David Pearce Energy and the Environment Professor Reza Toossi Solar Powered Trike David Pearce Energy and the Environment Professor Reza Toossi

Objective: Build a green vehicle that runs for free purely off of the sun’s energy Eliminate the need to drive everywhere, especially short trips. Promote the usage of green alternative energies

Performance Goals The solar panels must fully charge the batteries in a practical amount of time, similar to that of a plug in charger. The vehicle must be legal to ride on the street. The pedaling function must remain unmodified Must be emission free

Design Simple 3 wheeler, battery powered High efficiency mono-crystalline solar panels to charge batteries Baskets provide for batteries, storage and solar panel mounts 36V, 700 Watt peak Brushless Hub motor integrated in front wheel, kit w / all components including 110V-36V charger/ transformer Minimal modifications to trike

Calculations: Batteries 3-12 volt 20 Amp/hour batteries in series =36V and 20 A/hr, P =(36V*20A/hr) = 720 Watt/hr battery capacity Battery choice was determined by capacity, price, and weight. Bigger batteries= Longer range, but longer charge times, more money and more weight.

Calculations: Solar panels 3-22V Solar panels in series = 66V 1.2+ Amp current each panel Ohm’s Law P=(V*I) P=(66V*1.2A) = 80 Watts provided by solar panels Theoretical charge time: House hold current charges with constant wattage at a maximum rate of 1.5 A, takes 6-8 hrs to fully charge from full discharge voltage of 32V. Solar Panels charge at 1.2+ amps, slightly slower, but equivalent in charging speed if batteries are kept from fully discharging, above an experimentally determined cut-off voltage.

Calculations: Motor = 14.2 mile range 3 Phase Brushless motor, 700 Watts peak, 500 Watts RMS, 265 rpm ( no load) Theoretical top speed: : 265rev | 60 min | (2)*(3.14)*(13”) rad | 1 ft | mile min | hr | revolution | 12” | 5,280 ft = 20.5 mph top speed Theoretical range: : 20.5 miles | hr | 500 Watts RMS hr | 720 Watts | = 14.2 mile range

Calculations: Charging system A solar charge converter is needed to steadily and efficiently charge the batteries with the varying input power of the solar panels. A Maximum Power Point Tracking type solar charge controller was chosen for it’s high efficiency, and ability to run the panels at their peak output when conditions allow, which shortens charging time. Specifications Input range: 0-100V Output: 42.4V Charging method: constant wattage (P=constant, as voltage goes up current goes down)

Testing / Analysis Testing showed that in order to charge the batteries in a practical amount of time, the experimentally determined cut-off voltage needed was found to be around 36V. Thus voltage must not drop below 36 V (12V each battery), as inferred from the calculations, and the panels will charge at an equivalent rate to the household plug-in charger. This limits the range to around 10 miles, but longer trips can be made at the expense of charging time.

Performance The Solar panels charge the batteries in an adequate amount of time. 10+ mile range 18 MPH Climbs hills with pedaling

Conclusion: Solar energy is a viable source of power for a personal transport vehicle, and has great potential as photovoltaic technology evolves. Record high gas prices and excessive greenhouse gas emissions are creating a market for green alternatives to fossil fuel based transportation, such as the Solar Powered Trike. Total cost : $910 For more details, and to DIY visit www.instructables.com Search - Solar Powered Trike Purchase at www.solartrike.com - same concept, more refined / expensive

Resources / Cost Breakdown The Trike cost $910 to build Schwinn Meridian Trike $250.00 www.K-Mart.com Qcell Solar panels $330.00 www.Ebay.com.... Charge Controller $ 95.00 www.solarsellers.com Electric Hub Motor Kit $260.00 www.goldenmotor.com Batteries $ 60.00 Earl's industrial liquidation, Hawthorne High pressure tubes $ 15.00 Any bicycle store Total $910.00