degree above ambient for every dual hood i turned on (108w worth). Maybe thats normal for t5, maybe im just spoiled with the 6in cooltube.... dunno.

Overall, I think a solid MH/HPS supplimented with T5 or CFLs have given me the best overall results. THe suplimental light hasnt given me a noticable increase in weight, but it gives a better spread (tops on the sides grow as fast as the ones in the middle), less stretching and overall healthier and easier to manage girls. PPM uptake has been slightly higher with supplimental t5s, but only by a small amount (50-75ish).

Both style of lights have their advantages and disadvantages. Use them both to their strength and allow the other to correct the others shortcomings.

 

ya, only way to do it is with a power meter and light meter. I hope you try it, i would like to see the results. Can you add a T5 to your test?

 

don't forget to measure temperature differences! i look forward to some test results. i've spent a good minute trying to find this exact information. currently trying to decide between a 400w hps and a large array of cfl's, and i'm going to have to make my decision based on heat management. lumens per degree added, if you get what i mean.

 

Unless heat is a major problem HIDs (metal halide or high pressure sodium) are hands down the way to go imo...

 

if a 250w HPS gives off 25000-28000 lumens and a 250w CFL gives off about 12,000. Wouldn't that mean the excess energy that isn't converted to light/lumens would be given off in heat/infared or some other non visible spectrum radiation? I'm just wondering, it makes sense that the cfl would give off more heat right? I really don't know, any expert opinions?
-My bad i just looked back to page 2, very interesting that cfls don't even draw what they are rated at... I can understand the ballast of an HID drawing extra current, but to rate a cfl at 125w that only draw 90 is just ridiculous! I don't know, but I feel less guilty investing all this time into a cfl setup when you consider all the numbers.

 

There is more than light output to take into account. Light spectrum for example.

Hps have a peak output in yellow/reddish region, witch is more absorbed by plants. Hps is more like a source point of light versus a multipoints of cfls.

Light output is measured by an integration sphere. one bulb that emits xx lumens means all the light output in all directions.

Since we need the light on the canopy of plants, the reflected light suffer losses. Its common to see 15-20% of light losses by material absorption, light scattering and light trapping by objects.

Window Glass for example consumes 6% alone (ie. cool tube).

The technology of cfl is lil different from hps. Hps even heating up much more than cfl is much more efficient in terms of light output than cfl.

hps emits more heat (btu) than cfl, just because of its working principles.

 

The thing that is interesting is the ups puts out double the lumens with only an extra 50% power consumption and still creates more heat energy. I agree that the 250w Mark is a good estimate of where to stop using cfls and switch to hid lights.

 

http://forum.grasscity.com/advanced-growing-techniques/79988-chart-thread.html

theres actually a good bit of information that can be applied to this situation. you *can* determine what color light you are emitting, it'll tell you right on the box. you can then take that color and check some charts on this thread to see which colors effect which processes the most, and pick lighting colors based on those needs.

there's also a diagram illustrating the laws of diminishing light. i think you'll like that too.