Adjustable Voltage Power Adapter for Makita LXT 18V Batteries – LM2596 DC Converter

This is a 3D printed adapter for Makita LXT 18V batteries or compatible battery systems, which allows you to obtain a stable adjustable output voltage using the popular LM2596 DC-DC step-down converter.
The adapter is designed to power various devices such as LED strips, routers, modems, DIY electronics, and other DC-powered devices.
The design is compact, easy to assemble, and optimized for FDM 3D printing.

Features

• Compatible with Makita LXT 18V battery standard
• Uses a widely available LM2596 (DC-DC step-down converter)
• Adjustable output voltage
• Standard output connector DC 5.5 × 2.1 mm (DC-022)
• Power switch
• Voltage adjustment access hole
• Ventilation openings for cooling
• Additional enclosure version (battery_adapter_top_2.stl) for wall or shelf mounting (mounting tabs with 4 screw holes)

Applications

The adapter can be used to power:
• LED strips
• Wi-Fi routers and modems
• Arduino and other electronics
• small DC devices
• and more

A great solution if you already have Makita batteries and need a portable power source.

Required Components

To assemble the adapter you will need:
• LM2596 DC-DC converter module
• DC power jack 5.5 × 2.1 mm (DC-022)
• Mini round rocker switch KCD11, 15 mm, 2PIN, ON-OFF
• Wires
• Ring terminals with 3.5 mm hole diameter – 2 pcs
• Countersunk screws 3×12 mm – 11 pcs
• Brass contact plates (DIY) 10 × 58 mm – 2 pcs

Battery Contacts

The battery contacts are made from two brass strips.

Specifications:
• Size: 58 × 10 × 0.9 mm
• Quantity: 2 pcs

Each strip is bent at a 90° angle.

A Ø3.5 mm hole is used for:
• mounting the contact to the enclosure
• connecting a wire with a ring terminal

The battery contacts be made using simple tools:
a hacksaw, a drill with a 3.5 mm bit, and pliers for bending.

Important Notes

⚠ When installing the LM2596 DC-DC board into the enclosure, you must print 2 insulating washers (file: pcb_insulator_washer.stl) and place them between the board and the screw to prevent a short circuit.

⚠ Adjust the required voltage using a flat screwdriver through the access hole on the top of the adapter and always check the output voltage with a multimeter!

⚠ Batteries can deliver high current — use with caution!

⚠ Always monitor the battery discharge voltage. Not all Makita LXT 18V batteries have built-in low-voltage protection, which may lead to damage if over-discharged.

Disclaimer

This is an independent design and is not affiliated with Makita.
Makita and LXT are registered trademarks of their respective owners.
This product is intended for use with compatible batteries.