I’ve been recommending this for awhile since I saw it last year, but for an American-made light with a real warranty from a long-time player in the LED market, this cannot be beat for $500:
Light years better than any of the budget brands. Pun intended. 
No reason to go with the chicom crap from Alibaba and Mars Hydro.
heya, still on the road to building a flo space. I can’t really find something that fit my constraints (size, power) with the commercial offers. So I’m likely going the DIY way. Right now I’m thinking 4 of these: 50cm Alustripe with 98x Samsung LM301B LEDs 3500k and connectors - 14 LEDs parallel, 7 parts in series
Running them in parallel with couples being in series (is that clear?) I think it would fit with a meanwell HLG-120H-42B https://www.meanwellusa.com/upload/pdf/HLG-120H/HLG-120H-spec.pdf
Would be a bit expensive at the W/€ ratio (120 for maybe 150€), but not that much and should fit my needs so I’m ready to raise a bit the price.
Would such a design work? Just seeking confirmation or if I miscalculated something.
whats the area of your space just cause 500mm strip there should be plenty of commercial options depending on your width and height
Why not go with something like these small panel lights? If your space is narrow then using bars isn’t necessarily worth it, their advantage is spread over a larger space, in a small one the walk distance is so close that it doesn’t matter as much.
Thanks for your answers 
It will be approx. 1.1x0.5 meters, and something like 1.9m in height.
Well, for different reasons:
Realistically you should likely be in the 200-250w range for your space, also you have height to play with so even if you have say a smaller panel it will spread out with that height mind you have to run brighter the further away you are.
Alot of say the long panel options would work for your application and id be one to say buy something bigger xs2500 pro, or p2000 or the likes and then you can turn down to your wattage goals.
Cause i think you’ll fine you may build whatever find its under powered then will either want more strips which will require a different driver or an additional driver and spending more to get where you want, so go bigger either prebuilt or driver and tune down to give yourself some room.
Its all goals though as in what you want to hopefully achieve and with what, and others helping you maybe refine those metrics to be achievable.
Indeed, and you’re already helping a lot with this answer.
One thing is you’re demystifying something: I wrongly understood (who knows where I read it) that dimming won’t lower the wattage. But you’re saying different, and that’s already changing the game big time. It opens the door to more powerful options, and your point is relevant. 
I guess I based my maths on wrong numbers. I thought it was possible to go lower in wattage than that with leds . Also I come from a CFL/T5 world, so I’m used to play with light distance and get it lower to compensate on the lack of power. Guess it’s not that possible with leds.
Thanks for this reply anyway, I’m good for another hunt, and there’s good hints up here in this thread 
One can grow under lower wattage and produce fine bud, its just that more light = more bud to a point ignoring other factors, the metric i go by with modern led lights is you kinda want that 30-35w a sqft range for good growth, one can go higher and or lower depending on your goals but even still say in the 20-45w/sqft range covers alot of conditions, Less than that 20, your typically gonna have slow growth but can make up for it if you have alot of space to have plants in, higher than 45 you either have height to play with or are getting to where a closed system with co2 supplementation would be a benefit.
But yes dimming decreases wattage, 200w light running at 50% will be right around that 100w mark, its not like old style ac dimming where you use to have a big variable resistor to soak up that energy and off put it as heat.
Hmm I’ve done the maths once again. I aimed at 30w/sqft but you’re right 120W is close to 20. Must have messed my imperial conversion uhuh. No surprise, I don’t think I’ll ever get it right. 
That diming/wattage decrease news made my day, guess I was trap in the old tech.
Still, just for the exercise, I guess you could get the light closer if its leds are evenly spread all along the space (bars), compared to a more concentrated version (quantum boards, COBs, …).
Thanks to have brought my messy idea forward!
After a few solid joints and kind of a night (as well as some google), I’ve settled on a plan to follow your advice. I think I’ll try to put the extra bucks. I’ll start by a single vivarspectra p600, and with a bit of luck there will be sales on 420 for an additional p600 or a p1000. Or there will be coupons popping up Thanks again!
Cheap thanks! But says unavailable to me, 
Do you guys think that you still can buy the lm301b or should i blast the budget and go for the lm301h evo?
Anyone willing to help me figure out these MeanWell XLG series drivers? They’re “constant power” drivers. I’ve only dealt with HLG series, CC but mostly CV drivers.
I’m looking at the XLG 240w version. And I have Horticulture Lighting Group qb288 boards, qb648 boards (the former have FV of 54V, the latter of 56V), and I’d like to be able to run either boards on one of these drivers. Eg: two qb288 per xlg-240, or two qb648 per xlg-240.
I don’t know if I’d have to wire in series, or parallel, or if it’d be an option. And which model exactly to choose.
XLG-240-H-AB for parallel? XLG-240-M-AB for series? Or am I not thinking about this correctly?
Three of these drivers, for about $210 cad, and 720W, with 6 HLG quantum boards, is what I’m considering. I already have a bunch of quantum boards.
Thanks.
xlg-240 product page
xlg-240 datasheets
Edit/Extra:
They have almost all the features I want; dim-to-off / 0%, external dimming leads, Io potentiometer, but no Vo potentiometer (like the HLG series type-AB does).
With an HLG-320H-54-AB, for example, I could run qb288s at 54V. And also turn up the Vo pot to 56+ volts and run qb648. But it has no external dimming leads and doesn’t dim to off (and I don’t think is worth the price).
I can also get Inventronics 600S560DT for what I’m gonna call $275-300 cad (total, I think). It’s a CC driver, I think. It’s programmable, but you gotta buy the programmer, which I think would be around $50 cad? And I’d have to figure that out. So more money, but less wattage. But all the wattage is in one driver, so possibly easier setup/wiring setup. I like to remote mount drivers, not put on the fixtures/lights. So, three drivers per fixture might be a bit more wiring and thought to it. But honestly, that might be worth it for the price and wattage.
qb288 rspec v2: Max current per card 3000mA @ 54VDC
qb648 diablo: Max current per board 5000mA @ 56+VDC
And I think I’d prefer to wire in series this time. The opposite of what I used to and currently do. I liked the flexibility of being able to add/remove boards to a CV driver.
(Edit: I considered the XLG-320 (M or H? Or other?) as well. But now I’m not sure, because I’d have to run three qbs per driver, two drivers per fixture, and it’d cost more, for less wattage. Just thought I’d mention it, cause they’re in stock now - as opposed to being just “orderable”).
Well the xlg’s consider the voltage as self leveling, as in once you set you Io “current” the voltage will follow suit to match the current your boards are pulling so long as it’s within its voltage range that it’s capable of.
So saying that if running two qb288’s off a 240 one could do parallel off a 240-h-ab but your total wattage will be roughly that 240w across the two which just randomly guessing without knowing spec sheet power curves would be in that 50-52v at 2.3-2.4a range per board, as for the qb648s you would need to run a single driver per board for those if considering the 240’s and wanting to run those boards on there high end unless your plan is to underdrive them requiring less heatsink capabilities and what not by doubling them up then again parallel arrays make it easy.
My question would be more what size space you running and how much power are you thinking with board layout and such, also how many of what boards do you have ?
So no real difference between the lm301b vs H’s considering the same bin chips, now the evos depending are only about 3-6% more efficient, with the mintwhite versions being the most efficient comparably, now say one had a higher binned lm301h light and a lower binned lm301h Evo light, the former could easily be more efficient. Or if in reverse one could see 10+% efficient differences.
So if you know rough idea on the bins your getting is that extra efficiency worth it for you.
That information is in the first of the two posts I made, above. For area, call it a 4x4 if that helps. Link to the data sheet is in the post as well.
Only saw the below info which really isnt definitive as to what and how many but you know what you have and what your kinda planning.
And i ment datasheet for the boards not the drivers as those are easy to find and what you linked anyways, also i dont think those boards have ever had legit spec sheets as ive never seen one, but i gonna say my guesses are not too far off on what they will run at if done the way i was talking.
so if looking at three drivers of 240w, 720w total for 16sqft ish yeah i can see that for high light levels just need to get that layout evened out, either way running two boards for whatever they are off each driver would allow them to run cooler vs trying to max them out and you can do so with just doing parallel arrays with the 240-h’s instead of going with the M’s or whatever higher voltage versions, just best practice to not mix boards on the same driver obviously.
