FENIX 21700 4000 mAh (Li-Ion) - rechargeable batteries

The Fenix 21700 4000 mAh high-current rechargeable batteries (ARB-L21-4000P) with electronics protection (protected) are designed for discharge current up to 18 A. Li-ion rechargeable batteries are characterized by very high capacity, do not suffer from memory effect or self-discharge. Li-ion in the size 21700 are the best choice in terms of stored energy due to the size and weight of the battery, and are gradually gaining ground, for example in the automotive industry.

Fenix battery protection consists of internal safety mechanisms and protective electronics. Added electronic circuits prevent the cell from overcharging, over-discharging and against short-circuiting or excessive current draw. If the battery electronics assess that the limits have been reached, they safely disconnect the cell.

Internal protection consists of a separator, state-of-the-art Positive Temperature Coefficient (PTC) overheat protection and a special anti-blast valve. In the event that the gas pressure in the cell exceeds a certain limit, the internal separator separates the electrodes inside the battery and thus de-facto interrupts the exothermic reaction and the anti-blast valve releases the excess gas pressure outside the battery. The combination of electronic and mechanical (temperature and pressure) protection makes Fenix batteries among the safest Li-ion batteries available.

This battery is designed specifically for use in the Fenix LR35R LED flashlight. It can also be used in flashlights such as the Fenix HT18, PD36R, TK22 V2.0, TK22 UE, E35 V3.0. However, it cannot be used in 18650 battery flashlights due to its larger size!

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

Fenix 21700 4000mAh Battery Specifications

• Nominal voltage : 3.6V
• Capacity : 4000 mAh, tested at 0.2 C discharge current with termination at 2.5 V and 25°C
• Maximum current draw : 18 A (max. for 3 minutes, 10 A for long periods)
• Maximum charging current: 4 A
• Dimensions: 21.5mm (diameter) x 76mm (length) (+/- 0.5mm)
• Weight 70 grams
• Overcharge, full discharge and short circuit protection (>18 A). Protective circuit attached to the plus pole.
• Lifetime of more than 500 charge cycles
• Recommended operating temperatures: 0-45°C (charging), -20 to +60°C (discharging)

Recommended chargers

Due to the 76 millimetre length of the battery (including the protective electronics), it can only be charged in chargers that are designed for this length and are listed below. It will not fit in other models.

Fenix ARE-A2 charger
Fenix ARE-D1 USB charger
Fenix ARE-D2 USB charger
Fenix ARE-A4 charger
Sc2 USB charger
Sc1 USB charger

Caution
Do not discharge the battery below 2,5V
Do not short-circuit the battery (do not connect the cell poles with a wire)
Do not throw the battery into fire or water
Do not insert the battery into the charger in reverse (opposite polarities)
When using the battery, observe safety guidelines
Use only an adequate charger that supports Li-ion batteries