CREE Cob CXB3590 + Meanwell Driver Questions

Hiya all,

I've gone the route of DIY and sourcing parts directly from distributors and over-seas manufacturers instead of purchasing pre-made kits as I found I would be saving myself a significant mount of money over the course of a few grows in comparison to purchasing something already made of similar spec. I also like to get hands-on as well, so it's definitely a plus in my books. Yay, go me!

Essentially, I've been doing a lot of reading, and still not sure with regards to the terminology I should be using when researching what I'm about to ask - so I sincerely apologize in advance if my questions seem obvious to answer, as it's a lot to juggle working full time, doing my own side-business & trying to start up my grow.

Essentially, my past couple of grows were done under 3500K CXB3590 36V chips, powered by.... Meanwell HBG-100-48A.

Back then, I must have completely mis-read the driver voltage, and instead of purchasing 36V drivers (-36A variant), I purchased the 48A variant like a complete noob.

I am now re-assessing everything, and I have done some reading with regards to dimming the chips down so they aren't running at such high power, as to my understanding, the performance to power ratio starts to decrease the more power the CXB3590's are given - I've read some people dim them down to 50% power, around 50W each.

So I guess my questions would be:

1. Is it fine to run my 36V CXB3590 chips from Meanwell HBG-100-48A drivers, or am I best swapping them all out for the correct, 36A drivers? More clarification would be sincerely appreciated so I don't FKK up my COBs, as it seems I just completely derped it when purchasing the drivers.
2. How should I fine-tune each lighting fixture? As in, what is the most efficient way to run the CXB3590 chips to ensure I am getting a long life-span out of each chip, and to also ensure I'm not over-powering them, and wasting energy and just creating unnecessary heat? The Meanwell drivers I am running have in-built petentiomiters which I can adjust to my desire - I just need some help figuring out how to actually adjust them and to what power draw - I have a power meter which I can use in-line to figure out how much each lighting fixture is drawing in terms of Amps and Watts.
3. Are CXB3590 chips still OK to use in 2021 in terms of performance? Or have I jumped back onto an old bandwagon?
4. What are your thoughts on 2700K, 3500K and 6500K COBs? I tend to run 3500K + 1/2 6500K COBs during Veg, and then switch over to 2700K + 3500K during flower. Keen to hear some more thoughts more surrounding 6500K and if it's best for vegging?
5. Any further advice or information that would be useful with regards to the Cree CXB3590 + Meanwell HBG-100-36A would be sincerely appreciated.

Again, I am so sorry if these questions sound stupid - it's a LOT of information to take in, especially when you're building your own lighting fixtures VS purchasing pre-made ones. I do have a fair understanding of how it all works, though clarification and input is appreciated.

My suggestion is to lose he 48V driver for a 36A driver. If using the 100w then just connect 2 cobs in parallel and use at 50w each. You will have more output, the driver is currently wasting some power.

Cxb is all right but it wasn't actually ever as good as made out, their datasheet is slightly over spec. Many modern cobs beat it nowadays, if you go to @CobKits thread, or if he can dig out the graphs, theres been plenty testing on this. They are still good, just expensive for their spec. Should defo be run at sub 50w.

Rocket Soul said:

My suggestion is to lose he 48V driver for a 36A driver. If using the 100w then just connect 2 cobs in parallel and use at 50w each. You will have more output, the driver is currently wasting some power.

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Hello hello - thanks for your input, it is much appreciated.

Currently, the fixtures are setup in such a way where the driver and chips are mounted on a pin heatsink - so for convenience I've just got them all setup as individual fixtures. I definitely like the idea of running 2 in parallel, and to be quite frank, this may definitely be a consideration when I think about re-designing them. Maybe I'll speak with a manufacturer who can make a dual heatsink to fit 2 COBs on the one fixture.

With regards to powering the chips though, what is an optimal setup - let's say for now I stick with the 1 driver per COB fixture, should I be running the chips at 50% for optimal efficiency, or 60%, 70%, 80%? If I understand correctly, anything higher than XX% is just wasting power in heat generated by the COB. This is something I'd love to further understand, and how to dial in the chips to the right power.

Having a look at the data sheet for the CXB3590 - the COBs have a forward voltage of 36V at 2400mA, which would work out to be 86.4W. If I provide the chips with 86.4W, am I just wasting power, or do I need to dial them down? IE to 50W?

That would all lead me to try and ascertain how do I fine-tune the drivers output according to the best-recommended specification? Would I just hook the driver up to a power meter and adjust it until I reach the desired wattage draw? Or would it be a bit more complex than that?

I would also appreciate some understanding with regards to driving the LEDs with the 48V drivers - I'm probably going to fry the chips, hey? I've ordered 2 36A drivers for now (before this post, as I presumed I stuffed-up with the 48V drivers), though I've still got another 6 light fixtures on the 48V drivers - again, that's my rookie mistake, though I did manage to get two full grows from the fixtures and they're still performing just as good as day 1.

Again - I hope I'm not tearing anyones hair out, and sincerely appreciate all the input!

Rocket Soul said:

Cxb is all right but it wasn't actually ever as good as made out, their datasheet is slightly over spec. Many modern cobs beat it nowadays, if you go to @CobKits thread, or if he can dig out the graphs, theres been plenty testing on this. They are still good, just expensive for their spec. Should defo be run at sub 50w.

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I'm not sure if I missed this or you updated your post - apologies for that.

I see, and from the research I've done, I think you're right. Although, I did get some AMAZING yeilds in my first grow from the CXB3590 - running purely 3500K chips. I only have experience, prior to the COBs, with cheap Blurple lights (Viparspectra - absolute garbage performance, when comparing to the Cree's... Obviously).

Given I've already invested in the chips and drivers, there's no going back, so I'm just going to have to continue to dial everything in - I've already got quite a few chips and drivers so at this point, I would be just burning through money if I spent more money. I can definitely try to re-sell my 48V drivers, though I think given that I've already got the heatsinks and setups for the CBX3590 (IE: Pre-drilled holes in the heat sinks), it'll be too much investment and time for this round to consider alternative options.

When you mention that I should run them at sub 50W, I presume you mean at or below 50W power draw from the wall?

I sincerely appreciate your input, thanks!

Wait with selling those 48V drivers, they are quite usefull if you ever went for an upgrade. They match with several interesting cobs.

As for driving hard: you want to keep the temps of the diodes down. It kinda depends on how you're heatsinking them, how hot is the sink? If you can keep die temps under 50C the chips last much longer.

50w or below is what most people use. Cxbs are not, comparatively, great at higher power. For higher power most use bridge lux Vero or bigger Citizen chips.

Rocket Soul said:

Wait with selling those 48V drivers, they are quite usefull if you ever went for an upgrade. They match with several interesting cobs.

As for driving hard: you want to keep the temps of the diodes down. It kinda depends on how you're heatsinking them, how hot is the sink? If you can keep die temps under 50C the chips last much longer.

50w or below is what most people use. Cxbs are not, comparatively, great at higher power. For higher power most use bridge lux Vero or bigger Citizen chips.

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Ya the 48V is great because they also mAtch the Samsung strips and the the QB288s.

Hey guys (and gals, if there are any reading). I received my new 36V drivers today. I am going to fine tune my COBs - so just to confirm, around 50W each COB is best, efficiency wise? I've dialled it in so the driver provides 50W per COB as per the recommendations.

I'm genuinely curious to hear more thoughts regarding a 6500K COB - I purchased two on sale so I thought to grab them to help with vegging alongside a couple of 3500K lights. I'd like to hear some personal opinions on 2700K, 3500K and 6500K COBs!

On a side note, do I just tune the petentiomiter on the driver until I see a 50W power draw, or do I also need to take other factors into account? Cheers!!

Thanks heaps for the replies, it is genuinely appreciated

RockStonedJesus said:

Hey guys (and gals, if there are any reading). I received my new 36V drivers today. I am going to fine tune my COBs - so just to confirm, around 50W each COB is best, efficiency wise? I've dialled it in so the driver provides 50W per COB as per the recommendations.

I'm genuinely curious to hear more thoughts regarding a 6500K COB - I purchased two on sale so I thought to grab them to help with vegging alongside a couple of 3500K lights. I'd like to hear some personal opinions on 2700K, 3500K and 6500K COBs!

On a side note, do I just tune the petentiomiter on the driver until I see a 50W power draw, or do I also need to take other factors into account? Cheers!!

Thanks heaps for the replies, it is genuinely appreciated

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Is this still 100w drivers? If I where you I'd connect 2 cobs in parallel to one driver, rather than keeping them dimmed forever: the driver works more efficient when on 100% dim.

Cobs get about 10% more light per watt every time you half the input power. Some like their cobs at 50w for soft driving, some like their cobs giving as much light as they can. Personally I feel the most important thing is to reach low diode temps; under 50C. A 100w cob gets real hot, I've seen people lighting a cigarette from the light.

6500k : not used it but I've seen plenty of people complaining that 5000k gives them too short internodes, some indicas just becomes a ball of leaves with almost no vertical growth. I'd wouldn't use 6500k for vegging. Possibly on very low dim if 3500k won't keep your plants as short as you like.
There is definitely a too much blue, even for vegg.

Rocket Soul said:

Is this still 100w drivers? If I where you I'd connect 2 cobs in parallel to one driver, rather than keeping them dimmed forever: the driver works more efficient when on 100% dim.

Cobs get about 10% more light per watt every time you half the input power. Some like their cobs at 50w for soft driving, some like their cobs giving as much light as they can. Personally I feel the most important thing is to reach low diode temps; under 50C. A 100w cob gets real hot, I've seen people lighting a cigarette from the light.

6500k : not used it but I've seen plenty of people complaining that 5000k gives them too short internodes, some indicas just becomes a ball of leaves with almost no vertical growth. I'd wouldn't use 6500k for vegging. Possibly on very low dim if 3500k won't keep your plants as short as you like.
There is definitely a too much blue, even for vegg.

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I think I'm too new to the forum to like or react to your reply, though I must say thanks for your input. It is genuinely appreciated, and will definitely help me make better decisions moving forward.

The reason why I am using single fixtures with single drivers is simply because my design currently only allows for 1 driver - 1 heatsink and 1 COB - this fixture is hung from an adjustable hook. As such, it is not possible for me, at this point in time, to run 2 COBs off the 1 driver, as I would have no way to hang the COB + heatsink fixture.

I will have to come up with a better alternative, possibly a rail that holds 2 heatsinks and 2 COBs, running on the one driver.

For now though, I will continue to run the single drivers and tune them down to about 50W. I understand in terms of efficiency from a power conversion aspect, the drivers aren't running at their maximum efficiency, though for now, I will have to stick to this until I can go back to the drawing board and come up with a better-designed fixture.

If I dial in the COBs at 50-60W, I presume this will be fine for under-driving them, in turn, I hope that it can give them a longer lease on life.

Would using 6500K light in addition to 3500K (Let's say 4 3500K fixtures + 1 6500K), be fine? Or is it bad to have 6500K light in the tent at all, due to being "too blue"? I wouldn't be giving the plants ONLY 6500K lights, I would just add one in there to help supplement alongside the 3500K lights.

I guess everyone has their opinions, until I action everything myself and learn what works best for me. I am still keen to hear personal opinions, as they definitely help drive my actions.

RockStonedJesus said:

I think I'm too new to the forum to like or react to your reply, though I must say thanks for your input. It is genuinely appreciated, and will definitely help me make better decisions moving forward.

The reason why I am using single fixtures with single drivers is simply because my design currently only allows for 1 driver - 1 heatsink and 1 COB - this fixture is hung from an adjustable hook. As such, it is not possible for me, at this point in time, to run 2 COBs off the 1 driver, as I would have no way to hang the COB + heatsink fixture.

I will have to come up with a better alternative, possibly a rail that holds 2 heatsinks and 2 COBs, running on the one driver.

For now though, I will continue to run the single drivers and tune them down to about 50W. I understand in terms of efficiency from a power conversion aspect, the drivers aren't running at their maximum efficiency, though for now, I will have to stick to this until I can go back to the drawing board and come up with a better-designed fixture.

If I dial in the COBs at 50-60W, I presume this will be fine for under-driving them, in turn, I hope that it can give them a longer lease on life.

Would using 6500K light in addition to 3500K (Let's say 4 3500K fixtures + 1 6500K), be fine? Or is it bad to have 6500K light in the tent at all, due to being "too blue"? I wouldn't be giving the plants ONLY 6500K lights, I would just add one in there to help supplement alongside the 3500K lights.

I guess everyone has their opinions, until I action everything myself and learn what works best for me. I am still keen to hear personal opinions, as they definitely help drive my actions.

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You can always try trowing in the 6500k cob in your veg area, keep it dimmed to a minimum and dial it in according to your needs. If you keep your cobs high then there should be enough light mixing in order to not getting an uneven canopy due to the 6500 cob inhibiting stretch.