Fenix 21700 Rechargeable Battery 6000mAh 21.6Wh Now in Stock

Key Takeaways

1. Fenix has launched new 21700 batteries with 21.6 Wh (6,000 mAh at 3.6 volts), SKU “ARB-L21-6000.”
2. A USB Type-C version of the 21700 batteries is planned for the future, but it is not yet available.
3. The new batteries maintain 75% capacity after 500 charge cycles, weigh 2.8 oz, and have dimensions of 0.87 x 3.02 inches.
4. The ARB-L21-6000 batteries are compatible with several Fenix flashlights, but users should check device measurements before use.
5. Priced at $24.95 each, the new batteries are comparable in price to Fenix’s earlier 5000mAh variant, entering the market later than competitors like Nitecore.

At IWA 2025 in Germany, Fenix has announced that their new 21700 batteries, offering 21.6 Wh (6,000 mAh at 3.6 volts), are officially on the market. These cylindrical batteries, recognized by the SKU “ARB-L21-6000,” follow the earlier release of their 18650 batteries, which provided 14.4Wh/4,000 mAh and have been around for a while now.

Battery Variants and Features

The previous 18650 batteries come in two types; one has an integrated USB Type-C port, while the other does not. However, this option isn’t available for the new batteries. In a conversation with Notebookcheck, Fenix confirmed that a USB-C version of the 21700 batteries is in the works. They also mentioned that this upcoming version would be a bit longer due to the necessary USB charging components. Other than that, the two batteries are the same.

Specifications and Compatibility

The official specifications indicate that the battery will maintain 75% of its initial capacity after 500 charge cycles. It weighs 2.8 oz and has dimensions of 0.87 x 3.02 inches, making it slightly bulkier than the brand’s 5000 series, which measures 0.85 inches in diameter. Fenix claims that the ARB-L21-6000 is compatible with several flashlights, including the Fenix TK22R, Fenix HT18R, Fenix HT32, Fenix PD40R V3.0, Fenix PD36R V2.0, and LD45R. It is advisable to take precise measurements before using these batteries in other devices.

Market Position and Pricing

Until recently, Fenix was only selling 21700 batteries with 18 Wh or lower capacity. As a result, they are somewhat late to enter the 21700 battery market, especially when compared to rivals like Nitecore. For instance, the competing NL2160 battery has been on sale since late January 2024.

Nonetheless, the new lithium-ion batteries are now available for purchase at $24.95 each from Fenix’s official online store. Interestingly, this pricing matches that of the previously mentioned 5000mAh variant with 18 Wh.