LED MeanWell power supply?

[evilc66]

Well I am slightly confused now, I just read this whole thread from start to finish. Last week I knew nothing about electrical circuits. I learned that wiring leds in series adds voltage to the line, while wiring in parallel adds current to the line. We therefore use constant current, variable voltage drivers. As long as you stay under the max voltage, the current remains constant. If you use a 1A buckpuck capable of firing 6 3.7v leds, wiring them in two strings of 3 would yield 22.2V and 500mA to each LED. So my questionable area and my limited understanding is..

 

Almost. You tripped up on the parallel strings. Two strings of three LEDs would only net 10.2v (3 LEDs in series) at 500mA per string (1000mA total).

 

 

with these new drivers, say you used the 48V 1.3A version... You could run 13 LEDs off of the voltage, but the onboard potentiometer only dials down the current to a little less then 1A. So we would not be able to adjust color temp because all the leds would run at 1000mA. We could only adjust the number of leds of each color, which is not good because we still need a certain number for coverage. So we wish to buy the controllable drivers and then wire in a homemade pot so that we will be able to dial down the current farther, just like on a buckpuck. But we can't buy the controllable ones because they don't manufacture them large-scale.

 

The onboard pot is only designed to limit the maximum current limit. It really isn't useful for full dimming control. The dimmable version that we can get can only be dimmed by a pwm signal. You can use the circuit I posted earlier to accomplish that. The dimmable version isn't very practical when you are only buying one or two. If we can get a bunch ordered, the price is a lot more attractive. I have been contemplating offering these on my next group buy (soon!).

 

 

I'm wanting to light my ten gallon. Could I not buy two of these with the +3/-25% pots:

 

Run 10 or so cree Q5 whites on one driver at 1A.

Run 13 cree royal blues on another driver wired in two strings in parallel adjusted between 700mA and 500mA? I could also run some uv leds on this circuit..

 

In my situation.. would this be effective? this could give me an adjustable color between 10K and 14K?

This would cost me $60 for the drivers as opposed to $80 for buckpucks.

 

Well, you could use them, but with running strings in parallel, there is a lot more to go wrong and harder to diagnose if you don't know what you are looking for. You also need to have equal strings when running in parallel (can't run 13 LEDs total).

 

If you can wait, I'm sure we can get a bunch of people that want to buy these and organize a group buy for them so you can get the adjustable version.

[Reefer Al]

Almost. You tripped up on the parallel strings. Two strings of three LEDs would only net 10.2v (3 LEDs in series) at 500mA per string (1000mA total).

 

 

Cool, that's what I thought, I just typed it incorrectly

 

 

The onboard pot is only designed to limit the maximum current limit. It really isn't useful for full dimming control. The dimmable version that we can get can only be dimmed by a pwm signal. You can use the circuit I posted earlier to accomplish that. The dimmable version isn't very practical when you are only buying one or two. If we can get a bunch ordered, the price is a lot more attractive. I have been contemplating offering these on my next group buy (soon!).

 

Okay, I believe I will be able to easily wire that up considering you posted that nice list and diagram. So would I need one pwm for each driver?

 

 

Well, you could use them, but with running strings in parallel, there is a lot more to go wrong and harder to diagnose if you don't know what you are looking for. You also need to have equal strings when running in parallel (can't run 13 LEDs total).

 

Well that won't be a problem if I build the pwms

 

If you can wait, I'm sure we can get a bunch of people that want to buy these and organize a group buy for them so you can get the adjustable version.

 

I can definitely wait. I'll be looking out for a group buy. Should I have around $50 saved up if I want to buy 2?

[evilc66]

$65-$70. After 5 units, the drivers were about $32 each and you will need to cover shipping.

[zingtaw]

I have been running the non-dimming versions with out issue for a couple months, so I was working with the Arduino and decided to order two dimming versions. They arrived today, and I was hooking it up to the Arduino using the PWM function, I know it only drives at 5 volts, but just to play with dimming. It worked to 50% dimming (100% duty at 5v.) I was measuring the current, and the lights would fire up at .25 amps (.125 amps per string) and ramp up to .66 amps. Evil do you have a circuit on allowing the Arduino to drive to 10v still using PWM from the Arduino, or any other thoughts on getting this to work fully? Thanks.

[keli]

Evil do you have a circuit on allowing the Arduino to drive to 10v still using PWM from the Arduino, or any other thoughts on getting this to work fully? Thanks.

 

I'm not evil, but you probably need to use a fast NPN transistor to switch a 10v source using the outputs on the Arduino. Should be cheap, about $1-2 for a few transistors at radioshack You need to provide a 10v source if the meanwell supply doesn't do it.

[evilc66]

Exactly.

[npain316]

Any progress on a mod to make the non-dims into dims?

[evilc66]

Haven't had a chance. Been focusing on my new tank. As soon as that is up and running (today), I will have more time to look at it.

[npain316]

Haven't had a chance. Been focusing on my new tank. As soon as that is up and running (today), I will have more time to look at it.

Cool.

Any shots of the new tank?

[evilc66]

I have shots in my tank thread. Check sig.

[Sherman]

Just receive my ELN-60-24P today.

Connect up 2 strings of 6 LEDs per string in parallel.

The LED never light up.

Try to adjust the voltage and current port on line.

But still cannot light up?

Is it I need to connect up at least 4 parallel strings then can work?

Or I need to add a resistor per string if less than 4 strings?

Please advise

[evilc66]

These power supplies don't have an inverse input curve, meaning, you have to supply voltage to the dimming control to get any light out of it. Other drivers will go to 100% output with zero input.

 

You can either get a 10v DC power supply and wire a pot inline, or use the pwm circuit I posted earlier in this thread.

[Sherman]

Thank Evilc66. So the Dim + and - need to be connected before it can work.

My is a PWM model(end with P) so I need a PWM to work right?

Or I still can connect a 10 vdc with pot across the Dim + and -

 

Cheers

[evilc66]

This was something I never got a real clarification on, even though I asked the question. If you have access to a 10v power source, try it. Use something like a 10K pot. If it doesn't work, the pwm will.

[Sherman]

Thank evilc66.

I will try out and see which one work.

 

Cheers

[Ocean Flyer]

Thank evilc66.

I will try out and see which one work.

 

Cheers

 

Hi Sherman,

 

What's the outcome? 10V workable? or still need PWM circuit?

[Sherman]

Busy at work.No time till weekend.

[iMaGin3]

Is this the Australia supplier that was mentioned? I was debating ordering but it seems they take my credit card info down before giving a shipping quote and I was a bit skeptical?

 

http://www.computronics.com.au/meanwell/eln-60p/

 

 

Australia currency is 45 converted to USD is about $32 + whatever shipping costs.

[evilc66]

6-12 week lead time from them, plus shipping time. Wait a few weeks for my group buy and you can get them at a good price.

[iMaGin3]

excellent! i cant wait for the group buy!

 

 

My question is that if i use the eln-60 at full power running 4 strings of 5 leds (10 whites and 10 royal blues), how would that work out? Unless i missed something, the 4 strings would be running at each just under 700mah? Would this work out? I plan on waiting on the dimmable ps group buy, but was just wondering how this would work out on a non dimmable, not fiddling with an external pot. thanks evil for all the help btw, very much appreciated!

[evilc66]

Depends on which version you buy. The ELN-60-24 will be your best bet to do this. The 2.5A current will be divided by each string of LEDs. With 4 strings, you are looking at 625mA at the LED.

 

Honestly, I wouldn't recommend running LEDs in parallel unless you know exactly what you are doing. Ideally, you should be running current mirrors (3 total) to make sure the circuit is safe if there is an LED failure. If you run unprotected parallel strings, a single LED failure can destroy your entire array. Series strings are much safer in that regard. The ELN-60-48 will support 13 LEDs in series at 1A.

 

Unless I can find a simple, cheap way to implement current mirrors, I will probably be only ordering the ELN-60-48 in the group buy just to make sure that everyone has the most success and reliability.

[McJosh13]

Depends on which version you buy. The ELN-60-24 will be your best bet to do this. The 2.5A current will be divided by each string of LEDs. With 4 strings, you are looking at 625mA at the LED.

 

Honestly, I wouldn't recommend running LEDs in parallel unless you know exactly what you are doing. Ideally, you should be running current mirrors (3 total) to make sure the circuit is safe if there is an LED failure. If you run unprotected parallel strings, a single LED failure can destroy your entire array. Series strings are much safer in that regard. The ELN-60-48 will support 13 LEDs in series at 1A.

 

Unless I can find a simple, cheap way to implement current mirrors, I will probably be only ordering the ELN-60-48 in the group buy just to make sure that everyone has the most success and reliability.

 

 

Evil, I respectfully disagree on this point. If iMaGin3 decided to run 4 parallel strings at 625mA ea I think this would be a safe setup without current mirrors. Lets say a led did happen to fail on one string. Then the current would be divided between 3 strings instead of 4 and each string would be receiving 823 mA. This is still very safe. In the unlikely event that another string failed, then the current would be divided by 2 strings which would result in 1.25 Amps per string. While this is not good long term, it still does not spell disaster in the short term with good heat sinking, and he will have plenty of time to notice the burnt out strings and fix them before any possible damage could occur.

 

I agree that it may be a problem in setups which are already pushed to the max to begin with but in cases like the one above I believe there is no problem running series-parallel circuits of LEDs.

[evilc66]

The problem doesn't lie strictly with current though. The change in forward voltage will affect all LEDs in that string potentially causing damage as the driver attemps to keep the voltage high enough for the other strings. It is widely accepted in the high power LED world that series strings are desireable, and parallel is not.

[iMaGin3]

Okay, Ill probably just run the ELN-60-48 with a string of 13 in series. Ideally, I would like enough lighting over a 12" cube and I think 13 will be enough running 7 royals and 6 whites. Keeping softies and LPS, perhaps a clam too (temporary of course! ) So the current for the string would be running at 1.3A at max ( I know too high)? With the dimmable PS, can I turn the string down to about 800mah or so? Would I have any trouble with the colors (hopefully about 14k or a bit "bluer" ) running them all on the same string at the same current? Thanks!

[npain316]

The problem doesn't lie strictly with current though. The change in forward voltage will affect all LEDs in that string potentially causing damage as the driver attemps to keep the voltage high enough for the other strings. It is widely accepted in the high power LED world that series strings are desireable, and parallel is not.

Current Mirrors? Is that you are talking about (red arrow).

 

Source: Meanwell Powersupply Tech note.