DIY Battery Spot Welding Pen – Red Copper Core, Threaded Tip, High-Current Ready

Take your DIY battery pack builds and spot welding projects to the next level with this handheld battery spot welding pen. Crafted from genuine red copper — not brass — this pen delivers 3–5× better electrical conductivity than brass alternatives, keeping heat generation minimal even under high current loads. The threaded-tip design locks your welding needle firmly in place for consistent, reliable welds every time.

Key Features

Pure Red Copper Body: Significantly higher conductivity than brass — 3–5× better electrification rate with minimal heat buildup during high-current operation.
Threaded Fixed Tip: The spot welding needle is secured via a threaded tightening mechanism for a stable, firm hold during use.
3mm Core Diameter: Spot welding needles are manually processed with an approximate 2.3–2.4mm core diameter; length is approximately 100mm, cuttable into 2 sections for extended use.
Copper Tube Inner Diameter – 8mm: Accommodates a maximum cable gauge of 4AWG (approximately 7.5mm). Feed wire smoothly with a 10–15mm cable reservation for best contact.
Hydraulically Tightened Joints: All connections are hydraulically crimped for maximum current safety and reliability — superior to screw-fixed alternatives. Use of hydraulic pliers is strongly recommended for installation.
DIY-Friendly Design: Ideal for home battery spot welding, 18650 battery packs, and other electronics DIY builds.
Plastic Handle: Lightweight, insulated plastic body for comfortable, safe handheld use.

Specifications

Material: Red Copper (pen body & core), Plastic (handle)
Core Diameter: ~2.3–2.4mm (manually processed; ~8mm error on length)
Copper Tube Inner Diameter: 8mm
Max Cable Gauge: 4AWG (~7.5mm)
Needle Length: ~100mm (can be cut into 2 sections)
Origin: Made in China
Package Includes: 1 × Spot Welding Pen Set

Installation Tips

Strip your cable end to expose approximately 10–15mm of wire for insertion into the copper tube.
Smooth and twist the wire strands tightly before slowly feeding into the 8mm copper tube.
Use hydraulic pliers to crimp and tighten all joints for maximum contact and current-carrying reliability.
Insert a 100mm welding needle (or cut into two ~50mm sections) and tighten via the threaded tip mechanism.

Note: Due to manual manufacturing, please allow a ±1–3mm dimensional tolerance. Actual product color may vary slightly from images due to monitor differences.

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For general electrical safety guidance when working with high-current DIY electronics, refer to the U.S. Consumer Product Safety Commission (CPSC) and OSHA's Electrical Safety guidelines.

Frequently Asked Questions

Q: What is the advantage of a red copper spot welding pen over a brass one?

A: Red copper has 3–5× higher electrical conductivity compared to brass. This means less resistance, less heat buildup, and more efficient energy transfer during spot welding — making it the preferred choice for high-current battery spot welding applications.

Q: What cable size fits the copper tube on this spot welding pen?

A: The copper tube has an 8mm inner diameter and accepts a maximum cable gauge of 4AWG (approximately 7.5mm). Strip and twist the wire strands, then slowly feed 10–15mm into the tube before hydraulic crimping.

Q: Do I need special tools to install this battery spot welding pen?

A: It is strongly recommended to use hydraulic pliers to crimp and tighten all connections. Hydraulic tightening ensures full, firm contact between the cable and pen body, which is critical for safe and effective high-current spot welding. Screw-fixed alternatives are not as reliable for this application.

Q: Can the welding needle be reused or resized?

A: Yes. The included 100mm welding needle can be cut into two sections for double usage. The threaded tip mechanism allows easy installation and replacement of the needle as needed.