Fenix ​​21700 5000 MAH Li-ion battery

Fenix 21700 5000mAh rechargeable battery (ARB-L21-5000U) with its own USB-C charging connector. It can be charged by connecting a cable to the USB-C connector (e.g. from a computer, power bank, or mobile phone charger) as well as in a traditional Li-ion charger. Fenix 21700 5000mAh rechargeable batteries with electronic protection (protected) are based on advanced LiNiCoO2 technology, which provides higher safety and longer lifespan. Li-ion rechargeable batteries have a very high capacity, do not suffer from memory effect or self-discharge. Li-ion batteries in 21700 size are the best choice in terms of stored energy considering the dimensions and weight of the battery, gradually gaining popularity in industries such as automotive.

The protection of Fenix batteries consists of internal safety mechanisms and protective electronics. The added electronic circuits prevent overcharging, excessive discharging, and protect against short circuit or excessive current draw. If the battery's electronics evaluate the limit values being reached, it will safely disconnect the cell.

The internal protection consists of a separator, the most advanced protection against overheating (PTC - Positive Temperature Coefficient), and a special explosion-proof vent. In case the gas pressure in the cell exceeds a certain limit, the internal separator separates the electrodes inside the battery, effectively interrupting the exothermic reaction, and the explosion-proof vent releases the excess gas pressure out of the battery. Thanks to the combination of electronic and mechanical (temperature and pressure) protection, the Fenix battery is one of the safest available Li-ion batteries.

This battery is intended for use, for example, in Fenix LED flashlights HT18, PD36R, TK22 V2.0, TK22 UE, E35 V3.0. However, it cannot be used in flashlights for 18650 batteries because of its larger dimensions!

Due to the length of the battery being 76 millimeters (including protective electronics), it can only be charged in chargers that are designed for this length. See recommended chargers below.

Specifications of Fenix 21700 5000mAh USB battery:
- Nominal voltage: 3.6V
- Capacity: 5000mAh, tested with a discharge current of 0.2C ending at a voltage of 2.5V and temperature of 25 °C
- Maximum current draw: 8A
- Maximum charging current: 5A
- Charging current of the built-in USB-C connector: 2A. Charging time is approximately 3-4 hours.
- Dimensions: 21.5mm (diameter) x 76mm (length) (+/- 0.5mm)
- Weight: 72.5 grams
- Protection against overcharging, complete discharge, and short circuit (>8A). Protective circuit attached to the positive pole.
- Lifespan of more than 500 charging cycles
- Recommended operational temperatures: 0-45 °C (charging), -20 to +60 °C (discharging)
- Package includes: one piece of Fenix 21700 5000mAh USB battery (ARB-L21-5000U)
- Charging cable is not included. If needed, a basic USB-C cable or a colored USB-C cable can be purchased, or a micro-USB to USB-C adapter can be used.