Veg light LED build - need advice


I actually havent heard of these boards before. I know the HLG boards are high quality. But these boards are popping up all over the place now, they are probably fine and will do what you need them to do.


The difference between v1 and v2 are the lm561c or lm301b chips. The v2 boards are like 5-6% higher in photon efficacy. Same driver for v1 and v2 boards in most cases.


Yeah, then I’ll stay away from them since they’re 2x as expensive! Lol. If you’d have said, “Oh yeah, they’re the best lights out there right now” maybe I’d spend the extra. Guess I’m just going to be sitting on my hands until those Samsung V2 boards drop in 4K. Thanks man!


@dbrn32 I’m headed into the big city today and I will be able to pick up some aluminum angle stock for building my veg light. Could you give me the dimensions of the angle stock I’ll need and suggest an overall length I should purchase to build a fram for 4 of these new QB120 V2 boards? I may be able to get them to cut the pieces I need - that’s sure make it easier to get into the car. I’ll be doing a 4x4 tent; but if I could build it so that it could also work in a 3x3 (in case I ever wanted/needed to downsize, that’d be awesome!


Off the top of my head, like two pieces around 30” and 4 pieces around 24” would work and land you fairly ideal.


Would 1” x 1” x 1/8” angle work ok?

Should I get 2 pieces of, say, 1” x 1/8” flat stock to go across the top for the driver to sit on?


Ya that size will be ok. You can do the flat stock too.


Thanks man! I missed them because they closed earlier than I thought. But I can call it in next time and they’ll have it cut and ready for pickup!



While I’m waiting on those QB120 4000k to drop, can I ask you a comparative question? I was perusing the Fluence website and ran across their Spyder2x that’s 345w at the wall and has a PPF OF 875umols (2.6 umols/j efficacy) for $880. I know this is a full spectrum light and not what I need as a veg light but I’m curious how it compares to that HLG 600H 3000k light I put together that was like $750?

Do they actually compare? I’m using my 600H kit in a 5x5 and you said that’d be plenty of light and it sure seems to be. So, I’m not understanding how a light that draws around 1/2 the wattage of my light could be putting out anywhere near as much light or be enough for a 4x4 or be WORTH $880. IS it putting out anywhere near the amount of light that my 600H kit is? Wouldn’t a 600H kit be even better than the Fluence in a 4x4 (for a full grow cycle) at a savings of $130?

Trying to learn and understand here and you are ‘da man’ on all things “light!”

Here’s a link to the Fluence spec sheet:

I couldn’t find a spec sheet listing the PPF for the HLG kit. I only found its PPFD number and I don’t know how that converts to PPF


Here is ppf of hlg-600

The 600 kit doesn’t run as efficient at that power level though. And it doesn’t carry the fancy fit and finish of the fluence light or the same electrical safety ratings. The fluence light that would be more of a comparison is something like $1400. As a buyer you would be weighing that hang and plug in vs diyish product at the end for half the cost.

For some a $1400 light is out of the question. You figure any of qb kits are designed as an inexpensive alternative to get into the high performance stuff. Each individual is going to come in a little differently there.



Thank you sir! I don’t give a hoot about fit and finish! Lol. I thought the HLG numbers were PPFD and not PPF and didn’t know the difference; but I see my Dyslexia got the better of me. As always, I really appreciate your help!


No problem. The fluence lights are definitely nice, they’re just really proud of them. Gavita the same way.


@dbrn32 those QB120 V2’s in 4000k are back in stock on HLG’s website! Before I hit that BUY button, I wanted to ask about the 3500k which look like they may be available shortly - even though I’m wanting a veg light for a 4x4, would the 3500k spectrum be 90% as good for veg but also give me the option to flower in a smaller (say, 3x3) tent?

Or, am I just being silly? At this price I suppose I could just buy a 2nd set of boards later, in 3000k and swap them out from the 4000k when I wanted a flower light?


Nope, you can go dual purpose with 3500k no problem


10-4 I’ll give them a shout and see whether it’s going to be a short or a long wait on them. Thanks buddy!!



Ok, the 3500k boards are in and I’m going to order them today. I’m thinking about getting the HLG-240H-C2100b driver just because it’s only a few dollars more than the C2100a and I found it in stock at RapidLED, where I can order the other parts from and just pay 1 shipping charge. My understanding is that the b version only differs from the a version in that the b version is dimmable. Is this correct?

Could you give me a parts list for this build, down to the bolts and wire sizes you’d recommend and anything else you think I’ll need? I’m going to order the 1/8” aluminum angle along with a piece of 1/8” x 6” flat stock to mount the driver on.


Both drivers are dimmable. The a version has built in dimmer, the b version needs you to wire in a dimming device. Arrow electronics will ship for free if they have it.

For your angle get at least 3/4" x 1/8" wall. 1" may be a little easier to work with. You can probably get by with 12’, but make sure lengths will work with your build plan.

Grab 25’ spool of 18awg 300v solid hookup wire.

You’ll need a power cord, like 16/3 would be ideal.

A couple of 2 port wago connectors or similar

Waterproof barrel connector 3 pin

Four 1/4" eye bolts with two washers and nuts per eye bolt.

I believe bolt holes in board are 4mm. I’m pretty sure what I typically use is 8-32 machine screws but double check that either fit. You can use same hardware to mount driver, fasten angle, and mount boards. I would guess about 30 screws and nuts. If you use washers may as well get 2 per bolt or screw.

I think that should cover about everything you need. If you look on Amazon under the boards for items purchased with boards, I bet just about all of it pops up. Watch Amazon on hardware prices though, they’re usually expensive.

@Bogleg @Myfriendis410 @Not2SureYet can you guys check my list please. You should all have done similar light with the 4 boards.


Thank you sir! I’m going to order the boards direct from HLG’s website as the only boards showing up on Amazon are the 3000k. I called HLG today and they said the 3500’s are in and fixed the website after I told them they were showing up as sold out this morning.


I think you covered it. The eye bolts are for hangers, right?


Yessir! Could be substituted, but that’s what I typically use.