The Fenix ARB‑L18‑3500 is a high-capacity 18650 rechargeable Li‑ion battery, offering 3,500 mAh within a standard size that fits most high-performance flashlights. Built for safety and durability, it includes a button-top design, integrated protection circuitry against overcharge, over-discharge, short-circuit, and overheating, plus pressure relief vents to prevent buildup and reduce risk of swelling or rupture. A robust steel-infused anode structure further improves impact resistance and electrical safety. This cell is rated for up to 500 charge cycles, maintaining around 75% capacity afterward, and carries Fenix’s 12-month warranty.
Key Specifications:
A reliable, long-lasting, and safe power solution—perfect for tactical flashlights, headlamps, lanterns, and high-drain devices.
Note: This item is packaged and priced as one battery.
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: 4.863768 / 5 from 345 reviews.
The Fenix ARB-L18-3500U USB Rechargeable Li-ion 18650 Battery offers a high capacity of 3,500 mAh, providing reliable power for tactical flashlights and high-drain devices. Customers praised its durability, long-lasting performance, and excellent customer service. The built-in USB charging port adds convenience, and the battery is backed by a 12-month warranty.
Review topics: [].
"top quality batteries, longnlasting, excellent customer service"
"Love my Fenix lights"
"love the fenix equiptment! i am constantly showing co-workers and friends my lights and set up for charging. If fenix keeps the great quality going on in the future i will never be buying another brand of flashlight! I own multiple flashlights batteries and chargers!"
"Been using my TK35UE V2. 0 for a couple months. Great light. I carry and use it every day, all day. I used my TK35UE for 7 years until it quit and I replaced it with this one. It's definitely an upgrade from my original TK35. The spot focus gives good distance light while the fill light gives great area coverage."
"Excellent battery and excellent customer service."
"I have 2 for charging my headlamp for home auto mechanics, but one lasts 6 hours."
"The construction of the product is great at first glance. The feature to charge the batteries inside my TK11R and outside the light is great. I haven't had a chance to experience the battery strength over time to see how the battery will hold up, so that's why not giving five starts yet."
"I would dock it 1/2 star because battery lasted 3 years. But it may be the reasonable lifetime for the battery. Thanks."
"I keep one extra charged at all times , great battery."
"I have always had great results with Fenix brand batteries. This one was no exception."
