Fenix ​​Li-Ion Battery 21700 4000 MAH FE21700P40

Top-quality high-current rechargeable batteries Fenix 21700 4000 mAh (ARB-L21-4000P) with electronic protection (protected) are designed for a discharge current of up to 18 A. Li-ion rechargeable batteries are characterized by very high capacity, do not suffer from memory effect or self-discharge. 21700 Li-ion batteries are the best choice in terms of stored energy considering the dimensions and weight of the battery, they are gradually being used in the automotive industry, for example.

The protection of Fenix batteries consists of internal safety mechanisms and protective electronics. Added electronic circuits prevent overcharging, excessive discharge, as well as short circuit or excessive current draw. If the battery's electronics evaluate the attainment of limit values, it will safely disconnect the cell.

The internal protection consists of a separator, the most advanced overheating protection (PTC - Positive Temperature Coefficient), and a special explosion-proof valve. In the event that the gas pressure in the cell exceeds a certain threshold, the internal separator will separate the electrodes inside the battery, effectively interrupting the exothermic reaction, and the explosion-proof valve will release the excess gas pressure outside the battery. Thanks to the combination of electronic and mechanical (temperature and pressure) protection, Fenix batteries are among the safest available Li-ion batteries.

This battery is designed especially for use in the Fenix LR35R LED flashlight. However, it can also be used in Fenix flashlights HT18, PD36R, PD36 TAC, PD40R, TK20R V2.0, TK22 UE, E35 V3.0, and C7. However, it cannot be used in flashlights for 18650 batteries due to its larger dimensions!

Parameters of the Fenix 21700 4000mAh battery:
- Nominal voltage: 3.6 V
- Maximum charging current: 4 A
- Capacity: 4000 mAh, tested with a discharge current of 0.2 C with termination at a voltage of 2.5 V and a temperature of 25°C
- Maximum current draw: 18 A (max. for 3 minutes, continuously 10 A)
- Dimensions: 21.5 mm (diameter) x 76 mm (length) (+/- 0.5mm)
- Weight: 70 grams
- Protection against overcharging, complete discharge, and short circuit (>18 A). The protective circuit is attached to the positive pole.
- Lifespan of over 500 charge cycles
- Recommended operating temperatures: 0-45°C (charging), -20 to +60°C (discharging)
- Packaging includes: one piece of Fenix 21700 4000mAh battery (ARB-L21-4000P).

Recommended chargers:
Due to the length of the battery being 76 millimeters (including protective electronics), it can only be charged in chargers adapted to this length, listed below. It will not fit in other models.

- Fenix ARE-A2 charger
- USB charger Fenix ARE-D1
- USB charger Fenix ARE-D2
- Fenix ARE-A4 charger
- USB charger FC2
- USB charger SC1
- Eight-channel USB charger VC8