Fenix ARB-L21-5000 Rechargeable Battery

(37 customer reviews)
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ARB-L21-5000 is a high-capacity 21700 Li-ion rechargeable battery built for more power and longer runtimes. 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 5000mAh. 500 charging cycles. Currently recommended for the HT18, PD36R, TK22 V2.0, and TK22 UE.  The TK22 V2.0 and TK22UE require a charger to charge the battery. 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-L21-5000 Category:
Your discount is limited to 3 per SKU and a total of 7 items per year. For large quantity purchases, contact our Agency Sales Division at (888) 775-9996 x6


  • New 21700 battery type
  • 5000mAh high capacity
  • Protection circuitry to prevent short circuits
  • Pressure vents to prevent explosions
  • 500 charge cycles
  • Currently recommended for the PD36R, TK22 V2.0, and TK22 UE.

Capacity: 5000mAh
Voltage: 3.6V
Charging Current: Recommended 1A, maximum 5A
Weight: 2.6 ounces (72.5g)
Size: Length: 2.99″ (76mm) Diameter: 0.85″ (21.5mm)
Warranty Period: 12 month from date of purchase

37 reviews for Fenix ARB-L21-5000 Rechargeable Battery

  1. Kevan Western (verified owner)

    Good battery life

  2. David Phillips (verified owner)

    good to have a back up

  3. John P. (verified owner)

    Huge capacity. Works excellent and lasts a long time.

  4. Anonymous (verified owner)


  5. Brendan (verified owner)

    Charged up very nicely, will be interested to see how long it holds a charge.

  6. Frederick (verified owner)

    I’ve had great success in ordering from Fenix. They’re really on the ball. This is my second order of the same flashlight and battery as I was so pleased with the first order. I love the TK22 UE and the rechargeable battery as well. Thank you Fenix!

  7. Paul W. (verified owner)

    This thing is a beast. I haven’t used this one yet, I purchased it as a spare, and the one that came with the light is still going strong on the initial charge.

  8. Jose Salazar (verified owner)

    Two of the earliest batteries got distorted. Left in car and maybe that was the problem. Those were 18650 batteries. Hope these new batteries will prove to be better.

  9. Anonymous (verified owner)

    crazy long battery life

  10. Richard (verified owner)

    Bought this for a spare. Didn’t really have to because with the extra capacity they last a looooooooong time.

  11. Michael D. (verified owner)

    This battery lasts a seriously long time. Great value.

  12. Jason (verified owner)

    Already have the lamp which I love, battery packs alot of long lasting power

  13. Makenzi Hill (verified owner)

    Ordered additional batteries for my husbands flashlight near our wedding in November last year. The batteries now no longer charge or work. We have 1 working battery that the charger does read so we know it’s not the charger. Very disappointed in the battery life for such an expensive battery. Less than 6 months is ridiculous.

    • Dianne

      I will have warranty contact you.

  14. Martin A. (verified owner)

    Been using fenix batteries for years with no issues.

  15. Robert (verified owner)

    Good battery a little overpriced.

  16. Gary L. (verified owner)

    Have not used them a lot yet, should work very well, I plan to use them as back ups when long usage is needed.

  17. Joe G. (verified owner)

    All Fenix products are top of the line

  18. Bill M. (verified owner)

    Always like a back up battery just in case. The cost is minimal when ordering and can’t knock the convenience of ordering both at the same time.

  19. Ronald (verified owner)

    Good battery

  20. Robert (verified owner)

    Very high energy storage capacity in a small volume.

  21. Dan (verified owner)

    Great powerful battery! Will be buying a couple more for spares and future flashlights.

  22. William Naus (verified owner)

    Great service…third time buying and will buy again

  23. Theron T. (verified owner)

    Great battery, just wish it was a little cheaper.

  24. leonard m. (verified owner)

    Terrific power source long lasting.

  25. Ron (verified owner)

    Long lasting and powerful battery!!!

  26. leonard (verified owner)

    Great power supply long lasting!

  27. robert jolliff (verified owner)

    excellent, high capacity!

  28. James Fitzsimmons (verified owner)

    Good capacity battery

  29. Michael (verified owner)

    Light and powerful!

  30. Doug F. (verified owner)

    Lasts a long time

  31. Eric (verified owner)

    Great capacity in my new flashlight. Had it and use it daily, still charged after 2 weeks of morning and evening use.

  32. Murad (verified owner)

    Quality battery you’d expect from fenix

  33. Brandon Lambert (verified owner)

    Great battery

  34. Rich (verified owner)

    Took 3 hours to fully charge the battery, have not charged it so far. I use it on a daily basis and the PD36R shines through the darkness. Very good purchase.

  35. Ronald Makarewicz (verified owner)


  36. John E. (verified owner)

    Always good to have a spare battery. A real powerhouse at 5000 mAh. Charged pretty quickly using the usb-c of the PD36R.

  37. Todd R. (verified owner)

    Great product

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