Let's talk DIY lights

I have mostly run them at full blast because I was flowering, but would like to experiment with different settings. I’m not sure which metric to use. There are so many different opinions out there. Since I have no way to measure par, maybe just start with LED efficacy.

If it helps, 4 boards pull 495 watts out the wall.

I don’t really have the tooling or meters to test and give a solid explanation hands on. And I haven’t used the Samsung tool. But I believe led gardener had a link to the Samsung tool. I’ve calculated Cree stuff using their tool. But that’s more or less typing in the numbers. You will need at least tc measurements and/or tj measurement, possibly both.

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OK I am a member at ledgardener, so I will check that out.
Thanks

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No problem. I wish I had the numbers to just give them to you. But in the terms of accuracy, I would just be guessing. My guess is around 55% if they’re being cooled properly. Probably in the low 60’s at 700 ma. Let me know what you come up with please.

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I like your aluminum rack. I’m doing something similar and I have found you want to drill the rack holes with great accuracy. Don’t just eyeball it and think the aluminum angle stock will be easy to bend. It won’t be!

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I made a template so they are all in the right place lol

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@bob31 @middlecoast I did some digging last night on the calmag thing I was referring to in the other thread. I never found any hard scientific data, but I found a few theories I thought I would share. Put it here not to clutter up your thread any, and thought the majority of members following this thread may find it useful.

I tried to isolate my search to growers switching from hid to cobs, who cloned and had experience with their strains. At least the ones who should’ve had good baseline data on their grows. Not perfect by any means, but best I could do on limited time.

Theory 1
Needing more calmag is just a bandaid for under feeding your plants. The addition photons from more balanced spectrum makes happier plants that tend to feed more heavily. Most pre mixed calmag additives also contain nitrogen, and while they may need more calcium, it’s the overall feed of the higher ppm that makes calming appear to correct these deficiencies.

Theory 2
Plants transpire less with lower canopy temps of led. Calcium is supposedly taken by plants passively by the movement of water through the plant. (Personally not sure what that means) but this reduced movement of water makes less calcium available to plants even though it may be available in soil.

Theory 3
The increased intensity of blue wavelengths through flowering period stimulates resin production and overall plant health thus requiring more feed overall. Since the calcium and magnesium are very low in most media as well as most base nutrients, it requires them to be added.

Again, I can’t confirm nor deny any of these. They each make sense in a way, but are also suspect in other ways. I have experienced similar circumstances, but I can’t explain why the calmag seemed to help. These are just summarized explanations that seemed to be repeated the most. If anyone has anything to add, please feel free.

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I think the one thing I find the more and more I learn is that there’s no 100% gospel on anything when it comes to growing. One thing will work phenomenally for one person and then not so much for another. One example is defoliation. Some people say to basically strip your plants to let light in, others say leave it alone. I’ll have to dig more into the different theories your presented. I think in my case I needed cal/mag cause I was getting spotting on leaves. I think the one thing that could be considered for cobs is the general intensity. When designing my light I estimated that i’d be on the upper threshold as far as PAR. I haven’t measured this with a PAR meter, but because i’m putting out a lot of light maybe the lights are needing more nutrients to support growth due to increased photosynthesis. I’ll dig more into these theories but all are definitely something to consider.

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I agree. The biggest determining factor there is going to be the differences from one grow room to another. Types of water, nutrients, growing media, temperatures, lights, strain, and so much more will play into it.

As I stated in your thread, I would expect you to need some calmag. Probably more often than bob suggested, but not as often as you were applying. That certainly doesn’t make any of us right or wrong, it’s just the knowledge we have from different experiences. I do think that the majority of what @bob31 suggested was accurate and will at the very least get you to a point where we could narrow down and get to the root of whatever is going on. Based on the reading I did last night, he could just as well be 100% correct about the calmag too. My use could’ve been band-aid type fix. I just know I had similar rusty spotting, and that’s what fixed and kept away. Hopefully we get to the bottom of whatever it is, and learn something in the process.

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I have found in frequently grow autoflowering plants that they seem to need cal-mag on every grow. All of my plants get the same nutrients as the photos but every auto has shown defficiency.

I agree that if someone is under feeding that the addition of cal-mag will help. But I feel like it is a waste to do that if I already own the nutrients and following the feeding chart will resolve the issues.

I don’t know enough about lights to comment on that angle but I think those are all possible.

@dbrn32 @middlecoast There are multiple ways to do everything in life. Almost all roads will get you to the finish line. And I just don’t think it is wise for novice growers to do controversial things to their plants that could be detrimental to their grow.

My favorite line was… I cut all of the tops off my plant because they were getting too tall. The guide says they should be ready in 8 weeks and it’s been 10 weeks and they and they still aren’t ready … And then we sealed the deal with… Was it ok to do this? Hahaha.

:v::+1::palm_tree: Happy Thanksgiving

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It does make pretty good sense that if you are using more light then the plants will want more food, water, and CO2. The cobs do make more lumens then LEDs. I know I’m at about 125000+ lumens and that’s about 6 900w meizhi LEDs so I expect my plants to want more of Everything lol.

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Now that’s funny! The best part is, of course it’s alright to do. As long as you don’t mind harvesting the few popcorn buds that are remaining.

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LOL wow, ya I don’t think I’ve done anything that egregious. Completely understand where you are coming from and always trying to learn more about how to grow efficiently. One of the biggest take aways I’ve gathered from those offering advice is to listen to the plants which is what I’ve attempted to do on my grow. Definitely going to have to learn more on adding cal/mag cause that’s one nutrient not listed in quantity from the FF trio.

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We’ve located the issue with qualifying blurple led in lumens. 6 fixtures at 125,000 lumens is like just under 21,000 lumens per fixture. I grabbed your numbers, as I have no idea off the top of my head. But a $10 250 watt hps bulb is considerably higher, like 29,000 lumens.

So now I’m confused lol. It’s suppose to be 900 Watts, 900 Watts equivalent, or what? Without looking, I would bet it draws at least 250 Watts. So in terms of lumens, it’s actually less efficient than hps. We’ll be crushing led dreams everywhere! They ought to change their descriptions to 900w make believe power, 300 watt power consumption, equivalent to 150 watt hps. Then we’ll see how many lights they sell. We know the par levels tell a slightly different story, but it’s not by much.

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My meizhi 900w draws 417 at the wall but that’s including 3 fans and a less then efficient driver. So maybe 375 watts of light? And 21000 plus lumens. Granted it does have a more complete spectrum the any single hid and less heat. But to get the same lumens as my cob I would have to use 2400w worth of them.

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A 600w HPS will put out 85000+ lumens drawing about 650w. So my cob should really be comparable to hid output with less heat. Plus last alot longer with better coverage

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Cob, absolutely! Meizhi, not so much.

I’m busting on budget leds advertising really, nothing more. Like I stated earlier, if they go that route they essentially need to say their 400 watt light is equivalent to about 150 watt hps. Yet, none of them do. They do get bonus in that they target peak photosynthetic wavelengths, but they don’t do a good job of explaining that. Just throwing random numbers out, that the rest of us have to explain to new or unsuspecting members.

I like the 100 ten watt diodes too lol. Like that means a damn thing with 500-700ma driver.

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I think we all can agree most Amazon fixtures aren’t very good explaining actual wattage, equivalent wattage, PAR, wavelengths, and their less than efficient drivers. But they do produce light. I have yet to disassemble that one fixture that had COB’s fail, to check drivers and COB labels. I’ll do that sometime this week, then we will have more knowledge about it. If I’m not in too much of a food coma @dbrn32

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Just half way to solid buzz on a rant. I have no beef with the lights themselves. They are what they’re intended to be, low cost option to get into led growing. I would be a lot happier if they went with that, over trying to convince people otherwise.

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I think we need to Frankenstein that sucker into something cool regardless.

How are the cree’s coming along?