Introducing CobKits.com - specializing in DIY and Citizen COBs
Bubblin
Well-Known Member
OLD MOTHER SATIVA
Well-Known Member
update
no reflector
2 nichias 53 w ..at 12 " 550umols..
at 8" 640 and steady around 600+umols between them both
i do NOT know how these stack up to other cobs like cree vero and citizen..
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PhotonFUD
Well-Known Member
you know how i know youre a fake redneck? no stolen aluminum street signs in your garage to use for heatsinks
You can often buy them from surplus stores fairly cheap. I got a few for a buck a piece.
PhotonFUD
Well-Known Member
Without reading further, we all know that it isn't lumens we care about, it is PPFD. For light sources, we are looking for PPF which is just a raw count of photons. Lumens is a weighted measurement giving increased values for certain wavelengths so it means very little for us.
Lumens do provide a bit of guidance but that is about it. As long as you have something that appears somewhat decently efficient then you look into the SPD and figure out what you will have to work with in your environment.
CRI is a quality measurement in respect to lumens. It may or may not have an impact on the number of photons a light source produces but the simplest answer is whichever CRI produces the highest PPF.
PhotonFUD
Well-Known Member
That is up for debate.
I try to go for ~400 average (200-600) over the entire plant, not just the canopy.
Oh really? That's it? I see people with 800-1000ppfd all the time.
Are the CXB3500 36v still the most efficient at 700ma? I see they're at .64 currently.
Big smo
Well-Known Member
I have seen so many people get messed up with this including myself awhile back. Cobby think you should add in they need to be wired in parallel and not series.
Ive never built one in parallel. I could do it but thought that puts the LEDs at risk if one burns out. Im old school started with 3 watt Osrams and a hundred solder joints per light. Hes the expert and Im no engineer. Appears tech has blown by me. My last DIY light lasted 4 years. OK back on the short bus.
Big smo
Well-Known Member
It's debatable what way is the best. Cost wise parallel is the winner and I do like the fact you can really fine tune the string by adding more 13$ chips. Makes for s pretty inexpensive light.
CobKits
Well-Known Member
i'll try to make the driver page more explicit.
trying to be polite here, but its kind of not up for debate. Youre the only person who advises 400, every other person on this site would say 600-1200. and there is plenty of science to back that up. But there are other threads for that. im all for 400+ on the bottoms but top canopy really should have 600+
CobKits
Well-Known Member
citi 1818, citi 1825, citi 3618, vero gen7 B,C, and D versions all more efficient than cree at 25W (but not by much)
CobKits
Well-Known Member
if you want to run series get a hlg-240h-C1050 or -C1400
the hlg120-48A and 185-48A are designed for parallel low voltage operation
This is what I was kinda expecting, glad I asked.
I'm going to buy 4 36V 3500k 80CRI CBX3590's, and a single driver to run these at 1400ma for an 8sq ft area. Should give me 714PPFD if I did my math right?
Would this be a good driver? This will be a huge step up from that crappy Mars300 unit I had.
HLG-185H-C1400B
Thanks for reply. It is clear now. Been scratching my head for a week. I'm not the brightest LED on the string. LOL. Budget wise parallel wins hands down.
CobKits
Well-Known Member
seems low for 8 sq ft, thats only about 13 parW/SF so prob closer to 550-600 ppfd
Could you show me how you calculated that by any chance? I have a spreadsheet I messed up on apparently.
Big smo
Well-Known Member
Go with the citizen cobs. For the price you'll get much more bang for your buck