NiteFighter BT-40S Bike Light

Bike lights are a very lucrative and quickly growing segment of portable lighting. Every company seems to want to ensure their place in the rankings with at least one light designed for illuminating dark paths best traversed at speed on two wheels. Does NiteFighter have what it takes to set themselves apart amongst all the competition?

Biking in the summer (finally)
NiteFighter BT-40S

Meat and Potatoes

The NiteFighter BT-40S is exactly what I have come to expect from a bike light. A compact LED module head, switch, and handlebar attachment point connected to a remote battery pack. Cram all the electronics here and run the power source somewhere external. Honestly, I can see why. This makes for an efficient distribution of weight and allows you to easily swap out only the battery when it comes time to recharge.

Seems fairly common now for bike lights.
Proprietary battery pack

The battery pack of the BT-40S seems to be a quartet of 18650 cells. These supply all the electrons necessary to power a similar 2×2 array of Cree XP-G2 LEDs. The focusing elements for these LEDs is none other than my own personal favorite, the optical lens. In personal experience, lensing has always produced a smoother, more even spread of light than any reflector. This instance is no exception. Even the tighter clear lenses are already such an evenly spread beam that the hotspot to spill transition is hardly noticeable at all. Included in the package is a further diffused textured lens that spreads the light over an even wider area. By wider area, I mean it’s a true floodlight. This does cut down on the brightness of any one spot, however the BT-40S more than makes up for this deficiency through generous application of brute force.

1600 lumens of warm white light cuts a swath through the night wide enough to drive a truck through. I definitely had no issues riding my bike. This light has been a joy to test. This is the first time I’ve been able to test out a bike headlight during months warm enough to actually enjoy performing the tests. I’ve made sure to take it on a variety of rides in order to truly put it through it’s paces. This light is simply excellent. It is a useful, and yet small addition to my bike that will now be a part of my rides for the indefinite future.

User interface is about the best I’ve yet seen on a bike light as well. NiteFighter has seen the light, that single button interfaces are nothing but clunky, and when you’re using mounted hardware like this, you have the option to do better. They have chosen a simple two button interface that resembles a rocker switch. Pressing either button will turn the light on. If you want more light, press up. Less, press down. The light will cycle up or down through the 4 constant output modes until you get where you need to be to see the trail in front of you. The BT-40S will remember your last used mode as well, at least until you yank the battery pack to charge it. That’s not a real problem though, since it’s so easy to set in the first place. Turning the light off is as simple as holding one of the buttons for a few seconds. I wouldn’t want that method on a pocket flashlight, but for a bike light it makes perfect sense. Designed for specific uses, that’s what I like to see.

Up for higher, down for lower
Multibutton Switch

The really nice thing about that switch is that it includes a color coded battery status indicator. It starts off green, then transitions through blue to red and flashing red to keep you well informed of how much life and light you have remaining.

Constructive Criticism

Why do I force myself to always include this section? There are some lights that give me more trouble writing something meaningful here than the rest of the review combined. This is one of them for sure. I like this light. A lot. I guess if I had to say anything that could be improved here, it’d have to be the attachment. I’m not a fan of the “giant rubber band” method of handlebar connection. I’ve tried other lights that didn’t even function as well as this one with that method. It’s just never as stable as a more solid clamp in my experience.


This is a great light. I haven’t had any issues using it, and I love the option of either the naturally floody standard beam, or the extremely hotspot-free dedicated flood beam. If you’re wondering which one I’m using, I can’t help you. I haven’t been able to decide yet. I like them both too much to stick with one. Bright, powerful, and simple to use. Hopefully it lasts. Maybe I’ll have to do a long-term results article down the line.

I really like this one.
Compact and Useful

Provided for review by the kind folks at Nitefighter.