DIY LED guru's required

[VetSmoke85]

Hi All,

Really just looking for anyone with good DIY LED lighting knowledge to look over the setup I have planned and costed. Make sure there's no glaring errors and it will be fit for purpose, cost efficient etc.

My grow space is a stealth cabinet H=64cm W=42.5cm D=57cm. Currently got a grow going in there but want to upgrade the lights.

So I believe for this space 75-100W should be enough. I've decided to go for LED strips and use 25mm L-profile aluminium as the frame and heatsinks. Here's the parts I'm looking at.

10 x Bridgelux EB. Gen 2 280mm strips
BXEB-L0280Z-35E1000-C-B3
3500K
Forward voltage = 19.5V
Max Current = 700mA
Nominal drive current = 350mA
Cost £3.17 each

1 x MW HLG-185H-C700A driver
Voltage output 143-286V
Max Current output 700mA
Power max 200W
Costs £41.77

Aluminium profile, thermal tape, fixings, wire, connectors etc. costed up to £39.21.

The frame will be a size of 330mm x 475mm with a 25mm gap between each LED strip.

Total cost = £111.73

The driver is dimmable so by my calculations I should be looking at 102W if driven at 75% max current and 68W if driven at 50%.

The strips will be wired in series so normal forward voltage will be 195V.

I think that's most of the important info. I guess I'm just needing some reassurance from somebody more experienced that it will work and is worth spending that money on. Hard to find ready built lights that suit my grow space.

Thanks in advance.

 

[Old Salt]

700mA is the overdrive current, twice the nominal current. You can drive them that hard, but may experience premature failures.

The driver will handle both the minimum and maximum voltages for from 8 to 14 of the light strips.

Your design will work.

I recommend adding four more lights strips. During the design phase this is easy, not so after it has been built.

Back later with more...
Have to run my wife into town...

 

[Old Salt]

For your consideration...

Driver	HLG-185H-C700A	HLG-185H-C700A	HLG-185H-C500A	HLG-185H-C500A
No. of Light Strips	10	14	14	20
Minimum Power	68.25	95.5	67.4	96.25
Nominal Power	N/A	N/A	81.3	116.1
Maximum Power	143.5	200.9	139.3	195

Your space is W=42.5cm D=57cm or .25 sq meters or 2.6 sq ft. The minimum light from LEDs recommended during flowering is 30W / sq ft. Your minimum flowering requirement is 78W. I'd recommend a minimum of 40 W / sq ft or 104 W. Any of these configurations will do, but what happens if you need less light as for seedlings and early vegetative stages? Let's see what happens if you install a switch to short out as many of the strips as possible...

Driver	HLG-185H-C700A	HLG-185H-C500A
No. of Light Strips	8	11
Minimum Power	54.6	52.9
Nominal Power	N/A	63.85
Maximum Power	114.8	111.4

This is much better, and allows you to expand if you wish to do so later. Just for the halibut, let's look at other power supplies for these lights, something a little more suited to your current space...

Driver	HLG-80H-C350A	HLG-120H-C350A	HLG-120H-C500A	HLG-120H-C700A
Min. No. of Light Strips	9	12	8	6
Max. No. of Light Strips	13	22	16	11
Strips for Power Calcs	12	16	12	10
Minimum Power	48.13	64.18	92.64	82.95
Nominal Power	69.48	92.64	92.64	N/A
Maximum Power	80	109.2	159.2	143.5

I'm still not happy with these figures at the low end of the power output. The best so far appears to be the HLG-120H-C350A and 16 of the light strips. You can short four of them out to drop the low end power to about 48W. This is about 60% of the minimum required for flowering, and may still be too high for seedlings and the vegetative stages.

I'll post this and keep looking...

 

[VetSmoke85]

Much appreciated. @Katins has put me onto the quantum boards. Can get the 65W kit for £74.99 or the 110W kit for £119.99. Both dimmable. Maybe easier to get one of those.

 

[Old Salt]

Well, here's another option. Let's use two drivers and see what happens:

Driver	HLG-60H-C350A	HLG-60H-C350A (X2)
Min. No. of Light Strips	5	10
Max. No. of Light Strips	10	20
Strips for Power Calcs	7	15
Minimum Power	28.1	60.21
Nominal Power	40.63	87
Maximum Power	47.75	102.32

Eureka! I think we've got it!

We now have a bank of seven and a bank of eight light strips, each with their own driver. With only the bank of seven light strips turned on, we can go down to 28.1 W, which is 36% of the light required for flowering. I don't think this will harm seedlings, but if you notice problems you can short out two of the light strips to drop it down to 20W. Adding the bank of eight light strips will let you go up to 102.32 W, or 39.35 W / sq ft. That's 31% more than the minimum. What makes this design even more attractive is that at no time will you approach the limits of the light strips.

This is the design I'd go with for your grow space.

 

[Old Salt]

Much appreciated. @Katins has put me onto the quantum boards. Can get the 65W kit for £74.99 or the 110W kit for £119.99. Both dimmable. Maybe easier to get one of those.

Yes, It would be easier. You have a fairly severe height restriction in your grow space. You'd lose 25cm or more to the Quantum board, and the distance it requires to cover the entire canopy. I think building your own light would be better, as you will be able to cut the height above the canopy to less than 10cm. Just one more thing to consider.

 

[VetSmoke85]

Great info mate. Will be weighing it all up tonight. Why would I lose 25cm with a quantum board? Is that just because of the distance to get the spread over the canopy? Where as with the strips I can spread the coverage more evenly?

 

[VetSmoke85]

I've read, think it was the LED Gardener guide to building these, that run at 350mA these strips don't really need a heatsink. Think I'd get away with mounting them all onto say a 2mm aluminium sheet? For this setup the cost of 2 drivers and 15 strips alone is £100.

 

[Old Salt]

That's it exactly. The quantum is QB288 is 6.833" x 11.25" or 17.35cm X 28.57cm. The LEDs have a beam width of 90°.

That means that the absolute minimum height above the canopy should be the same distance as that from the outside LED to the edge of your grow space. Being generous this is the higher of:
(42.5cm - 17.35cm) /2 = 12.75cm or (57cm - 28.57cm)/2 = 14.21cm.

A better approximation would be using 1/2 the dimensions of the board so it becomes:
(42.5cm - 17.35cm/2) /2 = 17cm or (57cm - 28.57cm/2)/2 = 21.35cm. Add in a few cm for the fixture and you get the 25cm I mentioned above.

Some folks will move them closer to the canopy, but then you'll get an area of intense light under the quantum, and the edges won't get enough light. For your grow space I highly recommend spreading the light over the top of your cabinet as much as possible to get even coverage over the entire canopy.

Did you notice that HLG does not provide a PAR or Lux map at various heights for their boards? You have to go back to Samsung to get even the beam widths for the LEDs they use. They are good light assemblies. I won't argue that point. We just have to raise them to get the full benefit from them. You need to decide whether or not it's worth more than 1/3 of your grow space's total height to use one. Everything is a trade off...

 

[Old Salt]

I've read, think it was the LED Gardener guide to building these, that run at 350mA these strips don't really need a heatsink. Think I'd get away with mounting them all onto say a 2mm aluminium sheet? For this setup the cost of 2 drivers and 15 strips alone is £100.

I know from personal experience it gets expensive fast. I'd be tempted to go with 3mm aluminium plate, and thread the mounting holes. I'd use M3 X 5mm Plastic Nylon Cross Pan Head Machine Screws.

 

[VetSmoke85]

Yeah that makes sense. The board below I'm looking at is 2x QB132 V2 boards. So the total size is 30cm x 45cm. Pretty much my available ceiling space as the can filter takes up a bit of room. Also pretty much the same size as the DIY design. Always going to get less light under that can. It's the only way I can really mount it securely though. This board below will fit and give me 10-110W all in assembled and ready to go for £119.99. Decisions, decisions.

 

[Old Salt]

Yeah that makes sense. The board below I'm looking at is 2x QB132 V2 boards. So the total size is 30cm x 45cm. Pretty much my available ceiling space as the can filter takes up a bit of room. Also pretty much the same size as the DIY design. Always going to get less light under that can. It's the only way I can really mount it securely though. This board below will fit and give me 10-110W all in assembled and ready to go for £119.99. Decisions, decisions.

Can you move the can outside of the grow space?

 

[VetSmoke85]

According to Samsung the beam angle on these diodes is 120.

 

[VetSmoke85]

In theory yes but then would open another can of worms. Concealing ducting, pushing air through the filter rather than pulling, likely require a stronger fan etc. Oh the joys of stealth growing. I dislike where I live at times although I am a proud Englishman.

 

[VetSmoke85]

My gauge for these boards is seeing how katins is doing with one QB132 V1 board in his space. The V2 boards are slightly more efficient and that rig has 2 of them. I feel the 110W QB I'm looking at will work and be the easiest/cheapest option, whilst the custom build will be more expensive and require some labour but really squeeze the full potential out of my space. I really can't thank you enough for putting all this info together for me. Food for thought.

 

[Old Salt]

I really can't thank you enough for putting all this info together for me. Food for thought.

No problem. I remember what I went through last year when I designed mine.

 

[VetSmoke85]

Spent hours reading guides, thinking of combinations, pricing etc and you saved me a lot of time. It's all good knowledge to acquire though and I enjoy it. Really trying to make the best choice as I've already gone way over my original budget on this project but I don't mind too much as it's something I'm really enjoying and intend to carry on doing for as long as I can. Been a while since I've been as interested in doing anything as much as this. Got some passion back in me.

 

[Old Salt]

Spent hours reading guides, thinking of combinations, pricing etc and you saved me a lot of time. It's all good knowledge to acquire though and I enjoy it. Really trying to make the best choice as I've already gone way over my original budget on this project but I don't mind too much as it's something I'm really enjoying and intend to carry on doing for as long as I can. Been a while since I've been as interested in doing anything as much as this. Got some passion back in me.

I spent weeks trying to decide on what to build and how to build it. Now I need to build a custom hanger for it. I'm trying to do it with common hand tools so others can duplicate my efforts. I can machine custom screws, but how many of us have a lathe hanging around?

 

[VetSmoke85]

It's awesome you're documenting it to show others. Looks brilliant. Yeah not sure many have one hanging about in the garage. Ha ha.

 

[Chris Scorpio]

QBs for the win!!!

All I use now

Be careful on the mA on a BD, be sure the driver can go as high as the light/board needs (last numbers on the driver)
Learned that the hard way myself

I use 288, 132 and 120 bds, all have plusses and minuses