Fenix Full Battery Product Line Specifications
Fenix 18650 batteries are new and improved with new names!
Fenix has updated their naming protocol to keep things consistent and easy to understand across all battery types! All batteries will have a three-part name, each section separated by a hyphen. All batteries will begin with the prefix "ARB." This can be thought of as the name of the product line, the ARB Series Batteries. The second section will denote what type of battery it is. It will always start with an L and will have two numbers after the L which are the first two numbers in the battery type. For example, an ARB-L18 battery is an 18650 battery. Fenix also has ARB-L14, ARB-L16, and ARB-L21 which are 14500 batteries, 16340 batteries, and 21700 batteries, respectively. Lastly the name of the battery will end with the milliamp capacity (mAh) of the battery. The milliamp level is a rating on how much energy the battery can hold. Now let's put this into practice! What is an ARB-L18-3500? It is a Fenix brand 3500mAh 18650 battery. What is the ARB-L21-5000? It is a Fenix brand 5000mAh 21700 battery.
The last thing to remember is that some batteries will feature an additional letter at the end of the mAh number like a U or a P, or sometimes both! The U means that the battery has a built-in USB port for direct charging and the P means it is the "Plus" version of that battery. Plus versions are rare, but they are slightly different than the regular versions and may allow for longer runtimes or higher brightness outputs in some flashlights. So the ARB-L16-700UP that comes with the Fenix E18R flashlight is a 700mAh Fenix 16340 battery that features a USB port and is a Plus version, which is what allows the E18R to get the great output that it does!
Beyond just the names of the Fenix brand batteries you have the names of the batteries themselves. Why are they called these strange numerical names? Well, the names actually have a meaning behind them. The first two numbers indicate the diameter of the battery and the 3 numbers after that indicate the length of the battery, both measured in millimeters. So an 18650 battery is 18mm in diameter and 650mm long. It's as simple as that!
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The following information is outdated. Please see the above information for current model names.
Fenix has renamed many of their battery products to assist with identification of the battery type. Below is the new product names as well as the battery capacity of each one. Fenix batteries are buttonless, which results in a high-quality battery able to withstand impact created from drops or internal spring mechanisms inside of devices. Fenix protected batteries are the top-of-the-line in the industry. Don't cut corners when selecting batteries to operate your devices.