Fenix ARB-L21-4000P Rechargeable Battery

(3 customer reviews)


ARB-L21-4000P is a high-capacity 21700 Li-ion rechargeable battery built for longer runtimes at higher levels. These battery allows a high output flashlight like the LR35R to have its turbo setting of 10000 lumens to maintain it’s output by maintaining higher voltage for longer periods of a batteries charge.  Additional features include a protection circuit in the anode to help prevent short circuits, over charge/discharge and over heating. Pressure relief vents which expel waste gas in the rare case of an internal short circuit preventing an explosion. Battery capacity up to 4000mAh. 500 charging cycles. Important Note: THIS BATTERY IS NOT COMPATIBLE WITH 18650 FLASHLIGHTS OR OLDER STYLE CHARGERS. COMPATIBLE CHARGERS ARE THE ARE-A2ARE-A4ARE-D1 OR ARE-D2.

SKU: ARB-L21-4000P
EAN: 6942870307220
For commercial orders and large purchases, contact us at (888) 775-9996 x6, or
WARNING. Be aware of counterfeit Fenix merchandise in the U.S. marketplace.


Specifications of the ARB-L21-4000P Rechargeable Battery

  • 21700 battery type
  • 4000mAh high capacity
  • Protection circuitry to prevent short circuits
  • Pressure vents to prevent explosions
  • 500 charge cycles
  • Currently compatible with the HT18, LR35R, PD36R, PD40R V2.0, TK22 V2.0, TK22 UE, and TK30.

Capacity: 4000mAh
Voltage: 3.6V
Charging Current: Recommended 1A, maximum 4A
Maximum output current: 18A (less than 3 minutes)
Maximum continuous output current: 10A
Weight: 2.5 ounces (70g)
Size: Length: 2.99″ (76mm) Diameter: 0.85″ (21.5mm)
Warranty Period: 12 month from date of purchase

3 reviews for Fenix ARB-L21-4000P Rechargeable Battery

Based on 3 reviews
5 star
4 star
3 star
2 star
1 star
  1. Richard S. (verified owner)

    Great back up power.

    (0) (0)
  2. Will

    Is this a AA battery?

    (1) (4)
  3. Luke

    What is the difference between this and the arb-l21-5000?

    (4) (0)
    • Dianne (store manager)

      The 4000P is designed specifically for the higher settings and to maintain higher outputs more efficiently. Any of the batteries ending in a “P” are meant to be able to produce the higher power levels for a longer period of time.

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