The Light & Motion Imjin 800 really impressed me with its excellent beam pattern, and it's perfect for pitch-black commutes and off-roading. I did find a few issues though: my shorts tended to snag on the battery's mounting bracket, and connecting the battery to the head unit or for charging is awkward.
Having a powerful front light at this time of year is a necessity for those of us who live in the countryside. I started testing the Imjin just as the clocks changed, which was handy. My first commute home in the dark also coincided with Halloween – although I still failed to spot the small child who jumped me dressed as Dracula, and was in danger of turning my bib shorts an AG2R brown.
The Imjin 800 is effectively made up of two parts. There's the head unit that contains the Cree LED, and the battery that mounts onto the bike. Joining the two is a cable that is more than long enough to reach past the seatpost on my 54cm bike.
The head unit housing the Cree LED is a very compact design. This emits a maximum 800 lumens in a very direct beam. I found the visibility to be brilliant for night road riding with no other light. It gave very good visibility a good way into the distance. I could see the road well 50 metres ahead while also being able to see just past my front wheel axle, making spotting potholes and the like and then avoiding them very easy.
In faster situations, such as descending, this was doubly useful as I was able to plan my braking well ahead of time, never having to drag the brakes. I also took the light out for an evening cyclo-cross session. As ever, I stayed out later than planned, and the Imjin was great for spotting ruts, even in full darkness.
The compact design features just one button. Helpfully, for winter riding in full-finger gloves, the button protrudes out of the light's shell and is rubberised for grip. The battery level indicator is housed within the button, meaning you get a constant indication of how much juice you have left in the battery. The button is a little stiff to press, and you have to hold it in for a second or two to turn it on and off.
Using a separate battery means that the head unit can be smaller and lighter than a torch-style light, but it also leaves you with a cumbersome brick to mount somewhere on your bike. Having this on my winter bike or cross bike wasn't a huge issue, but I wouldn't want to mount it on my race bike for a fast evening ride. It's not the weight, which is relatively light for the size, it's more the mounting bracket. It doesn't seem the most paint-friendly out there, with no form of protection underneath it for your frame. Get any grit in there and I can't see it ending well. As a precaution, I cleaned the bracket every time I used it on my summer bike.
The 'feet' of the bracket aren't finished terribly well either, and the squared-off finish means there are sharp edges that my shorts were constantly catching on, no matter where on the top tube I mounted it.
The rubber strap itself is good, and secured the battery down well on a variety of top tube shapes. The same can be said of the strap for the light unit, which kept it in place well with no movement.
The light unit can also be mounted on your helmet, with the battery stored in your rear pocket. The battery did get quite warm, but on a cold night this was a bonus.
Another issue I had with the battery was the way it connected to the light unit or charging cable (they use the same connection port). It's quite a tight fit and you have to line up four thin metal prongs to four equally tiny holes. It'll only go in one way, but the possibility of ruining the light by being ham-fisted strikes me as very high. The connection port is circular and it would have been very helpful to have a square connection port, or at least some grooves to guide the head. There is a little printed arrow that you're meant to line up with a dot, but to my mind it's not sufficient for such a delicate connection system.
Once you've got the light connected, it's a secure and watertight connection.
What makes the connection problem a particular pain is that the battery doesn't last that long. Commuting 40 minutes each way, I've been charging the battery every night, highlighting the need for a quick and easy system – like being able to plug it into a laptop, as you can with so many lights these days.
It's worth noting that my entire commute is on unlit lanes, so I tended to use the full 800-lumen setting. If you were running this in town or on better-lit roads, you'd find the 400-lumen setting more than sufficient and would therefore get a much better battery life of 4 hours.
In terms of value for money, compared with other 'two-pack' lights, the Imjin 800 is expensive. Gemini's Xera 950 (reviewed by Neil, read the test here), is brighter and £50 cheaper, while Magicshine's £97 MJ-902 and £119 MJ-906 are both brighter according to the beam comparison engine, though we don't have full test results of what they're like to ride with yet.
Overall, for riding at night on dark roads and off-road, the Light & Motion Imjin 800 features a very well concentrated beam and plenty of visibility, but it's expensive, the mounting bracket could be improved, and I wish charging the thing was simpler.
Super-compact light with a well-concentrated beam, pricey though, and the battery is powerful but connection is a hassle
If you're thinking of buying this product using a cashback deal why not use the road.cc Top Cashback page and get some top cashback while helping to support your favourite independent cycling website
road.cc test report
Make and model: Light & Motion Imjin 800
Size tested: n/a
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?
From Light & Motion: "Imjin 800's powerfully focused beam and compact size make a versatile light for any type of riding and is perfectly designed to run on your helmet. Designed to maximize output in a compact design, the Imjin features an optimized reflector that uses micro peens to make the beam broader and smooth without hotspots. With an external battery for the longest of rides, the Imjin 800 is built with the epic in mind."
Tell us some more about the technical aspects of the light?
800 Lumen output certified to the FL-1 Standard
* Engineered with the best CREE LED and enhanced firmware.
* Custom engineered reflector optimizes the light to provide a smooth, even beam pattern that focuses the light exactly where you need it.
* Beam pattern was engineered to maximize riders' depth perception using optics that eliminates the snowball effect with a clean transition across the beam.
Generally very good, and with the light being small it sits on a helmet very nicely. The battery is a little chunky and gets quite hot if you put it in your pocket, and the mounting bracket catches on bib shorts if it's on the bike.
I'd like an easier battery connection design. Sometimes it's a pain to get the charging head into the battery.
The rubber strap is perfectly secure. I have an out-front mount with GoPro compatibility, so having a GoPro mounting option is really useful.
This survived many downpours and blasts from the hosepipe when cleaning.
The 2hr run-time is accurate and decent considering the power. At 400 lumens you get 4hrs, which is more than enough. Recharging is quite quick at 2hrs 45min, but the connection is awkward.
The beam is concentrated yet still has a wide angle.
Very impressive. It got covered in mud a few times and then blasted clean with no issues.
You can certainly get lighter 800-lumen lights.
At £169.99 the Imjin is expensive compared with other separate battery-pack lights we've tested, such as the £120 Gemini Xera 950, and Magicshine's £97 MJ-902 and £119 MJ-906 (reviews to come - though the beam comparison engine shows they're both brighter than the Imjin).
Tell us how the light performed overall when used for its designed purpose
Very well. It mounts easily and provides brilliant illumination.
Tell us what you particularly liked about the light
The beam pattern is fantastic and very well concentrated.
Tell us what you particularly disliked about the light
The mounting bracket caught on my shorts, and the charging connection is annoyingly difficult.
Did you enjoy using the light? Yes
Would you consider buying the light? Yes
Would you recommend the light to a friend? Yes
Use this box to explain your score
Performance is very good, but the battery bracket and difficult connectivity are annoyances on a £170 light; there are brighter and cheaper alternatives, so overall I'm giving the Imjin a score of 6.
About the tester
I usually ride: Cannondale Supersix Di2 My best bike is:
I've been riding for: 5-10 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: road racing, time trialling, cyclo-cross, commuting, club rides, general fitness riding, I specialise in the Cafe Ride!
Son of a Marathon runner, Nephew of a National 24hr Champion, the racing genetics have completely passed him by. Liam spends his time plodding his way through cyclocross races, very busy not winning. As an advocate for perfectly clean chains, he can be found cleaning his bike instead of training. A shop mechanic, Liam has many helpful skills, such as being able to identify 'cross tubs by the tread pattern alone. If you bump into him, he'll probably be eating.