Light & Motion Seca 900 Ultra Bike Light Review


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 —