Heat of LED vs HPS

[gego]

Very nice. I like what you guys are doing. I wish I can have a bigger greenhouse again. Nice healthy plants.

Just a comment, I did notice that the white LEDs I have caused some bleaching to some of the plants. Could be that I placed them too close. But I did notice that adding some warmer color close to 2700K added more green color to my plants. I have to cut down on the whites.

let me know what you guys are achieving or not achieving, okey? if you don't mind. there's a lot to learn.

 

[Bjorn]

Thanks naoki, explains a bit To take the heatsinks first; yes they are pre-drilled, got them from China on e-bay, but now they do not want to send them to Norway anymore (for some reason).
http://www.ebay.com/itm/381x113x26m...ilver-White-/380983967625?hash=item58b469ff89
With a proper fan glued on they take some 200W before the chips get fried.
I would not worry about the solder points too much, the voltage is only 32-36V so no reason to worry too much. Would not touch them though The drivers are elsewhere with proper isolation.
The setup in the Picture is actually running on some 6000mA (approx), as you can see, all the diodes are in parallell, two rated at 50W and one at 100W. Replacing the 50W by 100W chips would be a good idea, right?

 

[naoki]

The setup in the Picture is actually running on some 6000mA (approx), as you can see, all the diodes are in parallell, two rated at 50W and one at 100W. Replacing the 50W by 100W chips would be a good idea, right?

Thanks for the link to your heatsink.! Unfortunately, they don't ship to Alaska, neither...

6A?? I thought that the 3 LED matrices (1x 20LEDs + 2x 10LEDs) were connected in parallel to a single 3A CC driver (100W)? I think you meant 3000mA.

There is a diminishing return. If you replace two 10LED matrix with 20LED matrix, each LED gets 500mA (assuming 3A CC driver), efficacy of 139.9lm/W, total of 12984lm from the 3 matrices.

If you replace all 3 with Bridgelux Vero 29 (about $30 each in the US, BXRC-50C10K0-L-24), you get a bigger boost. I think your driver goes up to 36V, so it can handle 3x Vero. With 5000K CRI=70 (instead of redder ones since you are augmenting HPS), you can get 166lm/W and 19002 lumen from 3x Vero29. It is about 59% more output than the current setup. Here is the data sheet to vero29: http://www.bridgelux.com/sites/defa...3 Vero 29 Array Data Sheet Rev J 20150908.pdf

Probably 2x Vero29 will give the same output as upgrading two 10-LED boards with 20-LED boards, but I think your driver is a bit short in forward voltage (needs about 37V). It works, but CC driver will provide slightly less than 3A total, I believe. With 3x Vero29, the driver is ok because forward voltage becomes slightly below 36V.

 

[Bjorn]

Thanks naoki, think youre right. Replacing With Bridgelux can be an option, right now its not. Maximum light is not so important, as they serve as heating as well for me. It is an educating exercise though. I will consider to change the 10 LED arrays with 20 LED though. This should reduce the wear and increase the light I assume.

 

[Bjorn]

Recent info; I contacted the seller of the heatsinks directly, and they were willing to ship to Norway even if e-bay claimed not. So now I 3 extra heatsinks to play around with. I have an issue with my drivers though, they are (surprise surprise) not delivering what they should, not as much as 3000mA that they are rated at. Have to do some more testing to figure out the root-cause and what I have, but frankly its a minor nuisance since it does not harm anything luckily.

 

[naoki]

Cool, was the shipping cost decent?

Which driver are you using? You might have told us, and I probably forgot. If it is a chinese one, which I freqeuntly use, they gives lower current than what they are rated for. Sometimes, drastically lower. If this is not the case, is the forward voltage of the LED within the constant current range? If it hits the maximum voltage, the driver reduce the current until forward voltage of the LED drops within the range. e.g. I have cheap ebay 100W driver (Y-1010D, 2.8A, 30-36V, something like this), which can run Vero 29 at 1.897A with 37.07V (70.32W). But when I use it to CXA3070, it has to reduce the current drastically to 1.234A, because CXA3070 hits 37.32V, which appears to be the maximum of the constant current region for this driver. It is not bad since it is rated for 30-36V. Also it may be supply more current if I'm using the LED with lower forward voltage like CXB series (I finally got the current top of the line CXB3590, but I haven't had time to play with it).

I also got lots of parts for fun orchid electronics projects, but I haven't had a time to play with them or write blog pages... water-cooled CXA3070 for cool growing orchids, super-high efficiency CXB3590 (4x 50W), inexpensive wi-fi remote temperature/humidity logger with ESP8266 (similar to arduino), data logger for quantum PAR sensor etc.

I'll send you a very cheap source of CXB and Vero via email, so you can play with these on your new heatsinks.

 

[Bjorn]

Shipping cost was included, so not bad at all. Thanks a lot for your info, I see that there might be some measurments ahead of me if I am to understand the various aspects of this. The drivers are cheap Chinese, that is right and I have some creative wiring, so guess the problem can be solved just by changing wire dimensions a bit. Currently I'm using too long and too thin leads for the relatively high current and low voltage. But have to play a bit around before I know what's to be done

 

[littlefrog]

I'll send you a very cheap source of CXB and Vero via email, so you can play with these on your new heatsinks.

Can you send it to me, too?

 

[naoki]

Rob, I forwarded the price list. I wasn't trying to be secretive, I was a bit lazy. Sorry.

In case others are interested in, the company is KingBrite. The email address of the contact person is [email protected] If you contact Jerry, he will occasionally send you the update of stock list. Current price is $46 for CXB3590, $32.50 for CXB3070, $22.50 for CXA3070. I think the shipping is $10 (if you get only small items like COB and COB LED holders) + some paypal charge. If you check https://octopart.com , you can tell that it is very difficult to find any CXB in stock. It is quite a bit cheaper than any domestic sources. Also, he has some top bin (higher efficiency class), which is impossible to get domestically. Many knowledgeable people got these CXB from him and tested, and they appear to be genuine Cree. CXA3070 is the older generation (CXB3070 is the one which came out this year), so less efficient. But it is still very good for the price.

Recently, I saw another post where we can get CXB3590. Check this post where you can get a discount coupon for CXB3590 and CXB3070. Cutter Electronics is an Australian company, so the price there is in AU$. They seem to stock the top bins. The shipping via air mail is around AU$14.10 (for a couple COBs) or AU$25 for DHL + about AU$6 handling. For example, the total cost of 4x CXB3590 (including shipping and discount) is $183.5 (about $45.87 ea). This is even better deal than KingBrite! The price of CXB3070 is also better than KB.

Also, they have smaller CXB2530. This is unfortunately high CRI90 (less efficient for plants), but only US$9.50 ea.
Here is the post about this deal.