Fenix’s BC21R headlight has been one of Fenix’s most popular bike lights thanks to its removable battery design. With the new BC21R V3, Fenix has not only made the light brighter but it is also more visually attractive. The light retains its $74.95 retail price but has an updated 1200 lumen output from a single Luminus LED. As with other Fenix products, the BC21R V3 has a removable 18650 Li-ion battery, a rare feature for bike lights. Despite the removable battery design and spring loaded tail cap the light retains an IP68 rating and has a USB-C charging port. The light also uses similar housing design and all metal housing as the recent BC26R light with backlit power button.

The Fenix BC21R V3 offers a more premium metal design and brighter 1200 lumen output than previous versions.

Retail Price$74.95
Rating9.0 / 10
Weight (in g)156 (headlamp), 28 (mount)
Likes+ Replaceable battery 18650 lithium ion battery
+ Intuitive user interface and battery indicator
+ Premium looking and feeling metal housing
Dislikes– Proprietary mount (although you can use ALD-10 adapter to GoPro mounts)
– Only has a night time flash mode (alternates between low-high intensity)
– Lacks the dual beam lens of the previous version
Where to Buy (US)Fenix


The Fenix BC21R V3 comes in a compact transparent plastic box with specs printed directly onto it. Inside the box you’ll find:

  • BC21R V3 headlight
  • Handlebar mount + rubber spacer
  • USB-C charging cable
  • Instruction manual
  • Warranty card

With most brands moving toward environmentally friendly and recyclable packaging it’s a bit unusual to see so much plastic packaging.


As with the previous version of the BC21R, the V3 uses Fenix’s proprietary quick-release tab mount design that simply slides in. The plastic mount is built directly into the base of the light and is a basic rectangular design that slides into a corresponding slot. Fenix includes their pivoting camlock style mount with the light that can be used on various handlebars. A large thumbscrew at the end locks the cam in place and holds the light securely. The mount even has about 30 degrees of rotation side-to-side with indexed positions to allow you to fine tune the beam position. Although it’s not as nice as a standard Garmin mount the cam style is easy to use and doesn’t require any tools. Fenix also offers the ALD-10 mount accessory to attach the light to GoPro for sleeker mounting under out-front mounts like the Topeak UTF mount.

Fenix BC21R V3 LED Bike Headlight Review - Side View
Fenix offers the optional ALD-10 adapter that allows the BC21R V3 to be mounted onto GoPro mounts for optimal placement.


Having recently reviewed the Fenix BC26R it’s easy to see the resemblance with the updated Fenix BC21R V3. Both lights have a premium dark gray finish and all metal cylindrical housing. Heat fins are cut directly into the housing to help with thermal cooling and add some visual styling. The lights are nearly identical in design aside from side cutouts and indentations on the BC26R. Compared to the partially plastic design of the BC21R V2, the latest V3 version looks and feels more premium. Branding is limited to Fenix and BC21R printed on the sides of the light. The USB-C charging port is on the bottom of the light in front of the mount with a tight fitting rubber cover to protect it from the elements.

The light has a single Luminus SST-40 LED with a non directional beam inset into the housing. Unlike the V2 version of the light which had a “dual beam” lens design (simple vertical deflectors to reduce glare), the V3 has a non-directional beam. Although this means the light does have more glare, it is not a StVZO light like the Lupine SL AF 4 which have proper beam cutoffs, it does mean you can mount the light upside down without an issue.  On the rear of the light is a spring loaded twist on tail cap which holds the 18650 battery securely in place. Fenix includes their own 2600 mAh 18650 battery with the light, but you can swap it out with any comparable quality battery. Despite the removable battery design, the BC21R V3 still has an impressive IP68 rating.

Fenix BC21R V3 LED Bike Headlight Review - 18650 Li-on Battery
One of the best features of the headlight is the removable 18650 Li-ion battery that is held in place with a spring tail cap.

In terms of user interface, the Fenix BC21R V3 has a simple one-button with an illuminated metal button on top. The light has a two level interface with a single flash mode separated from four constant modes. Holding the button powers the light on or off, while a double press switches between the flash mode and constant modes. A short press will cycle through the four available constant modes. As with the Magicshine lights, the color of the button indicates the battery status (green / red / flashing red) and will even illuminate when pressed with the light off to allow you to quickly check the battery status. It’s a simple but effective design that makes it easier to stay on top of the battery status.


Fenix has incorporated five different output modes into the BC21R V3. There are four constant modes and a single flash mode that all operate the single LED. The constant modes vary from 50 to the full 1200 lumen output with claimed runtimes of 33 to 2.2 hours. There are large jumps in the lumen output for the constant modes which makes it easy to determine which mode you’re in. The only flash mode is a night time style flash with 400 lumen output which alternates between low to a high mode and does not have a published runtime. Although we would have preferred a more traditional on/off flash that would be more visible during daytime use, the flash mode can still be used during the day.

We found the Fenix BC21R V3 to be effective for both day and night time riding. The simple round beam doesn’t have any cutoff but has a uniform spread and good distance to see what’s ahead of you. The low 50 lumen mode is good for urban settings if you just need to be seen, while the high and turbo modes are better suited for dark trails. With flash mode separated from the constant modes, you also don’t have to worry about accidentally triggered flash while changing the light intensity. The main downside with the light is the lack of side visibility, as the lens is recessed into the housing with no side cutouts.

Fenix BC21R V3 LED Bike Headlight Review - LED Lens
Unlike the previous BC21R V2, the V3 uses a single LED with a non-directional lens.


Overall, we found the Fenix BC21R V3 to be a brighter and more visually attractive iteration of the BC21R light. With its 1200 lumen output, the BC21R V3 is bright enough for urban or rural use on dark trails. The all-in-one light has a relatively compact form factor with premium metal body with USB-C charging. We expect most buyers will choose the light for its removable 18650 battery design which allows you to extend runtime by carrying extra batteries and future-proofs the light as you can easily replace the battery. The main downsides of the light is the proprietary mount and the night-time only flash pattern (low/high instead of on/off). That said, if you’re looking for an easy to use bike headlight with replaceable battery the BC21R V3 is a strong contender.

Disclaimer: The product for this review was provided by Fenix Lighting. The views expressed on this website are solely those of the authors and are here to help people make an informed choice before a purchase. The authors or the blog itself does not get any monetary compensation from the product manufacturer or third-party websites/vendor links that are posted here.

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