Set the voltage level a little above the LED Vf (at operating temperature). Set the current pot to what you want to run them at.
Thanks TP. So set the voltage slightly above vF @operating temp, and then adjust current. How much higher should the voltage be than vF?
Do you know how much more voltage I can get away with?
For instance,
- 1750mA vF=27.9V
- 2800mA, vF=29.4V
What would happen if I powered them at 1750mA @29.4V? Smoke or safe?
The way these usually work is the voltage setting sets the max voltage it will output. The current setting sets the max current. Whatever limit the supply sees is what it will run at.
You want the current to be the controlling variable. Setting the voltage higher than what the LED wants means that the current setting will kick in first. If you set the voltage too low, you won’t get full current to the LED. You could set the voltage way higher than the LED Vf as long as the current is set properly. Setting the voltage a little higher than the LED Vf provides some protection against faults.
Thank you. Your explanation makes perfect sense to me for one emitter (in my case). But since the driver is incapable of providing a destructive amount of current to the array (3 emitters in parallel), how much voltage above vF at operating temp could I safety run without damaging the emitters?
It looks like I can crank the current pot to max, but Im note sure where the voltage should be set. Sorry if I missed your point.
As long as the voltage setting is above the LED Vf you should be OK. Look at the LED data sheet and see what voltage would cause too much current for the LEDs and set it there.
LEDs have quite a bit of variance in their V-I curves and the slope is rather steep, so a little change in voltage/temperature can cause a lot of change in current… that is why current limited drivers are used.
Thanks TP, this PSU appears to be strictly a CC driver when wired to the emitter. The voltage adjustment pot does absolutely nothing and has no effect on voltage or amperage. I tested it full range several times to make sure. When its not connected to an emitter it works, but when connected it does nothing. The Amp adjustment pot works well and locks in the set current and holds it there precisely. As expected, the voltage drops as the emitter heats up and the current remains constant.
To summarize setting up this particular driver:
Use the current pot to set emitter output. The voltage pot adjustment does nothing, at least with my applications. I have 15 of these drivers and tested several just to make sure. They are also genuine Meanwell, not some cheap chinese knockoff.
I just mounted one of the emitters to a 20 pound AL heat sink and wired it to the PSU. All I can say is WOW! :bigsmile: These things are bright! :bigsmile: Im running at 3.75A for 7140 lumens, which is 100% rated output and 102 watts being consumed by the psu. Power factor was measured at .97, so these PSU’s are super efficient. A quick glance around the room quickly shows the value of 97 CRI and 3000 K… simply gorgeous light when the entire living room is richly bathed in it.
Cool, sounds real nice. Those warm Bridgelux emitters should do put out gorgeous light. I've only used the 9 volt versions. 2 in series can be driven nicely by an 18 volt laptop power supply. 2 of those can light up a big room nicely. Hard to picture how bright those 30 volt puppies are.
Do you have a bridgelux part number or a link for the ones you picked up? Are yours mounted and in use, or just for play? Fun stuff!! Its amazing how much light these suckers belt out, especially for for the wattage.
I'm guessing I bought them a couple years ago (maybe more). I think I bought them from Digikey, but searching their site revealed nothing that seems to match. The closest I can find is something like this. If I recall correctly (probably not), they are only like 80cri (not 97 like yours).
I have two mounted in parking lights enclosures that I use as axillary headlights in one of my cars. I don't use them in traffic. Used old heat sinks extracted from old computer supplies to mount them on. I used simple linear regulators that have 3 Vdo to reduce the amount of voltage they have to burn up. Still get pretty hot though. Actually need more heat sinking than the emitters.
I only played with them in the house, but haven't yet decided how I want to implement them. I kind of like the idea of using wall sconces to keep the heat away from the wall. Light aimed up to the ceiling for indirect lighting.
I just keep putting flashlight projects ahead of home lighting.
Ive considered an LED DRL conversion but have been afraid to melt the plastic housings during a hot day. If I was cognizant of them (as you are) I’d put them on a switch and use them only while moving… but Im sure Id eventually forget and suffer an expensive plastic melt-down. I have several heat sinks to chose from, but they would all eventually need air flow while stationary.
The indirect lighting approach with the bridgelux seems to be the best one so far. I have the test bed on a table with the emitter pointed up at the ceiling and it lights the entire room in bright light with smooth transitions. I have 12 foot ceilings in the garage, so I might try the emitters with ledil flood reflectors to see if that cuts the glare and makes them more useful.
Ledil makes several asymmetrical reflectors that would be excellent for wall sonace mounts.
I dialed the PSU back to 2.80A to the emitter for 5350 lumens (75% rated power). Recording an hour on my kill-o-watt meter yielded 0.07 kWh. Multiplying that by the kWh charge on my electric bill yields a cost of 0.00506 per hour to run. So an 8 hour run would cost 4 cents, or about $14.78/year @8 hrs per night.
In case anyone is still interested… while running 2 emitters wired in parallel with the Meanwell cranked up to 100% netted the following results:
117W to power the PSU
4.33A into both emitters
1 hour run recorded 0.11 kWh
2 hour run recorded 0.22 kWh.
.11 x $0.072355 per kWh = $0.00795905… so about 0.06 cents per 8 hours x 365 = $23.24/year
A very substantial 20 pound aluminum passive heat sink stabilized at 104 degrees F after 3 hours of continuous operation and vF was measured:
Left emitter = 22.72V Right emitter = 22.69V
A .03V vF variance is very impressive for a parallel setup of this type. I havent had a chance to test the remaining emitters to see if I can vF match a few more pairs, but I doubt there will be any problems.
To my eyes, 2 emitters produces A LOT more light at 4.33A (2.17A per emitter) than a single emitter at 3.75A (emitter max rating). I might break out the lux meter later and record a few ceiling bounce tests to measure the differences. Ultra high CRI warm is the only way to go for wide area lighting and I couldnt have been more impressed. :bigsmile:
My 200 watt metal halide outdoor fixture took a dump last year. When I turn it on, the bulb flashes for a fraction of a second and the transformer only hums. It might be time to try an LED conversion. Now if I can just find a cheap 80-120mm 120 VAC fan.
I probably wont chance it, but I wonder how one of these arrays would take to dedoming and if it would all come off if soaked in gas, naptha, acetone, xylene or MEK? Its hard to tell exactly but all the phosphor appears to be contained within the dome material and not coated over each LED. It would be an expensive mistake if it wasnt successful but it would be cool to have a high powered blue/purple flood light. Any thoughts?
Has anyone tried to dedome a bridgelux brand array yet?
Just a quick update:
Ive been running one of these emitters @100 watts while mounted to a fan cooled CPU heat sink for several months and with no signs of deterioration. These emitters are designed for commercial applications and should run for several years. Now that the emitter is broken in, Im observing a 100% power factor efficiency while measured through my kill-o-watt meter. The marriage of the high quality Meanwell cc driver + the bridgelux RS emitter are an impressive combo of efficiency and true 97 CRI lighting.
I'd be interested in knowing what the lux is under and around that.
My light meter is at the airport and I’ll try to remember to grab it the next time I swing by. When the bridgelux is powered on, a btu shocker on turbo added to the ceiling bounce is hardly noticeable, but it does detract from the gorgeous 97 CRI.
What an excellent photography light source this could make! Equivalent to what, 400watts in tungsten but with a better tint and higher CRI? Awesome! Could it be run with a potentiometer to dial down total output as desired? Or even a Leviton wall switch with rotary control?
Probably over my head, but interesting as all get out!
You truly have to witness the light quality to appreciate it. I dont know that I could put into words in how blow away I am every time I turn it on. The drivers are large chunky metal boxes designed for sustained commercial applications in wet locations. Ive researched this line of meanwell drivers and couldnt find a mod thread where anyone ever attempted to remove the internal pot and wire an external one in its place. I removed the metal covers and the entire driver cavity is encapsulated in a heavy potting compound similar to dried latex silicon. I could probably take an exacto blade to it and carve a nice neat channel to expose the pot and then go from there. Access would be on the top of the PCB so I couldnt desolder it from the under side. Id have to attempt a removal from the top side, which might or might not be an easy proposition. If I destroyed the pot during the removal process, I wouldnt be able to measure it with a dmm to find its rating. Its just one of those things where I have come to appreciate the comforts of high levels of quality light without shadows, and while bathing everything in brilliant light. I can just see everything a whole lot better and with greater clairty. So Im not sure that Id turn the light down even if I had that as a remote feature. Also, the driver can deliver more power than is recommended (which is 100W max sustained at the emitter) so a pot mod would have to have a corresponding set limit… not sure how to pull that one off without resistors inline. Maybe there is a pot with adjustable limits.
These type of drivers cant be dimmed by a dimmer switch. Wouldnt that be nice if they could?
My only thought for dimming is taking portrait pictures, people can be sensitive to bright light and squint and then get attitudal which doesn’t make for the best portraits. I could always diffuse it, bounce it, whatever.
That sounds like such an excellent set-up, with it being sealed it’d work great for outdoor shoots without worry. Did you say how many lumens you think it’s making? 7000-9000?
I have been thinking of using a commercial 2’x4’ fluorescent bay with daylight white tubes, special tubes designed for the workplace. But I’m just about positive they wouldn’t work well for photography. This set up of yours sounds ideal, and so perfect for product shots as to be droolworthy. :heart_eyes: