Rechargeable battery Fenix 21700 5000 mAh (ARB-L21-5000U) with its own USB-C charging connector. You can charge it by connecting a cable to the USB-C connector (for example from a computer, power bank or mobile phone charger) or in a conventional Li-ion charger. Fenix 21700 5000 mAh rechargeable batteries (ARB-L21-5000U) with protective electronics (protected) are based on cutting-edge LiNiCoO2 technology, which provides higher safety and also longer lifespan. Li-ion rechargeable batteries are characterised by very high capacity, do not suffer from memory effect and have no self-discharge. Li-ion in 21700 size are the best choice in terms of stored energy relative to the dimensions and weight of the battery, and are gradually becoming established for example in the automotive industry.

Protection of Fenix batteries consists of internal safety mechanisms and protective electronics. Added electronic circuits prevent overcharging of the cell, excessive discharge and also short circuit or excessively high current draw. If the battery electronics evaluate that limit values have been reached, they safely disconnect the cell. Internal protection consists of a separator, the most modern protection against overheating (PTC - Positive Temperature Coefficient) and a special anti-explosion valve. In the event that the gas pressure in the cell exceeds a certain threshold, the internal separator separates the electrodes inside the battery and thereby effectively interrupts the exothermic reaction and the anti-explosion valve releases excess gas pressure outside the battery. Thanks to the combination of electronic and mechanical (thermal and pressure) protection, Fenix batteries are among the safest available Li-ion batteries.

This battery is intended for example for use in Fenix LED torch PD36R, TK22 V2.0 or TK22UE. However, it cannot be used in torches for 18650 batteries due to its larger dimensions. Due to the battery length of 76 millimetres (including protective electronics), it can only be charged in chargers that are adapted for this length. See recommended chargers below.

Specifications of Fenix 21700 5000mAh USB battery

• Nominal voltage: 3.6 V Capacity: 5000 mAh, tested with discharge current 0.2 C with termination at voltage 2.5 V and temperature 25°C
• Maximum current draw: 8 A
• Maximum charging current: 5 A Charging current of built-in USB-C connector 2A.
• Charging time approximately 3-4 hours. Dimensions: 21.5 mm (diameter) x 76 mm (length) (+/- 0.5mm) Weight 72.5 grams
• Protection against overcharging, complete discharge and short circuit (>8A). Protective circuit is attached to the positive pole.
• Lifespan more than 500 charging cycles
• Recommended operating temperature: 0-45°C (charging), -20 to +60°C (discharge)

Package contents:

• one piece of Fenix 21700 5000mAh USB battery (ARB-L21-5000U)
• Charging cable is not included in the package.

Charging via USB-C connector
Connect a USB cable to the side USB-C connector, during charging the indicator light at the positive pole of the battery lights red. Once fully charged it lights blue. Recommended chargers Fenix ARE-A2 charger Fenix USB charger ARE-D1 Fenix USB charger ARE-D2 Fenix ARE-A4 charger SC1 USB charger Warning If possible do not discharge the battery below 2.5 V Do not short circuit the battery (do not connect the cell poles with a conductor) Do not throw the battery into fire or water Never insert the battery into a charger in reverse (with opposite polarity) When using the battery follow safety principles Use only an adequate charger supporting Li-ion batteries

Warranty
Two-year warranty.

We offer a 30-day period for returning or exchanging goods if, for any reason, you are not satisfied with your order.

For more information, please see our Return Policy here.

Orders received by 14:00 are dispatched the same day. Delivery usually takes place on the next business day, depending on the selected shipping method. During busy periods, please allow 1–3 business days for order processing.

Free delivery from €200 / for oversized shipments from €400

Free of charge, ready for pickup on the next business day

For more information, please see our Delivery page.