DiY LED - Cree CXA3070

mdsjb930 said:

has anyone heard about cxb 3070 jerry at kingbrite says hes getting them in the next two weeks. I got ab 3070 from him for $30

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I got 4x CXB3070s yesterday from digikey. Might be a week or two till we finish up the light though. Hopefully it turns out and I'll def post some pictures.

Unrelated, I have some questions regarding powering fans. I have 4x .6A CPU coolers. I also got the B version of a Meanwell driver which means it has the external dimmer feature which requires 10v and a pot. So I was thinking of getting a 12v power supply (at least 2.4+ A) and then trying to lower the voltage to 10v for the dimmer and run the fans a little bit slower. Would this work? Could a simple resistor inline take care of the voltage drop? Am I totally off base? How to most people get the 10v to the dimmer circuit?

Abiqua said:

or could I just ground the Driver Neutral and EMI neutral to a frame themselves....in one location? Then 2 wires instead of a 3rd?

Thanks again Supra

Tool!, been a fan since like 92 before I was a freshman even,,...they have been in Oregon, once or twice, lol......it all makes sense now...

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So the idea is to run a ground to all the heatsinks or metal parts of the build, then tie all the grounds together. You could use a Wago push nut, lever nut or those terminal strips if you jumper them. It is true that the neutral is connected to ground in the breaker box but there are technical reasons why they should not be connected anywhere but the service entry, something along these lines "neutral current resulting from phase unbalance can energize the metallic parts of the appliance".

Tool, favorite music. APC also great art. A bit dark maybe but I find it hope inspiring for some reason.

MrDavis said:

So supra maybe I'm not doing the math right.

For your above HPS comparison

275w (12 cobs 22.9w) x .4248 (what is this number?) = 117.24 PAR w

117.24/9sqft= 13PAR/w Sqft?

I know that is a little different than the 18 you posted (could be my math, I stuck at it).

Just want to know if I am doing that right?

I think with the heat difference alone 5par/w isn't an issue lol.. As you said bleaching is really easy to do without burning haha.

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Yes your math is correct except the .4248 would be .587. As sevren pointed out, that number represents the COB efficiency, which changes drastically based on the drive current.
275 * .587 = 161.45 PAR W
161.45/9 = 17.93 PAR W/ft²

bizfactory said:

I got 4x CXB3070s yesterday from digikey. Might be a week or two till we finish up the light though. Hopefully it turns out and I'll def post some pictures.

Unrelated, I have some questions regarding powering fans. I have 4x .6A CPU coolers. I also got the B version of a Meanwell driver which means it has the external dimmer feature which requires 10v and a pot. So I was thinking of getting a 12v power supply (at least 2.4+ A) and then trying to lower the voltage to 10v for the dimmer and run the fans a little bit slower. Would this work? Could a simple resistor inline take care of the voltage drop? Am I totally off base? How to most people get the 10v to the dimmer circuit?

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Good news, you can use a 100K POT on its own to dim, no power source necessary.

So .6A fans on the CPU probably indicates they are high RPM aka tornadoes at 12V. If they will start reliably at 5V I would recommend that, if not you could try 6 or 7.5V. They will draw a lot less than .6A each at those lower voltages. Maybe something like this:
http://www.ebay.com/itm/ALCATEL-MICRO-USB-TRAVEL-CHARGER-WUS550mA5V00-02-/161474251570?pt=LH_DefaultDomain_0&hash=item25989d8b32

SupraSPL said:

Good news, you can use a 100K POT on its own to dim, no power source necessary.

So .6A fans on the CPU probably indicates they are high RPM aka tornadoes at 12V. If they will start reliably at 5V I would recommend that, if not you could try 6 or 7.5V. They will draw a lot less than .6A each at those lower voltages. Maybe something like this:
http://www.ebay.com/itm/ALCATEL-MICRO-USB-TRAVEL-CHARGER-WUS550mA5V00-02-/161474251570?pt=LH_DefaultDomain_0&hash=item25989d8b32

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Seriously about not running the voltage to dim!? Thats excellent!! Do I just hook a 100k pot to the Dim+ and Dim- leads? I am running just 1 HLG-185H-C1400B.

Thanks for the suggestion on the fan psu. I have one in front of me (micro usb charger) that is 5V 1.1 A. That should work, right?

SupraSPL said:

Yes your math is correct except the .4248 would be .587. As sevren pointed out, that number represents the COB efficiency, which changes drastically based on the drive current.
275 * .587 = 161.45 PAR W
161.45/9 = 17.93 PAR W/ft²

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That makes sense. Is the efficiency the number on the driver?

So if the driver says 95% efficiency I would use .95?

So the driver efficiency is a separate issue, and the .95 number is yet another issue (power factor) LOL. You can see the COB efficiency in the chart I posted in column 8. That chart only applies to the CXB3590 3000K 80 CRi and assumes a junction temp of 50C.

When I was calculating $/PAR W earlier I was not including the driver power and cost or heatsink cost because it is variable and we were just focusing on the potential of the lights themselves, which is just a starting point for a design. Once you have a design in mind, the next step to take driver/heatsink cost and efficiency into account to compare the $/PAR W of complete lamp systems.

bizfactory said:

Seriously about not running the voltage to dim!? Thats excellent!! Do I just hook a 100k pot to the Dim+ and Dim- leads? I am running just 1 HLG-185H-C1400B.

Thanks for the suggestion on the fan psu. I have one in front of me (micro usb charger) that is 5V 1.1 A. That should work, right?

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That is correct, wonderfully useful, simple and efficient, thanks to @guod and @stardustsailor for helping me learn how to dim the B version. Yep that charger you have could run many fans.

Yep and I thought someone asked recently but if you are trying to run multiple drivers off one pot- you just get a (example) 100k/2 instead of just a 100k

Yep, 50K for 2 drivers, 33K for 3 drivers, 25K for 4 drivers ect.

I dont think there are any 33K POTs, but if you use a 50K it will still work because it goes from 0-50K. So as you turn the knob, the drivers will reach maximum output when the POT reaches 33K and will stay at max output if you continue to turn it higher.

guys another question,

how do you know kingbrite is legit? is there a way to test with a multimeter or something to that extent that makes knowing if what I got is the real deal?

second, I'm not sure why it's so hard for cree to stamp a code on the top of the chip...

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just a mention, as I've thought of this, wonder your opinion supra, do the best red / blues beat out these top whites? as I saw a graph you did, and whites are putting out an awful lot of green.. so makes me wonder if red / blue chips would still yield higher, or are you guys just using white for simplicity and cut down on leds to attach?

another question, who makes the most efficient blue chip and red chip?


honestly man, I think you need to tell us your paypal, and I'm sure we'll all start chipping into a fund for you.

MrDavis said:

So supra maybe I'm not doing the math right.

For your above HPS comparison

275w (12 cobs 22.9w) x .4248 (what is this number?) = 117.24 PAR w

117.24/9sqft= 13PAR/w Sqft?

I know that is a little different than the 18 you posted (could be my math, I stuck at it).

Just want to know if I am doing that right?

I think with the heat difference alone 5par/w isn't an issue lol.. As you said bleaching is really easy to do without burning haha.

Click to expand...

275w (12 cobs 22.9w) x .5872 (efficiency at given current) = 161.48 PAR w

161.48 / 9 sqft= 17.95 PAR W/sqft

I wondered the same thing. What if he's just buying available chips and reselling them as the best of the best for cheap. Then I did the math and honestly he's within 5-10 bucks of a decent price from anyone else after shipping.

And I got my top bin 5000k/80cri 3070s in the mail today and the sticker supplies the part number- not in the order I remember my abs coming in, but still comforting with the original packaging



Could someone (supe) reiterate what the N means after the 3070 on the chip for clarification? Thanks dude

FYI ... those alpine 11 plus CPU coolers for $9.99 w/free shipping are back in stock this morning at newegg ... 18 left.

im also very interested in those big cheap cob leds as quick cheap alternative to hps. i know it would be awhile before somebody tries them in a grow. but would consider buying them if they truly seem worth a try in comparison to hps. maybe to of the 300w instead of a 600w hps if the spectrum is good is would use about the same electricity but should give better results correct?

There are 4 classes for the CXA series.
C = 9V
F =18V
N = 36V
R = 72V

SupraSPL said:

There are 4 classes for the CXA series.
C = 9V
F =18V
N = 36V
R = 72V

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That's bad ass 36v what is up with that.

Since we love the HLG-185H-C1400, if you plan to run CXA3590s hard the 72V class is the way to go.

But if you were to use CXA3590s for vegging and want to run them very soft for mega efficiency, the 36V class would work with the HLG-120H-C350 or HLG-185H-C500.

If you are going to run them in the middle at 38-50W, you could go with either class.

SupraSPL said:

So the idea is to run a ground to all the heatsinks or metal parts of the build, then tie all the grounds together. You could use a Wago push nut, lever nut or those terminal strips if you jumper them.

Click to expand...

So I just ended up attaching a three prong cord to the driver with a 2 way wago [412] for each of the 3 wires, gave it 2 layers of protection [the ole' double bag] and called it a day

Also have a 3 way wago, that I will install a frame ground with at some point and maybe the EMI too...been putting off researching practical thermal cutoffs to use...Now is the times to start...

but could you elaborate that last little bit, now I am thinking that multiple grounds might be a bad idea??

It is true that the neutral is connected to ground in the breaker box but there are technical reasons why they should not be connected anywhere but the service entry, something along these lines "neutral current resulting from phase unbalance can energize the metallic parts of the appliance".

Click to expand...

Tool, favorite music. APC also great art. A bit dark maybe but I find it hope inspiring for some reason.

Click to expand...

Probably one of my favorite bands, if I could say that about anyone....In fact ever since the 3rd eye went up, I started youtubing full albums as I was putting my light together...I mean I went from Lateralus back to Opiate all the way, then Salival and the San Francisco Philharmonic cd, that was put out ten years ago?

Literally the last cd I bought was 10K days, lol, but I really haven't been all that faithful over the last few years... I also remember this local access show in 92 [sorta old guy here] that played Tool [Prison Sex] and RATM and NOFX and Eric B and Rakim, back to back....that was unheard of, still had Mich Jax, Nirvana and C+C Music Factory on the damn radio then...what a time

:

You are OK to tie the grounds together, it was just referring to using the neutrals as a ground. Apparently that used to be commonly done but turned out to be a bad idea LOL.

Same here have been letting a bunch of their live shows play while I am working. No albums since 10K days, but rumors that they are moving forward on a new album. MJK turned farmer near Sedona