i buy battery because i
"i buy battery because i have a flash light TK20R and i replace battery and still no work what i can do"
SIGN UP FOR EMAILS and get 10% OFF your first purchase • MILITARY/FIRST RESPONDER DISCOUNTS available at checkout • FREE SHIPPING on purchases over $25 
More Information
Specifications of the ARB-L21-5000U Rechargeable Battery
- 5000mAh high capacity
- USB Type-C rechargeable battery (charging cord NOT included)
- Protection circuitry to prevent short circuits
- Pressure vents to prevent explosions
- 500 charge cycles
- Indicator light on battery is red while charging, blue when charged
- Compatible with all lights using a 21700 size battery.
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
*Battery does NOT include charging cord.
Overall rating: 4.816547 / 5 from 278 reviews.
AI Generated Review Summary
The Fenix ARB-L21-5000U Rechargeable Battery offers high capacity, long life, and good quality at a reasonable price. Customers appreciate its USB-C charging port and built-in protection features, though it is not compatible with 18650 flashlights or older chargers.
Summary topics
- Customer Service: 4%
- Battery Life: 4%
- Product Quality: 5%
Review topics: ["quality","light","service","issues","design","battery","charger","works","power","customer service","replacement","price","cord","use","flashlight","life","lasts","runs","fenix","feature","holds","headlamp","chance","usb","recharge","friend"].
Review highlights
- "Excellent service very fast process and the product is of excellent quality." —
- "Good quality battery at a very good price." —
- "Charges quick and nice long life." —
Reviews
Long lasting light
"Was my trusted light when cycling in a far away country. Lasted from before dawn to mid day."
5000u battery
"Great battery, has charging capability built in."
My second set of these
"My second set of these 5000mAh batteries, now upgraded for direct charging. the first set worked for more than 5 years before the charge started to dwindle. A great value with no headaches."
Built in charging is THE BEST!
"I absolutely love these batteries for the convenience of built in charging (no extra charger needed) and the power they offer in a flashlight. Because of these features, they are my favorite flashlight battery. This purchase is a gift for a relative (along with a TK16 flashlight), because my original two batteries I bought with my TK16 and use daily are still going strong, no need to replace them. Highly recommended!!"
Fenix TK16 V2 another super light!
"One of my favorite lights and batteries. I bought the TK16 V2 for someone as a gift, taking advantage of their Black Friday deals (bought a different one for M-I-L), I have a TK16 and quite a few other lights and batteries from Fenix. Best products and have had no problems with any of them!"
Rechargeable battery
"Awesome. Thank you"
Having to charge the battery
"Having to charge the battery is a tiny bit cumbersome but the power is great"
Best light and batteries I've
"Best light and batteries I've ever had. My head lights went out on my 4 wheeler while deer hunting I just turned my Fenix head light to high beam and kept driving. . . plenty of light to drive through the woods to my stand location. Thanks!! Fenix"
Great Customer Service
"I had an issue with the delivery. Customer Service quickly remediated! Thank you!"