Yes but you don’t want wasted driver space. Slightly larger then you need but filled completely.
2 Likes
You’re sometimes asking for problems if you load to exact amount, but leaving nearly a whole cob worth of headroom isn’t necessary. Especially when math comes out to something like 5.95 cobs per driver. Your cost per watt is usually a lot better in a different driver application.
1 Like
I don’t think we have cooling capability to be above 50 watts. Or at least, he knows they’re good there. So I’d prefer to keep them there or less.
Which takes us to the 50 volt cob thing. We can save some money that way without giving up any efficiency using them over the 36 volt or going with a cxb. I didn’t really type that out anywhere, but that’s where my brain is right now.
1 Like
I spent several hours online looking at multiple vendors for COBs and drivers. I only looked at Cree, Bridgelux, Citizen, and Luminous. There are a lot of choices and wild swings in price that’s for sure. I need some help to narrow it down. I want to make this build a community thing. I think it would help if anyone who wants to post a photo of their DIY light, please do. I’m planning on being completely transparent about this. I want to show it from start to finish. It’s going to take a while to get the components I see. Most of the COBs you all are talking about aren’t in stock at several places. Also I appreciate any ideas like @1BigFella has about thermal protection. @Daddy your light frame pic is going to be a big help when I build my frame.
2 Likes
Did anything particularly catch your eye? I have an uncanny way of finding said components as long as they’re already released.
I’m also having a hard time finding a good layout in those 50 volt cobs. So will probably be diverting back to some 36 volt models. Have you been around what @Bogleg did with the citi 1212’s at 40 watts? Would something like that be on the table?
Anything is on the table as far as I’m concerned. To answer your question about anything that stood out to me. I added a bunch to my Cart at several vendors. I’ll get the part numbers and post them later. I haven’t seen boglegs thread.
Don’t go through the hassle of copy pasting. Just screenshot the cart contents, should be good enough.
Unfortunately I lost arrow electronics and another vendor because I hadn’t registered and the cart was empty. But here’s rapid and digikey.
I see the drivers are going to be where the big money is going to be spent.
1 Like
I think you forgot to upload?
Sorry, I fat fingered the reply too soon.
2 Likes
No worries haha!
So one thing that jumps out, you had that hlg-240-2100 in your cart. That driver is gonna have too high of an output current for anything we do on your current heatsinks. On a 36 volt cob, you’re gonna be about 75 watts. A 50 volt cob is gonna be around 110 watts.
I’ve been checking and can’t really find a good fit for the 50 volt cobs at that low of power.
Cobkits has gen 6 citi 1216’s for around $17 bucks. They’re solid in a 36 volt chip at 50 watts. I can run and double check, but a quick glance appeared 5 of them would fit on an hlg-240-1400.
Three sets of 5 would put you around the 750 watts we were looking at. You’d probably expect a few extra bucks per cob for holder and thermal material. Probably an extra $10 if you wanted to add reflector. But you can always get a holder that’s compatible and add that later if you wanted.
If you wanna go cheaper, they have 1212 for as low as $9. It’s not as efficient and better at 30-40 watts per cob. But totally up to you. We can certainly grab a part number and see if someone else has the 1216’s cheaper too.
I was just guessing at the drivers. Most of last night’s research was cobs. Can you point me to the vendors you use? I wasn’t counting the accessories, but I know I have to buy them.
One thing I would try for is to make multiple smaller lights, each with their own driver. That way you can easily switch them around to different tents, etc. If you decide you want to mount several lights to a common frame for ease of adjusting height, that would just take some more angle aluminum.
I am thinking about doing exactly that @1BigFella. I was wondering if it would be the way to go because I really have 3 different heights of plants due to staggering their starts and also I usually have 4 autos growing along with the fems.
I was figuring at 3 different fixtures that way, all being it’s own row of cobs, One driver per row.
Would you like to do it a different way?
I just checked cobkits, didn’t compare prices. If we narrow down components you’ll probably find it easier to just type part number into internet search bar and go from there.
1 Like
Your on target with the three fixtures. I don’t see a single fixture working in my situation. Three 250 watt lights would replace what I’m using now with much better light that’s dimmable @dbrn32
1 Like
Following. I love this shit 
2 Likes
Well the only thing I’m thinking is that you would probably have to grow in rows that way. Not that it’s a problem, but not everyone likes to do that. Unfortunately I don’t see a way to divide 15 cobs on three drivers up much better.
If you would rather, we can drop down to hlg-185 and run 4 cobs per driver on 4 drivers. Then two separate fixtures running 8 cobs each and divide the room in half? Figure that would give you something like this?
2 Likes
If I can get the coverage, I’m fine with the 8 light frame. I typically grow in rows anyway.
The two fixtures might work. I keep forgetting that the PAR and Luminous flux are going to be a lot better, so I may be able to put the shorter plants with the autos and grow under the two 400 watt lights. I think I should probably buy a 40 watt and 50 watt cob and 2 small drivers to drive them so I can make sure my heatsinks will be ok on temperatures. Any thoughts on that @dbrn32?