Rechargeable 18650 Li‑Ion battery Fenix ARB-L18-3500U 3500 mAh

Fenix ARB-L18-3500U is a rechargeable 18650 lithium‑ion battery with a nominal capacity of 3500 mAh. Designed for devices that accept standard 18650 cells, this battery provides extended runtime and stable voltage suitable for demanding portable equipment such as flashlights, headlamps and other handheld electronics. The cell follows common lithium‑ion charging and discharge characteristics and is intended for repeated recharge cycles.

Advantages

The battery delivers high energy density in the 18650 form factor, offering long runtime compared with lower‑capacity cells. Its rechargeable lithium‑ion chemistry supports multiple charge/discharge cycles while maintaining consistent output voltage under typical loads. The cell fits most devices designed for 18650 batteries and enables straightforward replacement or capacity upgrade. Built with standard safety features of consumer li‑ion cells, it is compatible with widely available chargers that support 18650 chemistry and voltage.

Suitable for

• Flashlights and tactical lights that accept 18650 cells
• Headlamps and worn lighting for outdoor activities
• Portable power banks and DIY battery packs using 18650 cells
• Handheld electronic tools and devices with 18650 compatibility

Key specifications

• Cell type: Rechargeable lithium‑ion (18650 form factor)
• Nominal capacity: 3500 mAh
• Typical voltage: 3.6–3.7 V nominal
• Form factor: 18 mm diameter × 65 mm length (standard 18650 size)
• Rechargeable: Yes — designed for repeated charge/discharge cycles
• Intended use: High‑capacity power source for consumer and professional portable devices

How to use

Insert the battery into any compatible device following the device’s polarity markings. Use a charger designed for 18650 lithium‑ion cells and observe the charger manufacturer’s instructions for charging current and termination method. Do not attempt to force the cell into devices that do not accept 18650 dimensions. Allow the battery to cool if it becomes warm during use or charging and avoid deep discharge below the device’s recommended cutoff voltage to prolong cycle life.

Usage recommendations

Store and transport the battery in a cool, dry place and avoid exposure to extreme temperatures. Charge the cell with a charger that supports lithium‑ion chemistry and recommended charge rates. Inspect cells regularly for damage and discontinue use if the cell shows swelling, leakage, or other signs of failure. Follow local regulations for disposal or recycling of lithium‑ion batteries.