18650 Li-Ion Battery Specifications

General

• Battery Type: Lithium-Ion (Li-Ion)
• Cell Size: 18 mm diameter × 65 mm length (hence “18650”)
• Nominal Voltage: 3.6 V – 3.7 V
• Fully Charged Voltage: 4.2 V
• Discharge Cut-off Voltage: 2.5–3.0 V

Capacity

• Typical Capacity: 1800 mAh – 3500 mAh (depends on manufacturer)

Electrical

• Continuous Discharge Current: 2 A – 20 A (depending on battery type, e.g., standard vs high-drain)
• Maximum Pulse Current: Up to 30 A (high-drain variants)
• Charging Voltage: 4.2 V (per cell)
• Recommended Charging Current: 0.5 C – 1 C (depends on battery)

Physical

• Dimensions: 18.6 mm × 65 mm
• Weight: ~45 g – 50 g
• Cell Type: Cylindrical, single cell (no built-in protection in standard 18650; some come with PCM protection)

Safety & Features

• Overcharge, over-discharge, and short-circuit protection recommended (via external protection circuit module or built-in PCM)
• High energy density
• Rechargeable up to 300–500 cycles (depends on usage and charging method)

Applications

• Laptops, power banks, flashlights
• Electric vehicles and e-bikes (as battery packs)
• DIY electronics and robotics
• Portable power tools