First Impressions – Luxos U Dynamo Light

by Andy Amick on March 20, 2014

in Bikepacking, Cycling, Gear

For my Tour Divide setup, I decided to go with a dynamo hub and light system.  This is my first experience with dynamo based lights, but I can say that I’ve been thoroughly impressed.  I pedal and then the light and my GPS turn on.  Magic!  There is no need for batteries.

Luxos U 70 lux dynamo light

After researching a variety of lights, I chose the Busch and Muller Luxos U light which also has an integrated USB charger.  It’s true that an integrated system has the drawback of having both parts potentially break at the same time.  However, I already have a helmet mounted light for backup and my GPS could run off of batteries if needed.  The single point of failure is a risk I’m willing to take for the benefit of a simple setup.

So far, I’ve only ridden with the light on dirt roads.  Once the snow melts and trails dry out, I’ll test it on singletrack.


The light operates at 70 lux during normal operation with an option to switch to a 90 lux flood light for extremely dark or technical terrain.  There is no real way to convert lux to lumens for comparison.  From my testing, 70 lux is really bright and plenty strong for night riding.  Back in college, we used to ride with 15W lights, and those would not even come close to the brightness and power of the Luxos U.

The weight is…well, I have no idea and never even looked into the weight.  Based on the fact it has the light, a cache battery, and the USB output, it’s going to be a bit heavier than other lights.  Even though I’m a weight weenie for some gear, I was willing to go with a larger, heavier light to get the built in USB integration.


The first thing that jumps out about this light is the width of the beam.  On a two lane road, it illuminates the entire road surface.  For trail riding, I imagine this will help light the trail during turns.

Turning on the light can be done with the switch connected to the light, or with the switch located on the USB output.  Both of these switches are easily operated when wearing bike gloves.

Luxos U USB chargerThe USB charger powers my eTrex 20 GPS unit without any issues.  After a few minutes of riding, the cache battery charges up and will keep the GPS powered for several minutes after stopping.  Even if the cache battery is depleted, the GPS unit powers back up after riding for a minute or two.  Instead of letting the GPS deplete the cache battery, it’s best to turn the GPS unit off if stopping for more than a minute or two.

Charging phones with the Luxos U is also very easy.  My iPhone will charge 30% per hour when it’s plugged into the USB output.  Since most chargers have a USB plug, the Luxos U should work with almost any phone without any extra cords.

More To Come

Once I’m able to test the light on some singletrack and capture some pictures, I’ll do a more in-depth review.

If my initial testing is any indicator, the Luxos U will perform exceptionally well for trail riding.

About Andy Amick
A little bit nutty in general, a lotta bit nutty about bikes. Each of his boys received a bike helmet for their first birthday and the three of them have been biking together ever since.

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