Fenix BC21R USB Rechargeable Bike Light – DISCONTINUED

Max Lumens: 880
Modes: 5
(15 customer reviews)

$96.00 $74.95

Out of stock

This item has been discontinued. Please see the new updated BC21R V2.0

SKU: BC21RL2BK Category: Tags: ,

This rechargeable bike light is designed for both mountain biking and urban settings. For the commuter, the BC21R features two side red lights and a flashing mode for additional rider safety. Its quick release mount makes it easy to detach the light, ensuring the light won’t be stolen. Mountain bikers will love the light’s dual beam system for up-close and extended visibility.

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WARNING. Be aware of counterfeit Fenix merchandise in the U.S. marketplace.

Max Lumens: 880
Modes: 5


fenix bc21r bike light specification specs

Length: 4.4” (113mm)
Width: 1.6” (40.5mm)
Height: 1.7” (42mm)

Weight: 3.2 oz. (91g) excluding battery and bike mount

Batteries: 18650 3.6V/2300mAh rechargeable battery with Micro-USB charging

Included: Bike mount, mounting shim, mounting strap, spare O-ring, 18650 3.6V/2300mAh battery, USB charging cable

Warranty: Limited Lifetime Guarantee from Fenix Lighting U.S.

  • Uses one Cree XM-L2 T6 neutral white LED with better color rendition
  • Powered by one 18650 rechargeable Li-ion battery or two CR123A Lithium batteries
  • Optimized Dual Distance Beam System
  • Micro USB direct charging
  • Built-in over-charge, over-discharge protection
  • Battery Level Indication
  • Low power warning reminds when battery replacement needed
  • Over-heat protection to avoid high temperature of the surface
  • New-type quick-release bike mount for easy and secure adjustment of the light direction
  • Four brightness levels and one flashing mode
  • Digitally regulated output maintains constant brightness
  • Made of aluminum alloy with excellent heat dissipation design
  • Waterproof to IPX-6 standard


  1. The Flash mode will flash at 380 lumens and 100 lumens alternately.
  2. The bike light is equipped with red side lights, it will be activated simultaneously by default. This side red light will be constant-on when the main light is on and flashing red when the main light flashes.
  3. The above-mentioned parameters (lab tested by Fenix using one Fenix ARB-L2-2300 18650 rechargeable Li-ion battery) are approximate and may vary between the bike lights, batteries and environments.

*The runtime of the Turbo brightness level is the accumulated time. The runtime can be longer when uses 18650 battery of larger capacity.


Press and hold the light button for 0.5 seconds to turn ON/OFF the light.

Output Selection
With the light on, click the light button to cycle through Low→Mid→High→Turbo→Flash.


  1. As with any performance light, the bike light builds up heat when it runs for an extended period. Intelligent circuitry in the bike light downshifts the light to lower brightness level to guard against overheating.
  2. The bike light retains the last-used brightness level.
  3. When the battery power level is critical, higher brightness levels can not be activated, and the bike light is programmed to cycle through lower brightness levels.

Battery Level Indicator
With the light off, single-click the light button, the side light will indicate the battery power level conditions, and then go out after 5 seconds.

  1. Side light constant-on (sufficient power level): 60%-100%
  2. Side light slow flashing (low power level): 20%-60%
  3. Side light quick flashing (critical power level): 1%-20%

Low Power Warning and Intelligent Output Downshift
Low Power Warning: With the light on, when the battery level is lower than 20%, the light button will blink red constantly, to remind you to downshift to a lower brightness level to extend runtime or recharge the bike light.

Intelligent Output Downshift: If non-stop use is needed, the light will downshift to a lower output level to extend runtime. When it downshifts to the flashing mode, the bike light will go out soon. Please stop riding and replace the battery or the bike light.


Operation Points: Remove the anti-dust plug at the bottom of the bike light to reveal the charging port, and plug the Micro USB end of the USB cable into the light’s charging port, then connect the other end of the USB cable to a USB power adaptor.

Charging Indicator: The indicator light in the bike light blinks red to indicate the charging process has begun. The indicator light turns solid green when the battery is fully charged.


  1. Turning on the bike light under charging state is not recommended by Fenix. But it will be okay if under emergency situations, the bike light can light up at Low and Mid output.
  2. Once charging is completed, disconnect the USB cable from the light and be sure to secure the anti-dust plug cover.
  3. Fenix recommends using a power adaptor with output over 5V 1.5A. It takes about 4 hours to fully charge the bike light.
  4. The bike light can be connected to the USB cables for digital products such as mobile phones with standard Micro-USB charging port.

15 reviews for Fenix BC21R USB Rechargeable Bike Light – DISCONTINUED

  1. Michael M. (verified owner)

    This was bought as a backup return home at night light. I’ve only used it a few times. My impressions are, great build quality. The light is excellent build quality and has a great light beam for my needs. I’ve not had any issues with the mount moving, then again it is not used mountain biking. It’s seemed to hold a charge long enough for me to use it 4-5 times. I don’t use it on Blaze setting, I think it’s the middle setting.

    The folks at Fenix Lighting are top notch. Colt helped me out with an issue on my E12 flashlight and reached out to some people to help me. Props to everyone there.

    Don’t forget to remove the small dark thin plastic disk that is on the battery or it won’t work. I think this was the problem with some of the peoples complaint about it not working.

  2. David (verified owner)

    This light is quality, and a great value for the money. I purchased it for a 400-mile bikepacking race and used it to ride technical singletrack and descend on fast gravel roads. It met every expectation. Being able to choose between charging while I ride (from a battery bank) or swap to a fresh battery was the main reason I chose this light. Some reviews say the mounting strap is flimsy. I beg to differ, as my rigid mountain bike on rocky descents threw everything it could at the light and it didn’t budge.

  3. Joerg Jaeger (verified owner)

    The best light i bought so far. Great plus, the removable rechargeable battery.

  4. John Roadie

    There’s nothing to fault with this light, it ticks all the boxes (price, quality, performance, features).
    I especially wanted a light with a replaceable battery for unlimited runtime. Luckily Fenix came to the rescue with the awesome BC21R!
    Contrary to many who have written here, in my experience the mount does not move over bumpy roads and the ladder strap design is easy, lightweight and universal.
    I can think of just one improvement, a +/- button would be much better than having to cycle through the levels via a single button – please all bike light manufacturers take note there’s an opportunity here!

  5. Artec (verified owner)

    A great light. Highly versatile and the ability to change out batteries during a ride is why I purchased this light. Beam pattern and runtime are exceptional. I wish that the handlebar mount was a little more sturdy for trail riding.

  6. Jennifer H. (verified owner)

    Love it

  7. craglcimb (verified owner)

    I have purchased and loved many Fenix products over the years, but this one is a definite miss. While the light itself is fine, the mounting bracket and strap are woefully inadequate. The strap is the thinnest rubber-mounting strap I have come across. Given the weight of the light and how high the light sits in the mount, it will rotate around the handlebars and on rough road. Definitely not a light for mountain biking. Not even really a good light for a road bike until they address this issue, as you constantly have to mess with it to keep the light properly aimed. I have two PD model flashlights mounted in ALB-10 Fenix mounts that work great. I thought a model designed specifically for biking would be an improvement, sadly mistaken.

  8. Christopher A. (verified owner)

    The light is 5 Stars but the mounting strap and bracket…. common Fenix! If you plan to use this for anything but smooth pavement look elsewhere until the mount is improved…. floppy and sloppy is how best to describe it. The light will bounce around and rotate on the bars. I’m afraid too pull the strap too tight because it’s so thin ( thinnest rubber mounting strap I have every seen). That said, I also have two other PD series Fenix lights mounted with the bomb-proof Fenix mount on my other bikes… wish I would have stuck with what worked. Figured a bike-specific light would be an improvement… sadly mistaken

  9. Joel (verified owner)

    I actually mounted this light on a four wheeler to run my dog! This light is bright, I have had cars flash there brights at me, and this is on the lowest setting, the light stays in place even with all the bouncing around, nice and durable. Thank you Fenix!

  10. anonymous

    Purchased for first double century. Wanted 6 hours light so got extra Samsung battery. Charged both batteries using light so didn’t need separate recharger. Haven’t used other lights.

    Light worked fine for DC (Only had to use it for 2 hours at high)

    After 4 months of use

    Riding 4x/week 45 minutes before sunrise. I use light on blinking mode. Other settings are much brighter but my hope is blinking is more visible; especially when reflective road signs in front reflect the blink. Use light for 1 hour. Roads when dark – flat, smooth, clean, no lights in places. Riding speed using light – same as daylight but I know the roads. Conditions – dry, temp 50F-60F. Bike – carbon endurance type which minimizes bumpiness

    Light shifts on rough parts of road so I’m taking off one star. FYI, friend’s light (don’t know brand) does the same. I shift the light up after 45 minutes.

    What I like
    * extra battery when I forget to recharge
    * easy to take light on-off

  11. Anonymous (verified owner)

    This is an excellent light. Functionally, it has all of the features I want for commuting – flashing light for daytime, bright light for nighttime, side flashers, and quick release so I can put it in my pocket when locking up outside. The figure 8 style light pattern is great too, both for keeping from blinding oncoming traffic, and illuminating potholes / garbage / etc. right in front of your wheel at night.

    There are many similar lights on the market, but this is singular (from what I can find) in that is has a removable lithium battery. If you’re going to spend the money to get a high-quality bike light, I can’t imagine choosing one that you’ll end up throwing away after a few years when the battery loses its ability to hold a charge. If you don’t happen to have an 18650 charger, you can just use the built-in USB port to charge the battery right in the light. Thanks to Fenix for turning what might otherwise be a disposable product into a potentially life-long investment.

    The only complaint I have with this light is, as others have mentioned, the mount. As someone who regularly rides several different bikes, I love the idea of quickly removing the mount from one bike and strapping it on to another. Unfortunately, it’s not grippy enough, and the light tends to gradually tip forward or backward as you ride over rough terrain. It’s tolerable in town, but essentially unusable for me on the trail.

    Note that I originally had the mounting strap on what I thought was moderately-tight. After a few rides, I stretched it onto the next hole, and the light was considerably more stable after that. To Fenix’s credit, the light came with extra rubber parts (mounting pad, strap, and waterproof O-ring), which gave me the confidence to really stretch the strap, knowing I had a backup if I broke it.

    The way the light clips into the mount isn’t as good as it could be, either. You have to push pretty hard, and it’s not always obvious when the little latch clicks into locked position. Consequently, on my very first ride, the light popped out of the mount going pretty fast downhill and tumbled end-over-end on the pavement for tens of feet before coming to rest. I figured it was trashed but, to my surprise, everything still worked great, save for a few minor scratches. The build quality of this light is definitely up to par with other Fenix products that I own.

    Overall, I would recommend this light. It’s bright, tough, and has a great, user-replaceable battery. My only reservation is the mount. I’ve been debating buying two more for other family members, but haven’t done so because of the mount. I’m hoping that Fenix will redesign the mount in the future; if they do, I’ll be back for another pair.

  12. Sproule Love

    This light is excellent and makes me feel safer bike commuting in NYC. The 2017 Gear Institute pick is definitely merited. However, as mentioned in the Gear Institute review, the ladder rubber band is not a solid way to attach the light to handlebars. I have to adjust it often after going on bumpy roads. I don’t have a lot of confidence that it will last.

  13. Fenix Lighting U.S.

    We do send replacements to customers who have these break, but no alternatives. We have had requests for a broken strap, but it’s been a very low number of request.

  14. Chris (verified owner)

    buyer beware: the light duration times as of 8/21/16 are NOT correct for the battery that ships with the light. They ship it with a 2300 mAh battery and then post times for a 3400 mAh battery.. which is kinda shady to me. I am going to email them about correcting this. Until they correct this, I will leave my review at 3 stars to try and make sure others read this

    • Fenix Lighting U.S.

      Chris-I think you were the one that alerted us to a change by the factory. Thanks. We have now corrected it.

  15. Daniel Hadley (verified owner)

    Excellent handlebar light for night riding and as a emergency light to keep in the saddlebag. It is plenty bright enough and very easy to mount.

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