AAA → AA Converter (Mini Cell → Standard Cell)

A 3D‑printable adapter that allows you to use a AAA battery inside a device designed for AA batteries, while maintaining proper dimensions, contact alignment, and reliability.
The design is made of two parts and uses a simple M4 screw as the central conductor.

🧩 Main Features

• Two‑part design for cleaner printing with no supports

• M4 screw as the conductor: cheap, replaceable, and easy to source

• Precise pole alignment thanks to the internal geometry

• Robust structure with optimized walls for strength and insulation

• Compatible with most AA‑powered devices

🔧 How It Works

The AAA battery is inserted into the lower shell.
The M4 screw, placed in the upper part, ensures conduction between the AAA’s positive terminal and the device’s AA positive contact.

The screw length compensates for small tolerances and ensures a stable connection.

🖨 Recommended Print Settings

• Material: PLA or PETG

• Layer height: 0.2 mm

• Infill: 20–30%

• Supports: Not required

• Perimeters: 3

• Orientation: Print parts vertically for maximum contact precision

📐 Dimensions

• Total length: 50 mm (AA standard)

• Outer diameter: 14 mm

• Internal AAA housing: 10.5 mm

• Screw seat: Standard M4

🪛 Assembly

1. Insert the AAA battery into the lower part.

2. Screw the M4 bolt into the upper part until it makes contact.

3. Snap the two parts together.

4. Insert the adapter into your device like a standard AA battery.

⚠ Safety Notes

• Do not use in high‑drain devices (powerful motors, camera flashes, etc.).

• Ensure the screw is properly tightened to avoid poor electrical contact.

• Do not use damaged batteries.

📎 License

This project is released under the Creative Commons – Attribution license.

🔖 Suggested Tags

battery, adapter, AAA, AA, converter, M4 screw, electronics, 3dprint, useful, tool, diy