Are there any benefits to oversizing an LED grow light.

[Spock]

Hello everyone,
I was wondering if there were any benefits of oversizing an LED grow light and then dimming it to 1/2 or 2/3 it's wattage? Would the same amount of heat be generated from a 600 watt LED light running at 300 w as a 300 watt LED running at its full 300 w? Will the diodes last longer running at half power? Does anybody oversized their light and run it a little less than full power?

Thanks in advance for any opinions or knowledge.

 

[chemistry]

Its not good for your LED's to be run at 100% all the time if you want them to last long enough get your money back, so I bought over size with dimming ability.

 

[totamus]

I dont think there is any advantage other than having the ability to adjust light should you ever need it. A larger light, that is dimmed, will generate MORE heat than a light that is running at 100% and generating the same light output. This is because the power supply is larger for the larger light and it requires more idle current than a smaller power supply. That said, I prefer larger lights because I find that I am always reconfiguring and trying different things - thats the fun part for me!!

 

[Spock]

Its not good for your LED's to be run at 100% all the time if you want them to last long enough get your money back, so I bought over size with dimming ability.

I was thinking the same thing. I'm thinking of adding a supplemental light type of thing for flowering because sometimes my grow gets a little big. I think it would benefit by adding another light as my plants grow sideways. So I'm looking at the Mars hydro sp3000 or the sp6500. I probably only need 300 watts but for like an extra $200 I could get the sp6500 which has a lot more diodes and double the wattage. And then I would probably only need to run it at around 300 watts. And if it lasts me longer that would be worth spending the extra money.

 

[Spock]

I dont think there is any advantage other than having the ability to adjust light should you ever need it. A larger light, that is dimmed, will generate MORE heat than a light that is running at 100% and generating the same light output. This is because the power supply is larger for the larger light and it requires more idle current than a smaller power supply. That said, I prefer larger lights because I find that I am always reconfiguring and trying different things - thats the fun part for me!!

So it would run hotter. Darn I was hoping the opposite would be true. Thanks for the info!

 

[growsince79]

So it would run hotter. Darn I was hoping the opposite would be true. Thanks for the info!

The best benefit I can think of is more uniform light distribution. The higher the light the better the distribution. That only works if you have a very powerfull light and enough vertical space.

 

[Spock]

Its not good for your LED's to be run at 100% all the time if you want them to last long enough get your money back, so I bought over size with dimming ability.

Do you think the manufacturers exaggerate the amount of hours these LED lights are good for before there light output drop substantially? I haven't had mine very long.

 

[tbd100]

Do you think the manufacturers exaggerate the amount of hours these LED lights are good for before there light output drop substantially? I haven't had mine very long.

Probably. They are usually quoting average rated life, which means half of the chips will die before. And the chip manufacturers they buy from are probably quoting optimum figures in optimum conditions.

 

[Ponky]

Under driven loses efficiency.

 

[Dub_City405]

Get the 6500.

 

[Frankster]

Hello everyone,
I was wondering if there were any benefits of oversizing an LED grow light and then dimming it to 1/2 or 2/3 it's wattage? Would the same amount of heat be generated from a 600 watt LED light running at 300 w as a 300 watt LED running at its full 300 w? Will the diodes last longer running at half power? Does anybody oversized their light and run it a little less than full power?

Thanks in advance for any opinions or knowledge.

Dialing back quality diodes vastly increases end lifespan and long term efficiency of the diodes, absolutely. It can be used to distribute light more efficiently, allows you to get the plant closer to the light source, further increasing overall efficiency. Also, it allows some flexibility as to the overall improved intensity at any given time to the grow. ie. overdrive mode.

The answer is yes, but with caveat it needs to be done within spec, (correct voltage, decreased mA) Usually, there is a specified range, and sufficient cooling, most cheaper manufactures throw in fewer diodes, then simply overpower the units. Once you get it fired up, and the unit sufficiently warm, I would advise dialing in your voltage, then bumping past any "flicker" by raising the mA by a few thousandths overall. (for the entire light) Just to be in that "efficient" range.

I've grown veg units on 33w with great success. With that entire area filled to the brim.

But LED is a very complicated subject, cause there's so many different range for diodes. You almost need a lab grade power supply (I have two of them) just to make these types of fine tune adjustments. Also, without multiple redundant overprotection in place, it's easy to burn things out also. There's nothing straightforward about LED lighting.

If I was getting a SF setup, with the nice dials for variable light settings, I would absolutely oversize the light, and get the biggest one possible, that's spread out the furthest... Like the SE7000 series. Having that dial is a huge plus.

 

[chemistry]

So it would run hotter. Darn I was hoping the opposite would be true. Thanks for the info!

My LED's run cooler the lower I dim them, brighter uses more power, dimmer less power consumed, so runs cooler.

 

[Spock]

The best benefit I can think of is more uniform light distribution. The higher the light the better the distribution. That only works if you have a very powerfull light and enough vertical space.

That's an excellent point! And could be well worth the extra cost even if that was the only benefit.

 

[Spock]

Get the 6500.

I have always liked quality Electronics. So I agree with you. But I've also probably wasted alot of money buying things that I don't fully use LOL. So I thought I would get some opinions on this one.

 

[Spock]

Dialing back quality diodes vastly increases end lifespan and long term efficiency of the diodes, absolutely. It can be used to distribute light more efficiently, allows you to get the plant closer to the light source, further increasing overall efficiency. Also, it allows some flexibility as to the overall improved intensity at any given time to the grow. ie. overdrive mode.

The answer is yes, but with caveat it needs to be done within spec, (correct voltage, decreased mA) Usually, there is a specified range, and sufficient cooling, most cheaper manufactures throw in fewer diodes, then simply overpower the units. Once you get it fired up, and the unit sufficiently warm, I would advise dialing in your voltage, then bumping past any "flicker" by raising the mA by a few thousandths overall. (for the entire light) Just to be in that "efficient" range.

I've grown veg units on 33w with great success. With that entire area filled to the brim.

But LED is a very complicated subject, cause there's so many different range for diodes. You almost need a lab grade power supply (I have two of them) just to make these types of fine tune adjustments. Also, without multiple redundant overprotection in place, it's easy to burn things out also. There's nothing straightforward about LED lighting.

If I was getting a SF setup, with the nice dials for variable light settings, I would absolutely oversize the light, and get the biggest one possible, that's spread out the furthest... Like the SE7000 series. Having that dial is a huge plus.

Thanks for the detailed response! You seem to know your stuff. You are also confirming that the diodes will last a lot longer which in itself could justify the extra expense. You also mentioned a lot of other good points regarding flexibility and efficiency. It's starting to seem like a no-brainer. It looks like you build your own lights. I don't know how I can dial in voltage and ma etc. Can I buy a separate lab grade power supply / driver and do you think it's worth it?
Thanks

 

[Frankster]

Take the samsung lm301 as an example. It's a 0.2w LED. That is the power that it's rated at. Then look at a 288QB and you see it's about 60w of LEDs. We run them at 120w though. This means we don't get the numbers that samsung give us. If you want samsungs published performance from a QB, then you actually need it to run at half power.
The driver running at half the power, will be about half the heat. It's efficiency changes just a few percent.

I put a little fan on my QB. The power my fan used, gave more lumen's than putting that power into the LED's themselves. As dropping the temperature increased the panels efficiency a few percent. Yet the fan was tiny.

I like the 288 standard, as after 4 or 5 years you change the board. Then about 8-10 years, the ballast fails. Presuming you took it off the back of the light. That's a reasonable service life. If you don't change the board it should last, but at that age it's efficiency is dropping, and it's colour shifting towards the blue. Meanwhile, new LEDs have come on the market. Putting the gap between the old board and a new one at about 20% if it's been cooking all it's life.


I have 720w a meter, but it's never been over 550. 80% is the magic number for ballasts.

It's all in the datasheets, but as a rule of thumb, don't run them flat out if you want a long service life.

The Samsung 301 (B&H series) runs at a range of different settings actually. Not just 0.2w as you quote here. But the critical part of all this is it's voltage setting, cause the light wont even fire on, if that criteria isn't spot on. Voltage is the requirement here, not watt's... 0.2w might be it's most efficient input, or possibly it's maximum inputs, not sure. Also, the ambient air temperatures influence output requirements, so there's that part also, alongside the efficiency of the heatsinks being utilized.

Watts are a terrible way of understanding low powered LED lights anyhow, IMO. Cause it's only showing us the consumption. watt=amp X volt.
Like I stated before, it's not a straightforward subject. Ideal thermal resistance is also an important factor in how efficient these units operate.

Specifications are as follows;
Mid Power LEDs
LM301H

• Horticulture Lighting Solution
• 0.56 μmol/s, 3.10 μmol/J @ 65 mA, 25°C
• Anti-sulfurization

LM301B
Middle Power LED Series 301B
0.3W class middle power LED. Mold resin for high reliability. Standard form factor design flexibility 3.0mm x 3.0mm.

• CRI (Color Rendering Index):70 ~ 90
• Current - Max:180mA ~ 200mA
• Current - Test:65mA
• Height - Seated (Max):0.033" (0.85mm)
• Lumens/Watt @ Current - Test:162 lm/W ~ 218 lm/W
• Mounting Type:Surface Mount
• Package / Case:1212 (3030 Metric)
• Size / Dimension:0.118" L x 0.118" W (3.00mm x 3.00mm)
• Supplier Device Package:3030
• Thermal Resistance of Package:7.5°C/W
• Viewing Angle:120°
• Voltage - Forward (Vf) (Typ):2.75V

 

[Moshmen]

So it would run hotter. Darn I was hoping the opposite would be true. Thanks for the info!

If the power supply is outside the growing area it is cooler and better for the diodes it’s all about efficiency and electricity usage - and then penetration

 

[Frankster]

Thanks for the detailed response! You seem to know your stuff. You are also confirming that the diodes will last a lot longer which in itself could justify the extra expense. You also mentioned a lot of other good points regarding flexibility and efficiency. It's starting to seem like a no-brainer. It looks like you build your own lights. I don't know how I can dial in voltage and ma etc. Can I buy a separate lab grade power supply / driver and do you think it's worth it?
Thanks

Yea, the cheap way to go about it would be to buy something like one of the SF units that have dials in them. (all but the sf1000 has them) or something equivalent. There's certainly a lot of decent quality equipment to be had on the market, no doubt.

But yes, if your like me, and you enjoy fooling around with the stuff, custom making what you want, or need. Building is the way to go. But it's going to be more expensive, no doubt. Either find the components that you need, or a lab grade unit. Just make sure your voltage inputs for your light, and the power source line up. If your not using a lab unit, you want to have the correct drivers onboard, measured in mA output.

Something like this is sufficient: I've got (2) 10 amp units similar to this; Which runs about $70 a pop on ebay. I keep the extra for backup or a second project. Some of the units have a macro and mico dials (see my unit above) which make it easier to precisely make micro adjustments.

 

[Frankster]

If the power supply is outside the growing area it is cooler and better for the diodes it’s all about efficiency and electricity usage - and then penetration

Agreed mosh, they only thing I suggest is keeping the lines short as possible, and using extra thick gauged wires. Sometimes distance can create problems, but if your inside say 10-12 feet or so, you should be just fine.

I was actually considering putting my lab units up on top of the tent, then fish the wires down to the lights below.

 

[Pushrod Monkey]

I was thinking the same thing. I'm thinking of adding a supplemental light type of thing for flowering because sometimes my grow gets a little big. I think it would benefit by adding another light as my plants grow sideways. So I'm looking at the Mars hydro sp3000 or the sp6500. I probably only need 300 watts but for like an extra $200 I could get the sp6500 which has a lot more diodes and double the wattage. And then I would probably only need to run it at around 300 watts. And if it lasts me longer that would be worth spending the extra money.

Buy big and turn it down.