Introduction: How to Make an LED Fairy-Light String Using MR16's

Picture of How to Make an LED Fairy-Light String Using MR16's

This instructable is a super simple, easy and fun way to make an LED Fairy-Light string using MR16 LED downlights.

It's also my first instructable!, finally after years of various DIY and tinkering fun. ^_^

So, getting down to business:, the first question really is.... why?

What is this even for?

 * This is a cheap, quick and easy way to put together a useable 12v string of lights, which can be utilised wherever there is a 12v power source!

* For those of us who might have small scale solar and wind power, while still moving around and renting homes, this can be a quick and efficient way to light:
spaces / rooms / studio's / cubby's / garages / porches / etc.., using our stored electricity, but without making any alterations to an already established house + it's electrical wiring.

* For any outdoors fun, (i.e. burning man, confest, rainbow family gathering, festivals, etc..) this can be a simple way to light an entire camp off just a small scale solar/wind/hydro temporary set up!

But why build it like this?

* This project can be built in 1 hour, with all resources except for the MR16 bulbs, available from a local hardware shop/electrical store.

* The total cost for this project was:   $150,  
   which includes: 
    - 10 Warm-white LED MR16 (3-watt) downlights       ($11 each)
    -  5  Amber LED MR16 (1-watt) downlights                 ($5 each - clearance special!)
    - 10 mtrs of medium thickness core speaker cable       ($1.50 p/metre)

* This setup can also be extended easily at any time once completed by simply adding more cable length. However, care must be taken to account for the total amp load on the cable, and not exceeding the maximum cable amp limits.

i.e. 10 white LED MR16's @ 3 watts each = 30 watt draw ( 2.5Amp @ 12v ),
but 20 white LED MR16's @ 3 watts each = 60 watt draw ( 5Amp @ 12v )

* The final and major benefit for this kind of setup, is the ability to add + remove lights in 2 seconds whenever needed.

e.g., if towards the end of a long night the stored solar power is starting to run out, but all you really need is to have 2 lights on for reading, instead of the 10 or 20 originally on for dinner/cooking, then you can simply walk along and, "ping", pull out the bulbs one by one, to create the perfectly suited lighting environment for the moment.

Ok then, let's get started!

If you're interested, and it's sounding like a good idea, then let's move onto the 1st step in building it:   --->

Step 1: Step 1 - Sourcing the Parts

Picture of Step 1 - Sourcing the Parts

Step 1   -   Sourcing the Parts

Once we've gathered all the various parts for this project together in the same place, it takes only 1 hour to put together a fully working LED MR16 Fairy-light string, and hook it straight up in your car, home, studio, camp, etc..

This project can be built with various numbers of bulbs / types / colours / etc.., so to make things simple, this instructable will demonstrate how to make a 10metre long string of 15 MR16 based LED lights, 10 warm-white and 5 amber coloured. 

This will give us a 10 metre cable of warm bright light, with a total power draw of 
35 watts p/hour  ( this works out to be a draw of 2.9 Amps p/hour @ 12v )

The tools required are:

  -   A pair of pliers (for cutting cable and stripping the ends back for the wires)
  -   Small flat-head screwdriver (for tightening / loosening electrical terminals )
  -   A 30cm ruler (for measuring the cable lengths when cutting)
  -   Voltmeter (optional. this simply helps for checking continuity and battery voltage)
  -   Some silicon gap sealant / epoxy resin (to weatherproof / protect the wires + connectors)

The parts required are:

  -   10x Warm-white MR16 LED downlights  
               ( I sourced mine from: in Brisbane / Australia $11 each)
  -   5x Amber coloured MR16 LED downlights  
               ( again, sourced on clearance special from $5 each )
  -   15x MR16 sockets  
               (these can be purchased from most electrical stores, again I purchased mine
                from ledshoponline $2.50 each (i've seen them cheaper, $0.50c each)
  -    10 meters medium sized 2-core speaker cable
              (I sourced mine from the local Dicksmith's electronics, @ $1.50 p/m, with a load rating of up to 15 amps)
  -    A small sized electrical plastic junction $0.25c each
             (sourced from dicksmiths, to screw the cable ends into, and attach different plugs onto the other end,
              i.e. 12v car cigarette lighter plug, aligator clips, etc..)
  -    2x Small cable terminating plastic caps
              (any hobbiest / electrical store sells them in packs, cables go in the one end,
               and a screw locks them in place, safe from shorting on other wires.)
  -    2x Small aligator clips
             (had them lying around from an old project, but the can be found at electrical stores)

Once we've gathered all the parts needed, and have our tools ready, lets move onto Step 2   --->

Step 2: Step 2 - Construction

Picture of Step 2 - Construction

Step 2  -  Construction

Now that we've got all our parts and tools in one place, it's onto construction.

The first thing to do is to prepare the speaker cable into lengths, and then strip all the wire ends, ready for twisting onto the MR16 connector cables.

Lay out the length of cable on the ground, and stand back to get a better perspective on it.
You will want to work out at what distances you want the LED bulbs.

As a basic guide, if you are making a 10 Metre long cable, with 10 white LED MR16 bulbs, then placing 1x roughly every metre would work well.

However, since we are using 10metres of cable, and we have 15 LED bulbs in total, then we need to place 1x LED bulb roughly every 60cm's along the cable. This will also give us about 1metre extra cable at the end, which will come in handy for roping around trees, holding up to hang lights, etc..

*  So, Grab the pliers, and cut the cable into 60cm lengths (and note that there should be approx~ 1mtr left over at the end.

*  Next, Take the cut lengths of cable, and strip back the plastic sheathing from the wires on both ends by about 1 inch, to get to the bare wire inside. Note, that once you've got the bare wires, gently twist them together a few times to keep them safe and secure, we'll be getting onto them soon.  ^_^,  Do this for every piece of cable length that you have got, except for one, which will be at the very end of the Fairy-light chain, and there is no need to strip the cables, as they will just be put in terminating plastic caps to keep them safe anyway.

*  Once you've finished stripping the wires back, take out the 15 MR16 connectors, and do the same thing to them all, preparing the wires.

Onto the next step: --->

Step 3: Step 3 - Finishing Up

Picture of Step 3 - Finishing Up

Step 3   -   Finishing up

Once you've stripped and prepared all of the cable lengths and MR16 connectors, the next step is simply twisting the the cables together with the MR16 connectors, and another piece of cable length (see the photos below for more detail).

Place the MR16 connector, and the ends of both cable lengths together on the ground, in the way that they are going to fit together.

Each piece of speaker cable has 2 wires running through it,
Choose one to the be the (+) terminal, and the other to be the (-) terminal,

It doesn't matter which you choose, as the LED MR16's can just be unplugged and put in the other way around anyway, but just for continuity's sake, keep a standard while working, and use the same standard for each length of cable and the connecting of the MR16 connectors to the speaker cable.

So long as you keep the speaker cable wires away from the other side of the cable, it doesn't matter which one you wire to which connector. (Again, see the photos below, as it will explain this much better than words. ^_^ )

*  Once you have connected each of the MR16 connectors to the cable lengths, you should now have no more cable or connectors left over, and one end of the cable will be longer than the other (ready to be connected to a 12v battery,etc..) and the other end of the Fairy-light chain should end in non stripped cable ends, (ready to have the 2 wires separated by about 1 inch, and then each wire terminated inside a wire-terminating plastic cap.)

*  All thats left to do to prep the cable and connectors, is to use a little silicone gel (or any kind of weatherproof / non-conducting epoxy or resin), and coat each of the bare wires at each connector fully, so that they are weatherproof and happily safe from shorting out if they come into contact with the wire on the other side.

*   Thats it for preparing the connectors and cable lengths,
the final pieces of the puzzle are to terminate the ends of the cable that will be the end of the fairy-light chain
(for this, separate the wires from each other, still inside their plastic sheathing, by about 1 inch, and then place each piece in a separate plastic cap used for terminating electrical wires). - No doubt there is a much better way to do this, maybe sealing the ends with a hardened epoxy resin too?

*   And finally to attach the small plastic junction to the other end of the fairy light chain cable (the end which will be attached to the battery)

All done?, then lets go onto the final page, with some notes and ideas about the Fairy-light chain, and a final wrap up with photos. ^_^     --->

Step 4: Step 4 - Ready to Plug In!

Picture of Step 4 - Ready to Plug In!

Step 4   -    Ready to plug in!

By now, the cable should be finished, with all the connectors wired in, and all the bare wire connections sealed with a silicone gel or epoxy resin.

At the shorter end (with the terminated wires), tie the cable off in a knot, and tie some rope through it, this will give you a point to hang the lights from at one end,

On the other end of the cable, with the plastic wire terminal, attach alligator clips (probably with more cable so the lights can be run up in a tree, camp tarp roof, etc..)


Attach the alligator clips to a 12v battery (from your solar/wind system, or a car battery, and attach the LED MR16 bulbs one by one. (you could also simply attach a cigarette lighter plug instead of alligator clips, and run them from your car for a beautiful van setup)

If the bulbs don't light up when you plug them in, and you've checked that there is 12v on the line, try plugging in the lights in the other way around.

The warm-white LED MR16's that I bought were uni-directional (so they worked regardless of which way they were plugged in), but the amber LED MR16's would only work when plugged in correctly (with the set (+) of the light connected to the (+) wire, etc..)

I found that alternating Amber and Warm White LED's every 1 or 2 lights worked really well and gave an overall bright, warm-white light with a candlelight feeling.
Since the amber LED's are also only 1 watt per bulb!, it makes it handy when the night is getting on, and the lights have been on for hours, and I simply pull out the warm white 3 watt bulbs, and reduce the draw on the system.

I hope that you found this lots of fun to make as well!,   
    These have saved me so many times as festivals, and moving home, traveling in the van, etc..,
         and I've put together kits of them for festivals like Confest here in Australia, just imagine what a great spider-web grid of customizable lighting you could make by having each of the cable lengths end in simple 3 way or 4 way plugs!. ^_^,

That's the next project. =)

     - Sylph


iApple guy (author)2012-03-26