If you have an old computer or camera then you may already be familiar with the LSL3 battery (A.K.A. 1/2 AA). They're not easy to find but when you do find one, often it has leaked it's corrosive guts out all over a beloved vintage electronic.

To avoid a destructive battery situation you can replace ancient LSL3 batteries with 2x AA batteries in a convenient pack. The advantage of creating this battery placeholder is that the real batteries can be placed somewhere less dangerous if they should ever burst or leak.

Supplies

AA Battery Adapters ($6.58 at the time of posting)
Wire (I used old speaker wire)
Soldering Iron
Reliable ruler or calipers
Tape
Small saw

Step 1: Getting Started

The concept is very simple; the AA battery adapter is just under 50mm long but our LSL3 is just under 25mm (hence the name "1/2 AA").

It's easy to see what needs to happen — we must make the AA adapter shorter by ~25mm. This particular AA adapter is tapered, meaning the end is a smaller diameter than the center.

You've got this!

Find a suitable marker and shim it to the correct height, the felt tip of my marker was at 12.5mm
- If you want to test this first, just rotate to make a small line and measure the distance.
- I used a small piece of rigid foam to shim my marker to the correct height but you could use old gift cards, cardboard, etc.
Rotate the one half of the AA battery adapter along the edge of the marker.
- Make sure the opening side of the AA adapter is on the table or you will cut your adapter half too short!
After both sides are marked, go ahead and confirm the following:
- You have marked the adapter half with the correct side (open side) on the table
- You have marked your line at the correct height.
Once you double checked your work go ahead and cut it!

Cut it out!

When it comes to cutting you have a few options. I have done this several times and each time had the opportunity try something different:

The first time I skipped marking with a line and directly scored and then cut the surface with a box cutter. This works okay, but if you push too hard as you're cutting down then the resulting cut will be deformed and will need sanding.
The second time I used a hack saw blade. It works fine and it was fast but I again applied too much pressure while sawing and ended up with a warped cut.
For the purpose of this instructable I made my most recent LSL3 replacement using a small scroll saw. It worked great!

Step 2: Give Me Power!

This isn't just a pretty sculptural project; the terminals on the AA adapter must have power running to them. So, let's see how the wires are attached.

Start by removing the metal terminals from the AA adapter.
- I went a little ham on mine and left some dents. Use a soft touch!
The inner faces are where we will be soldering our wires.
- It's optional, but you could add some flux to the side you will be or thoroughly clean them with isopropyl alcohol.
When you solder your terminals you may find they're difficult to get the solder to stick to. Let me explain:
- You may want to consider bending the wires so that they neatly face the inner face of the terminal. You can see this in my second photo.
- The terminal is acting like a heat sync, before the solder will adhere the terminal must be brought up to temperature.
- This means while you're working on the terminals and immediately after finishing, the metal terminals are going to be as hot as the hinges of hades. Be careful!
Simply wire the other side of the wires to the battery pack. Make sure to connect positive from the battery pack to positive on the battery adapter.

Step 3: Keeping It Together

It's rough out there, I know. But let's focus on keeping our LSL3 battery replacement together now that we have the AA adapter cut correctly (you did get it cut correctly, right?).

When I have done this in the past I used Epoxy, assuredly thinking to myself there's no way this would ever break. I was right but that level of adhesion is probably overkill. That's why this instructable will recommend using tape instead!

Get it together!

To get it all together I used packing tape. I simply cut a strip to match the width of the assembled tube. But are we forgetting a step?

Wires

I assume you want a few wires sticking out, y'know... for power? Make two notches in the edges of your cut AA adapter halves to match the size of your wire. You can see that as well as the tape in mine. If you're being a good little boy or girl then you wouldn't have taped it before reading this note. Hope you're not feeling trolled!

Step 4: You're Done!

Amazing — you did it!

Just think, hundreds of years from now when your ancestors boot up the old computer you lovingly restored they will think kindly of your efforts... Or at least in a few years when you want to revisit those childhood games or introduce someone you love to a part of your childhood. I hope you enjoy!