21V 18650 Battery Case Holder 5S 50A – DIY Screwdriver Pack

Build or repair your own 21V power tool battery packs with this versatile 21V 18650 Battery Case Holder. Designed for 5-series (5S) configurations with a 50A continuous discharge rating, this case supports 5×, 10×, 15×, 20×, and 30× 18650 cell arrangements — making it ideal for DIY power tool battery assembly, replacement pack builds, and custom battery projects.

Constructed from a durable plastic and metal composite, this holder is built to withstand the rigors of hands-on use. An integrated circuit monitors individual cell voltage and tracks current usage history, helping you maintain optimal pack performance and balance over time.

Key Features

• Wide compatibility: Fits 5×, 10×, 15×, 20×, and 30× 18650 lithium cells in 5S configurations
• High-current rated: 50A continuous discharge supports demanding power tool applications
• 21V output: Ideal for standard cordless screwdriver and drill battery replacement builds
• Integrated circuit monitoring: Tracks cell voltage and current usage history for smarter battery management
• Durable materials: Plastic and metal construction for long-lasting performance
• Multiple configurations: Choose from 10 color/configuration options to suit your project needs
• DIY-friendly design: Intended for users with hands-on experience in battery assembly and cell performance knowledge

Product Details

• Voltage: 21V (5S configuration)
• Max Discharge Current: 50A
• Compatible Cells: 18650 lithium-ion
• Cell Count Options: 5×, 10×, 15×, 20×, 30×
• Material: Plastic + Metal
• Application: Cordless screwdriver / power tool battery pack building & repair

⚠️ Safety Note: This product is intended for individuals with knowledge of lithium-ion battery performance and hands-on experience in battery assembly. Always follow safe battery handling practices. For guidance on lithium battery safety, refer to CPSC Lithium-Ion Battery Safety Information.

Frequently Asked Questions

Q: What is the 21V 18650 Battery Case Holder used for?

A: This 21V 18650 Battery Case Holder is designed for building or repairing cordless screwdriver and power tool battery packs. It supports 5S (5-series) configurations using 18650 lithium-ion cells, making it a great DIY solution for custom replacement battery packs with 5×, 10×, 15×, 20×, or 30× cell arrangements.

Q: What is the 21V 18650 Battery Case made of?

A: The battery case is constructed from a combination of plastic and metal, providing a sturdy and durable enclosure suitable for demanding DIY battery assembly applications.

Q: Does this battery case include a built-in protection circuit?

A: Yes — this 18650 battery holder features an integrated circuit that monitors individual cell voltage and tracks current usage history, helping to keep your battery pack balanced and performing optimally during use.

Q: Is this product suitable for beginners?

A: This 21V battery case holder is intended for users with prior knowledge of lithium-ion battery performance and hands-on experience in battery assembly. If you are new to DIY battery builds, we recommend researching 18650 cell safety and 5S pack assembly before use.