Hervé's solar bike


My first Sun Trip, I did it with a Bosch motor Moustache bike. I was quickly frustrated by the constraints: I couldn't charge my battery with my solar panels while it powered the engine. I needed 2 batteries, one to power the engine while the other was recharged with the solar panels. When the first one was discharged, I swapped the batteries, it was restrictive.

So I decided to equip myself with a real travel bike on which I installed an electric assistance. Now I use it on a daily basis to go to work. For travel, I add a solar trailer.

Technical description


I bought a Histoire Bike bike, it is a mountain bike, steel frame, robust, that I found used on a very famous classifieds platform.

  • 1 single 38T tray
  • 29" wheels, DT Swiss rims
  • H-Bar handlebars
  • Seat shock absorber: Suntour deformable parallelogram
  • Berthoud leather saddle (French manufacturer), to preserve the buttocks

I opted for a motorization on the hub of the rear wheel:

  • Direct Drive wheel motor – Nine Continent RH212;
  • Grin Technologies Baserunner v4 Controller
  • Cycle Analyst v3
The battery

I chose to install 2 identical batteries 48V 12Ah, mounted in parallel, for an overall capacity of 1152 Wh.

The solar trailer

I bought an Aevon trailer, single wheel with suspension, fully foldable for transport.
I built a support for the panels with aluminum tubes of square cross-section, fixed by rivets and bolted brackets. The panels are glued to the structure with 3M double-sided adhesive tape.

Solar panels: 1 panel of 150 Wp permanently exposed, and on each side, with a hinge, 2 panels of 100 Wc, placed vertically when I drive. When stopped, I unfold the 2 side panels for a total power of 350 Wc. The width of the trailer of 55 cm makes it possible to sneak everywhere.


  • I really appreciate the comfort and safety of the steel frame, the comfort of the 29-inch wheels. My engine never heated up in the mountains.
  • I use my bike on a daily basis and when travelling. To date, I have traveled 12,000 km including 4,000 km with the trailer, for the trip, and 8,000 km to go to work, without trailer.
  • What saved my Sun Trip Alps: the fact of having 2 medium capacity batteries rather than one large capacity. Indeed, in Slovenia, a battery was no longer charging because the BMS was defective. I was able to ride with only one battery while waiting to be able to repair the other. If I had only had one battery, I would have been stopped on the spot.
  • I am pleased to have chosen a folding trailer: when the holidays are over, I can fit the dismantled solar trailer into a roof box. My bike and my wife's bike are placed on a bike rack, in the back of our car (small city car).
Areas for improvement
  • At first, I had a lot of breakage on the spokes of the drive wheel, which caused me a lot of trouble. I had to replace them with spokes of higher cross-section, in a stronger steel. I advise you to check the quality of the rays before leaving for a long trip.
  • In the Alps, I found my bike too heavy (50 kg with trailer, no luggage).
  • I regretted the poor efficiency of the panels, probably due to the poor quality of the photovoltaic cells.
  • I regretted not having a larger panel area permanently exposed. The autonomy of the bike often suffered.


For the Alps, a single tray of 38 teeth was insufficient, I will evolve to a double tray system 34 / 40T.
I am tempted by the addition of a suspended front fork, for more comfort and safety.

My next bike

Maybe one day I will switch to recumbent cycling for reasons of comfort and less fatigue at the end of the day.