Seeing the light: The case for dynamo lighting

From the depths of winter, where the days are short and the darkness is long, I thought I'd write something about dynamo lighting and bicycle lighting in particular.  Many things about bicycles are somewhat idiosyncratic, particularly the types of bikes people tend to ride; in particular aspects like luggage, convenience and lighting.  The trend toward racing bikes for non-racing purposes has meant that lighting has become an optional extra, and even then it is by default battery based.  Most of the bikes ridden around the world are for transportation purposes, not racing, yet most in the Anglophonic world use battery based lights. A car that had lighting attached with silicon rubber bands or velcro and had to be recharged weekly would be totally unacceptable.  People are used to the convenience of being able to jump in the car and be able to drive at night with integrated lights, why is this different with bikes?

My own experience with lighting on bicycles:
  For a long time the lighting on my bikes was battery based, starting with some good quality Cateye flashing type lights, however the bike got stolen and subsequently returned without the lights.
Over the next few years I used a mixture of cheap torch style lights bought online which ran on AA batteries.  In the winter though I would be using them for the ride home every day which meant I would be going through a set of AA's every second week, even then towards the end of the period the light output was at a diminished capacity.

I finally bit the bullet and bought some proper rechargeable lights, from  which are an Australian company that is quite well regarded amongst MTB'ers and road cyclists alike.  These blew away anything else I had, and consequently I felt a lot safer.  Cars treated you with a bit more respect and you could actually see what was on the road in the dark.

I used this for several years, I had encountered dynamo lights before on a few bikes, but mostly of the sidewall variety.  At that point in time I didn't really have much of an opinion of them, I could see the convenience as a plus, but the inability to swap them onto different bikes would be a negative, also the lights I had seen were less than spectacular.  I had however started to see some good modern LED based dynamo lights on other bikes, they looked smart and they didn't go out when the bike stopped.  My own personal adventure with dynamo lighting started when I bought a Raleigh Twenty which had a Sturmey Archer AG dynohub on the rear.  I did a bit of research and ended up installing some LED dynamo lights on it myself.   This was my first personal taste with modern dynamo lights, they were quite cheap to add because the hardest part, the dynohub was already there.  All I had to do was wire the front and rear lights up.  Although initially I did get this the wrong way around and the lights were on permanently regardless of the switch position.

However this experience was generally all positive, sure they weren't as bright as my Ayup lights but they put all the light on the road in a nice comparatively even trapezoidal shape.  The Ayups tended to project a semi-ellipse shape with a hot spot in the middle.  What I really loved the most about this set up was that I could jump on the bike and basically just ride anywhere without having to think about charging lights or anything like that, the experience was like using a car, like proper transport.  The other positive was that I would always flick on the lights whenever it was overcast or rainy.  With battery lights, conserving energy was always on my mind, so in reality I would only ever turn on my battery lights when I really needed them at night.

The Ayups still had their place, on my Cinelli and Mr Ramen my touring bike, neither of which was used for day to day commuting but more for recreational and sport riding.  I used them several times a week on morning club rides on the Cinelli.  However, fast forward to today and I'm a big advocate of dynamo lighting on bikes for most utilitarian purposes and some recreational purposes.  I've thought about why that is and listed them below:

1.  Convenience
The sheer ability to never ever have to worry about charging lights, batteries running low or flat, replacing batteries after a few years and being able to use them when you need them; without the worry about them running flat.  If you typically commute on a very rigid predictable basis, then recharging batteries may not be that much of a hassle.  However my lifestyle would mean that occasionally I might decide to go out after work or go for an early ride or late ride during the week or weekend, basically less predictable.  Dynamo lighting means you just ride whenever you want to without having to let your bicycle lighting influence your choices.  It gives you flexibility and freedom, which I think are exactly the kind of qualities I enjoy about cycling generally.

Lights on is just a flick of a switch
or even automatic when it gets dark
if your headlight has a light sensor.
  When you ride all you need to do is flick one switch and start riding, if you have a front light with a light sensor you don't even have to do that.  With battery lights you have to mount them again front and back if they were removed, then you have to usually press the rear light button several times to select the correct mode.  Then on the front you have to connect the battery pack to the light unit if they are separate and then turn it on.  A car which was this much hassle would not be sellable!

2.  Reliability
I've rarely had any failures with my current dynamo light setups, one time on the Twenty I had a bungee cord get stuck in the chain which meant I had to pull the rear wheel out, I forgot to disconnect the dynamo wiring and accidentally tore off the connectors which meant I had no lights until I fixed the connectors.  Other than that, riding in rain, snow and sunshine they have never failed me.  I have had many many failures with battery lights, the most common ones being the lights falling off their mounts. This is however more common with really poor quality battery lights.  Also I've had many battery lights fail due to water ingress shorting them out and rendering them useless.  This includes the Planetbike Superflash that I still have, the switch is located on the bottom of the unit where water will tend to pool if it gets past the seals.

3.  Mounts
I have nary seen a battery light with as good a mount as a typical dynamo lamp, even the old crappy halogen lamps you find on old 3-speeds is a lot more secure a mounting than A$300 Ayups which fix with zip ties...  However this is probably due to the different design intent, dynamo lights are meant to be fixed once and rarely removed.  Most battery lights are meant to be removed and refitted every time the bike is locked up in an insecure place; however this begs the question, shouldn't lights just be a permanent integrated fixture of the bike much like on cars or motorcycles?  The problem with this as well is that each time you unmount and remount the lights they have to be repositioned, there are some lights which have a quick release system which holds it's position but they still are somewhat semi-permanent.

The Ayups shown on my bike above, show that even high end lights still attach with... zip ties.  Whereas a cheap entry level dynamo light like on the Twenty below is a steel bracket bolted through the brake bolt hole, much more secure and permanent.

The other problem with poor mounts is that typically almost all battery lights mount on the handlebar which is circular in profile and positioned perpendicular to the direction of movement, this typically means that less than perfect mounts will tend to rotate downwards towards the ground.  I'm sure anyone with any experience with handlebar mounted lamps will know what I mean, this is exacerbated as lights get brighter and therefore larger until you get ungainly monstrosities like this:

Because of the nature of dynamo lights, they are much less of a theft target, dynamo lights are a pain to manually install and you have to know what you're doing.  Most battery lights are really just LED torches with mounts for the handlebar.

Beam shape:
When I first started riding with modern LED dynamo lights the first thing I noticed was the properly designed beam shape.  This was a world away from the Ayups which are really just a conical beam with a hotspot in the middle.  The B+M unit I had, had a focused trapezoidal beam shape which is evenly distributed onto the road, it also projected a diffuse light around a 270ยบ arc for side visibility.  From then on, whenever I used the Ayups, I noticed that the hot spot it projected onto the road actually decreased my visibility comparatively; my eyes would adjust to the brightness of the hotspot and therefor the road surrounding the hotspot would be less visible.  With the B+M unit the whole beam would be evenly lit and I could actually see more even though they weren't pumping out as many lumens.

B+M Dynamo headlight beam shot

Ayup beam shot showing the hotspot in the middle
The other factor to consider is that the beam shape is a lot more friendly to oncoming traffic, be it other cyclists, pedestrians or drivers.  Almost all modern dynamo lights have a vertical cutoff in their shaped beam design, much like the low beam of a car headlight.  Thousands of hours of labour have gone into designing the lenses and reflectors to create a beam shape that will light the road up but not blind people.  The Ayups have a tendency to create glare for oncoming traffic, I have witnessed other cyclists with these lights or worse the infamous Magicshine.  This is also due to their intended purpose, lights like the Ayups are really just glorified torches, they are meant for off-road and closed circuit racing, much like using the auxiliary lights on an off-road 4WD.

Dynamo lights put almost all the light onto the road and the space just above it.  Typical battery lights just create a symmetrical cone of light forwards and a lot is wasted on the space above the road, there is no way around it other than to have a properly design reflector or lens.

I tend to see dynamo lights as effectively safer than battery lights inherently.  They are more likely to be turned on because the rider never has to worry about running out of battery and also because they either turn themselves on or they turn themselves on if they are automatic.  Weather sealing is on average a lot better, usually they are designed with proper seals and drain holes.  Mounts are much more solid so they are less likely to break over bumps and leave you in the dark with a broken mount.

More importantly, they always run in solid light mode, no flashing.  One of the big reasons that battery lights tend to flash by default is to save battery light as well as to attract attention.  However the problem with flashing lights is that they are harder to track when the object is moving, also front flashing lights don't let you see where you are going, rather they only alert others to your presence.  Typically the beam designs on dynamo lights are much better designed, most battery lights are really just high powered LED's with little thought to how that light is distributed.  So often I see battery lights being used that are very dim because their batteries aren't at 100% charge, dynamo lights stay at 100% brightness once you are above about 10-15km/h, typically they are at about 80-90% at about 10km/h.  Most dynamo lights are built to meet German StVZO standards which are the strictest in the world for bicycle lighting.

Even though I am a big advocate of dynamo lighting, I realise that they have their shortcomings as well.  The first and biggest shortcoming is installation and setup.  Other than enthusiasts and custom jobs, most people will never use dynamo lights because they are too difficult to retrofit onto an existing bikes.  The problem is that most bikes sold in the Anglosphere don't come with them from the factory which compounds the problem. Also they are not quickly swappable from bike to bike like battery lights, which means if you have several bikes you like riding at light, they can't really share lights easily.

Secondly the other problem is that the shaped beam of a dynamo light may not be as useful for most for off-road riding where a large flood beam is better suited for spotting stray branches and other obstacles. The other factor to consider is that battery lamps can typically put out more lumens at an instant, where most dynamo lamps are limited to the nominal 3w 6v standard.

Thirdly, the dynamo creates extra drag and weighs more than your typical battery setup.  The drag is more of an issue with sidewall dynamos, however these are mostly falling out of use except on very entry level setups.  Most hub dynamos are very efficient in comparison, with the most high end ones creating only a tiny amount of drag - the Schmidt SON hubs create drag equivalent to a 1m climb over 1km when switched off.  This minuscule amount of drag does matter if you're racing, however I'm quite happy to be a few seconds slower if it means I don't have to spend 5 mins every week fiddling with batteries and mounts.

Dynamo lighting is not for everyone, however it tends to be more or less standard in countries like the Netherlands and elsewhere where cycling is everyday and utilitarian.  The bike should be seen as an integrated machine which can carry luggage in inclement weather and be ridden at night as well with the minimum of fuss.  If only more bicycles came with integrated lighting then cycling would be seen less as a recreational fringe activity and more as transport.

I would wager that many people, given the choice when purchasing a bike for commuting would be happy to pay a little bit more to never have to deal with charging batteries or attaching and unattaching battery lights.  The Dutch buy less bicycles per capita than a lot of other nations, however they get many times over, more mileage and don't replace them as often.  Even if a dynamo equipped bike might cost more to begin with, they do not take long to pay for themselves.


  1. Nice and thorough! Welcome to the "light" side!

    I've been a big proponent of dynolighting as well, with it on two of my bicycles. I really like the beam, as even my really nice rechargeable headlamp is just a conical beam. I'd like to get dynamo lighting on my mtb, but that will have to wait a bit. (Or I may experiment with a sidewall dynamo for a bit.) I've gotten around the whole handlebar mount for battery lights by doing a hack:

  2. Heya, nice hack you have there for your Wald basket. I had to fudge a similar light mount for my Wald basket except for a standard dynamo light front brake bolt fitting

    I've still got the battery setup on my touring bike and have been thinking about converting it to dynamo at some point, although I don't quite ride it often enough in the dark to justify it.