In your case if its a similar light spectrum you could use a cheap lux meter. Lux meters aren't good at measuring actual par but are good to measure relative intensity if it is the same spectrum. If different spectrum all bets are off. Then you could set your lights up and possibly raise and angle, lower and angle, etc until you get some even coverage. Or center the 600w over 2/3 of it and the 300w over 1/3 of it if you go no meter. Putting it in all in the middle would still work, just not as even. Up to the grower how much they value their time screwing around.
Do two 300W LED lights equal 600W?
- Thread starter Justones
- Start date
The LI-COR LI-1500 seems to sell for $1600 to $1,950, and that may or may not include the sensor (if not, add a few hundred dollars, probably). But this seems to be the real deal (and is well thought of by lots of people), should last for many years, and maybe you could share the use - and the cost - of it with friends in order to help offset your expenses.
There are cheaper ones being sold. I just saw the "Sun System PAR Meter w/ Remote Sensor" on Amazon for $329.95. But one reviewer stated: "Wrong reading 30% off compared to a real spectrometer will vary with different LED spectrum and for the price definitely not worth it. It is just a reprogrammed LUX meter that you can buy at 20 dollars." So, as in all things, it would be a really good idea to do your research before purchasing a random PAR meter, because it might turn out to be a "PAR" meter
.I found a video on YouTube that discusses the LI-1500, and you might pick up some useful general information from that. It also compares three cheaper meters. The video is presented by a reefer, and intended for others in that hobby - so you'll notice that they're using underwater sensors and/or underwater-specific versions of the meters. But I would expect the quality of those companies' similar-priced "terrestrial" products to be comparable, so it could still be worth the time (18m 15s) to view it:
Moderators: I would consider the video to be relevant to this discussion. In other words, not off-topic
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Th34v4t4r
Well-Known Member
I'll have a look at how much lux meters are. The par meters are well to far out of price range for the sake of a small hobby grow... it would be interesting all the same.
The lights will be exactly the same. The only difference is the 600w has 120leds on 4 boards and the 300w has 60 on 2 boards.
The angles, spacing and power take per led is all the same .. I'm sure if I bang them as close together as possible it'll just increase my coverage and canter par reading. Obviously I can't prove this... not unless someone throws a meter my way
The lights will be exactly the same. The only difference is the 600w has 120leds on 4 boards and the 300w has 60 on 2 boards.
The angles, spacing and power take per led is all the same .. I'm sure if I bang them as close together as possible it'll just increase my coverage and canter par reading. Obviously I can't prove this... not unless someone throws a meter my way
The specs that you posted list the draw on the 300's is 136 watts. I am with purple gun rack. The 300 rating is the max for the diodes. 60 diodes rated at 5 watts a piece (60 X 5=300). The companies don't run them at 100%. It's usually 40-50% of max to get The maximum life out of them.
If they did, without seriously upgrading their heatsinks and fans... Most of their usable lifetimes would probably be measured in seconds.
Just another reason why advertising a (just for example) 136-watt device as a "300w" one ought to be considered fraud, and be an offense that such sellers could get prosecuted for, IMHO.
parnelli
Well-Known Member
Has anyone daisy chained a cfl lamp with an LED lamp? I have a slight concern that plugging the cfl into the LED daisy chain socket might damage the LED power supply. Any thoughts?
Th34v4t4r
Well-Known Member
Yh I wouldn't do it no way. Chancing overloading the chipboards through the cheap circuits ain't going to do anybody any favours.
Leopold Bloom
Well-Known Member
I went through the same thing I had blurple lights so I said to hell with them and bought me a Quantum board problem solved
Fuzzyroots
New Member
Yes, if the lights are a true 300w, putting them on the same circuit will give you 600w from the wall. They are both still 300w led lights though and it's not the same as having a 600w light. The footprint is larger, penetration may be slightly better but par is virtually the same.
Fuzzyroots
New Member
Yes, you will pull 600w from the wall but the lights will still be 300w lights. Par will be virtually the same. Footprint and overall lumins will increase. You will produce higher yield, but still won't be the same as having 1 600w light.
More "angles of light" = less shading on lower canopy...
Without considering efficiency:
Think of a 100w flashlight beam (single light source like a spotlight) and you put your hand in front of it... the shadow would be huge and block most of the light....
Now take a 100w LED panel where the leds are spread out (like a floodlight) and put your hand in front of it... only a small portion of the light will be blocked and the shadow will be much less dark because of the "angles of light" from all of the other diodes
More surface area of lights will allow for less shading and better canopy penetration, than a single light source hung above... same reason why a lot of growers in the HID era used light movers with success, which eliminated shading and hotspots on the canopy.
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Penetration in terms of plant lighting also has a lot to do with spectrum. A white LED light will have better penetration than a "blurple" because the white LED has more green in the spectrum, which is absorbed, but not as efficiently as red/blue, therefore it reflects off leaves better and the reflected light can penetrate deeper into the canopy than red/blue. This same concept also happens within the leaf itself, where green light penetrates deeper in the leaf mesophyll because the green light bounces off the chloroplasts within the leaf hitting the stacks where light is absorbed much better than blue/red.
At the end of the day, a single light source or 2 light sources are not going to make a huge difference if using the smae wattage... Personally I would go with 2x 300w lights vs 1 600w because you have much more flexibility, less shading and can get the lights closer to the plants... the aim for all growers is to have a nice even canopy lighting, no hotspots and have even PPFD across the canopy.
Delps8
Well-Known Member
In terms of PAR that can be used for photosynthesis, there is no usable par below the canopy level if there is a leaf between the light source and the target.
