Dynamo + USB + Front & Rear Lights setup

Gear / Kit

There are many pros and cons to discuss on whether a dynamo should be used or not. This is not the article for it, it assumes you’ve weighed those up and have gone the dynamo route.

Now, you have a dynamo installed (in my case SON Deluxe on the HUNT’s SuperDura Dynamo Wheelset). But you are not using it. The next decision is do you want to connect only lights or you also want a USB charger in there. I’ve decided to have all of those (again the reasons are personal).

Lights and USB charger

So here’s what my choices for lights and USB charger look like:

Good alternatives for the front light would be the

And alternatives for USB chargers:

Additional connectors

Connecting them together

There are multiple ways to connect all components together. This is where I struggled the most in deciding. But a few key considerations made the decisions for me.

  • Easily switch off the lights and use them during the night and be able to charge using the USB during the day. Have the option to charge and have the lights on if needed.
  • The USB charger didn’t need to disconnect from the system as it would only draw energy if something is plugged in the charger (if you prefer to be able to switch it off, you can use the kLite switch harness).
  • I wanted to be able to disconnect all elements at any point for either swapping them out or maintenance. This meant no permanent soldering, they would all connect via connectors.

A note – my Supernova front light has a on/off switch which is very handy as I can turn it on and off while riding. Because of that, I didn’t need to have a separate switch. If your light doesn’t have a switch, you might need to either a) be able to disconnect the cable or b) install the above kLite switch.

The USB charger really doesn’t need to disconnect (in my opinion) and this could simplify your system. But if you wanted to, then you can consider unplugging the cable (possible with my system below) or adding another switch (really?).

The system

The barebones of the system:

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The system with some comments:

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Real components preview:

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This system is what I would have liked to see when making my decisions. It does look quite daunting if you haven’t been exposed to something like this before. I will add some more details based on comments and requests.

An important note is that I didn’t trust myself to do the soldering and asked Mike from Tony Butterworth Cycles (Sheffield) to do it for me. He did an amazing job, but while watching him do it, I was glad I didn’t do it myself. In particular, soldering the wires into the connectors is quite delicate and I think you need to know what you are doing.

You can skip the connectors and the junction box and just solder everything together, that would be the simplest solution. It is perfectly fine and would function no worse at all. In fact, it might be more weather-proof depending on your skills.

However, I do love the connectors and the adaptability of this system. It means I can swap any component (apart from the junction box which is soldered to the front light) if I wanted to fairly easily without disrupting the rest of the components.

Also, the SON adapter that connects to the dynamo is very solid and has an extremely good connection (it won’t budge). Which is important and I prefer it to the other alternatives I’ve seen out there.

Finally, make sure to follow the instructions in the junction box kit. It comes with heat shrink wraps which you need to put around all the soldered bits (connector, junction box). Make sure you put the heat shrinks onto the cable before you solder components together, otherwise you won’t be able to put them on afterwards.


I love this system and it is the result of months reading and researching (you don’t want to see my notes). Many of the components can be argued, but this is not the idea of this post (it’ll be too long). It simply shows you my solution. If you have any comments and questions please put them bellow and I will update the article respectively.

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