Bottle Dynamo fit to a Light

How Bicycle Dynamo Works | Best Dynamo Lights

How Bicycle Dynamo Works | Best Dynamo Lights

There are a lot of moving parts in a Bicycle, but one of the few important parts that actually produce free electricity is the Dynamo Hub. Not a lot of bicycles have them because these are essentially add-ons.

Bicycle Dynamo uses the Farraday principle to produce electricity when a magnet attached to the rim of the tire. When this magnet spins over a coil that remains stationary, Direct Current is produced. The major use of this is to create Direct Current to power additional fittings like Bicycle Lights or even a Cyclometer. There are different types of dynamos used in Bicycles, read on to know more.

Why is Dynamo used in a Bicycle

If the main purpose of the Dynamo is used to produce electricity, then replace it with a battery unit! This is what I initially thought. However, Dynamo is the simplest example of how physics can be used to produce free electricity without having to pay for it! Yes, the simplest dynamo costs around 600 INR or less than 10$ plus the cost to fit in the bicycle(considering a decent dynamo), and can be used to produce electricity to power lights and other DC electronics on the bicycle for free.

Dynamo is a free source of current to power the bicycle lights, they do not run out of electricity at all, takes 0 maintenance costs and are absolutely clean on the environment. If required, attaching a battery pack to store the Direct Current is a brilliant way to provide an endless supply of electricity for firing up the bicycle lights and your cyclometer.

Types of Bicycle Dynamos

There are primarily 3 types of Dynamos used currently in bicycles,

  • Hub Dynamo – The popular choice among a lot of bicycle riders. The Hub dynamo is light in weight and directly goes into the Tire hub. The Hub dynamo is also sturdier and fits tight. No worry of rain as it is completely concealed inside the hub. They are also efficient as it produces consistent current without any loss in the magnetic coil.
    The picture below explains how the Hub Dynamo is used on the rear tire of the bicycle.

    Hub Dynamo
    Hub Dynamo(Source: Bikeforums)

    The Hub dynamos produce either a 6V or a 12V DC depending on how the hub is fit. A typical current supply is around 6V for lights and cyclometers to work and that is also the regulated range in most of the countries.

  • Bottle Dynamo – These are dynamos that are dependent on the use of a bottle like attachment fitting to the tire of the bicycle. The bottle is fit very close to the tire and it typically spins when the tire spins. This, in turn, turns the coil and the electricity is produced. The picture to show how the Bottle dynamo is used is shown below
    Bottle Dynamo fit to a Light
    Bottle Dynamo fit to a Light

    This picture is a good example of how the Dynamo is fit. The bottle that is seen as an additional component behind the light is kept close to the tire and spins every time the tire spins. The problem however with Bottle Dynamo is that it is prone to slippage if the fitting is not proper. It also produces wear and tears on the Tire or the Rim with a bottle like fitting continuously running over it. Bottle dynamo is really easy to mount and is also cheaper in price compared to the Hub Dynamo but, current produced is minimal.

  • Bottom-Bracket Dynamo – No longer manufactured, this dynamo, however, was good on a city bike without any treads. It would quietly stay below the chainstay and in-between the pedal and the rear tire. They were good powerful dynamos but were not useful on a lot of modern bicycles with treads, hence they have been discontinued from manufacturing.

Are Dynamo Lights good

The answer to this question is through another question. How important is bicycle lighting for you? are you currently in a place where it gets dark fast and it is quite unsafe to ride without any lighting equipment on your bike? Then the answer is yes, Dynamo lights are an excellent choice for providing free electricity compared to battery-powered lights.

Even though the setup costs might be anywhere from 15$/ 900 INR to 100$/6000 INR, these lighting setup is great for night riders. No worry about the battery running out and most importantly replacement and maintenance worries. The average dynamo works for 7 Years with minimal wear and tear after which the copper coil inside does get a bit of wear and tear and does not produce the same output as earlier.

As far as lights on the bicycle are concerned, there is some really good lighting equipment which pairs well with the Dynamo, check this article on Lights for Nightriders to buy one.

Cyclometers are also another important equipment that requires electricity, even though a lot of modern cyclometers run on batteries only, some of them can be modified to be run through a Direct current power supply. Doing so would also increase the lifetime of the Cyclometer since, the inbuilt battery would mean, the lifetime is anywhere from 2-3 years max after going to multiple charging cycles!

Make your choice based on the need, as dynamos are a really cost-effective way of keeping your bicycle equipped with lighting almost all the time!

“Happy bicycling”

Leave a Comment

Your email address will not be published. Required fields are marked *