Meanwell LDD driver: for those who want to dim to 0 using Arduino
- Thread starter pwreef
- Start date
I was going to ask the same question, but didn't want to pose that question until the total power needed was figured out. Now that you have brought that up,... Pokha if you think you have the total power your led's will need,...look at the specks for the HLG you linked. Take a look into these PS's and check to see what they are capable of providing amps, voltage, ect. (specks)
http://www.powergatellc.com/mean-well-enclosed-with-fan-power-supplies.html :thumbsup:
http://www.powergatellc.com/mean-well-enclosed-with-fan-power-supplies.html :thumbsup:
jedimasterben
LED world domination!
I hope you're not planning to run all 70 from the HLG-40... you originally said only 25x of those LEDs, if you try to run all 70 then you'll probably let out all the magic smoke lol
The HLG is a constant current driver OR a constant voltage power supply depending on the load, if attaching LEDs to it it switches to constant current mode. The HLG are very power efficient and IP67 or IP65 rated and are really the only power supplies I'd use anywhere near a tank.
From the datasheet of the 240H:
http://www.meanwell.com/search/HLG-240H/HLG-240H-spec.pdf
Pokahpolice,
Lets create an example:
Lets say you have 10 LEDS in a string (wired in series). Each LED has a fV of 3.5v and a max of 500mA.
Lets say you have 5 identical strings.
The strings are wired in parallel.
Each string will need : 10 x fV(3.5) = 35v
Each string will need to be run at 500mA.
Remember current runs through the LED it does not get absorbed. Think of it as humans eat food(volts) but we breathe air(current).
Now if we look at a power supply rated say at 40v and 10Amps. Remember the following you can divide the Amps but not the Volts (unless with a volt divider which does apply to you at the moment). In other words if you divide the power source by the 5 strings and the result output will be as follows : each string will receive 40v 2Amps if you were to connect them directly to the PS. Now we use LDD's between the PS and string the give us a constant current value (depending on LDD spec) which is suited to the leds on the string.
It does not matter how much voltage goes through the LED as it will only absorb what it needs and let the rest pass through. Unlike current which will damage the LED if it is too high.
So back to our example you would use 1 LDD500 per string which is supplied by a PS with a rating of at least 40v 3Amp min.
I hope the above is clear.
Lets create an example:
Lets say you have 10 LEDS in a string (wired in series). Each LED has a fV of 3.5v and a max of 500mA.
Lets say you have 5 identical strings.
The strings are wired in parallel.
Each string will need : 10 x fV(3.5) = 35v
Each string will need to be run at 500mA.
Remember current runs through the LED it does not get absorbed. Think of it as humans eat food(volts) but we breathe air(current).
Now if we look at a power supply rated say at 40v and 10Amps. Remember the following you can divide the Amps but not the Volts (unless with a volt divider which does apply to you at the moment). In other words if you divide the power source by the 5 strings and the result output will be as follows : each string will receive 40v 2Amps if you were to connect them directly to the PS. Now we use LDD's between the PS and string the give us a constant current value (depending on LDD spec) which is suited to the leds on the string.
It does not matter how much voltage goes through the LED as it will only absorb what it needs and let the rest pass through. Unlike current which will damage the LED if it is too high.
So back to our example you would use 1 LDD500 per string which is supplied by a PS with a rating of at least 40v 3Amp min.
I hope the above is clear.
Pokahpolice
New member
Thank you for spoon feeding me. I appreciate it. Things are still a bit fuzzy but I'm getting there. I think I've figured out the wiring. Here is a rough sketch. Anyone see any problems here? The Arduino will be powered separately with 9V power cord and the green (ground) on the ACL/ACN side is not used. The DIM +/- are also not used. :reading:
Hope you can see this alright
The piece that I'm fuzzy with is still the math. So let's do this backwards...
My PSU is 48v - so each LED has a FV of 3.5V so 48/3.5=13.71
Am I doing this correctly? I can only power 13 LEDs with this power supply?
Next is current (AMPs) each LED is rated at 350mA and the rated current of my PSU is 0.84A (840mA?). If I understand this correctly each string needs 350mA so I take 840/350=2.4 - so I can only run two strings?
Last is wattage. The PSU is rated at 40.32 and each LED is 1W so I can power approx 40. Do the LDD drivers 'use' any wattage?
I'm sure some of this is incorrect so please explain which concepts I have right and which are incorrect. Now that I kind of know what's going on I obviously should have figured all this crap out BEFORE buying anything but that didn't happen. I now need to figure out with the components that I bought what can I build?
Once again thanks for being patient with me and walking me thru.
Hope you can see this alright
The piece that I'm fuzzy with is still the math. So let's do this backwards...
My PSU is 48v - so each LED has a FV of 3.5V so 48/3.5=13.71
Am I doing this correctly? I can only power 13 LEDs with this power supply?
Next is current (AMPs) each LED is rated at 350mA and the rated current of my PSU is 0.84A (840mA?). If I understand this correctly each string needs 350mA so I take 840/350=2.4 - so I can only run two strings?
Last is wattage. The PSU is rated at 40.32 and each LED is 1W so I can power approx 40. Do the LDD drivers 'use' any wattage?
I'm sure some of this is incorrect so please explain which concepts I have right and which are incorrect. Now that I kind of know what's going on I obviously should have figured all this crap out BEFORE buying anything but that didn't happen. I now need to figure out with the components that I bought what can I build?
Once again thanks for being patient with me and walking me thru.
jedimasterben
LED world domination!
On the previous page you asked only how to power 25x of those LEDs. The HLG will power 25x of them. The LEDs you have are rated at 1.33w each, not 1w each.
You also have them running in parallel on your drawing. Connect the Vout + terminal to the + pad of the first LED, then connect the - pad of the first LED to the + pad of the second LED, and so on, until the last LED's - pad goes to the Vout - terminal.
You also have them running in parallel on your drawing. Connect the Vout + terminal to the + pad of the first LED, then connect the - pad of the first LED to the + pad of the second LED, and so on, until the last LED's - pad goes to the Vout - terminal.
Pokahpolice
New member
Correct. I only asked to power about 25.
I just don't understand how you get that number. 40/1.33w=30...so 25 makes sense here. But when I look at amps and voltage I don't understand.
Pokahpolice
New member
Makes sense thank you
Pokahpolice
New member
So where does the number 25 come from then?
Pokahpolice
New member
Thank you! This clears up EVERYTHING. I now understand.
Are there cheaper options on PSU? I paid $50 for this one and it will only run 25 1w LEDs. Seems like there should be some cheaper options out there.
oscarinw
New member
Good people, I have a Reef Angel and have the Rapid LED retrofits hooked to 4 Meanwells ELN-60-48P. What drivers do I need to control those lights 0 through 100%??
I wanted to see if I could find this on this thread... only it's 103 pages long!
Any info would be appreciated... If you know the answer and don't mind PM'ing me, I'd be forever thankful
I wanted to see if I could find this on this thread... only it's 103 pages long!
Any info would be appreciated... If you know the answer and don't mind PM'ing me, I'd be forever thankful
@ Pokahpolice
your power supplly, HLG-40H-48 is it the A or B model? From your sketch it would seem to be the B model, which does not have a voltage adjustment screw. It should still work but since you cant set the output voltage it may behave oddly? I don't know that I've seen this done before. Theoretically it should adjust itself to supply up to 48 volts if that is what the LDDs and LED strings are trying to pull from it.
Don't forget that the LDD needs 2-3 volts to operate so you basically need to count it as an LED. In your case you would actually only be able to run 12 LEDs per string.
Wattage rating of the PSU is not really important in this example, just know you will be using less than 40 watts, this is preferable as you never wan't to max out a power supply, though technically you can max out the HLG as it is designed to provide up to it's rated max voltage and current levels, unlike a standard voltage supply, which would be rated in maximum output only and not designed to run at that level for long.
your power supplly, HLG-40H-48 is it the A or B model? From your sketch it would seem to be the B model, which does not have a voltage adjustment screw. It should still work but since you cant set the output voltage it may behave oddly? I don't know that I've seen this done before. Theoretically it should adjust itself to supply up to 48 volts if that is what the LDDs and LED strings are trying to pull from it.
Don't forget that the LDD needs 2-3 volts to operate so you basically need to count it as an LED. In your case you would actually only be able to run 12 LEDs per string.
Wattage rating of the PSU is not really important in this example, just know you will be using less than 40 watts, this is preferable as you never wan't to max out a power supply, though technically you can max out the HLG as it is designed to provide up to it's rated max voltage and current levels, unlike a standard voltage supply, which would be rated in maximum output only and not designed to run at that level for long.
