I finally made a decision on my lights! Normally I like to use lights that can easily be removed to keep the bike looking sleek-ish. This bike is, however, not sleek. It's more like a giant monument to bike dork-dom. So big, flashy, sophisticated lights sounded like the way to go.
Behold the German-made Busch and Muller Luxos-U! It's the top dog in dynamo-powered lights. There isn't much that's brighter and this is the only light I know of that has a built in USB charger for charging almost any electronic device smaller than a iPad.
First there's the light, because most importantly it has to work well as a light. The light is very bright but spread out very evenly. You get a beam about 15-20 feet (4.5-6 meters) wide across with usable light across the entire beam. The light at the top of the beam is the brightest which makes sense since it would be shining on the road farthest ahead of you. The light also powers a tail light which is a Busch and Muller Toplight. The rear light is equipped with its own capacitor that keeps the light on for 3 or 4 minutes when fully stopped.
What's really remarkable with this setup is Busch and Muller designed the headlight to be sensitive to the amount of current coming from the dynamo. This tells the brighter LED's to shut off when the bike slows down and directs power to the smaller LED's at the front of the light for visibility. Busch and Muller said the light should dim at around 9 mph (15 kph) yet it seems the dynamo provides a substantial amount of power; enough to keep all the LED's on down to 3 mph (4 kph). So it's only when I'm pretty much at a full stop that the light starts to dim at all. This is excellent for slow climbs or technical terrain where a lot of light is needed but there isn't a whole lot of speed to power the dynamo. The SP Dynamo has exceeded my expectations.
At the rear of the light, there's a multifunction button. You hold it to power the light on or off and tap it for the floodlight function. A second button on the USB charging port does the same thing. The floodlight basically pumps extra current from an internal battery to the light for a more powerful beam. The difference is definitely noticeable. The lights at the back indicate normal beam / floodlight / tail light status. The orange light in the picture is just saying the headlight is on.
I tested the USB charging feature on a long ride and hooked up my Samsung Galaxy S4 to the port. The USB port works exactly as you would expect with one exception. The internal battery in the light has to be topped off before any current can be spared to charge your cell phone. This means that if you stop at an intersection, the charging will be interrupted. It will start again after you've pedaled for a minute or two. This is because at each stop, the battery takes over to keep the light on since there's no current coming from the dynamo. I suppose if you turn the light off, the charging can go uninterrupted but I haven't tried doing that yet.
This is the light as a motorist would see it when the bike is stopped at a junction. The front light stays on under it's own power for quite a while before shutting off. The USB charging port can be seen just below the stem on the steerer tube.
One of the biggest trade-offs with dynamo lighting is the unsightly wires that have to be routed throughout the bike. I was able to avoid some of the ugliness by routing the leads from the dynamo to the headlight inside the fork leg. The wiring from the front light to the rear light however was a different story. Since there's a lot going on underneath the down-tube, I decided to pair it up with the rear brake cable. I might reroute it some other way in the future but for now this is the best I can do. It's not the worst wiring job ever seen... is it?
For all of those who are interested in seeing the light in action, I took a couple of photos from about 18-20 feet (5.5 - 6 meters) away from the fence in my backyard. The lighting in both photos is as close to the actual lighting as I could get. This light is BRIGHT.
I've become a fan of this light for it's features and the extremely good visibility it provides, both for the rider and for those nearby. Anyone looking for self-sustained visibility should take a look at a dynamo setup like this.