Lighting DIY Mars to Cree Cob conversion

[Baxterwolfe]

Where did you find the cobs so cheap?

I found them on Digikey.com

 

[Baxterwolfe]

I'd go for the cxb2530 over the cxa series. Top bin comparison of 3000k 90cri

View attachment 597159

Huge efficiency jump and they're about the same price(the cxb2530 3000k 90cri t2) $12 per

http://www.cutter.com.au/proddetail.php?prod=cut2827


You need to look for top bin chips as well, the Cree PCT is good for comparing different bin chips.

http://pct.cree.com/dt/index.html


Make sure you're in the voltage range of the driver, the cxa2530 pulls 36.9v at that current, cxb2530 pulls 35.8(same Cree PCT), couldn't fit 3 on one driver if it's 100v Max.


View attachment 597173

And the 3000k 90cri is the fullest option. Best bang for your buck on the mars drivers I can find. Next jump is the 72v cxb3590, 1 per driver, $45 per.

It just sucks that its $25.00 shipping from cutter to the US. I found the cxb2530 on digikey but they only have a couple spectrums that you can do small orders on the CXB. The CXA2530 3000k are $8.80 a piece with $7 shipping for 5.

 

[Baxterwolfe]

And do you think the CXB2530 compared to CXA2530 would be enough difference for about double the price with shipping and everything? Sorry Im a noob when it comes to figuring out this lighting shit.

 

[Atulip]

Would be about 36% efficient through the leds with cxa2530, about 46% with the cxb2530 and about 56% with cxb3590. That's if they're all top bin too. If those are lower bin cxa2530s they'll be even less efficient.

 

[Baxterwolfe]

I went with the cxa2530 I got 4 3000k and 1 5000k I was planning on a setup like this MS paint drawing. I got them for $53 shipped and should be here Saturday or Monday. I'm going to use the heat sink provided and measure temp differences. I will be grabbing another heat sink more than likely but I just wanna see how everything works at a minimum and then tinker from there lol. I would like to be able to possibly spread the lights even more by cutting into the housing some but at that point I might as well do a custom setup. I need to grab a meter so I can test the light output but idk what one would work well for LED.

 

[Baxterwolfe]

Hey @Atulip what type of meter did you use to get your lux? I want to get one so I can take some measurements to see how my setup compares to the Mars 300w vs HID vs other diy builds. Or any suggestions on what type of meter to get that isnt $120 lol

 

[Ripper]

Hey @Atulip what type of meter did you use to get your lux? I want to get one so I can take some measurements to see how my setup compares to the Mars 300w vs HID vs other diy builds. Or any suggestions on what type of meter to get that isnt $120 lol

Search eBay some cheap ones on there

 

[Atulip]

Yes, eBay for lux meter. I just got a cheap one of these.

http://m.ebay.com/itm/Digital-Lumen...-3-Range-Tester-TR6Z-/252193751149?nav=SEARCH

Lux isn't as useful for comparing different spectrums, since it's weighted to how we see light, not how plants use it. But a lux meter is cheaper than a par meter and gives a general idea. And you could use a known conversion for lux to ppfd, like .0124 for hortilux HPS, and .0143 for Cree phosphor 3500k 80cri. QER/LER to get this conversion number.

So a 100,000 lux reading under an hps would be around 1,240 ppfd. (100,000*.0124=1240)


Biggest benefit I see is getting light spread right for your space.

 

[Baxterwolfe]

Yea thats why Im gonna try and get the COBs as close to all 4 corners as possible for the best spread in the mars case. The 5k in the middle should be enough blue for good veg growth and extra light. Im gonna use kapton this time and do a quick mounting on this one. If it works really good my next 2 Im gonna run COB holders and run all my wiring really neat.

 

[Baxterwolfe]

The lights will be here tomorrow so Im gonna try to get them all wired up and mounted. Ill make sure to take pics of the process and how they end up being setup as well as some shots with it running to test brightness.