The BTwin VIOO 320 Bicolour bike light is a reversible red/white LED with two modes. While I'm not totally convinced by BTwin's claims regarding visibility distances, at 22 and 7 lumens respectively, it's a surprisingly useful contingency light – the sort you might lend to a mate should one of their blinkies unexpectedly power down.
As the photos illustrate, it's a very compact design, although it occupies more handlebar space than some of the thimble-sized blinkies, such as the Lucas F-40 and similar. However, at £8.99, it's considerably cheaper.
Despite this, materials and build quality seem reassuringly good. Inside that familiar rubberised monocoque shell cum strap (which is very secure, although benefits from some gentle pre-stretch before being mounted to beefy bars) sits a single diode, lithium-ion battery and switchgear.
The battery is designed to serve 500 charge cycles, so at a conservative estimate that's at least three years' hard use and the retail giant's standard two-year, no-quibble warranty adds further peace of mind.
A full mains charge takes just under two hours and the diode emits a subtle red pulse during this phase. Similarly, when reserves dwindle, it flashes intermittently, giving 28 minutes and a sporting chance of getting home before powering down.
There's no IPX rating, but so long as you've reinstated the USB port cover properly, there's little chance of water/similar ingress getting inside. Cursory blasts from the garden hose made no impression either.
The simple top-mounted switch is intuitive to use, requires a definite two-second prod, and is easily operable in middle-weight full-finger gloves. Ours defaulted to white steady, another prod engages flashing, and two further nudges selects the red beams.
LED technology is improving all the time in terms of output and efficiency. Curiously, despite the disparity in power, both flashing settings are reckoned to achieve 9 hours from a full charge. Calling their bluff, I'm pleased to report 8hrs 54mins and 8:56, which should be accurate enough for all but the most pedantic.
As I mentioned earlier, in both settings, it's quite a potent little light, especially relative to some household names costing twice as much. The highest, 22-lumen front flash isn't quite a daylight mode in the sense of being visible to other traffic on brighter days. However, it's surprisingly useful when skies are overcast, thanks to the combination of pace and pure white diode.
Past dusk, oncoming traffic seemed to register at around 300 metres, not quite the 450 metres quoted, even along otherwise deserted lanes with starry skies.
This also compensated for the lens's relatively small peripheral punch around town. Even in the latter context, paired with my Univega's potent Exposure Revo dynamo lamp, the BTwin registered first. Distance-wise, by my reckoning it's between 150 and 200 metres. Again, short of those cited on the packaging, but good nonetheless.
The steady mode is quite piercing and reckoned to project a pool of light to 11 metres (36ft in old money). It's not intended as a light in the legally accepted sense but passable for tackling roadside mechanicals, map reading, pannier foraging and similar close detail stuff. Visible to 450 metres? Not by my reckoning, although, with main systems switched off, a very reasonable 200m is nearer the mark, and that's along unlit roads on clear nights.
The red, or rear, setting is brighter than 7 lumens would suggest, and again BTwin cites 300 metres in constant and flashing. Fellow riders concurred with my estimate of 200m in flashing, less around town; on the flipside, it's less intense at close quarters than some, so passable for group riding, although my generally diplomatic persuasion erred towards the constant setting.
Used thus, visibility is around 80 metres, dipping to 40 in suburban/urban settings – a few split-second stealth moments when exiting roundabouts left me slightly uncomfortable, although the same could be said for other bijoux models in a comparable context.
When all's said and done, this is still a very capable contingency system and deserves a place next to the patch kit in a wedge pack.
Some doubts over the claimed visibility, but nonetheless an inexpensive and surprisingly bright contingency light
road.cc test report
Make and model: BTwin VIOO 320 USB Dual Bike Light
Size tested: 22 lumen white, 7 lumen red
Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Visibility Lights up to 11 m, visible from 450 m. Two-tone LED, flashing/continuous modes.
Autonomy 3h in continuous mode, up to 9h in flash mode. USB cable to charge (500 cycles)
Easy assembly / dismantling Universal, one step, tool-free attachment."
My feelings: Bargain LED that converts from reversible front/rear light at the push of a button. Output an lumens are relatively impressive given the asking price too.
Tell us some more about the technical aspects of the light?
Visibility B'TWIN has created the B'VISIBLE label to designate products that improve your visibility while cycling. It guarantees high-performance visibility that has been scientifically tested and approved in the lab, available on a full line of B'TWIN products.
Performance Battery capacity: 210 mAh.
- White mode: 22 Lumen,
- Red mode: 7 Lumen.
COMPOSITION / ADVICE
100.00% Styrene Ethylene Butadiene Styrene (SEBS)
100.00% Polycarbonate (PC)
Inside Shell - Main fabric
100.00% Battery - Lilo
Restricted use : Not a substitute for bicycle lights required by law
Tell us how the light performed overall when used for its designed purpose
Overall, the VIOO 320 bicolour light is a remarkably good contingency light that is surprisingly bright in both settings – at least in the being seen with sense. It's intuitive to use, generally well made and quick to charge; arguably, two could be the perfect companions to a tyre-driven dynamo on a commuter bike, or as contingencies when enjoying longer summer evening outings on the best bike.
Tell us what you particularly liked about the light
Super-compact, well made for the money and surprisingly bright.
Tell us what you particularly disliked about the light
Nothing, when everything's taken into account.
Did you enjoy using the light? Yes
Would you consider buying the light? Yes, as tertiary/contingency lighting.
Would you recommend the light to a friend? Yes
Use this box to explain your score
Cheap and extremely cheerful contingency lights that work surprisingly well in both modes.
About the tester
I usually ride: Rough stuff tourer based around 4130 Univega mountain bike frameset My best bike is: 1955 Holdsworth Road Path and several others including cross & traditional road
I've been riding for: Over 20 years I ride: Most days I would class myself as: Experienced
I regularly do the following types of riding: cyclo cross, commuting, touring, fixed/singlespeed, mountain biking
Shaun Audane is a freelance writer/product tester with over twenty-eight years riding experience, the last twelve (120,000 miles) spent putting bikes and kit through their paces for a variety of publications. Previous generations of his family worked at manufacturing's sharp end, thus Shaun can weld, has a sound understanding of frame building practice and a preference for steel or titanium framesets.
Citing Richard Ballantine and an Au pair as his earliest cycling influences, he is presently writing a cycling book with particular focus upon women, families and disabled audiences (Having been a registered care manager and coached children at Herne Hill Velodrome in earlier careers)