Three posts. I have done three posts in the last three years, and not very interesting posts. You haven't heard how I quit smoking, lost weight, took up Pilates, travelled to Paris, or any of the other interesting things that have been going on in the past few years. You might never hear about them. I suck.
That's about it for whining then. Let's talk about lighting.
You're a bicycle commuter, and you've decided to commute through the winter. You've made it through a couple of winters commuting on nice days, hopefully without getting killed or the bejesus scared out of you. You are officially a full-time commuter; you may even have given up the car completely. Maybe you're contemplating fenders, or you've got some kind of detachable fenders for when it rains or gets gunky outside (slushy, salty, wet roads that happen be more of the riding you do than actual ice- and snow-riding). You may not have a fixed gear, yet, but you are definitely commuting all year round. You need to start thinking about lights.
You know about wet, but you haven't thought much about dark. However, by the time we've gone off daylight savings time, we are commuting for months in the dark.
Most places require lights on bicycles under the same rules that cars are expected to follow; bike-friendly communities actually enforce these laws. Lots of commuters buy a cheap blinkie and some sort of battery-operated headlight. These are inadequate solutions, because they fail to keep you covered: if the batteries fail, and they will, you're stuck in the dark, in violation of the law, but more importantly, completely invisible to cars. Running without lights has never been recommended for cars, though they seem to do it with about the same frequency that they run lights and stop signs, all the time complaining that cyclists pay no attention to these rules; the problem seems to be that cyclists get away with it more often.
You need a better solution. You don't want carry a huge battery pack to power a couple of blinding-bright halogens: those have to be charged all the time. You need human power. Lights that are always there, that never need recharging, that remain lit even when you are not moving, that even turn themselves on. And that is where generator lights come in.
Technology has been a huge boon to electrical lighting systems, and generator lighting has greatly benefited. Bottle generators still exist (remember the ones that rode on the sidewall of the tire? I know, it's almost before my time as well), but there are better options.
Generators come in hubs now. The hub is what the wheel turns around, and makes a very effective place to put a dynamo: a rotating part moving around a non-rotating part. It can be sealed against the elements, doesn't rely on friction from the sidewall, and generates power any time the bike is in motion. Shimano makes one of these.
But it is not just the generators that have advanced; so have the lights. Lights are available now that remain lit even when the bike is stopped, without using batteries. One of the mandates of the German laws under which all these developments came about was that battery-powered lights, or battery-backups, were too unreliable, and outlawed them as a bicycle lighting source. These laws were also responsible for insisting the lights not blink. Voltage regulators in the lights prevent them from burning out at high speed.
LEDs also make the lighting better. They last significantly longer than their halogen equivalents, and they handle variations in current better.
