Sofirn 21700 4000mAh Flat Rechargeable Li-ion Battery - 3.7V 40A High-Drain Flat-Top Cell

Power demanding flashlights with confidence using the Sofirn 21700 4000mAh flat rechargeable lithium-ion battery — a high-performance flat-top cell optimized for high-drain applications. This battery delivers a nominal capacity of 4000mAh (minimum 3900—4000mAh) at 3.7V (working range up to 4.2V), paired with a powerful 40A maximum continuous discharge current, making it ideal for bright, sustained high-output LED torches.

The flat-top configuration ensures broad compatibility with flashlights and devices designed for unprotected or protected 21700 setups. Built with high energy density and robust construction, it supports fast charging capability and maintains excellent performance across repeated uses.

Key specifications and highlights:

• Capacity: 4000mAh (minimum 3900—4000mAh)
• Nominal voltage: 3.7V (up to 4.2V max)
• Maximum continuous discharge current: 40A (high-drain rating)
• Discharge rate: Max 5C (supports high current demands)
• Cycle life: Up to 1000 times for long-term reliability
• Dimensions: Diameter 18.30 mm, Length 65.20 mm
• Weight: 69 g (product), approx. 150 g gross package weight
• Intelligent battery pack design with environmentally friendly chemistry
• High power density and fast charge capability
• Certifications: CE, RoHS, FCC

This high-current 21700 cell excels in scenarios requiring both good runtime and extreme power delivery, such as tactical flashlights, search lights, or high-lumen everyday carry torches. Its durable build and 1000-cycle life make it a cost-effective, eco-conscious choice over disposable alternatives.

Important safety and usage notes: Charge only with a compatible lithium-ion charger rated for high-drain 21700 cells. Do not exceed discharge limits, overcharge, short-circuit, puncture, crush, or expose to water, extreme heat, or fire. Use in devices with appropriate protection (especially for high-current applications). Store in a cool, dry place, partially charged. Avoid deep discharges to maximize lifespan. For best results, follow manufacturer charging guidelines.

Upgrade your high-power lighting setup with the Sofirn 21700 4000mAh flat-top — balanced capacity, massive discharge capability, and dependable Sofirn quality!