Confirm Wiring and LED Driver Compatibility? (And Dimming!)

[MPTESE]

Hello,

I desire to power (4) 300W LED COBs simultaneously via a single 120v AC plug. Each COB has their own 300W driver. The driver is AC input and DC output. It is a constant current driver.

Here's the spec sheet of the driver. I assume I would be using the H-AB, which provides a DC voltage range of 29-58v, and 3-in-1 dimming which is another part of this.
https://www.meanwell-web.com/content...C-300-H-AB.pdf


Here's the spec sheet of the COB:
https://download.luminus.com/datashe..._Datasheet.pdf


Here's a crude drawing..

1. What are your thoughts on compatibility between the LED COB and LED Driver? Seems like a good match to me, I just don't want any chance of frying the LED so would like some other eyes to confirm. Similarly, are there any precautions or additions one should make to prevent overload in any way?
2. Please let me know your thoughts on the wiring. Some might question a 10amp draw like this, and the addition of a plug, but it is very normal for my specific application.
3. I plan on implementing dimming, but need to ensure flicker-free for camera application up to 2,000FPS. I imagine I can go the PWM dimming route via the driver, but will have to test it. Other than just a potentiometer/analog, what is an efficient way to dim the LEDs and ensure flicker-free application? I understand if this means adding an additional component vs utilizing the driver's internal dimming functionalities.
   Source URL: https://www.electriciansforums.net/threads/confirm-wiring-and-led-driver-compatibility.185855/
   
   I plan on implementing dimming, but need to ensure flicker-free for camera application up to 2,000FPS. I imagine I can go the PWM dimming route via the driver, but will have to test it. Other than just a potentiometer/analog, what is an efficient way to dim the LEDs and ensure flicker-free application? I understand if this means adding an additional component vs utilizing the driver's internal dimming functionalities.

Thank you very much for the help and support.

 

[JustAnOldFashionedLEDGuy]

Hello,

I desire to power (4) 300W LED COBs simultaneously via a single 120v AC plug. Each COB has their own 300W driver. The driver is AC input and DC output. It is a constant current driver.

Here's the spec sheet of the driver. I assume I would be using the H-AB, which provides a DC voltage range of 29-58v, and 3-in-1 dimming which is another part of this.
https://www.meanwell-web.com/content...C-300-H-AB.pdf


Here's the spec sheet of the COB:
https://download.luminus.com/datashe..._Datasheet.pdf


Here's a crude drawing..

1. What are your thoughts on compatibility between the LED COB and LED Driver? Seems like a good match to me, I just don't want any chance of frying the LED so would like some other eyes to confirm. Similarly, are there any precautions or additions one should make to prevent overload in any way?
2. Please let me know your thoughts on the wiring. Some might question a 10amp draw like this, and the addition of a plug, but it is very normal for my specific application.
3. I plan on implementing dimming, but need to ensure flicker-free for camera application up to 2,000FPS. I imagine I can go the PWM dimming route via the driver, but will have to test it. Other than just a potentiometer/analog, what is an efficient way to dim the LEDs and ensure flicker-free application? I understand if this means adding an additional component vs utilizing the driver's internal dimming functionalities.
   Source URL: https://www.electriciansforums.net/threads/confirm-wiring-and-led-driver-compatibility.185855/
   
   I plan on implementing dimming, but need to ensure flicker-free for camera application up to 2,000FPS. I imagine I can go the PWM dimming route via the driver, but will have to test it. Other than just a potentiometer/analog, what is an efficient way to dim the LEDs and ensure flicker-free application? I understand if this means adding an additional component vs utilizing the driver's internal dimming functionalities.

Thank you very much for the help and support.

The driver has a 0-10V analog dimming input to which you can attach a standard 0-10V dimmer. Even if you feed PWM into the dimmer input of the driver, odds are it converts that to analog and dims the driver in the analog domain. Odds are it will be flicker free.

You adjust the driver current with the POT. THE COBs would likely be fine with the 5.6A, but you may want to dial them back a bit to their nominal 5A, not to mention at 5.6A, you could be over the 300W driver limit.

The driver is relatively efficient, so odds are you are drawing <1350 watts and won't trip any breakers.

Make sure you have substantial heat-sinking on the LEDs and a good contact LED to heatsink across the whole back of the LED.

 

[MPTESE]

The driver has a 0-10V analog dimming input to which you can attach a standard 0-10V dimmer. Even if you feed PWM into the dimmer input of the driver, odds are it converts that to analog and dims the driver in the analog domain. Odds are it will be flicker free.

You adjust the driver current with the POT. THE COBs would likely be fine with the 5.6A, but you may want to dial them back a bit to their nominal 5A, not to mention at 5.6A, you could be over the 300W driver limit.

The driver is relatively efficient, so odds are you are drawing <1350 watts and won't trip any breakers.

Make sure you have substantial heat-sinking on the LEDs and a good contact LED to heatsink across the whole back of the LED.

Great. You confirmed a lot of what I thought. *ordered*

If I wanted to dim all units at the same time, by joining the Dimmer input leads to a single PWM controller, there shouldn't be any precaution there. However, 0-10v dimmers are more than a controller, and actually carry current - yes? So if using 0-10v, the only precaution would be to make sure it's rated to carry the current from all (4) units?

 

[JustAnOldFashionedLEDGuy]

Great. You confirmed a lot of what I thought. *ordered*

If I wanted to dim all units at the same time, by joining the Dimmer input leads to a single PWM controller, there shouldn't be any precaution there. However, 0-10v dimmers are more than a controller, and actually carry current - yes? So if using 0-10v, the only precaution would be to make sure it's rated to carry the current from all (4) units?

No the 0-10V dimmer wires (which are also the PWM input wires on the MEANWELL Driver) do not carry current, at least not much at all, 100uA per driver. 4 of them together and you have 400uA. North American 0-10V dimmers will typically have an AC switch in them as well, that just switches the 120 (or 277), but has no impact on the 0-10V dimmer output. Technically you could just use a linear potentiometer, a 25K ohm would work for all the driver 0-10 wires in parallel, but would not work properly on 1-3 units.

 

[MPTESE]

No the 0-10V dimmer wires (which are also the PWM input wires on the MEANWELL Driver) do not carry current, at least not much at all, 100uA per driver. 4 of them together and you have 400uA. North American 0-10V dimmers will typically have an AC switch in them as well, that just switches the 120 (or 277), but has no impact on the 0-10V dimmer output. Technically you could just use a linear potentiometer, a 25K ohm would work for all the driver 0-10 wires in parallel, but would not work properly on 1-3 units.

Got it.

Here's the heatsink I'll most likely use. I have a sample in front of me. It has a little circuit board on it that can input any voltage from 11-72v, and knocks/adjusts it to the proper input for the fan (11-48v). So the driver can power the heatsink fans, I'll likely tie these into the DC output leads that go to the COBs.

On another note, any recommendation on thermal paste? I also plan on finding a COB holder that can accept a LEDIL 60degree reflector.

 

[DIWdiver]

I've just been doing some research on thermal paste. I was all ready to settle on GD900, as it performs as well as or better than most others, but costs much less. Then I heard some whisperings that it might dry out and lose effectiveness over time. I haven't been able to confirm this, but I don't think I'll take my chances. I'll leave that to the overclockers who change their paste every month or so anyway.

Ultimately I decided to go with Arctic MX4. It's not the top performer, but I felt it was the best combination of good performance, high durability, reasonable cost, and good availability. I want to build this thing once and use it for years. Durability of most of the pastes is discussed and reviewed little or not at all, at least that I found. Arctic (not Arctic Silver, which is a different company) advertises 8 year durability.

Stay away from any of the cheap China sites. There's no telling what crap you will get there. I've watched the reviews that demonstrate it.

 

[JustAnOldFashionedLEDGuy]

I would second the Arctic MX4 and stick to something that is at least >= 5 w/m* (MX4 is 8.5). That will ensure you have limited temperature drop across the thermal interface. I can't emphasize enough, as thin a layer as possible, targeted a few thousands of an inch (50-100um). It is very important the mating surface is flat, so send those heatsinks back if they are not.


With the 0Q-101, you are running 57C over ambient + drop across the thermal grease (count on 5C if you do a really good job with MX4). So they are running hot, but not brutally hot. The MP-101 is louder, but would run 12C cooler.

 

[LedTed]

(REDACTED)
I can't emphasize enough, as thin a layer as possible, targeted a few thousands of an inch (50-100um). It is very important the mating surface is flat, so send those heatsinks back if they are not.

(Rant Warning)
Yes, thank you for saying that!

Being soldering and soldering inspection certified, I'd also like to add that solder-joints should be conformal. I don't know how many times I've seen terrible solder-joints on LED flashlights; even from professional manufacturers.

And, don't get me started on the lack of ESD precautions used; again even from professional manufacturers.

Time to step off my little soapbox.

Hope this helps,

—
LedTed

 

[MPTESE]

Thank you all for the info. It is always appreciated.

i am almost done with one of the four frames. I've tapped and fastened the heatsink to the frame with m5 screws. While I await the cobs arrival, I am looking further into lending solutions. I was originally going to go with a simple reflector, but my suspicions tell me I might be disappointed in the quality of light. I am wanting an efficient throw, but also a homogenous beam/field of light when thrown onto its surface. I am having trouble finding an efficient lensing/housing solution for my size cob (32mm les). Ideally, it'd be cool to have an adjustable fresnel attachment, like the aputure300d fresnel attachement. Does anyone have any recommendations for my size, or perhaps maybe combat my suspicions about reflectors ability to produce quality beams for filmmaking?

 

[DIWdiver]

To create decent throw with an emitter that large would require a massive optic.

Obviously you aren't trying to create a light saber. But that doesn't mean that the rules of optics don't apply.

I won't pretend to be able to spout formulas or specific theorems, but they work out to say the following:

1. To create perfect focus, you need a point source of light.
2. With a non-zero emitter size, you cannot achieve perfect focus.
3. The larger your emitter size, the poorer your focus can be.
4. The larger your optic size, the better your focus can be.

Now think about how these rules apply to video lights. In commercial lights, how big is the emitter (filament, LED, or flash tube)? How big is the optic (almost always a reflector)? What kind of throw are they achieving?

How much throw are you looking for? How big is your emitter? How big do your optics need to be? The answer to the last question is "roughly proportional".

I can think of one kind-of-exception to these rules, because it doesn't really use 'optics'. That's the use of umbrella-type reflectors (I have no idea what photographers call these things). These aren't meant to focus the light, but just the opposite - they diffuse the light to eliminate harsh shadowing. With these, the size of the emitter is almost irrelevant, as long as it isn't a significant fraction of the size of the umbrella. Another way of saying that is that the size of the umbrella needs to be MANY times the size of the emitter.

Again with the emitter size. It's almost like I'm saying that for a focused beam you want a small emitter size.

Okay, I'll say it. For a focused beam you want a small emitter size. For a 33mm emitter, you will want optics in the 150mm+ range. That's diameter for lenses and depth for reflectors.

 

[MPTESE]

Hello DIWdiver,

Thank you. Let me clarify some goals. I wish I had hard scientific numbers, but I'm not well versed in formulas, only visual experience with different lights. You're suggestion of 150mm+ seems right, as most cob fresnel leds that are "decently bright" (I know, subjective) attempting to mimick a "hard single source" utilizing cobs do indeed seem to be that size or larger. I've even seen some reputable companies manufacture a larger array of LEDs, not a tightly packed cob, within a 7" radius or so, with only a 10" lens or so lens. Not on par with your ratios, but your thoughts are correct as the raw beam produces "shadow stepping". I don't know if that's a poor fresnel, larger led emitting source that's not consistent, or combo of both.

the diffusion umbrella you're talking about is probably a parabolic reflector.

I am not attempting a natively soft source, but a large throw and a beam angle of around 45-60degrees. I don't necessarily need "hard shadows", it's unrealistic to mimick the hardness of a tungsten filament or hmi with LEDs, as you pointed out it not being as small of a source. My heatsink and frame would support the mounting of a 150+ optic, i justa having trouble sourcing some options. I can find the lens, but don't have any housing/holder options. I get the feeling most of the housings are custom made, and not a stocked item. I don't have that commissioning ability.

 

[MPTESE]

Okay, after some more research I believe my best bet to maintain efficiency is to decide between a simple reflector and an LED collimator aspherical lens. My cons are coming next week, so would like to know what range of lenses I should trial to get my desired result. It seems the lens should be fairly close to the led, I'm sure this varies based on the mold. Since were talking aspherical collimation, how does that affect the size ratios of the lens for my 32mm les? I am now open to achieving a homogenous beam between a 35-60degree beam.

 

[MPTESE]

Sorry for the double posting.. But I wired my cob to do a quick test and it's BRIGHTER than I expected.. I went with the Arctic MX-4 as suggested and will begin fastening to the heatsink tomorrow. I have a BJB cob holder that fits form factor wise, but it's only rated for 3AMPS. I would be pulling ~5AMPS. Do you suspect the holder connections to melt if I continue with this cob holder? There's one other solution from B+W but it does not give me any compatibility with mounting/optics systems. So I'm considering forgetting about a cob holder. Can I just mount the COB directly to the heatsink? Any precaution there?