The Fenix BC21R v2.0 bicycle headlight is an interesting alternative that slots between the typical flashlights and bicycle headlights. If you’ve done some research into an affordable bicycle light, chances are someone has recommended using a flashlight as a cheap alternative. By avoiding the ‘cycling’ label (and hence the cycling tax!), flashlights are significantly cheaper to purchase and can easily be used for other activities such as hiking or camping. Higher-end flashlights also have features you don’t typically see with bicycle lights such as replaceable batteries and modifiable optics. However, some of the major drawbacks to using a flashlight are: inadequate heat dissipation, poor beam spread and lower power output.

Fenix is a well regarded tactical flashlight company and has entered the cycling market in the last few years with some bicycle lights. What makes the BC21R v2.0 unique, is that Fenix used their expertise in tactical and EDC (every day carry) flashlights to create an affordable light with what they describe as a ‘dual beam’ for better optics. Although the BC21R has the standard flashlight form, it also boasts a removable battery and a convenient bicycle mount.

In this review, we’ll take an in-depth look at the Fenix BC21R v2.0 from unboxing to beam patterns. As the name implies, the BC21R v2.0 is the latest iteration of their BC21R bicycle light and offers a number of updates from the previous model including a higher, 1000 lumen, output. The BC21R also features USB Type-C charging, something the bicycle light industry has been slow to adopt. With a retail price of only $74.95 this bicycle head light is a great value. 

CategoryBicycle Head Light
Retail Price$74.95
Likes+ Competitive price
+ USB Type-C charging
+ Battery Indicator
+ Beam cutoff
Dislikes– Single button interface
– Run-time limited on turbo
– Limited compatibility with mounts
Where to Buy (US) Fenix Lighting

A high-output bicycle light that blurs the line between flashlights and traditional bicycle lights. The BC21R v2 boasts many features typically limited to more expensive lights such as USB Type-C, beam cut-off  and replaceable battery.


The Fenix BC21R v2.0 comes well packaged in a plastic box with well designed graphics.  Inside the box you’ll find:

  • BC21R v2 Light head
  • Handlebar mount attached with thick rubber pad included
  • 2x different thickness rubber pads
  • Spare O-ring
  • USB Type-C charger cable
  • User manual
  • Warranty card

The light fits well in the packaging with the extra parts tucked behind the form-fitting plastic holder. A 2600 mAh Fenix branded 18650 Li-ion battery is included and pre-installed in the light head with a small piece of insulation that needs to be removed before first use.


With v2.0, Fenix has modified the BC21R to use an integrated metal light head. Although we haven’t reviewed the original BC21R, the second version is an excellent improvement visually and in specifications. At only 116 grams, the entire unit including the battery, is very light and compact. The light is only slightly longer than the 18650 Li-ion battery it houses. Visually the two tone gray and black colors look professional, with the mounting slots being cast directly in metal as well. 

Fenix bc21r v2.0 360 view
360° view

The USB Type-C charging port is located on the bottom of the light, which does mean you need to remove the light in order to charge it. A thick rubber cover ensures the port remains water resistant, and the location means it should be safe from debris. Removing the battery is also tool free and simple, as you only have to rotate the rear portion of the light body to lock and unlock it. One of the best features of the light, in our opinion, is also the battery indicator feature. With the light turned off, a short press on the rubber mode selector button will light up the LED below it with a specific color to indicate the battery state (red, orange and green).  


Fenix includes a round handlebar mount that uses a more traditional hard plastic and rubber design. Rubber pads with multiple thicknesses are provided to accommodate different diameter bars, and a simple pivoting bolt is used to tighten the mount to the handlebar for a tool-less installation. The mount also allows the light to rotate about 20 degrees in either direction, which is a feature you don’t typically see anymore. However, this feature also results in a small amount of side-to-side play due to looser tolerances. Overall, we like this mount style more than the Magicshine Eagle mount and it feels more sturdy than the common rubber straps other manufacturers use.


Fenix boasts that the BC21R v2.0 is a dual distance beam system which protects oncoming traffic from glare. This is otherwise known as a beam cut-off, and something automotive headlights are required to have. This feature is critical if you ride in higher traffic areas or local bike trails at the dark, as you can blind oncoming cyclists and pedestrians.  In the BC21R v2.0, this has been accomplished by adding deflectors in the upper half of the single LED lens. This diverts the upper half of the beam (which typically blinds oncoming traffic) downward and toward the ground.

fenix bc21r v2.0 beam comparison
Beam Comparison

Looking at the beam comparison photos, without angling the headlight downward, there is a substantial amount of light diverted to the ground. The beam pattern ends up looking more like two circles, giving it a ‘dual beam’ appearance despite only one LED emitter. The light features 4 constant modes: low (50 lumens, 30 hr), medium (150 lumens, 13 hr), high (400 lumens, 6 hr) and turbo (1000 lumens, 2 hours). There is an additional flash mode that alternates between 400 and 50 lumens, but the runtime is not published (safe guess is somewhere between 6-30 hours). What is unique about this light, is that a single click cycles through the constant modes and a double click enables the flash mode. The advantage of this is that while riding, you don’t have to cycle through flash to access the different modes. The lumen jumps between the constant modes are large, and as you can see in the comparison photos there is a significant visual jump. On low or medium, the light works well as a ‘to be seen’ light and has more than enough runtime. While the high setting is sufficient for using the BC21R v2.0 light as a primary light, the Turbo mode is where the road really lights up. Despite the excellent optics, the beam spread is still more limited in terms of side-to-side flooding you find on dual-beam lights.

fenix bc21r v2.0 light output modes
Output modes


Overall, the Fenix BC21R v2.0 bike headlight has some impressive features for an affordable price. The light incorporates USB Type-C charging and a battery indicator that is accessible when the light is off.  In terms of design, the BC21R v2.0 is also a great blend between a flashlight form factor and a typical bicycle light with a compact and lightweight body. Although the light output at full 1000 lumens has limited run-time, the dual beam output means you’ll get the most out of the lumens. Even though there is no LED screen with run-time display, the Fenix BC21R v2.0 has what we like to call “a near-perfect single button interface” by incorporating a battery indicator and separating flash mode from the standard mode selections.

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.

10 Replies to “Fenix introduces an updated version of their popular BC21R bicycle light”

  1. Thank you for posting this excellent review. After 5 years my cygolite expillion finally lost its charging abilities (although that was my fault cos I allowed the charging port to become clogged with debris). The Expillion series also allow battery swapping, which as you noted is quite rare in the cycling-lights industry. It just makes so much sense to bring spare batteries! Glad that you noted the battery charge port is tucked underneath the fenix’s main body). Based on your awesome review, I just purchased the Fenix BC21RV2.0 as a direct replacement for my trusty old Cygolite. I ALSO purchased a couple of extra 18650 batteries and I made sure to get the ones that actually include a micro-usb charge port built right into the battery. Fearless all-night rides with endless battery-capacity (even in high-power modes) will now be possible with this sweet new light. A nice bonus is that the 18560 lithium ion batteries are fairly ubiquitous and very affordable, (the cygolite proprietary “stick” batteries aren’t cheap – $30+
    and they also don’t include the handy built-in usb charge port). All in all, the Fenix BC21R V2.0 seems like a well-designed, engineered and practical unit that should end up easily outlasting most bike lights many times over!

    1. Hi Joshua, thanks for sharing your experience! Hopefully other light manufacturers take note and incorporate replaceable batteries into their designs.

  2. I’ve got some rough data for you guys regarding runtime on a higher capacity cell. I am not a fan of the method they use for measuring the light runtime, I believe they go right down to 10% of initial output. As far as I’m concerned the “useful” runtime is the runtime to something closer to 50%.

    The cell I used is an efest 3500 mAh IMR cell. It appears to have low output resistance and behaves in colder temperatures. Great choice for a bike light IMO. Only set back is that I needed to add a spacer magnet to allow positive contact to the driver PCB.

    I don’t have a proper lumen measuring setup but just using a visual comparison to a light with approx 400 lumens I tracked the runtime until I felt the Fenix was below this threshold. Not very scientific but helpful I hope:

    0 mins – Begin
    32 mins – Battery indication light turned Yellow
    1 h 15 mins – Battery indication light turned Red
    1h 30 mins – Output is visually about equal to the “test” 400 lumen light.
    1h 40 mins – Battery indication is now Blinking Red.
    1h 43 mins – Output is now showing to be slightly below test light, also the difference between high and Turbo has essentially disappeared. Immediately after this the light kicked down to low-mode. I am terminating the test here.

    I am sure there is more runtime to be milked out of the light but I am not inclined to push it, I do not know how low the voltage cut-off built into the light is and I don’t want to risk cell damage.

    Approx 100 mins of “real” runtime is a significant improvement over what it appears the stock cell offers.

    Overall this cell provides longer useful runtime than what I believe the stock cell offers (which of course should be expected with more capacity). I don’t have a lumens sphere but I also suspect the light generally outputs more lumens with this cell too because voltage drop is going to limit current draw more with the stock cell, just speculation though.

    1. Hi Justin,

      Thanks for sharing your findings. It’s great you have the option to run different cells and get better output. You should consider visiting the flashlight sub on Reddit – there’s a lot of people there who do customization and breakdowns.

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