Solar Bear

A hybrid Sun/muscle-powered trike!

The purpose of the Solar Bear is to:

• Transport people inside cities,
• Reduce the gas emissions,
• Reduce noise inside cities,
• Consume electrical energy where it is produced,
• Be safer than a bike,
• Occupy less parking space than a car,
• Motivate people to exercise,
• Motivate people to build their own trike.

Technical specs

• recumbent trike,
• 2.7m long, 1.7m wide (including wheels),
• weight: 120kg (excluding driver, including panels),
• assisted pedalling,
• motor max speed: 25km/h,
• motor (continuous) power: 250W,
• solar power: max 600W,
• battery: owner choice.

Maker

Mihai Oltean

Project inception location

Town: Cugir, country: Romania.

CAD files

Solar Bear CAD

Materials

• solar panels: front 2x Victron 1485x668mm, back 2x Victron 1030x668mm,
• battery: TBD,
• motor: Bosch Active Line,
• rectangular tube 50x30x2: 7m,
• rectangular tube 40x20x2: 80cm,
• round tube 3/4: 2m,
• round tube 1/2: 70cm,
• aluminium profiles sigma 20x20: 24m,
• bike chain: 4m,
• bike parts: pedals, brakes, speed changer, etc,
• threaded pipe M12: 8pcs of 1m,
• screws, nuts, washers (M5, M6, M8, M10, M12): many.

Tools

• Band saw (able to cut 80x40mm rectangular tube at 52 degrees angle). I have a PILOUS ARG 130 mobil. A panel circular saw (with blade for metals) is also good if you do not have a band saw.
• Drill machine. I have a Milwaukee M18 FDD3.
• Welding machine. I have a Lorch Handy 160.
• Panel circular saw, (I have a Bosch - GCM 12 SDE).
• Screwdriver (preferably electric).
• Drill bits.
• Many others...

Software

• OpenSCAD - for design.
• Real Cut 1D - for minimizing the waste when cutting bars.

Build instructions

• Cut the bars to required size and angle,
• Build (weld) the structure,
• Reinforce solar panels,
• Place solar panels,
• Connect eletrical installation,
• Go!

More details will be given here, soon ... instructions.md

Cost

• Prices do not include manufacturing (which I did it by myself) and tools (which I already have).

• 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).

• Prices include VAT.

Material	Quantity	Unit	Price per unit	Total price (EURO)

Will be updated ...

Pictures and videos

A video will be posted soon ...

More pictures soon ...

License

MIT

You may do whatever you want with this information as long as you mention the author.

Cite as

Mihai Oltean, Solar Bear; A hybrid trike, 2025.

Warning

• I offer NO warranty for the information provided in this project!

• I am NOT an expert in ANY of the subjects used in the design and construction of this project!

• Use it on your OWN risk!

• This is a work in progress. Everything might change depending on the experiment results.

Special thanks to

Dorin Popa, Nicolae Oltean, Cristian Simina, Emil Roșu, Sam Rabern Luck, Mihaela Roșu, Zuga Răzvan, Călin Rusu ... and many others ...