Seeking Help - Building Custom-Designed DIY LED Grow Lights using CREE CXA3070 COBs

Gaius

Gaius

Active Member
AeroDonkey said:
Might wanna check out luxeon star leds too. May save ya an assload of cash. I use their leds for other projects. They are blinding bright and spectrum specific. Few bucks each instead of 40 and different wattages. NASA uses them as well.
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Thanks Aero. These look promising, but unfortunately they are sold out of all the good color temps. :/

Positivity said:
http://www.futurelightingsolutions.com/en/Search.aspx?dsNav=Ntk:PlainTextSearch|Inventronics|3|-P_FlsView|1|1|,Ny:True,Ro:0,Nea:True,N:4294886037-4294913983

heres a good source for inventronics drivers. The 1.05a drivers look to be a good match for the cree cobs. They have a higher voltage range that would allow you to upgrade to cxa 3590 if you wanted.
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Thank you too Positivity! Would you mind recommending a driver that'd handle the nine CXA3070s, and the upgrade to nine CXA3590s? I'm fine with either 1 driver per chip, or 1 driver per 3 chips -- whichever's better.

[HR][/HR]
Everyone's being so helpful by sending these sweet lists of parts. Now I'd love if someone could recommend specific parts for the design shown in the OP. I have a ~$400 budget left over after buying the chips. I still need to get the heatsinks, cooling fans, drivers, hardware, and any other parts required.

Specific BOM recommendations here will be overwhelmingly helpful.
 
caretak3r

caretak3r

Well-Known Member
Gaius said:
Look about right?

$167 - 3x 150W Dimmable LED Driver Waterproof + Dimmer DC25V-36V 0-4.5A ouput

or

$104 - 3x - 150W Power LED Driver AC85-265V input 30V-36V/4.5A output 120-150W Adjustable

or

$144 - 9x - 30W 40W 50W Adjustable Round LED Driver AC85-265V input DC31-36V/1500mA DC12V Two-way output

If the $167 option is the cleanest build (and waterproof), then I have no problem spending the extra dough.
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of the 3 you listed, the only one that works is the 1 driver per COB ($144 9x) because you don't run these in parallel. You can run them in series, which means you have to add up the voltage per COB, so for 2, the driver would have to output ~80V and for 3 it would have to output 120V. There are some new meanwell drivers that can do this - HLG-185H-C series - they come in 500ma, 700ma, 1050ma, and 1400ma and can be had in dimmable form
 
SupraSPL

SupraSPL

Well-Known Member
Yep the $144 is the best option IMO. If you use drivers with higher vF ranges you have to be a lot more careful isolating your build because you are working with more potentially dangerous voltages.

All three options listed would require 9 drivers.

You could get the job done as cheap as $100 shipped but that would be without dimming and would be 88% efficient. So you are paying an extra $44 for dimming which isnt too bad plus you get the 12v fan output.
 
Gaius

Gaius

Active Member
caretak3r said:
of the 3 you listed, the only one that works is the 1 driver per COB ($144 9x) because you don't run these in parallel. You can run them in series, which means you have to add up the voltage per COB, so for 2, the driver would have to output ~80V and for 3 it would have to output 120V. There are some new meanwell drivers that can do this - HLG-185H-C series - they come in 500ma, 700ma, 1050ma, and 1400ma and can be had in dimmable form
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While certainly cool, these are over $100 each, which makes them far out of my price range.


Guess I'll just order nine of those round drivers from satisled. Should I buy the 50-60-70 watt version if I plan to eventually upgrade to 3590s?
 
Gaius

Gaius

Active Member
SupraSPL said:
Yep the $144 is the best option IMO. If you use drivers with higher vF ranges you have to be a lot more careful isolating your build because you are working with more potentially dangerous voltages.

All three options listed would require 9 drivers.

You could get the job done as cheap as $100 shipped but that would be without dimming and would be 88% efficient. So you are paying an extra $44 for dimming which isnt too bad plus you get the 12v fan output.
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Fuckin GOLD! You guys are all effin fantastic!
 
Gaius

Gaius

Active Member
Found some really great DIY LED tutorial videos.

Sponging in all dis sheeit medicated.

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Gaius

Gaius

Active Member
I think I understand about the PC PSU now. You get a double penalty by converting twice, and in my earlier design you'd pay an additional penalty from the fan speed controller.

Is there an AC to DC driver that can handle 2 3070s at 1200mA? Is it usually better/cheaper to just use 1 driver per chip?

I'm a bit confused about how running 2 chips off one driver would work. The CXA3070 spec sheet mentions a voltage of 38.5V at 1200mA. Does that mean for two chips I'd need 1200mA@77V, 2.4A@77V, or [email protected]?
 
smokey the cat

smokey the cat

Well-Known Member
Gaius said:
I'm a bit confused about how running 2 chips off one driver would work. The CXA3070 spec sheet mentions a voltage of 38.5V at 1200mA. Does that mean for two chips I'd need 1200mA@77V, 2.4A@77V, or [email protected]?
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You can run cobs only in series, not in parallel.

So that's 77V @ 1200ma - pretty high V for a driver. The brand name drivers to look for are probably that high V Meanwell HLG-185 to run several CXA in series, or an LPF-60 to run one driver per emitter.

Cobs are a pain in the arse to drive compared to traditional single emitters - pissed me right off when I was planning my build. Series-Yes/Parallel-No applies to constant current and/or constant voltage drivers. Now I don't understand the what the issue is with running them parallel - maybe someone can pipe up with the problem - maybe it was likely to bump into the current limiter of the driver, or thermal runaway?


To run COB in parallel you need a proper bench top DC power supply - which allows you to set exact voltage, set exact current, and ensure you're not getting into an issue of thermal runaway which burn out your gear. Psuagrow has a nice thread on testing Bridgelux vero using a proper benchtop supply - he bought his used cheap of Ebay. Could be worth considering.
 
Gaius

Gaius

Active Member
Fluke multimeter the one to get? Or will a $10 special do the job?

For the cxa3070s do I want the 30/40/50 drivers from satisled or the 50/60/70s?

i just ordered some CPU coolers and thermal paste for heatsinks. Ditching the long single panel idea.
 
M

mtnstream

Active Member
Advise against thermal paste unless you have chips screwed down. In the beginning, I smoked a 3050 chip not attached permanently with a screw and paste. Run
lightly....





Gaius said:
Fluke multimeter the one to get? Or will a $10 special do the job?

For the cxa3070s do I want the 30/40/50 drivers from satisled or the 50/60/70s?

i just ordered some CPU coolers and thermal paste for heatsinks. Ditching the long single panel idea.
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SupraSPL

SupraSPL

Well-Known Member
I have been using Ceramique, Prolimatech PK2 and PK3. They are thermal pastes but not adhesives. Thermal paste has a significantly better heat transfer than thermal adhesive. On the other hand, Mr Flux pointed out that the layer is thin enough that it may not make much of a difference which you use.

I have been aiming to have my cake and eat it by using thermal paste rather than adhesive and not drilling holes in my heatsinks. So I rely on the vacuum effect of the thermal paste and kapton tape to keep the emitters in contact with the heatsink. PK2 does kind of dry and adhere the LED to some extent. It has worked great for me, especially for larger stars and COBs but fair warning your results may vary.
 
Gaius

Gaius

Active Member
Yeah I hope that means no drilling...

Just solder the scooter chargers directly to the chips, then use the adhesive to adhere the chips to the cpu fans.

I'll have to drive the cpu fans separately. Going to use an old pc power supply I already had with that fan speed controller I linked earlier.

Have to change up the design from the OP a bit, but still plan to group these in rows of 3 chips hung from 1 hanging kit.
 
Gaius

Gaius

Active Member
So after reading the link about wall warts and LEDs, I'm unclear whether the scooter charger I ordered is safe to directly solder to a cxa3070 as a power source. Are they saying the COB will try to pull more current than the ac adapter can handle?

The charger I ordered is limited to 36V@1500mA, no? Would adding a current-limiting resistor in series with the LED make the scooter charger an effective driver? They are enclosed in plastic, already have a wall plug, and have free 2-day shipping. If they work well directly soldered to the chips, then sweet! If all they need is a resistor, then hey no biggie right? Seems like a cheap/easy way to quickly build a moisture resistant driver... ...Unless I'm missing something here again.

I'm really hesitant to order the satisled drivers after reading that the 12V fan port is somewhat worthless, but also because I'd have to wait another 2 weeks to get them. Anyone know of a reasonably-priced driver for the CXA3070s that ships from the USA?

Edit: Found a great write up on modding cheap wall warts into decent fixed/variable rate power supplies.
 
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