Fenix ARB-L21-5000U Rechargeable 21700 Battery
$26.95
The Fenix ARB‑L21‑5000U is a high-capacity 21700 rechargeable Li‑ion battery delivering 5,000 mAh of reliable power for high-drain flashlights and gear. Equipped with a built-in USB‑C charging port, you can recharge it quickly with common USB‑C cables—no separate charger required. Ideal for extended runtime and convenience.
Safety is front and center: it features comprehensive protection circuitry (overcharge, over-discharge, short-circuit, and overheat protection), as well as pressure relief vents for safe energy release. The button-top design ensures compatibility with a wide range of devices. Rated for 500 charge cycles, it maintains dependable performance over time.
Key Specifications:
A robust and convenient power solution—perfect for tactical flashlights, headlamps, outdoor gear, and emergency devices.
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.
Overall rating: 4.8040543 / 5 from 444 reviews.
The Fenix ARB-L21-5000U Rechargeable 21700 Battery offers high-capacity power with a 5,000 mAh capacity, USB-C charging, and comprehensive safety features. Customers praise its exceptional performance, long life, and quick charging. The product is well-regarded for its quality and value for money.
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"Original battery lasted years with continuous use , probably overused and far exceeded manufactures specifications. I’m sure its replacement will perform to the same standards."
"My flashlight recently stopped working after charging it overnight. I thought it was the battery so I bought a new one. It still didn't work and I'm confused because the flashlight worked perfectly fine before I charged it. I reached out to the company to inquire about this and got no response."
"Exactly what i thought i was getting. Took awhile to get but I was in no rush. Wanted OEM batteries to keep charged and on back up. Modern day flashlights are insanely powerful in small packages but at the highest setting they dont last long. Get get everything so its nice having back up batteries and these will do. USB charging with all the protection included. Don’t want to use cheap batteries in nice flashlights. Thats not nice to them , give your lights the fuel to run at 100%."
"Took some time to recieve but got it"
"This is perfect for my flashlight."
"I’m unclear about what I’m about to say, but it’s something that confuses me. The battery is 5000 mah, however when I charge it with a smart charger and it only charges up to ~4000 mah when it indicates “ FULL” I’d lov to hear an explanation of why that is."
"BEST BRAND EVER!"
"Always great products"
"I’ve bought at least ten different head lamps and twice as many batteries. They claim 500 charge cycles. The last ten batteries I’ve bought arrived completely drained. They don’t hold a charge. Customer service told me I wasn’t using the correct usb port. Lithium batteries should be stored at 60 percent capacity not dead. Very disappointed"
"Much needed extra battery."
