Replace Batteries with DC Power Supply

I have some fairy lights used to light up some lanterns at home.

The lights are battery powered. I’m using rechargeable batteries but it’s still a hassle replace the batteries when they die. I decided to replace the batteries with a DC power supply which I can just plug in to an ordinary electrical outlet. I could then use a smart outlet to programmatically turn on the lights whenever I want.

To convert the batteries to use a DC power supply, here’s what I did.

  • Since the lights take 3 AA (1.5V) batteries, the total voltage I need the DC power supply to provide is 4.5 V. I an AC (120V) to DC (5V) power supply on Amazon with barrel to wire connector adapter for $9.
  • 1/2″ diameter round wood dowel from Home Depot (3 ft for ~ $3)
  • Speaker wire

I cut the wood dowel to the length of a AA battery. Drill a hole in one end. Partially screwed in a screw. Stripped the end off of a bit of speaker wire. Wound up the end of the wire around screw and screwed the screw in.

I then identified the positive and negative terminals in the battery pack and inserted my fake batteries in them. The wires from each fake battery were then connected to the corresponding positive and negative terminals to the DC power supply. Everything works.