Originally Posted by
ItsJustMe
How do you get a decent lighting system if you only have 3 watts to deal with? I run 5 watts just on my tail, and I certainly would not be willing to reduce that. Even with an efficient shaped beam I'd think you'd want at least 3 watts up front as well. My current light draws 8.5 watts, I imagine a shaped beam could get that down to 5 and still seem reasonable, but I'd think 10 watts would be a minimal amount of light I'd want to commute with in total.
I'm not trying to diss dynos. I'm getting involved with the discussion because I'm interested. Just not sure if I'm interested enough to drop $250+ and build a wheel in the middle of the winter, rather than just continue to use the $30 light that I'm reasonably happy with now.
What light are you using on your tail light? A quick search for 5 watt tail light only found a 0.5 watt tail light for me (admittedly, a very very quick search).
To your wattage question, I own a long list of lights, from very expensive (Seca 1400), to middling expensive (2 Dinotte 400L's), to cheap (a Dinotte 200l AA), and a Lumotec Cyo dynamo light.
The weird thing is, on my road bike I put 2 Dinotte 400L's on it, so 800 lumens total. The difference between low, medium, and high power is doubling the lumen output at each stage. But one of the weirdnesses of light is that turning up the power only gives me a perceived increase of about 10% more light. Believe me, I tried it again and again and again, and I just couldn't believe it - making the light twice as bright only helped a very little bit.
The shaped beam on a dynamo doesn't *just* avoid wasting light off to the sides. One of the problems with my big battery lights is that you up the power, then your adjust adjust to more light, losing some of the effect. When I moved to a dynamo light, one of the advantages was that I could still see off the the sides much like I could when the light was off. If I have my dynamo light I can see everything around me just like as if I didn't have the light on, but I can also see better in front of me where the light is actually hitting. (Note: This is also likely because I live in the city where there's some peripheral light, if you lived in the country things might be different)
You mentioned in another thread that you just bought and returned a Phillips Saferide, other than the abysmally crappy battery life, how did you like the light from the light itself for riding? A dynamo light will be similar to that (they also make the Saferide in a dynamo version).