Keep it up brother. Saving money always rocks.
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110 F is very good. They should last decades at 110 F. Of course, now you’ve got a bunch of 110 F air to get rid of. Don’t want that around your plants. Like I said before: Heat your house or vent it outside in summer.
Great if you can use the heat. Just run a big box fan to get the air circulating in your house. I’m in a perfect place to do that because we have to use propane to heat and that’s almost as expensive as electricity.
@1BigFella I pull a bunch of air. I built an air box that sits over a central air vent and has 2 in line fans pulling 240cfm in from another room and 6" exhaust pulling 400cfm out. I have 3 circulating fans on the wall in each room that are on 24/7. I use about 300 watts on air circulation. I have propane heat also, but only when we don’t get up and stoke the wood stove in the middle of the night. I’m struggling to keep the flower room above 72° day and 60° nights even with 800 actual watts of LEDs. I’m at my limit on electricity spending, so I won’t be using a space heater. Hopefully low 70s won’t affect the flowers.
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I’m sure a lot people get sticker shock when I recommend expensive cobs and passive heatsinks, but this is exactly why. You could flower out a 3x3 growing area with what your spending on electricity to cool the “cheap” low performance cobs.
I know at this point you’re just trying to make things work with what you have, so I’m definitely not trying to take a dig at your project. But it’s a prefect example of why you would bite the bullet and spend a little more up front. Both from an energy use standpoint, and from having to get additional components adding to build cost.
And you would most likely still have the power to run a heater as well.
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If the driverless COBs can be reliable and have decent light. They should be the way to go. They can’t be overdriven and I was reading in LED magazine that they can be 92% efficient. The huge drawback can be voltage that can kill you. The big test will be what can these pink lights grow
At under 100 lumens per watt, I would respectfully disagree. The poor efficacy is just begging to differ with the 92% efficiency as well.
Being able to overdrive an led is a good thing, not bad. Not that I would recommend doing so. But overdriving an led means running above test current. If they will remain stable doing so, that means the product is built beyond its intended use. For someone with the knowledge to be able to apply as needed should be a feature, not something you’d want to avoid.
Are you able to link that article? I’d be curious as to who thinks they’re that efficient. There’s certainly no way for us as an end user to test them with basic multimeter like we can everything else. So it would be real easy to throw a random number out that we couldn’t verify.
They could be 92% efficient electrically but lousy at producing light. Even Vero29s are only about 50% efficient at producing light. There is a way to calculate lumens to watts conversion but the easy way is to look at heat production versus lumens. If you are driving the COB with 80 watts and have to heatsink 40 watts, it is 50% efficient at making light.
On the other hand, maybe your driver is 92% efficient at turning 120 VAC into drive current. That is not all that hard. Buck switching regulators often get 92% efficiency.
My driver is 83% efficient but my COBs are making over 180 lumens per watt of drive current, just for comparison.
@OldSkunk I do have to disagree with @dbrn32 and @1BigFella to a point. the point is being we are looking at numbers only at this point and they arent even close to other techs which they are correct about. Just one of my veros has about the same lumens as my 900w meihzi. The easiest way to figure out where you are at, is throw some plants under them. at the end just figure out your watts per gram (lights and cooling) and see where you are at. if you are close to blurple production at less cost its still a win correct? we know they wont produce at better tech levels but that wasn’t the point, it was to make a cheap grow light.
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My comment was based on there not being enough room to hold that kind of circuit with one of those cobs, and probably more certainty in not for the cost. You’re familiar with the components, what do you think?
Good point! Any of them are just a light until they grow weed. Regardless of cost, or how the numbers look on paper.
Your build was pretty much text book, why did you choose the components you did over cheaper options? I’m guessing it’s because you put the research time in. You could’ve easily bought cheaper cobs, a cheaper driver, a smaller heatsink, or pushed your cobs harder for more power. But you didn’t, why not? I’ll go out on a limb and guess it was because of performance. Anywhere you had the opportunity to save money wasn’t really saving money. It was just paying less for less performance.
I don’t have any issue at all with saving money, I actually prefer it lol. But I feel it’s important to identify the differences in what you’re getting for the money. I don’t believe for a minute that the driver circuit on these is anywhere near 90% efficient. Otherwise most of the current power supply manufacturers will be out of business within the next month or two. Why pay $20-$40 for something to do what’s already included with these cobs for a few dollars? If they were even 80% efficient the efficacy on them would likely be quite a bit higher.
My position on this on this is one of being able to recommend other members following suit. And I don’t think I can. By @OldSkunk’s own account they are dim, and a real pain to cool. And from where he’s at right now, probably not saving any money on build cost. And certainly not on operating cost with 300 watts of cooling. There’s just too many other options.
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My build was to fit a very specific window of performance and cost really wasnt the biggest factor, but I know alot of other members have a very strict budget and can only grow within that. I think if @OldSkunk spends the money on really good passive heatsinks and doesnt have to pay for the cooling then he might just come up with a usable cheap light. But if nothing else…we all get to learn from his success or mistakes 
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but yes efficiency isnt even in question, we know they are horribly inefficient just because of the amount of heat they kick out, thats just wasted energy.
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I didn’t save the article. I was just looking for a valid schematic for these COBs and came across the article. I didn’t even know there is a LED magazine. I doubt they’re 92% efficient myself. The article claims that they can be. I have about $20 in each light so
I can switch to non “grow” COBs (4000k) and use them for veg. I hate to give up just yet. @Daddy @1BigFella.
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Gotcha. 90+% efficient drivers are indeed plentiful. They just come in a quite a bit larger package, and are usually pretty pricey on a per watt basis.
Hopefully you get something going with them. I wasn’t meaning to be discouraging at all. Hindsight being what it is, I just meant your project is appearing to not be as cost efficient as I’d did in the beginning.
The 300 watts is for all my fans only.
6 circulating fans
1 exhaust fan
2 in line fans
I wish there was a way to use less power for air movement, but I haven’t seen anything that would work for me.
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Yep. We at least can figure out if these things can be of any use to anyone for growing anything decent.
@dbrn32
@1BigFella
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Copy that. What kind of current does the inline pull? They’re not cheap, but you can get into some real efficient options there. Could potentially save you some power if you get to the point you need it.
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.4A draw and 43watts actual. They’re a low buck way to pull air from other room and from outside. I thought about using computer fans which I have a lot of, but the inline fans push 240cfm.
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That’s pretty good. I have a 6” that does 315 cfm and pulls like 37 Watts. And a 4” that moves 150 cfm for about 17 Watts. Both are dc mixed flow so they do quite a bit better when slowed.
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I am running a single 8" duct fan at 40 watts, and that exhaust fan is ducted to pull in air through the COB heat sinks. Works great because the heat sinks are running at about 90 F. I need another little table fan to get air moving around but I don’t have it on right now because of Santa Ana conditions putting the humidity at about 5%.
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