3.7V 21700 3000mah Rechargeable Cell (11.1Wh)

3.7V 21700 3000mAh Lithium-ion Rechargeable Cell (11.1Wh)

The 3.7V 21700 3000mAh lithium-ion cell is a high-capacity, high-performance power solution engineered for demanding portable electronics, hobby projects, and custom battery packs. Delivering 11.1Wh of energy in a compact cylindrical 21700 form factor, this cell offers longer runtime, improved energy density, and reliable performance across a wide range of applications.

Why choose this 21700 battery?

• Higher energy density than 18650 cells, giving more capacity in a slightly larger, robust package.
• Designed for long cycle life and stable voltage output to power modern devices reliably.
• Versatile for single-cell use or assembling series/parallel packs for higher voltage or capacity.

Key features

• Capacity: 3000mAh for extended usage time
• Nominal voltage: 3.7V
• Energy: 11.1Wh
• Form factor: 21700 (21mm diameter × 70mm length)
• Rechargeable: Hundreds of cycles (500+ typical)
• Lightweight: ~70g per cell
• High energy density: More power in a compact size

Technical specifications

• Battery type: Lithium-ion rechargeable cell
• Model: 21700
• Nominal voltage: 3.7V
• Capacity: 3000mAh
• Energy: 11.1Wh
• Charging (max) voltage: 4.2V
• Discharge cutoff voltage: ~2.75V (do not discharge below this)
• Standard charge current: ~1A (recommended)
• Max continuous discharge current: typically 5A to 10A depending on cell build and application
• Dimensions: Ø21mm × 70mm
• Weight: ~70g
• Cycle life: 500+ cycles under standard usage

Typical applications

• Power banks and portable chargers
• Flashlights and LED torches
• RC cars, drones, and hobby electronics
• E-bikes, electric scooters, and portable power tools
• DIY battery packs (single-cell or multi-cell series/parallel configurations)
• Robotics, IoT devices, and sensor systems
• Small-scale solar storage and backup systems

Safety information and handling guidelines

Proper handling and charging are essential for long life and safe operation of lithium-ion cells:

• Use a dedicated lithium-ion charger and do not exceed 4.2V when charging.
• Do not discharge the cell below the recommended cutoff voltage (~2.75V).
• Avoid short-circuiting the terminals and keep the cell away from conductive materials.
• Store and operate the battery within recommended temperature ranges; avoid extreme heat, cold, and open flames.
• Do not expose to water or physical damage. Replace if casing is punctured, swollen, or otherwise compromised.
• Use 21700 cells only in devices designed for lithium-ion batteries and follow device manufacturer instructions.

Charging and pack-building recommendations

• For single-cell charging, use a regulated charger set for 4.2V and appropriate charge current (1A recommended for typical charging).
• When building packs, match cells by capacity, age, and internal resistance. Use a proper battery management system (BMS) for balance, overcharge and overdischarge protection.
• For higher current applications, confirm the cell’s continuous discharge rating and consider cells with higher current specifications if needed.

Comparison with 18650 cells

The 21700 format provides greater capacity and energy density than common 18650 cells, enabling longer runtimes and fewer cells for equivalent capacity in pack designs. This makes 21700 cells particularly attractive for high-capacity power banks, e-bikes, flashlights, and professional tools.

Ordering and support

If you need single cells for prototyping or bulk quantities for production, this 3.7V 21700 3000mAh (11.1Wh) cell is suitable for a wide range of projects. Contact support for assistance with pack design, BMS selection, or recommended charging setups for your application.

Important note

Images are for illustration purposes only. Always follow local regulations for shipping, disposal, and recycling of lithium-ion batteries.