DIY LEDs - The write-up

[jkopp36]

I don't think the dimming capabalities will be effected by this. It's the adjustment range before dimming.
It's like the ELN, the more you dail down the SVR, the less output, the lower you can dim the lights.

I was wondering about this too and I'm hoping your're right Jimmy however I do not recall seeing anything anywhere on an adjustment on the HLGs similar to the SVR adjustment on the ELNs. Got any more info on that? My HLGs will be here tomorrow so I guess I can check it out more then too.

 

[Jimmy54]

I hope so too.
And you are right, there ar no int. potmeters in the B series, however ...
Next to the 'CURRENT ADJ. RANGE' it says; "Can be adjusted by internal potentiometer or through output cable" - so I would think an external potmeter or a fixed resistor before dimming, would do exactly the same. The only "problem" is the dimming range which is going to shift from 100% > 10% to something like 80% > 5% or with a little bit of luck 1 -2 or 3%.
I'm in the same boat with the HLG 185 B and 150 B series trying to get a decent sunrise/sunset effect. I'm still in doubt using a pot, resistor or 1 or 2 diode's to get the job done.

 

[Jimmy54]

And reading it back again, it says 'output cable'
not sure if that's actually the output to the LEDs, or the dimming wires (??)

 

[TheFishMan65]

Jimmy, right if we stay above 110 we can go 100%, but does anywhere have dips below that? How low can a brown out go?
I always read "Can be adjusted by internal potentiometer or through output cable" as the dimming wires. Maybe it only relates to the one with internal controls.

 

[Jimmy54]

Of course, I wasn't thinking of the 110Vac you have in the US.

I also think the "output cable" refers to the dimming wires, however not only to the driver with internal pots.
If that was the case, they would have mention that like they did with the 'VOLTAGE ADJ. RANGE' note. 6.

I'm going to try a few things next saturday, see what works and what doesn't work.

 

[TheFishMan65]

Look forward to hearing. I have contacted Meanwell technical support so maybe I will know something by the week end.

 

[jgwinner]

- The load must be 50% or the power factor drops too much and so does the efficiency (graphs on page 5).

Wouldn't that mean if you run them at 10% dim the efficiency goes down and your PF is worse?

Then again at 10% efficency you wouldn't care so much but if people dim at 50% on a regular basis, you could make the argument for a smaller driver.

== John ==​

 

[TheFishMan65]

That is the discussion. If load is watts then even if you started with a max of 54 volts and full current as the current dimmed to half the load would be less than 50% since the voltage would have dropped some. So the problem is that no one here seems to know how to read the datasheet for the B versions.

I think in general you want to pick your desired voltage, and then get the one the matches the current you need and go to the one that will suppl that much current or more. My plan was then to purchase a 100k pot and add in parallel whatever size I needed limit my current.

For instance (just because the math is easy) say you need to limit the current to half because of the number of strings. That would say you need make sure the potentiometer can not go above 50k. One way would be to purchase a 50k pot, but what if the number was something like 87k? Well using the parallel resistance formula
- R = (R1 * R2) / (R1 + R2)
So for 50k add a 100k resistor in parallel
- R = (100k * 100k) / (100k + 100k) = 50k
or
-87k (100k * R2) / (100k + R2) solving for R2 = 670k.
Since there is very little current these can be made from a bunch of 1/2 resistors. So buy several 10k pots and a bunch of cheap resistors and you can limit the current to whatever you need.

 

[brassmonkyballs]

guys i don't think we should be confusing voltage and current adjustment range with the dimming function. 1st only type A can adjust the voltage and current range via an internal pot "by removing rubber stopper" and does not have active dimming. Type 'Blank' apparently can be had with some sort of I/O cable to adjust V and I similar to Type A. There is now a Type D which has a Timer dimming function and says to contact Meanwell for details. Type B of course has 3-in-1 dimming via feedback circuitry as shown in the block diagram. (not sure what happened to Type C but maybe they will have something planned for it since the skipped right to D)

So type B is the only dimmable one and does not offer adjustable V and I so the ranges they quote do not apply.

Type A does not dim but you can adjust V and I down to 50% and up slight above max V.

Thats how I read it and based on our collective experience on how the B dims just fine down to 10% the adjustment ranges are not applicable to the HLG.

All the latest specs are available at meanwell.com http://www.meanwell.com/search/hlg-185h/default.htm

 

[Jimmy54]

I don't think we do.
We're only trying to find the output cable, as in 'Can be adjusted by internal potentiometer or through output cable'.
And I think that this 'output cable' revers to the dimming wires, because at the top of the data sheet it says;
'B : IP67 rated. Constant current level adjustable through output cable with 1~10Vdc or 10V PWM signal or potentiometer'
And there's the output cable again.

 

[brassmonkyballs]

well then thats a lot of words and debate for trying to find the output cable

 

[Jimmy54]

Well, that's me and my Dutch way of asking and explaining things .. I guess:spin1:

 

[TheFishMan65]

Sure is a confusing datasheet. I think bmb has it right. I never realized that the blank version had any adjustment.

I think:
blank has a cable for current adjustment
A has pots for setting max current and voltage similar to an ELN
B has 3 way dimming
D has timer timing

 

[jkopp36]

So brass, are you saying that the current range listed on the sheets (where min his half of max) are mostly for the non-dimmable or "A" version and that for the "B" version the range is acutally 10% to max (or so)? Hope that question makes sense.

 

[TheFishMan65]

That is what I think - now. Same for voltage.

 

[brassmonkyballs]

So brass, are you saying that the current range listed on the sheets (where min his half of max) are mostly for the non-dimmable or "A" version and that for the "B" version the range is acutally 10% to max (or so)? Hope that question makes sense.

That is what I am suggesting. Type B voltage range is auto set within the range based on load and current is set via dimming method.

I will try tonight to take a quick reading of V and I on a string with dimmer set to max and min.

 

[brassmonkyballs]

Quick Measurements

Quick Measurements

I took some quick measurements tonight to see the characteristics of voltage and current of the driver when dimming.

Driver - MW HLG 185-42B
Running 44 Cree XPE RB LEDs - 11 in a string times 4 strings
dimming via 100k ohm Potentiometer

Measurements:

As set normally during light period: 34.2V & 450ma

Dimmer set to Minimum: 29.4V & 20ma (my meter only goes to 2 decimal places and read as 0.02A)

Dimmer set to Maximum: 36.2V & 1.08A

Very interesting to find I am only running them at 450ma...and I was worried I would not have enough LEDs.... Reality is it comes down to coverage of the tank more than output of the fixture. This means I am only running the blues at a total of 61.6W. Max'd out it would be over 150W.

I didn't take a reading of the whites because they had cycled off for the night. That driver is an HLG 120-42B running 24 whites and 6 RBs in 3 strings of 10 and I know they are around 31V & 900ma per string at Max from when I set them up...but I have them dimmed down to 50% on the dimmer. Unfortunately there's no correlation to dimmer position and actual readings. Will have to measure tomorrow as now I'm curious on actual power being used!...and I suspect its 40W or less. If correct I would only be using 100W of power over my 4x2x2 120G......baffling. Someone check my math please.

Note that I recently added optics and dialed back the fixture and will likely eventually ramp it back up some as I monitor my corals but as set now its rather impressive.

Back to the driver discussion - when set to max power voltage across just the string is 36.2V and dims down to a minimum of 29.4V. Again at max output the current is 1080ma but dims down to 20ma .... far less than 10%.

Given that at min setting the string voltage is 29.4V that works out to 2.67Vf per LED which is the minimum I think before they turn on but I would expect more like 50ma at that Vf. if you look at the radiant flux curve vs forward current it makes sense http://www.cree.com/products/pdf/XLampXP-E.pdf page 10 bottom curve. Coupled with the measurements I took I feel the driver dims from zero to 100% understanding that zero is the min power required to run the LED...similar to the diode test on your meter.....and not off.

The one thing I cannot test is the 10k ohm equals 10% rated current....it probably does but a pot goes below 10k ohms obviously...probably less than a 1 ohm.

Note that the HLG spec sheet does not specify a min/max voltage range for constant current operation either.

Comments?

 

[TheFishMan65]

For blue
34.2V * .45A * 4 = 61.56 watts
for white
31V * .9A * 3 = 83.7 watts (oops 50% so 41.85)
So 103.41 watts yep you need to check your math

Now do you by chance have par numbers with this set up?

 

[brassmonkyballs]

For blue
34.2V * .45A * 4 = 61.56 watts
for white
31V * .9A * 3 = 83.7 watts (oops 50% so 41.85)
So 103.41 watts yep you need to check your math

Now do you by chance have par numbers with this set up?

Only 100 watts.....amazing. No the PAR readings I gave were max'd without lenses. I have to find the sheet I documented the readings on but i did take some at about this setting based on the pots but without lenses. I can tell you the corals are thrivings and I've had to move some to down.

 

[jkopp36]

Good stuff brass! Thanks!

I will be dimming via 0v-10v so I'll do some testing too once I have things running. I got my drivers yesterday and plan to have everything together enough to at least fire things up and start balancing strings - hopefully by the end of the weekend. I'll do some testing at that point too.

So if I am understanding all this correctly, the current on the "B" versions is only set by the "ouput cable" and since I'll be using an Apex controller I will need to have bulletproof programming in place to insure not going over my target max current or some sort of max current limiting device in place as a safeguard? Anybody have a recommendation for such a device that is adjustable?