18650 Battery Holder – 2S2P Configuration

This is a 3D printed battery holder for four 18650 cells, configured as 2S2P (two in series, two in parallel).

The design is built from three main parts:

• two end caps with integrated current paths,
• and a central body.

Electrical connections are created using aluminum tape applied directly inside the printed channels, forming the required 2S2P configuration. 
 

The end caps connect through the center section, creating a compact and functional battery pack structure.

I originally built this pack for a small RC project, where I needed a clean, custom-sized battery solution without spot welding.

🧾 Printing & assembly

• Designed for standard 18650 cells
• M3 screw and nut required
• 2S2P layout (nominal 7.4V configuration)
• No supports required
• Aluminum tape used for conductive paths

⚠️ Skill Level & Safety ⚠️

This project requires basic DIY and electronics knowledge.
You should be comfortable with polarity, series/parallel configurations, and safe handling of lithium-ion cells.

Always:

• Double-check polarity before inserting cells
• Avoid short circuits at all times
• Use matched cells with similar capacity and condition
• Consider using a proper BMS if your application requires charging through the pack

Lithium-ion batteries can be dangerous if assembled incorrectly.
Build and use at your own responsibility.