Li-ion Battery 3.7V 18650 Rechargeable Cells

An 18650 battery is a widely used, cylindrical lithium-ion rechargeable cell. The name simply describes its physical dimensions: it is roughly 18mm in diameter and 65mm in length (the "0" indicates a cylindrical shape). They are known for packing a high energy density into a compact size and are the standard power source for everything from laptops and LED flashlights to DIY battery packs and electric vehicles.

Here are the standard technical specifications for most 18650 cells:

• Nominal Voltage: Usually 3.6V or 3.7V (this is the average voltage during a typical discharge).

• Maximum Charge Voltage: 4.2V (the cell's voltage when it is 100% fully charged).

• Discharge Cut-off Voltage: Typically 2.5V to 3.0V. Discharging the battery below this point can cause permanent damage, which is why many devices use a battery management system (BMS).

• Capacity: Genuine cells typically range from 1500mAh to 3500mAh. Any 18650 battery claiming a capacity significantly higher than 3600mAh (such as 5000mAh) is almost certainly counterfeit or overstating its capabilities.

• Continuous Discharge Current (CDR): This measures how much current the battery can safely supply without overheating. High-capacity cells may only offer 5A to 8A, while specialized "high-drain" cells can deliver 20A to 30A for power tools or demanding devices.

• Cycle Life: Quality cells are usually rated for 300 to 500 full charge cycles before their capacity permanently drops to about 80% of its original rating.