Pierre’s solar cargo bike


Initially, I was a cycle tourist in my spare time. In 2021, I came across a Sun Trip video that fascinated me. Go to China by solar bike! Great!
At the end of 2021, I started to delve deeper into the subject by viewing everything that was possible. I was particularly interested in Eric Morel’s bike, a cargo bike on a Douze Cycles base. After a few weeks of reflection, a first draft took shape: it would be a cargo bike, as light as possible with panels at the front. On the other hand, at this stage I had a problem: if in terms of cyclo mechanics, I have a minimum mastery, for electricity, it’s something else, I’m close to zero…
So I left for the looking for a Douze Cycle cargo bike and at the same time for someone who could help me assemble this bike in a reasonable time. At the end of 2021, Douze Cycles was out of stock and despite my repeated requests, it was impossible to get a bike. It started off badly! Well, at the same time, Douze is reliable and solid but it’s heavy, and a little in contradiction with my idea of lightness.
Concerning the assembly, I contacted Guillaume Devot from Déclic Eco: a great welcome and good advice, It’s decided: we’ll work together…if I find a bike.

My specifications:

  • Most importantly, a bike that can be transported by car on a bike rack. So a light and easily disassembled bike.
  • A bike that also allows you to take the train (on this point, I was a little optimistic).
  • Stay on 2 wheels for performance (rather than 3).
  • Have a maneuverable bike with the lowest possible center of gravity and good mass balance.
  • Have a tilting solar panel to sunbathe when stationary and around 200 Wp.
  • A bike that can go fast on the flat. If it’s to only ride at 25km/h, I can still do it with an unassisted muscle bike, lighter and simpler.
  • A Direct Drive engine for silence, rusticity and to go quickly on the flat.

Technical description

The bike

At the start of 2022, I’m setting my sights on a Dutch OMNIUM WiFi cargo bike.

This cargo ship seems to have a lot of advantages:

  • lightness: the bike weighs 12.5 kg
  • a simple and solid steel frame
  • a single chainring and adapted developments, however in 11 speeds. Will there be room for the engine?
  • 2 solid mounting plates for the front tray which allow the solar panel support to be easily attached
  • and the icing on the cake, a psychedelic glitter color shining brightly in the sun varying from blue to purple depending on the orientation :-))
The bike

A word about the wheels.
The original rear wheel was changed for a much stronger DT SWISS with reinforced spokes. I didn’t want to mount the engine on the 20-inch front wheel. For the mountains this would obviously have been better for engine efficiency but at the expense of speed. On the other hand, to ensure the damping of the front of the bike and the relative protection of the panels from vibrations, the Schwalbe Big Ben front tire is underinflated to around 2 kg. It works very well and is very comfortable. On the other hand, I couldn’t see myself with an engine of this power on an under-inflated tire without the risk of rapid destruction of the tire!


The engine is a Direct Drive RH212 mounted on a 29′ wheel, it’s a bike designed for flat terrain. It’s true that by pressing a little we reach a…respectable speed. For the rest, a Baserunner controller, a crank sensor, a Cycle-Analyst V3.
Guillaume Devot from Déclic Eco did a great job, a clean and very professional assembly.

Consumption is low and you can do 200 to 250 km per day without much effort. In the mountains and in particular for the Sun Trip on the Tour de France, I had no problem with overheating despite the high temperatures. Maximum engine temperature: 60° on the Cycle-Analyst but it is true that we were riding rather light. To be tested on a major pass in the Alps.

The battery
Solar equipment or solar trailer
  • 1 300W MPPT solar charger fixed under the panels.
  • 2 panels one behind the other of 120 Wc each for a total surface area of 78×160 cm. These are the panels fitted to the Sun Travel from Déclic Eco, with SunPower cells. These panels have a matte appearance that does not dazzle the driver. They are mounted on a rigid frame made of Bosch aluminum profile with a 20x20mm section, all mounted on 4 ball joints and a central mast still made of 30x30mm Bosch profile.
  • The panels are adjustable using a system of cords and cam cleats which are simple and effective to use.

One of the initial objectives was to obtain a stable bike with a very low center of gravity.

The luggage is located under the panels with a 10l waterproof container in the center and 2 15l side bags located 10 cm from the ground. Above, 2 small racks for camping equipment. All fixed to the frame by curved threaded rods sheathed in flexible plastic tubes to protect the paint of the frame (the famous psychedelic paint! :-)).
The bag in the center of the frame was custom made by Déclic Eco.

At the bottom the battery and possibly the charger, at the top another storage space. It’s really well done.


Positive points

I am very satisfied with the result, after a few thousand km, no technical problems.
For long trips, it would probably be necessary to put an additional panel at the rear or on a single wheel trailer.
And then it’s quite rare for a solar bike, it can be easily transported on a car bike rack slightly adapted in width.

The total cost of the operation, new Omnium cargo bike + electrification + solarization: around €6,500.