Fairy lights are great for small wearable projects because the wires are thin and don’t have plastic insulation, the bulbs are waterproof and have a low profile, and there are many strands available that run on coin cell battery packs.
Unfortunately, there are also many challenges when working with these light strands. Most of the issues are related to the robustness (or lack thereof) of the electrical connections. Luckily I have come up with a few fixes that should help keep your fairy lights glowing strong!
Three Main Areas of Concern:
Connection Between the End of the Light Strand and the Cable to the Battery Pack:
If the connection has already broken:
Resolder the joint (remove the batteries first!!!!):
To keep this from happening in the future:
Hot glue the battery pack cable to the battery pack. Make sure to add extra hot glue to make the connection strong and secure. This will keep any pulls in the line from putting stress on the soldered connection inside the battery pack.
Connection Between the Battery Pack Cable and the Switch:
If the connection is already broken:
Remove the heat shrink, separate the wires and strip the insulation from the cable of the battery pack.
Slide a fresh piece of clear heat shrink over one of the wires before you connect them:
Twist the wires together, solder the connection and secure with clear heat shrink:
To prevent the connection from breaking in the first place:
As soon as you take the fairy lights out of its packaging, add an extra layer or two of clear adhesive heat shrink to the joint to reinforce it.
Connection between the contacts on the battery cover and the battery:
The top contacts of the battery pack are in the lid. The lid is made out of thin plastic and can easily be bent out of shape. This can result in a loss of connection.
Buy battery packs with four sets of screws holding the two halves of the battery pack together (a surprisingly high percentage only come with two, despite being manufactured with 4 screw holes). Or add two extra screws to secure the lid to the battery pack.
Remember, whenever you are using electronics for wearable projects, you are going to run into issues with the flexing and bending of the wearer putting stress on the electrical connections. So keep this in mind as you work on your projects!