Club 315w lec

Carolina Dream'n

Well-Known Member
Heat is based off watts used, so HPS is not hotter than another light that uses the same amount of watts. 1 watt = 3.41 btu
I disagree with this. Brand of ballast and bulb used/length of cord can change bulb temp. DE bulbs run hotter than SE bulbs watt for watt. MH bulbs run different temps than HPS. 110v vs 220v wiring will change temps. Too many variables to simply claim 3.41 btu per watt.
 

Yodaweed

Well-Known Member
I disagree with this. Brand of ballast and bulb used/length of cord can change bulb temp. DE bulbs run hotter than SE bulbs watt for watt. MH bulbs run different temps than HPS. 110v vs 220v wiring will change temps. Too many variables to simply claim 3.41 btu per watt.
Take that up with the first law of thermodynamics not me, it's why you can directly convert watts to btu.
 

Carolina Dream'n

Well-Known Member
Take that up with the first law of thermodynamics not me, it's why you can directly convert watts to btu.
Well considering the first law of thermodynamics is law of conservation of energy "energy can not be created nor destroyed it can only be transferred from one form to another."

Heat and work and your two forms.
When we turn on a light bulb we are converting electrical energy into light (work) and heat. as long as the sum of those two equal the internal energy then the law has been followed.

I will throughly stand behind the fact that is not an accurate way to measure heat output from lamps.
 

Chip Green

Well-Known Member
So, I wandered into my local liquidator store to pick up a seedling mat....
There in front of me on the shelf, is a factory sealed box, containing a Sunburst 315 CMH with a Phillips 4200k bulb.... for $150....
There's no way I could leave that just sitting there right? I didn't. I brought it home. I had to.
As a DIY LED enthusiast, I have zero experience with CMH, but I've been quite curious, and tempted to get one for some time now, so I feel like today was a bit of a stroke of good fortune.
Had plans of a new build in the works, but now? This honey ought to suffice for at least 3x3 of a 4x4 tent right?
Absolute worst case, these are fantastic VEG units?
 

Yodaweed

Well-Known Member
Well considering the first law of thermodynamics is law of conservation of energy "energy can not be created nor destroyed it can only be transferred from one form to another."

Heat and work and your two forms.
When we turn on a light bulb we are converting electrical energy into light (work) and heat. as long as the sum of those two equal the internal energy then the law has been followed.

I will throughly stand behind the fact that is not an accurate way to measure heat output from lamps.
Transformed into heat....plants don't absorb enough to make a difference so eventually all watts turn to heat thats why they can be directly converted, proof is in the pudding.
 

Carolina Dream'n

Well-Known Member
Transformed into heat....plants don't absorb enough to make a difference so eventually all watts turn to heat thats why they can be directly converted, proof is in the pudding.
Not sure what pudding you're referring to.
Real life tells me otherwise. Dealing with almost every brand of ballast and bulb out, it's not that simple.
 

ColoradoHighGrower

Well-Known Member
Watt is a unit of power, watt-hour is a measure of energy. High power (fast consumption of energy) is almost always less efficient compared to a lower power option for conducting the same amount of work (i.e., more energy is converted directly to thermal energy and lost to surrounding environment). So two 300w lights will almost always be more efficient par-for-par compared to a single 600w option. Also, balast/cabling/voltage of opperation are almost guaranteed to dominate the differences in efficiency between two lights, not just the bulbs (e.g., a 315w Plix is gonna run different than a 315 Sunsys with same bulb)...
 

ColoradoHighGrower

Well-Known Member
Next run, instead of smoking your stuff, just go ahead and burn your enitre crop and see how much that burning plant material can heat up a CC of water. That would give an approximate measure of energy your plants consumed and converted to chemical potential energy from your fancy heat makers ;)
 

gr865

Well-Known Member
Just a short update on the Monster in my 4 x 4 under the twin 315's.
Day 42 and another trim session. Mainly fan and lower growth.
Around 3 weeks to go.
As I worked on her I would tie her back in a counter clockwise rotation.
20180611_092501 (3).jpg

Got her laid out but have the whole back side to complete.
20180611_092308 (2).jpg
The Mass.
20180611_092302 (3).jpg 20180612_000458 (2).jpg 20180612_002323 (2).jpg 20180612_090028 (2).jpg 20180612_090042 (2).jpg 20180612_090217 (2).jpg

I know I will be doing a bunch more tying and bending.

GR
 

ThaMagnificent

Well-Known Member
I moved my space around and have my plants vegging over my 315s but still using the 3100k bulbs. Plants are drooping and some leaves dying off. Could this be because of the spectrum?
 

gwheels

Well-Known Member
The 4k bulb works start to finish. I used a 3k and I think the 4k would have resulted in better veg and tighter inter-nodal distance. Great deal for 150 and I bet you wont see that again !
 

DemonTrich

Well-Known Member
I found my.clones dont like the t9 942 Philip's cmh too much. Too much ava/b for them, and they start to get purple leaves. Kinda like hardening off a plant for outdoor.
 

ilovetoskiatalta

Well-Known Member
I had them under a 150 w MH and they were fine until I moved then under the 315 and the big girls look like this
My clones go from t5 to 315 cmh 4200k and I raise the light way up(3 feet) and after a few days I lower it a little, I continue this until I get to 20". I do not run cooled hoods. Some strains react better and some react worse.
 

Yodaweed

Well-Known Member
Not sure what pudding you're referring to.
Real life tells me otherwise. Dealing with almost every brand of ballast and bulb out, it's not that simple.
It's called the first law of thermodynamics, you might want to pickup a basic science book bro you have zero understanding of how heat works.

Watts are a measurement of energy.

read this thread if you still cannot grasp this

https://www.rollitup.org/t/heat-from-1200w-of-1212s-vero-29s-cxm-22-cxb3590-compared-to-2x-600w.936071/

Here's a quote you might want to read to get a better understanding of heat.

Yes, good LEDs put out more light.

That light eventually also turns into heat..
Photosynthesis while endothermic is very inefficient so negligible.


Energy that's stored inside the plant doesn't turn into heat (only a very tiny amount).
So 1200W of LED practically produces just as much heat as 1200W of HPS.

But the radiation of the 2 sources is different.
HPS has some IR which will radiate right on your plants and you can assume all of that will turn into heat the moment it hits your plant.
So even if room temp is equal, plants under HPS will have warmer leaves because of the IR radiating on the leaves. Something to consider.

Even funnier if you're trying to grow with incandescent, should be very hard since incandescent bulbs are extremely efficient IR producers and will easily fry your plants even if ambient temperature isn't very high.
 
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