I probably mountain bike at night more than most folks – usually once a week year ’round, including the summer. One thing I’ve found is that nothing takes the fun out of a night ride more than having a bad light. A proper mountain bike light should be durable and reliable while offering proper illumination on the trail, allowing you to ride the same way you ride during the day. The Light & Motion Seca 800 does all of the above better than any light I’ve owned.

So let’s start with the stats. On paper the Seca 800 features 6 LEDs pumping out 800 lumens for 2 hours and the whole package (battery and head unit) weighs in at 341 grams. In the real world the numbers turn out even better – I got at least 2:15 run-time on high at 328 grams. There are settings for low, medium, high, and flash mode; charging time is about 2.5 hours. Viewed from the side the Seca 800 looks like a bank of stadium lights torching the singletrack.

On the trail the first thing mountain bikers will notice about any lamp is the beam pattern and projection. Light & Motion likes to point out that lumen count is just one factor in determining a light’s effectiveness; the pattern the light forms is almost equally as important. And this is where the difference between the Seca 800 and a single bulb and reflector unit is readily apparent. The Seca 800 beam is hotspot-free and works equally well mounted on the bars or the helmet.

That last bit is a big deal (to me anyway). A bright single bulb light works OK as a helmet lamp because you can turn your head to point the light where it’s needed at any given time. But oftentimes that means making unnatural movements or worse, taking your eyes off the line in front of you when you can least afford to do so. Mounting the Seca 800 on the bars also places the weight of the light and battery on your bike rather than on your helmet or in your jersey pocket.

Even mounted on the bars and without a supplementary helmet lamp, the Seca 800 does a great job illuminating short drops and low hanging tree branches, better than any other light system I’ve used. On the trails I typically ride I’ve found I can get away with keeping the light set on low or medium for most of the ride, though I suppose if I was a faster rider I’d need to ramp up to high more often.

The included bar / helmet mount clamping system is really simple and effective – just pull the rubber strap tight and hook it over the plastic pin. Once the strap is in place it doesn’t move; in fact it’s so stubborn that whenever I need to angle the light up or down slightly I have the release the strap – it’s that tight.

Light & Motion uses robust cable connectors that create serious suction to keep everything connected during the ride. There’s nothing worse than having a cable snagged and suddenly being left in the dark. In more than 2 months of riding with the Seca 800 I haven’t had a cable jiggle loose or get disconnected.

The Seca 800 features an intelligent power management system that warns you when you’re running low on battery power. In my tests, after about 2 hours, 15 minutes on high the lamp dimmed a little. According to the manual, the green LED on the power button should start blinking at this point but mine never did (this isn’t really helpful anyway if the light is on your helmet). After the initial dimming I got more than an hour and fifteen minutes (!) of additional run-time on high, though at a slightly lower light output level. With just a few minutes of run-time remaining, the Seca dropped the light output again and flashed the main lamps. At this point the green LED on the power button should also flash rapidly. With such a conservative warning system, I never worried about being caught out in the dark by surprise.

High, medium, and low settings simulated using Adobe Lightroom software. Can’t see much difference? You get the same effect on the trail at night – switching from high to medium doesn’t change the beam pattern, just the intensity (and even that’s subtle as you toggle from high to medium to low).

I love the sleek headlamp design and even the battery is well thought out with a groove on one of its three sides to fit snugly against a frame tube or stem. The power button could use a little work in my opinion – it’s hard to find, especially with a gloved hand and it’s also hard to tell when you’ve pressed it since the button “click” isn’t very positive. A rubberized button might be just the trick here so the texture stands out from the smooth metal and plastic surface on top of the lamp.

If you’re looking to extend your mountain bike season with a new light this fall, don’t let lumen counts and battery life numbers blind you to what’s really important: performance on the trail. The Light & Motion Seca 800 ($499 MSRP, $129 for an extra battery) is easily the best light system I’ve owned and offers reliable, effective illumination in a variety of terrain. Don’t get caught out in the dark this fall!

Calling these bike lights “Ultra” is an understatement. There really should be a warning label on the box saying “DANGER! Do not look directly into the light as permanent eye damage may result.” After fully charging these monsters I plugged them in, lightly tapped the switch, and POOF! I can’t see. OK, so maybe the label would just be for people like me

Light & Motion introduced the Seca 900 Ultra bike lights (MSRP $699.99) this year for the serious rider and XC marathon / 24-hour racing crowd. These lights come with six Cree R2 LEDs which are the highest rated LEDs available anywhere. And as if it wasn’t enough to have six R2s in this lamp, Light & Motion also designed a very high quality reflector to efficiently direct and sculpt the beam pattern to maximize light output (this is key and where other lights fail). The Seca 900 includes a nine cell 11.1V  Li-Ion battery capable of tossing out 900 true lumens* for 3.5 hours of run time on the high setting. Other settings include medium (450 lumens for 7 hours), low (250 lumens  for 14 hours), and a flash setting that will run for 100+ hours.

The included Multi-Chem smart charger uses the ultra-efficient Delta temperature method of charging. This method basically monitors the temperature of the battery over the charging cycle to ensure that the battery gets both a full charge while not overheating. And it does the job in just 3 and a half hours.

The graphic on the right shows the test data for the Seca 900 and you can see that it produces more than the advertised 900 lumens. Actual light output during testing was more like 953 lumens but for sake of honesty and accounting for possible production variances Light & Motion keeps the rating at 900 (besides, Seca 953 just doesn’t have the same ring to it). You can also see most of the light is in the light-blue to white area of the spectrum which keeps everything as bright as possible.

Light & Motion uses a custom array to optimize and maximize the light pattern for night riding. The Seca 900 features a gem shaped beam that’s flat on top and converges toward your tire in a V-shape. Extra light converges toward the center of the beam for maximum distance.

Installing the Seca 900 Ultra literally took less than 5 minutes on my bike. The handle bar mount is a one-handed breeze: simply loop the light through the mount, stretch the strap to secure it on the hook, and adjust the angle. In setting the angle you’ll want the outer pattern to just touch your tire with the lower edge of the spot about 20 feet in front of the bike. Installing the battery was a matter of simply feeding the strap through the adapter slots, slipping the battery into the adapter, and strapping everything down securely.

On the trails I have to say these are by far the most powerful set I have tried. These lamps toss so much light it’s literally like riding in a perfect bubble of daylight. Even when the terrain got bumpy or required a lot of steering, I felt very comfortable thanks to the light intensity and pattern. I found I could go as fast as I wanted without fear of missing a root or obstacle in the shadows. The video below shows me on a pitch black trail with no external lighting. The only light in the video is coming from the Seca 900 which basically has about as much power as a nuclear reactor. Notice how the light illuminates the trail even when cresting bumps!

The Seca 900 system also includes something called “Race mode” that allows you to quickly toggle between low and high intensity light settings for climbing and descending (respectively). This means fewer clicks to get to the two light modes you really need during the race!

Overall I can honestly say if you can afford to spend the extra bucks on this bike light, you will not be disappointed in any way. With the Seca 900 Ultra you’re getting a superior product with incredible battery life and leading on-trail performance in a svelte, easy to use package.

If you don’t think your riding isn’t quite up to the level of the Seca 900, consider giving the Stella 300 Dual a try. At half the cost of the Seca 900, this system is a bit more affordable and provides enough light to navigate dark trails with a good degree of comfort.

* One lumen is defined as the amount of light produced by a light source that emits one candela of luminous intensity over a specified angle. This is a more consistent way of measuring output rather than using Watts.

Technical specification from Light & Motion:

Battery Type: 9-Cell Li-Ion
Battery Weight: 486g
Mounts: Helmet, Handlebar
Modes: Race, Cruise, Flash
Charge time: 3:30min
Charger: Multi-Chem Smart
System Weight: 686g

Run Time (HR:MM)

• High – 3:30
• Med – 7:00
• Low – 14:00
• Flash – 100+

Output (lumens):

• High – 900
• Med – 450
• Low – 225
• Flash –
  

The Light & Motion ARC was the top-rated light system on singletracks in 2008 but the bad news is Light & Motion doesn’t make the ARC any more. The great news is the replacement, the Seca series, makes some huge improvements over the popular ARC line.

The biggest improvement the Seca brings is the use of LED lamps instead of the HID lamps used in the ARC. LED uses less power than HID and is more rugged than other bulbs. The Seca uses 6 LED bulbs to produce 700 lumens when set to “high” – but as we found out raw light output isn’t the whole story.

The Seca is designed to maximize and focus the power of all 6 LEDs into the areas where you need to see the most. Three of the bulbs focus on a center spot for long distance visibility while the other lights illuminate the edges of your field of vision without wasting light around the top edges. The optical engineering that went into this design is pretty high tech as you can see from a prototype of the reflector here. The resulting beam pattern is in the shape of a closed eyelid as you can see in the center of the photo above.

Because LEDs produce most of their heat on the bulb side (rather than the beam side like HID) the Seca has an interesting looking heat sink on the back. Light & Motion sells three versions of the Seca (the 400, Race, and Ultra) but here’s the secret: They all use the same light, just different batteries! So if you can’t afford the top of the line just yet, buy the Seca 400 and upgrade your battery later – sweet.