18650 to AA adapter

I bought one of the Solarforce L2 + 16340 Extension deals (HERE) and the components to make a low-voltage, single-mode XP-G light. I found that a section of garden hose worked fairly well as an adapter for the AA batteries in the 18650 tube. The only “problem” is that the batteries are so snug in the piece of hose that they don’t just slide out when it’s time to change them. I have to remove the tail cap and adapter, take out the section of hose, and push out the batteries.

I made a second one of these to gift to someone who graciously towed my car during a recent snow storm, but I would like a more “elegant” adapter for the light. Something that would not require him to go through the same process to change batteries.

Anyone have something that’s worked for them? I’ve looked through our local hardware store for some kind of tubing with the correct ID / OD, but found nothing besides the garden hose.

Well, over here we can get PVC tubing for guiding cables within a wall (don’t know the english word for that).
They are usually not in the tubing section but the electrical section of the hardware store. 16mm tubing slit open on one side and and bend a little outwards works really nice. Maybe you can find something comparable at your place?


I use a piece of clear plastic/rubber hose that is split/cut lengthwise. It works perfectly for AA’s.

I use corrugated paper sheet, cut into length/diameter for two AA or 14500, further roll / curl up, re-trim to fit. :slight_smile:

18650 to CR123 adaptor guide

Adjust accordingly for the diameter of a AA cell. Wont really cost you anything except your time.

When I did a 2AA P60 host, I rolled my own adapter out of paper. The only problem is that when you don't get it straight, the ends look messy.

But if you soak the ends with liquid superglue (don't let it run inside the tube) you can sand the edges flat. This will also make the tube quite rugged.

Wow. The paper idea is a good one. I think I’ll give that a try. Might even get fancy and try black paper.

The ID of tubing I’ve tried has been a little too tight.

I’ve done the rolled cardboard on some of mine, but wanted something a little nicer for this one since it’s a gift.

Thanks for the helpful replies!

Have fun!

If you have some eneloops, it's best to use them as a "model" for the adapter because they are a tad thicker than most other batteries.

I first rolled one or two layers of paper around the batteries and secured it with sticky type, then I continued to wrap the adapter paper around that. When finished I just pushed the inner tube out. I didn't do that on the first try and the tube ended up too tight