A rechargeable Fenix 21700 Li-ion battery with 4000mAh capacity, predominantly orange with black text and detailing.
The back side of the Fenix ARB-L21-4000 Rechargeable 21700 Battery
Fenix ARB-L21-4000 Rechargeable 21700 Battery standing up
Fenix ARB-L21-4000 Rechargeable 21700 Battery viewed from the bottom
A rechargeable Fenix 21700 Li-ion battery with 4000mAh capacity, predominantly orange with black text and detailing.
The back side of the Fenix ARB-L21-4000 Rechargeable 21700 Battery
Fenix ARB-L21-4000 Rechargeable 21700 Battery standing up
Fenix ARB-L21-4000 Rechargeable 21700 Battery viewed from the bottom

Fenix ARB-L21-4000P Rechargeable 21700 Battery

$27.95
/
Shipping calculated at checkout.
  • Free shipping for orders over $25
  • Satisfaction guaranteed
  • Earn reward points - get discounts!
  • Backed by the Fenix Limited Lifetime Warranty
  • In stock, ready to ship
  • Inventory on the way

This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.

compatible accessories

The ARB-L21-4000P battery supports large current output making it ideal for powering lights and other items that are operated at higher power loads. The maximum current for the ARB-L21-4000P is 18A, with a continuous output current of 10A. The higher current allows the 21700 battery longer runtimes at higher levels in flashlights. As with all Fenix rechargeable batteries, the 21700 4000 mAH has three sets of overheat protection, including pressure relief, microporous, and PTC cathodal block. The pressure relief vents all gas to be expelled; this prevents secondary hazards.

Shipping Note: Lithium ion batteries are considered "dangerous goods" per US transportation regulations and can often only be transported via ground shipment. Orders containing loose batteries will typically take much longer than predicted to be delivered. Delivery times of 14+ days are not uncommon.  

Details

  • Type - ARB-L21-4000P
  • Size - 21700
  • Capacity - 4000mAh
  • Voltage - 3.6V
  • Charging Current 1A Recommended, 4A Maximum
  • Max Output Current - 18A (Less than 3 Minutes)
  • Max Continuous Current - 10A
  • Weight - 2.47 Ounces
  • Dimensions - 2.99" Height x 0.85" Diameter
  • Warranty - 12 Months Free warranty from date of purchase
  • Compatible with lights like the LR35R, PD36R, PD40R, TK22v2, TK22UE, and E35v3

THIS BATTERY IS NOT AN 18650, AND IT IS NOT COMPATIBLE WITH 18650 FLASHLIGHTS OR OLDER STYLE CHARGERS. COMPATIBLE CHARGERS ARE THE ARE-A2, ARE-A4, ARE-D1 OR ARE-D2.

  • Fenix ARB-L21-4000P (Qty 1)
Back to 21700

Overall rating: 5.0 / 5 from 27 reviews.

AI Generated Review Summary

Summary topics

Review topics: [].

Review highlights

Reviews

Fenox Battery

"Good quality battery"

— David N. (5/5)

Fast shipping

"Fast charging"

— Kai B. (5/5)

Too long delivery time & tracking not accurate

"Ordered batteries for my light October 10th & didnt recieve them unti October 28th. According to tracking they were supposed to be here by October 18th. I had to buy a new light because I was leaving for a trip Oct. 30th & had to have a light & couldnt take the chance on the batteries I ordered."

— Bradley B. (5/5)

Batteries

"The batteries took some time to charge up but they worked fine"

— joe A. (5/5)

Fenix Rechargeable 21700 Li-ion Battery - 4000mAh

"My flashlight would run out of charge too quick. Brought these batteries and it's charging fine. Just wish they just were a little cheaper."

— Denise R. (5/5)

Flashlight battery

"Fits well, good price, goid shipping"

— Douglas M. (5/5)

Thanks

"Thanks"

— Sukhwinder S. (5/5)

Battery lasts a long time,

"Battery lasts a long time, I am surprised"

— Paul D. (5/5)

Spare

"Haven’t used it yet"

— Robert M. (5/5)

Holds charge. Can't go wrong

"Holds charge. Can't go wrong with an extra battery"

— Amildo C. (5/5)

Q&A