Fenix BC45R Reference ManualUpdated 32 minutes ago

The Fenix BC45R is a dual-distance mountain bike light with a wireless remote switch. This summary is drawn from the manufacturer's official user manual — see the downloadable PDF reference manual on the product page for complete details.

Warning

Do not place this bicycle light in the reach of children.
Do not shine this bicycle light directly into the eyes of anyone.
Do not place the light head near flammable objects — high temperatures can cause objects to overheat and become flammable/ignite.
Do not use this bicycle light in inappropriate ways such as holding the unit in your mouth; doing so could cause serious personal injury or death if the light or internal batteries fail.
This bicycle light will accumulate a significant amount of heat while operating, resulting in a high temperature of the light shell. Pay close attention to avoid burns.
Turn off and lock the bicycle light, or remove the batteries, to prevent accidental activation when the light is placed in a closed and flammable environment such as pockets and backpacks.
The light sources of this bicycle light are not replaceable; the whole light will need to be replaced when any light source reaches the end of its lifespan.

Overview

3300 lumens maximum output, 286 meters maximum beam distance
Utilizes one SFT-40 cold white LED and four SST12 cold white LEDs, each with a lifespan of 50,000 hours
Powered by two included 18650-3400mAh batteries; batteries can be replaced
High beam and low beam can be controlled independently or in combination via switches on the wireless remote and bicycle light
OLED display clearly indicates the battery level, charging status, brightness level, mode, and other information
Inner waterproof USB Type-C charging port
IP66-rated protection and 1.5 meters impact resistance
Made of durable A6061-T6 aluminum alloy
Quick-release mount, easy to assemble and disassemble
Size: 4.92'' x 1.97'' x 1.46'' / 125 x 45 x 37 mm. Weight: 10.58 oz / 300 g (including batteries)

Operating Instructions — Bicycle Light

The bicycle light has two switches: the high beam switch controls High beam mode, and the low beam switch controls Low beam mode.

On/Off: press and hold the high beam switch for over 0.5 seconds to turn High beam mode on/off; press and hold the low beam switch for over 0.5 seconds to turn Low beam mode on/off.

Output Selection: in High beam mode, single click the high beam switch to cycle through Low → Med → High; in Low beam mode, single click the low beam switch to cycle through Eco → Low → Med → High.

Lockout Function: with the light off and unlocked, double click either switch within 0.5 seconds to lock (the light blinks twice in Eco output of Low beam mode). With the light locked, double click either switch within 0.5 seconds to unlock (the light enters the selected mode at its lowest output level).

Operating Instructions — Wireless Remote

The remote has three switches: the high beam switch controls High beam mode, the low beam switch controls Low beam mode, and the functional switch controls Special mode.

Connecting with BC45R: press and hold either switch on the bicycle light for 5 seconds until the OLED display shows "Connecting"; single click any switch on the remote until it shows "Pair?"; single click either switch on the bicycle light until it shows "Connected!" to complete pairing. Once paired, the remote automatically remembers the paired status — no re-pairing is required. The initial pairing must be completed within 60 seconds or it cancels automatically.

Output Selection: with the light on, single click the high beam switch to cycle through Low → Med → High; single click the low beam switch to cycle through Eco → Low → Med → High; single click the functional switch to enter Turbo, or double click it to enter Flash (single click any other switch to exit Flash and return to the previous output). If the battery is low while Turbo is on, it lights up at the highest brightness the current battery level supports.

Sleep Mode: with the light on, press and hold the functional switch for over 1.5 seconds to enter Sleep mode (the light goes out and shows a sleep icon on the OLED display). Single click any switch to wake it. Turn off the bicycle light with either switch to exit Sleep mode manually, or it exits automatically after two hours of no operation.

OLED Display: remains constantly on to show brightness level, mode, and battery level. If only one battery is inserted, a single-battery icon is shown. Below 10% battery, the icon blinks and High beam brightness is limited to 200 lumens while Low beam is limited to 50 lumens.

Intelligent Memory Circuit: the bicycle light automatically memorizes the previously used output, excluding Flash and Turbo. When turned on again, the previously selected output will be recalled.

Battery Specifications

Fenix ARB-L18 Series (18650, 3.6V): Recommended
Rechargeable Battery, Li-ion (18650, 3.6V/3.7V): Caution
Rechargeable Battery, LiFePO4 (18650, 3.2V): Banned

Do not mix batteries of different types or ages, as doing so may cause damage to the bicycle light or the batteries being used. 18650 Li-ion batteries are powerful cells designed for commercial applications and must be treated with caution and handled with care. Using low-quality batteries or mishandling batteries (such as short-circuiting or overheating) could lead to combustion and jeopardize the safety of users and property. Using quality batteries with circuit protection will reduce the potential for combustion or explosion.

Battery Replacement (Bicycle Light): rotate the tail cap button according to the "OPEN" logo, and pull out the battery case. Insert the batteries according to the polarity marks, then insert the case back into the light body and rotate the tail cap button in the opposite direction of "OPEN" once flush.

Battery Replacement (Wireless Remote): insert a coin into the back of the remote, rotate counterclockwise to open the battery cover, insert the battery, and tighten the cover clockwise. Replace the CR1632 button battery every 3 months.

Charging

Turn off the bicycle light and open the anti-dust cover, then plug the USB Type-C end of the charging cable into the charging port. The OLED display shows a charging icon while charging and a complete icon once finished. The Eco/Low/Med outputs of Low beam mode and Low/Med outputs of High beam mode can be used while charging, but this prolongs the charging time. With the light off, the normal charging time of the included ARB-L18-3400 batteries is about 3.5 hours from depleted to fully charged with a 9V/2A adapter; recharge a stored light every four months. The wireless remote cannot be operated while charging. Power specifications: charging voltage 9V, charging power 18W (9V/2A); this light supports fast charging. Use only a certified USB charging adapter that complies with local safety standards.

Mounting Instructions

Loosen the screw of the bicycle mount, fix it in the desired position on the handlebar, and fasten the screw. Hold the light and slide it into the mount until a distinct click is heard. Fasten the strap of the wireless remote to the desired position on the handlebar. Adjust the light's direction before testing power and functions. Use the shims provided according to handlebar diameter: thick only for 22-28mm, thin only for 28-32mm, no shim required for 32-35mm.

Technical Parameters (ANSI/PLATO FL1)

High Beam Mode:

High: Output 2000 lumens, Runtime 5 hours 15 minutes, Distance 269 meters, Intensity 18211 candela
Med: Output 800 lumens, Runtime 6 hours 15 minutes, Distance 174 meters, Intensity 7651 candela
Low: Output 200 lumens, Runtime 16 hours 45 minutes, Distance 85 meters, Intensity 1820 candela

Low Beam Mode:

High: Output 1500 lumens, Runtime 5 hours 30 minutes, Distance 142 meters, Intensity 5049 candela
Med: Output 800 lumens, Runtime 6 hours 15 minutes, Distance 102 meters, Intensity 2617 candela
Low: Output 200 lumens, Runtime 20 hours 15 minutes, Distance 50 meters, Intensity 629 candela

Special Mode:

Eco: Output 50 lumens, Runtime 59 hours 9 minutes, Distance 25 meters, Intensity 157 candela
Turbo: Output 3300 lumens*, Runtime 3 hours, Distance 286 meters, Intensity 20486 candela
Flash: Output 800-100 lumens

Impact Resistance: 1.5 meters | Waterproof: IP66

Note: Specs measured by Fenix using two Fenix ARB-L18-3400 batteries at 21±3°C / 50–80% humidity; real-world performance varies. *Turbo output is measured in total runtime including output at reduced levels due to temperature or the built-in protection mechanism.

Intelligent Overheat Protection

The bicycle light will accumulate a lot of heat when used at high output levels for extended periods. When it reaches a temperature of 55°C/131°F or above, it will automatically step down a few lumens to reduce the temperature; when the temperature drops below 50°C/122°F, it will gradually recall the preset output level.

Low-Voltage Warning

When the voltage level drops below the preset level, the bicycle light downshifts to a lower brightness level until Eco output is reached. At Eco output, the battery icon on the OLED display blinks to remind users to replace or recharge the batteries; the light will not turn off automatically, and the icon keeps blinking until the battery runs out. This only works with a Fenix ARB-L18 Series battery.

Usage and Maintenance

Disassembling the sealed head can cause damage to the bicycle light and will void the warranty.
Replace or recharge the batteries in time to ensure normal use for next time.
Fenix recommends using excellent quality batteries.
If the bicycle light will not be used for an extended period, remove the batteries, or it could be damaged by electrolyte leakage.
Recharge a stored bicycle light every three months to maintain optimum performance of the batteries.
Long-term use can result in O-ring wear — to maintain a proper water seal, replace the ring with an approved spare.
Periodic cleaning of the bicycle light and battery contacts improves performance, as dirty contacts may cause flickering, intermittent shining, or failure to illuminate.
If issues persist, contact the distributor.

What's Included

Fenix BC45R bicycle light, bicycle mount, bicycle mounting shim (thin/thick), wireless remote, CR1632 battery, 2x ARB-L18-3400 batteries, USB Type-C charging cable, spare O-ring, user manual, and warranty card.

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