The 18650 Lithium-Ion rechargeable battery is a standardized cylindrical cell measuring 18mm in diameter and 65mm in length (slightly longer with the button top). This specific variant features a raised positive terminal (Button Top), making it highly compatible with consumer electronics like heavy-duty flashlights, laser pointers, and specific battery enclosures that require a physical protrusion to establish electrical contact.

Specifications

• Form Factor: 18650 (Cylindrical)
• Terminal Type: Button Top (Raised positive contact)
• Chemistry: Lithium-ion (Li-ion)
• Nominal Voltage: 3.7V
• Fully Charged Voltage: 4.2V
• Discharge Cut-off Voltage: 2.5V - 2.75V

Features

• Button Top Compatibility: The protruding positive node ensures a firm connection in serial multi-cell configurations (where batteries are stacked end-to-end) and devices with mechanical reverse-polarity protection rings.
• Stable 3.7V Architecture: Delivers a flat discharge curve, meaning it maintains a relatively stable voltage output throughout the majority of its discharge cycle before dropping off near empty.
• High Energy Density: Packs a significant amount of power into a lightweight footprint compared to older NiCd or NiMH rechargeable chemistries.
• No Memory Effect: Can be topped off or partially recharged at any point without degrading the overall lifespan or capacity of the battery.

Common Applications

• High-Powered LED Flashlights: Standard power source for tactical, hunting, and outdoor headlamps.
• Portable Laser Pointers: Providing the high current required to drive intense visual laser diodes.
• DIY Power Banks: Drop-in replacements for portable power shells that feature built-in button-contact clips.
• Wireless Solar Security Cameras: Keeping outdoor security hardware running overnight on a daily solar-charge cycle.

Safety & Storage Guidelines

Lithium-ion batteries store a large amount of energy and must be handled with care:

• Dedicated Charger Required: Never charge these cells using a standard AA/AAA NiMH charger. They require a dedicated 3.7V Li-ion charger (utilizing a strict Constant Current/Constant Voltage profile) to prevent dangerous overcharging.
• Inspect the Wrap: The plastic insulation sleeve (shrink wrap) surrounding the battery is a safety barrier. If the wrap becomes torn, scratched, or peeled, stop using the battery immediately. A exposed metal casing acts as a giant negative terminal, creating a severe short-circuit and fire risk if it touches metal objects.
• Avoid Extreme Temperatures: Do not leave the battery inside hot vehicles or exposed to direct sunlight (>60℃). Never allow the battery to freeze.
• Loose Storage Warning: Never carry loose 18650 batteries in a pocket, bag, or drawer alongside keys, coins, or loose change. These metal objects can easily bridge the positive and negative ends, causing an immediate short circuit, thermal runaway, or explosion. Always store loose cells inside dedicated plastic battery cases.

Usage Recommendation

Note: These cells are recommended exclusively for hobbyist and experimental applications. For mission-critical, high-drain, or professional industrial use, we recommend using certified Tier-1 cells.