When QBs are cheaper than strips?

Humple

Well-Known Member
So I've been planning for a while now to redo the lighting in my cab. The cab has three chambers: the top is approximately 19"x48"x23" (D/W/H), and is where I keep seedlings and clones; the two bottom chambers are both 19"x23"x48" (D/W/H). This post concerns the two bottom chambers.

Currently, each chamber is lit by a single QB288. As these spaces are roughly 3 square feet each, the 288s are a bit overpowered; I've never run one past 100w. Been thinking of grabbing a new 2'x4' tent and moving the two 288s there, replacing them in the cab with something more appropriately powered. I love my QBs, so when the 132s hit, I started considering a 4-pack. I could put one QB132 in each chamber, and have two spares for any other projects that might come along. But then I started thinking about strips. After all, strips are the best bang for the buck, right? Well... Maybe not. At least not always.

I'm shooting for 75w to give me around 25w/sq foot, which is more than enough for veg (the normal use-case for the cab), and sufficient for flowering if I have any overflow from the clone chamber (the cab doubles as a backup bloom space). Pricing out Samsung F Series Gen 3 strips, with a no-heatsink requirement (for simplicity and economy), I discovered that QB132s are actually the better bargain. If I understand the F Series specs correctly (and someone set me straight if I'm wrong), I should be able to hit 75w at nominal with three of the 2 foot, single row strips, yes? Add an HLG-80H-24A, and I'm at about $80 per chamber: $15 per strip for $45 total, and $35 for the driver. So $160 to light both sides of the cab, and that's without any aluminum for frames. In comparison, a QB132 costs $35, and an HLG-80H-36A costs $40 (actually a little less than $40, but let's round up). And there's no need for a frame.

Even if I couldn't order the 132 in singles (I know the Amazon 4-packs take precedence for HLG, and understandably so), I feel like I'd be getting more bang for my buck with QBs in this scenario. And to top it off, it's far less work to wire and hang a single board than it is to wire, frame, and hang three strips. The only advantage I can see in the strip build would be controlling the light-spread, but in a space this small, I don't think it would make much difference.

Make sense? Can anyone point out any flaws in my reasoning?
 

Humple

Well-Known Member
216 vs 132 diodes.
Yes, I considered that, but my 2.5'x2.5' tents are both running 480 diodes at up to 250w (4xQB120), and I've been happy with the performance there, so I'm not fully convinced it's going to make enough of a difference. Especially in such a small space. I'm open to being convinced though!
 

caretak3r

Well-Known Member
don't leave out the 2nd generation bridgelux EB strips in your comparison... honestly I haven't compared pricing lately so I don't know if they are cheaper, but they are quite good (and efficient)
 

Humple

Well-Known Member
don't leave out the 2nd generation bridgelux EB strips in your comparison... honestly I haven't compared pricing lately so I don't know if they are cheaper, but they are quite good (and efficient)
With my no-heatsink requirement, I'm pretty sure the EB Gen 2s are actually a little more expensive. I'd need 6 of the 2 footers, which comes out to around $50, and the HLG-80H-20A is around $35. Granted, this would give me an extra 10 watts or so to play with, without worrying about going over nominal current. But I'd still have the added cost and work of the frame. I think the QB132 still seems like the better choice?
 

Viceman666

Well-Known Member
With my no-heatsink requirement, I'm pretty sure the EB Gen 2s are actually a little more expensive. I'd need 6 of the 2 footers, which comes out to around $50, and the HLG-80H-20A is around $35. Granted, this would give me an extra 10 watts or so to play with, without worrying about going over nominal current. But I'd still have the added cost and work of the frame. I think the QB132 still seems like the better choice?
Lets put it this way more diode for same power = less current/diodes = more efficient..

So effiency wise more diodes would make your set up more efficient (most likely not a big difference in your case) as you are already pretty efficient.

Strips are interesting for bigger foot print room because you can get a better spread of the light over the full surface vs single light point.. in a 3sqf space you dont benefit fom the strips as your qb board already fill all the space quite nicely so yes i wouldnt go for strips based on your design as it will be a bit more work and based on your calculation a bit more expensive as well.. ive seen people using 4 or 6 qb120 over a bigger surface.. but the issue in those cases for tent grower is air movement as the boards would cover all the top which is not the case with strips but either option will work well! Go with what works best for you!
 

Dave455

Well-Known Member
Lets put it this way more diode for same power = less current/diodes = more efficient..

So effiency wise more diodes would make your set up more efficient (most likely not a big difference in your case) as you are already pretty efficient.

Strips are interesting for bigger foot print room because you can get a better spread of the light over the full surface vs single light point.. in a 3sqf space you dont benefit fom the strips as your qb board already fill all the space quite nicely so yes i wouldnt go for strips based on your design as it will be a bit more work and based on your calculation a bit more expensive as well.. ive seen people using 4 or 6 qb120 over a bigger surface.. but the issue in those cases for tent grower is air movement as the boards would cover all the top which is not the case with strips but either option will work well! Go with what works best for you!
Just blow air from below going up...
 

Viceman666

Well-Known Member
This thread got me looking for those qb120/132 and at 133$ for 4 boards value was interesting for my next 4x4 tent (was thinking 8 of them) just to realize I was on amazon usa... when i looked at amazon canada it became 430$ cad.. and I can promise you its not a 4 to 1 convertion rate from usd to cad.. oh well was worth looking into it lol :wall:
 

Humple

Well-Known Member
ive seen people using 4 or 6 qb120 over a bigger surface.. but the issue in those cases for tent grower is air movement as the boards would cover all the top which is not the case with strips but either option will work well! Go with what works best for you!
Yeah, I've seen dudes fit them end-to-end, side-by-side, but I spaced mine out enough to give me airflow between the boards. Seems to work just fine!
 

nogod_

Well-Known Member
You only need 2 strips to match the diode count/output of the QB. If you're like me you have lots of random scraps of aluminum around to slap together a frame but even at 1.5a you wont need much of a "heatsink"

Youre not wrong that strips make less sense for such a tiny little project. They make a lot more sense when you get 40-50% off by buying in quantity.

In your case sounds like you want to pay a little more for the braindead easy solution...most folks do so buy the QB with confidence!
 

Humple

Well-Known Member
You only need 2 strips to match the diode count/output of the QB. If you're like me you have lots of random scraps of aluminum around to slap together a frame but even at 1.5a you wont need much of a "heatsink"

Youre not wrong that strips make less sense for such a tiny little project. They make a lot more sense when you get 40-50% off by buying in quantity.

In your case sounds like you want to pay a little more for the braindead easy solution...most folks do so buy the QB with confidence!
As I stated, I would have to buy the aluminum for a frame, and running two at 75w means more aluminum for heatsinking. So no, I don't want to pay a little more for the brain-dead easy solution, I want to pay a little less.
 

nogod_

Well-Known Member
Fair fight. I'd also never hang a naked pcb in my grow room so different strokes.

As I stated, I would have to buy the aluminum for a frame, and running two at 75w means more aluminum for heatsinking. So no, I don't want to pay a little more for the brain-dead easy solution, I want to pay a little less.
buy the QB with confidence!
 

knight mare

Well-Known Member
Some of the people on this site make me laugh, if you run the strips at there nominal vF and mA strap them to an old baking tray.
Or do what I did for mine, look on the net for metal suppliers got some nice 6063T6 channel for £22
 
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