The Shocking Truth

I have always believed that seeing things is important.  Here’s a photo of my bike from 1980+/-:

Raleigh Gran Prix 1980

See that white thing on the handlebars?  That’s a gen-u-ine bicycle headlight, vintage late ’70s, run off of two C-batteries, contained in the lower portion.  For me, this says something about how long ago it was that Americans started to ignore dynamo lighting.

It’s worth noting that dynamos continued (and continue) to have a healthy life elsewhere in the world.  But already, thirty-five years ago, we had turned away from the humble dyno.

Twenty years ago, I started seriously bike commuting.  By that I mean that I avoided driving unless the roads were icy, and sometimes even then.  But even more, I decided that the dark wasn’t going to stop me.  Here’s what I knew about dynamos/generators then:

(I also knew they were heavy.)

Clearly, sucky technology.

So when I installed lights on my bikes, they ran on batteries.  Cheap, easy to replace, light.  Sort of.  I graduated to rechargeable batteries.  Better, but heavy.  I went from 5-wattt to 10-watt halogen incandescent lights.  Good stuff.

Then, one November day in 2004, my wonderful light system failed me.  The mount went wonky on a rainy evening when I was returning from work.  No problem, I adjusted things and kept on.

And when I woke up some twenty minutes later, I was being put into an ambulance.

I never got that 20 minutes (or so) back.  I am told that as I was riding along, I apparently didn’t see a cut in the pavement that had been made earlier that day to allow replacement of a corner section that trucks had damaged.  In any event, I my front wheel dove into it and I supermanned over my bars and landed on my face.  Ensuing were serious road rash, a concussion (thus explaining the missing tape) and a broken jaw.  And an OTBSC T-shirt.

I recovered.  But during the six weeks my jaw was wired shut and I was limited to a liquid diet, I made a pledge to myself.  From then on, I was going to have good, solid, reliable lights.  And I would never be without them.  They would be mounted securely, and they would just work.

And so I entered the weird and wonderful world of bicycle electronics.  From somewhere, I secured a bottom-bracket generator, which seemed like it would be superior to the sidewall variety, and I installed this on my Kogswell D58.  I bought a BiSy halogen headlight, rated at three watts, but with a specially “shaped” beam designed to make maximum use of that power.  I wired these up and, lo and behold, there was light.  And it was good.

Around the same time, I started hearing about “hub” generators–very expensive units from SON, and less costly models from Shimano. When my bottom bracket dynamo started to show signs of slipping, I decided to bite the bullet (now that I could bite again) and I had Smith’s of La Crosse, a wonderful local shop, build a Shimano DH-3N70 into an existing rim, at a total cost (at the time) of around$130 or so.

It was heavy.  It was notchy.  Or so it felt off the bike.  But once I wired up my BiSy to it, I never once looked back.  I had light like a flamethrower, and only once a minor glitch, when I burned out the bulb in the BiSy after a long period of use (fortunately, I was carrying a spare).

Sidebar:  there’s a long history of people complaining about generators/dynamos burning out light bulbs when run at high speeds.  That’s really no longer true.  By the early 2000s, most headlights intended for dynamo use incorporated Zener diodes, which prevented the voltage across the light bulb from getting high enough to do significant damage.  There were also some third-party circuits aimed at optimizing halogen bulb performance through electronics.  I bought one, but never got around to installing it.  The Zener was good enough for me.

I played around with various halogen lights for a while.  I haven’t found any images of the BiSy, but this one is similar.  I liked it because the light’s reflector was surrounded by an external reflector that could be tagged by automobile lights:

These lights were very good, but there was news floating around of something better.  A light that was way more efficient and that lasted forever.  The Light Emitting Diode, or LED.  Unfortunately, LED headlights for bicycles were incredibly (for me) expensive.  So I bought some parts and made my own.  It looked like this:

(Actually, this was my second LED headlight.  The first was smaller, and used a single LED, but the idea was the same).

The housing was an old Sanyo headlight.  I gutted it, and installed the following extras:

1.  A switch (sticking out of the bottom of the light housing; the switch box behind it was something I installed later so that I could turn a headlight and taillight on and off at the same time).

2.  A rectifier.  LEDs are direct current, or DC, devices.  Dynamos pump out alternating current (AC).  A small bridge rectifier turns AC into pulsating DC–just what I needed.

3.  Two “3-watt” LEDs mounted to a heavy steel washer with thermal cement, the washer likewise cemented into the light housing.  The rationale for the heavy washer is that LEDs

4.  Lenses mounted to each LED–one was set for a narrow beam, the other for a wide beam.

This headlight was significantly brighter than any halogen I had used to date, and I settled in happily.  The ultimate power source, and the ultimate headlight.  What more could I possibly want?

Six or seven years later, I built up a new bike, lighter than the Kogswell.  I installed the dynohub, but discovered that LED lights based on reflectors, rather than lenses, now blew away my home-brew special.  I ended up with a first-generation Schmidt Edelux headlight and Spanninga Pixeo taillight, run happily off my Dynohub.  But there was something odd with the hub.

The bike was making a lot of noise on deceleration, and I traced this to the front wheel.  It wasn’t in the build of the wheel, but appeared to be related to some kind of resonance between the wheel and the fork.  That is, there was nothing wrong, but the wheel was uncannily noisy on braking.  Because I like my bikes silent, I decided that it might be time to look at other options.

And that brings us to today.  I have spent the last several weeks, and will spend the week to come, riding with and experiencing the pros and cons of various dynamo systems.  Later this month or early in August, I will begin a series comparing dynohubs, old-style sidewall generators, new-style sidewall generators, and bottom bracket units (though not necessarily in that order).

Bicycle lighting has changed a lot in the past ten years.  You’d be hard pressed to find any non-LED headlights.  But LEDs change the game in interesting ways, and they may make alternatives to the traditional battery and dynohub options more practical.  So tune in, same bat-time (or something), same bat-blog!


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2 Responses to The Shocking Truth

  1. Pingback: The Shocking Truth, Part 2 | Law School is So Over

  2. Pingback: Love Your Battery | Inter Alia

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