A hybrid Sun/muscle-powered trike!
The purpose of the Solar Bear Vehicle is to:
- Use solar panels as trike's body,
- Consume electrical energy where it is produced,
- Produce its own energy,
- Transport people inside cities,
- Be pedalable when there is no sun or battery,
- Power the home when stationary,
- Carry big luggage,
- Reduce noise inside cities,
- Be easily built at home,
- Motivate people to exercise.
- recumbent trike,
- 2.5m long, 1.45m wide (including wheels),
- weight: about 55kg (including panels, motor, battery, etc, excluding driver),
- assisted pedaling,
- motor speed: max 25km/h,
- motor (continuous) power: 250W,
- solar panels power: max 520W,
- battery: 12.8V, 20Ah (256Wh).
https://www.facebook.com/profile.php?id=61585957465461
https://www.instagram.com/oltean.mihai.nicolae/
https://www.youtube.com/playlist?list=PLQGhVlOwtdFBKP8Y_jEWzZ9uS2IxMESxs
Town: Cugir, country: Romania.
Prices are specific to my region (Cugir, Romania). I have not searched for better prices from distant stores. Prices do not include shipping (because I purchased the materials from nearby stores and the shipping was free).
Will be updated ...
| Material | Quantity | Unit | Price per unit (EURO) | Total price | Utilization | Where to buy |
|---|---|---|---|---|---|---|
| rectangular tube (steel) 30x20x2mm | 4.2 | m | ? | ? | base frame | local store |
| rectangular tube (steel) 15x15x1.5 | 2 | m | ? | ? | panels support | local |
| L profile (steel) 25x25 | 90 | cm | ? | ? | rear side | local |
| round tube (steel) 1" | 90 | cm | ? | ? | front wheels | local |
| rectangular tube (steel) 40x40x2 | 0.4 | m | ? | ? | Castor angle | local |
| conic bearings (14/35mm dia) | 4 | pcs | ? | ? | front wheels support | local |
| aluminium tubes (25mm) | 12 | m | 5 | 60 | solar panels frame | local |
| wheels (front): 20" | 2 | pcs | 50 | 100 | local | |
| wheel (rear): 26" | 1 | pcs | 50 | 50 | local | |
| solar panels (front) flexible 1510x660mm, 200W | 2 | pcs | 100 | 200 | web | |
| solar panels (rear) flexible 540x610mm, 60W | 2 | pcs | 50 | 100 | web | |
| MPPT (Victron 75/15, 12V) | 2 | pcs | 65 | 130 | front panels | web |
| MPPT (Victron 75/10, 12V) | 2 | pcs | 45 | 90 | rear panels | web |
| Smartshunt (500A/50mV Victron) | 1 | pcs | 100 | 100 | web | |
| motor (mid drive Bafang M820): 250W | 1 | pcs | 600 | 600 | Alibaba | |
| battery: 256Wh (Victron 12.8v, 20Ah, LiSP) | 1 | pcs | 200 | 200 | web | |
| 12V-36V (540W) step-up regulator | 1 | pcs | 50 | 50 | Amazon | |
| pedals | 1 | set | ? | ? | local | |
| seat | 1 | pcs | 250 | 250 | Thor composite | |
| chain | 4 | m | ? | ? | local | |
| brakes | 3 | pcs | ? | ? | local | |
| derailleur (7 speeds) | 1 | pcs | ? | ? | local | |
| gear shifter | 1 | pcs | ? | ? | local | |
| lighting system | 5 | pcs | ? | ? | local | |
| electrical cable | many | m | ? | ? | local | |
| horn | 1 | pcs | ? | ? | local | |
| screws, nuts, washers (M5, M6, M8, M10, M12) | many | pcs | ? | ? | everywhere | local |
- Drill / screw driver machine. I have a Milwaukee M18 FDD3.
- Welding machine. I have a Lorch Handy 160.
- Grinding/metal cutting machine. I have a Milwaukee M18FSAG125X.
- Drill bits.
- Many others...
- OpenSCAD - for 3D design.
- Real Cut 1D - for minimizing waste when cutting linear materials (bars) (if you have a lot of bars to cut from).
- Cut the bars to required size and angle,
- Build (weld) the structure,
- Install the motor, battery,
- Make the eletrical installation,
- Install the solar panels,
- Go!
More details will be given here, soon ... instructions.md
MIT
You may do whatever you want with this information as long as you mention the author.
Mihai Oltean, Solar Bear Vehicle; A hybrid trike, 2025.
- 2025, July 18. The idea!
- 2025, July (end of). Named it Solar Big Little Bear, later simplified to Solar Bear Vehicle.
- 2025, October 1, Installed solar panels on version 1 (V1).
- 2025, November 12, I gave a talk at ITDays in Cluj-Napoca.
- 2025, December 2, V2 build.
- 2026, March 2, V3 build.
- 2026, April 6, V4 build.
- 2026, April 11-12, at VELOBerlin, Germany.
- 2026, April 25-26, at SPEZI, Freiburg, Germany.
- 2026, August 15-16, at Maker Faire, Hannover, Germany.
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I offer NO warranty for the information provided in this project!
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I am NOT an expert in ANY of the subjects used in the design and construction of this project!
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Use it, build it, on your OWN risk!
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This is a work in progress. Everything might change depending on the experiment results.
Dorin Popa, Nicolae Oltean, Cristian Simina, Traian Mărginean, Liviu Știrb, Emil Roșu, Sam Rabern Luck, Dani Cotoară, Mihaela Roșu, Zuga Răzvan, Călin Rusu ... and many others ...