DMX2-18 Power Supplies

S

Steve Eggins

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Joined
Dec 16, 2017
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19
Hey Guys,
I am doing my first pixel build this year but a have 20000 or soo fairy lights from previous years I would still like to use as “Fill” in gardens etc.
I ordered a couple of the DMX2-18 from
Hanson but I am struggling with the power. I have seen a great video on our site here for powering one string but I am unsure how I would power 9? Do I splice in original power somehow? Or is there a better way?
Any help would be really appreciated
Thanks in advance
Steve
 
The usual practice would be to get a switchmode power supply with enough capacity to power all of the strings plus the DMX2-18. This power supply and the DMX2-18 would replace the original plugpacks on the strings.

The challenge with using traditional LED strings is that the exact voltage required varies from string to string. Once you have tested each string and know its required voltage, you have the following options to accommodate multiple voltages:
  • Modify the strings of lights to that they run at the same voltage
  • Use multiple DMX2-18 controllers each with their own power supply
  • Run at the lowest voltage and accept that some strings won't be at their full brightness
I am happy to explain how I test and modify strings of LED lights in my display but I'd need to know more details about the strings that you have.
 
That’s an amazing help! I will pull out all my crates tomorrow. I do have a lot of the same strings so if I could get hold of one of the switch mode power supplies I could do that.

what would you need from me?
Thanks so much for your help, I am a little lost here.
 
If you have lots of the same thing, let's start with whichever type of string you think is the most important to get working. Note that there can be manufacturing differences if you bought the same type of string in different years.

The DMX2-18 is compatible with strings of LED lights that originally had a blinker unit AND only two wires between the blinker unit and first LED.

Once you've decided which string you want to tackle first, we can have a look at the way that it is wired and calculate the current that it should draw. The details that I need to know are:
  • The number of times that the number of wires between the LEDs drops back to two. If there is a long section at the end with two wires between each LED then this should only be counted once.
  • The number of LEDs between the places where the number of wires drops back to two
  • Whether or not the string of LED lights is connectable.
  • The number of LEDs in the string
  • The number of wires that is connected to each LED. It is likely to vary from LED to LED so just tell me which number you see the most often. It should be two or four.
  • The voltage, current and/or wattage specified on the original plugpack
  • LED specifications as per the box (if available)
There are some icicle strings that I don't understand the wiring of. These are the icicles with four wires connected to most of the LEDs. I can still help with linear strings that have four wires connected to most of the LEDs and I can still help with icicles that have two wires connected to most of the LEDs.

I am erring on the side of having more information rather than less here. I have written the above list with the assumption that we're working with linear strings and not icicles. Once I have this information, I will be able to tell you the way that the string of LEDs is wired and calculate the current that it should draw. Increasing the supplied voltage will increase the current flowing through the string. If you supply a voltage that is too high, too much current will flow and this will damage the LEDs. When testing, I use a power supply with a variable voltage output and I measure the current with a multimeter. I start at 24V DC and gradually increase the voltage until the current is correct. I then know the correct voltage for the string of lights. It is usually somewhere around 31V. This is the voltage that I chose to use in my display once the strings have been modified. A power supply with variable voltage AND a current limiting feature would be better than what I have for testing (adjustable voltage supply plus multimeter) but what I have does the job.
 
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As said above, check all the strings have the same voltage. I use a DMX2-18 with a S200-31 power supply which I also got from Al Hanson. All of my strings just happened to be 31v strings which made it easy, but I understand not all strings out there will be 31v.
 
Cool that’s what I thought you meant, I think all my colors Are same and all white same so I can use the boards separately color/white and get some power from Hanson :)

thanks again for your input I really appreciate it
 
i13 said:
If you have lots of the same thing, let's start with whichever type of string you think is the most important to get working. Note that there can be manufacturing differences if you bought the same type of string in different years.

The DMX2-18 is compatible with strings of LED lights that originally had a blinker unit AND only two wires between the blinker unit and first LED.

Once you've decided which string you want to tackle first, we can have a look at the way that it is wired and calculate the current that it should draw. The details that I need to know are:
  • The number of times that the number of wires between the LEDs drops back to two. If there is a long section at the end with two wires between each LED then this should only be counted once.
  • The number of LEDs between the places where the number of wires drops back to two
  • Whether or not the string of LED lights is connectable.
  • The number of LEDs in the string
  • The number of wires that is connected to each LED. It is likely to vary from LED to LED so just tell me which number you see the most often. It should be two or four.
  • The voltage, current and/or wattage specified on the original plugpack
  • LED specifications as per the box (if available)
There are some icicle strings that I don't understand the wiring of. These are the icicles with four wires connected to most of the LEDs. I can still help with linear strings that have four wires connected to most of the LEDs and I can still help with icicles that have two wires connected to most of the LEDs.

I am erring on the side of having more information rather than less here. I have written the above list with the assumption that we're working with linear strings and not icicles. Once I have this information, I will be able to tell you the way that the string of LEDs is wired and calculate the current that it should draw. Increasing the supplied voltage will increase the current flowing through the string. If you supply a voltage that is too high, too much current will flow and this will damage the LEDs. When testing, I use a power supply with a variable voltage output and I measure the current with a multimeter. I start at 24V DC and gradually increase the voltage until the current is correct. I then know the correct voltage for the string of lights. It is usually somewhere around 31V. This is the voltage that I chose to use in my display once the strings have been modified. A power supply with variable voltage AND a current limiting feature would be better than what I have for testing (adjustable voltage supply plus multimeter) but what I have does the job.
Click to expand...
Wow you guys are amazing :) here I was worried to ask questions!! Thanks I will check them all tomorrow, i think my ocd has me keeping the boxes too ;)

thanks again
 
Yep, I use the 31v with my dmx2-18 aswell. Got rid of any lights that weren't 31v and cut my losses. Also spliced some 2 pin connectors into a single wire run (using ports 1 & 2 on the board, set to 9 channel so thay 'act' as one) and am working about 4 sets from that with no issues.

Edit: Also wanted to add that I was able to have a blinker unit between the controller and the first set (2 wire in/out) and am able to controll the "blinkyness" like normal. In xLights I just have them set to 'on'. Although some of the sets don't work properly with this so they'll plug into other ports on the controller.
 
I've still got the containers too lol. Just had a look at mine and a 1200 pack outputs 12W. So ( now I am no electronic engineer or mathematician ) but a 200W power supply could ( in theory ) power about 20000 lights or 16.666666 sets of 1200 lights.
 
The voltage will be specified on the original plugpack but I don't trust it to be precise. With LEDs, a small increase in voltage can result in a large increase in the current which will damage them. If you have a multimeter handy then you may as well check what voltage they should ideally use.

Please do ask questions. The community here is helpful and there may be other readers with similar questions.
 
I just went and dug out my crates of lights and supplies, yup Nearly all 31v with varying amps for lengths so that’s fantastic thanks for all your help.
I will try and do some videos of all the strings connected in a how too one I get the psu from Hanson.
 
I'm currently out of the 31V supplies but hopefully TNT will make it from Melbourne to Bendigo by Monday. They arrived there Thursday evening so hopefully I'll get them soon.
I also have plenty of stock of fairy light pigtails and extension leads that fit these style lights if you don't want to chop the leads at all.
 
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