How to Fix Dynamo Bike Lights | Step by Step

how to fix dynamo bike lights

You must love the dynamo lighting. Why won't you? It is more reliable and comfortable to use in all seasons. However, it is not a perfect light that will never need fixing. But for that, you have to learn how to fix dynamo bike lights first.

Fixing a bicycle bike light is quite an easy and possible task. If you have a basic understanding of electronics, you can light up a bike light again. Repairing requires a set of tools and electronics. Now, if you don't know the requirements for the fixation of a dynamo bike light, then you should go through this article.

But first, you must learn about the dynamo lights and their benefits. So, let’s start.

What is Dynamo Lighting?

The dynamo lighting gives you the advantage of not charging your bike lights; instead, you will produce light while pedaling. Not clear enough? While you drive, the mechanical energy generated is converted into electrical energy, and this way, light emits. It's a mechanism of rotating copper wire coils in a magnetic field.

A dynamo uses turns to produce electricity rather than using electricity to create rotations. A bicycle dynamo is commonly placed in two locations—beside the wheel (bottle dynamo) and in the middle of the wheel (hub dynamo).

how to fix dynamo bike lights

Why Should You Have Dynamo Lighting?

  • It's bright and provides consistent lighting in every weather. It's highly visible, and you feel safe riding with it.
  • You don't have to carry any battery or replacement; you can enjoy the ride without any tension.
  • It has an automatic activation system.
  • You can save the money for purchasing batteries or replacements or paying fines for not having bike lights.
  • Thieves find it challenging to steal these lights.
  • Its self-generating power system provides you with unlimited light.
  • These are durable and have long-lasting high-frequency LEDs.
  • The latest dynamo bike lights are silent, and you get to have a sound ride.
  • The new dynamo lights are high-performing and come with low resistance.

Now that you know the benefits of dynamo lighting, you should also know how to fix them. Yes, they are long-lasting and reliable, but what will you do if they are broken or are damaged. Will you dump them? Well, if you have the option to fix them, you should go for it.

Let’s learn how we can fix our dynamo bike lights.

Read More About: Best Bike Tail Light on the Market 2020

Fixing System of Dynamo Bike Lights

1. What are the problems you can have with your dynamo bike lights?

There are many types of dynamos. They have two electrodes generating the power and a rotating part. If you have the dynamo light that rubs against the tire side, there is a massive chance of breaking down after some years.

And if it gets worn out, you will have difficulties in riding as it will give a lot of resistance when pedaling.

What can you do?

My advice is to remove the whole thing and not bother replacing it. Just get some battery-powered lights; they are cheaper, more reliable, and don't add any extra resistance while riding.

In this case, you don’t have to bother replacing it. You should remove it.

2. Dynamos are attached to the light through some wires; this is a weak point here. Some bicycles have only one wire connecting to the light. You might have broken wires.

What can you do?

Usually, it is the most straightforward remedy. You can easily replace the whole thing if you have broken wire. You can try making the wire a spiral around the place where the frame and the front fork are connected.

How can you fix the broken wire?

You have to cut the wire open, cut off the insulation on each terminal. Using some heat-shrink tubing with a heat gun, you can join the pieces together.

Remember not to solder in the parts where the wire to be bend or flex. Well, soldering tin can break when stress is given once cooled down. It is not flexible.

3. Most of the dynamos for bicycle produces alternating current with a current limiter (max 1A). If, in any case, a part of the electrical circuit of your bike is accidentally moved to the ground, there will be no light. Again, if the headlight has more current than the dynamo can produce, then the current limiter of the dynamo might shut it down.

What can you do?

To inspect the problem, you need a multimeter with an AC voltage detection and a continuity tester function.

You have to determine which output of the dynamo is attached to the ground and which one is hot. In case there is only one output, then it's hot, and the frame is the ground. Apply the AC tester and check if your dynamo is generating 5 VAC when the wheel is rotating.

With the continuity tester function, see which output is attached to the frame ground. If one of the outputs is moved to the ground, then there will be a fault in your light.

You must check if the light is drawing more current. You can use 4AA batteries or USB power packs for this. You can even use the current function of the multimeter. Keep in mind that your light mustn’t drain more than 2A.


Many times, you forget to carry chargers or charge your light batteries and hop on the bike. Well, a dynamo light comes in to rescue in those cases. It is always ready. And you get unlimited light.

When it comes so handy in times, you must know the basics to repair the lights. And we have tried providing you with every detail on how to fix dynamo bike lights. It would be best if you repair the lights when you have the option to do it. This way, you can save money for a new bike light and enjoy your bike light benefits.

How to Fix Dynamo Bike Lights | Step by Step 1

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