Amazing Cree CXA3070 LED

Is this the one, Marni (3700 lumen from 38W, 97lm/W)?

http://www.costco.com/4’-LED-Shop-Light-with-Chain-2-pack.product.100223617.html

Here is another one I saw recently at our local warlmart:

http://www.samsclub.com/sams/4ft-led-shoplight-shoplight-led/prod16460030.ip

This is probably similar to what Marni is talking about, and it gets 4200 lumen out of 40W (105lm/W). A bit more efficient than Feit, but I'm not so sure about "Lights of America" brand.

 

For DIY COB, drilling and tapping heatsink is probably the most intimidating part. The rest is something which can be done by anyone who can strip wires and use a screw driver.

I noticed that Cutter is starting to offer pre-drilled heatsink + COB kit. It is not the cheapest, but for the people who doesn't want to drill, this could be an easy option.

passive cooling, CXB3590:
https://www.cutter.com.au/proddetail.php?prod=cut2901
About 50W for $80. You'll need to get your driver (about $20, including shipping) separately. I would prefer a bit beefier heatsink, but it probably works well.

The following is similar, but it comes with 4x COB (about 200W) and a driver (i.e. a complete kit):
https://www.cutter.com.au/proddetail.php?prod=cut2900

Active cooling version:
CXB3590 ($66)
https://www.cutter.com.au/proddetail.php?prod=cut2792
CXB3070 ($56)
https://www.cutter.com.au/proddetail.php?prod=cut2791

You'll need a driver and AC/DC adapter 5-12V (e.g. cell phone charger).

For the driver, you can use something like Meanwell LPC-60-1400 (data sheet:
Here is the current price (about $16+shipping):
https://octopart.com/search?q=LPC-60-1400

 

I came across this CXB3590 kit, which was released in 1-2 month ago:

http://timbergrowlights.com/200-watt-cree-cxb3590-4-cob-kit-meanwell-hlg-power-supply-free-shipping/

This is good for people who doesn't like to assemble since no assembly is required. It will be good to cover 4'x4' (or 8'x2') area for moderate light orchids.

Similar to the Cutter kit, but for the US, it is a bit cheaper. Good components; 4x top-bin CXB3590 driven softly (50W per COB) and the best MeanWell driver. I'm not familiar with the heatsink they use. It is all pre-assembled, so you don't need to do anything. You only need to figure out how to hang them. Dimmer is included (goes down to 10%). $399 + free shipping for 200W (4x 50W). If you assemble the components by yourself, you can save $100 or so, but for people who doesn't have time to assemble or not sure how to assemble, $100 extra may be worth. They also have 5x50W version for $499. http://timbergrowlights.com/products/diy-grow-light-kits/

This is pretty much the best in terms of PAR efficacy (about 2.5 micromol/J from my calculation), and most LED grow light can't touch it. The PAR efficacy is measuring how many photons relevant to plants are produced for a given amount of electricity. In comparison, Fluece (=BML) SPYDRx, released in early 2016, is one of the very best and achieves only 2.2 micomol/J. I said "only" 2.2, but it is a very high efficiency number. You should know that cheaper LED grow lights give about 1.0 micromol/J, only slightly better than T8 or T5HO. Very good HPS is around 2.0 micromol/J. In terms of lumen (not so relevant, but people are more familiar with it), it is giving about 177lm/W.

In terms of COB front, I recently learned about a better alternative to Cree. I don't need a newer grow light for me, but if you are interested in DIY route, I would definitely look into Citizen CitiLED COB Series Version 5. There are several sizes, but something around CLU048-1212C4 seems to be the sweet spot in terms of price and efficiency ($12.55 from CDI). This is a smaller COB, so you'll need 2 of CLU048-1212C4 to replace 1x CXB3590. At the moderate driving current, the efficiency is very close to CXB3590. Maybe you can drive it at 1050mA (36.8W), which gives 169lm/W @ case temperature (Tc) of 50C, or better yet at 700mA (23.7W), which gives 179lm/W (similar to CXB3590 @ 50W).

 

I just spent a bit of time to write up a blog post to help DIY LED grow light builders. The DIY COB post is one of the most frequently accessed post in my blog for some reason (even though I think other biological posts are more fun to me), so this is a follow up, and explain more fundamental principles of LEDs. In this post, I tried to explain the basics of driver selection and the design process. Here is the link to the blog post. It talks about the multiple LEDs driven by a single driver, basics of driver and LED efficiency, and super simple thermal protection. I tried to target beginners, but it might be too much information or a bit too technical. Hopefully, it is useful for some people since winter is coming (well, it's been here for a while in Alaska).

I also updated the original DIY COB blog post with newer information (i.e. there are much better/cheaper COB than Cree COB).

Here is my recently cleaned grow tent with 8x COB LEDs.


Here is a PPFD map of 4x CXB3590 with HLG-185C-1400B. It is showing amazingly even distribution of light over 120x120cm (4'x4') area in the grow tent. The unit is micromol/m^2/s.


Here is the relationship of dimming vs overall efficiency. So with this driver, using dimming function doesn't decrease the efficiency unless you dim it extremely (i.e., as long as you stay above 30% of the full power, it is explained more in the blog post).

 

Happy Thanksgiving!

Another DIY LED update. I made a plastic container based grow space. I used Samsung H series LED linear modules this time. This module was announced in Summer 2016, but it started to ship in October. This Samsung basically beats Philips XF-3535L (I posted about this previously) in all aspects. It has amazing efficacy (187lm/W), even higher than most COB LEDs. I haven't calculated the PAR efficiency, but I'm pretty sure there is no commercially available grow light with this high efficiency. It is a bit more expensive per light output than COB, but it is easier to assemble, and better for a small area. Also, it provides very even light distribution. It costs about $60 to cover 2-3 sq. ft.

I built this for pygmy Drosera, so it is targeting high-light plants. But if you increase the distance or spacing, it will work with orchids, too. I listed an alternative configuration with lower output. It takes about 1 hour to assemble.

Here is the link to my Orchid Borealis blog post.





Drosera dichrosepala ssp. enodes from Scott River. Catalogue #10a of Drosera Gemmae.

 

Thanks Calvin. I think that the C-channel is enough. I've been running XF-3535L, which is less efficient (=more heat), for a while with the same C-channel. It's been going ok. With Samsung H, which is 25% more efficient, I think it will be completely ok. I haven't measured the temp, but I can touch the LED surface, and I can feel that it is warmer than my body temp, but it isn't hot or anything.

I have expensive electricity ($.20/kWh), so I go for the maximum efficiency. If your electricity isn't too high, Samsung does have higher output (less efficient) linear modules called inFlux series: (link). This is very cheap. But with this, I think you need a better heatsink than C-channel. If you go with 30cm module, you could get cheap 300x25mm heatsinks from ebay or aliexpress. HeatsinkUSA has a cheaper heatsink, but I think the shipping to Canada might be too expensive.

Did you solve the flickering LED issue? I recently encountered one. It was working for a long time, but one of them started to flicker after my major clean up of the grow tent. I think the driver somehow became weak, and I'm guessing that it couldn't supply enough voltage, and the overvoltage protection was kicking in (so it blinked for every second or so). In your case, the driver was new, so I think your driver was not up to the spec. Those cheap Chinese drivers seem to have issues with quality control (lots of variability in the amount of current). I have 10 or so cheap ebay driver, but this is the first one which failed. I'm mostly going with Meanwell drivers now.

If you are considering more powerful COB, new Vero 29 and V22 (generation 7) is quite a bit better than Cree's offering at this moment. For Vero 18 class, Citizen CLU048-1212 could be slightly better than new Vero 18 (I forgot the detail). People are running COB with pin-fin passive heatsinks now; something like SST-120 from here. It's been sold out for a while, though.

 

I've been very happy with Samsung H-series (see post #30), but there is an improved version announced at the end of Aug. 2017. It is called Q-series. Very similar to H-series, but about 10% (actually more like 8%) increase in efficiency. Now it exceeds 200 lm/W at the nominal current! In comparison, typical house-hold LED bulbs or LED shop light you can get from Walmart etc. are barely 100 lm/W. The price is similar to H-series. It is more limiting in the driver selection than H-series, though. I've added possible drivers for the new Q-series in my previous blog post (scroll to the very end). Calvin and I were talking about this, so I thought I should let others know about the new option.

As a different note, which I have forgotten about, I was curious about the longevity of those super cheap eBay 100W COB LEDs. So even though it is cheaper to replace it with a high quality COB, I kept one running. It lasted 3 years with 13h/day. It was driven at around 45W, I think. It lasted shorter than Cree, but it lasted longer than I expected. Just as a data point.