@4d-Rock
Here is my buddies reply to some or all of your questions.
I assume these are probably better quality COBs as well but are you saying that they are a better grow light due to the 4000K light temp. vs what is in there currently?
Extra special attention there needs to given to the fact that they are 4000k 90cri cobs and not just 4000k. Sure, we would’ve preferred 3000k or 3500k 90cri. But we were taking advantage of some low cost leftover cobs too. Here is distribution graph for gen 5 90cri 1212
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Pay extra special attention to the longer wavelength peak around 630nm and how it provides at least some light from about 415nm all the way out to beyond 780nm. Vs what manufacturer provides
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Every published light study from McCree, NASA, Oxford, and Emerson supports that you now have a more photosynthetically efficient light spectrum that will also trigger different plant responses.
Did you conduct any test measurements of the light output of pre- and post- upgrade? Is it significant or is the main benefit the reduction in energy draw?
The simple answer here is yes. Citizen gives us minimum and typical output, roleadro not so much. You can probably guess why? Since light spectrum is different you would need par meter to even give close explanation. And you could buy and mod 2-3 lights for cost of par meter. So it doesn’t make a lot of sense to drop that kind of money to test it.
However, it is pretty standard knowledge across led diyers that a 50% reduction in drive current generally works out to be about 10% increase in electrical efficiency (par watt vs heat watt). Nobody is paying for sphere tests on the roleadro, I don’t really blame them either. But several tests have put the 1212 at 2.3 umol/joule at 1050ma. So we can probably estimate at 1200ma we’re around 2.2 umol/ give or take. The lights using epistar leds that have been tested usually come out between.9 and 1.4 umol/joule. Assuming this is inline with rest of their products we’re talking a range of about being in the range of 50-100% increase in par per watt. There’s obviously a lot of speculation there. But turning it on, your eyeball can probably validate that it’s at least better.
I’m not sure if it matters to you but I noticed that the fan noise is a bit on the high end.
I’m not sure, but I feel like we may have potentially discussed swapping fan in planning stages? If not, it was definitely with one of the other guys hacking. But yeah, inexpensive light is going to use inexpensive components. No surprise there. Amazon sells higher quality pc fans for $5-$15 depending on size. You can certainly upgrade them at any time if noise is a problem or you’re worried about longevity. Just verify voltage and current are within specs of the provided power supply.
but do you know why they use 2 drivers per COB? And why are you able to only use one driver per COB in your setup (more efficient COB?)? Could this reduce lifespan in anyway as using 2 drivers may share the load?
That was a choice not a requirement, and efficiency is absolutely one of the reasons. This chart explains that.
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But there is a bigger reason.
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If I remember, they’re constant current drivers which means the driver will provide priority to supplying current and then let the cob take the voltage it needs, provided it’s eithin the rating the driver. If we supply too much current the cob would require a voltage beyond the drivers rating. Obviously that cob isn’t rated for twice the voltage either, so running off a single driver with $9 cob is a no brainer in my opinion. We tossed around some other options, all at significant increase in cost that would be trading more power for a lot more money. Plus, not being exactly sure if they were doubling current or voltage there could potentially cause other issues. And we’d really need a data sheet on the factory drivers to see if it would go cv/cc mode if we needed it to.
The part about reducing lifespan is actually completely the opposite. The driver regulates power differently than something around the house. So that part is a non issue. The fact that we’re running at half the power means half the heat. And heat is everything when it comes to leds. The life expectancy of leds is directly reflective of the current/temp relationship. The higher the current, the case and junction temps will go up. The higher the temps go up, the less life expectancy will be.