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

2. 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

3. 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

4. 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

5. 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.

6. 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.

7. 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 | Watts RMS
hr | 720 Watts |
= 14.2 mile range

8. 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)

9. 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.

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

11. 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
Search - Solar Powered Trike
Purchase at - same concept, more
refined / expensive

13. Resources / Cost Breakdown
The Trike cost $910 to build Schwinn Meridian Trike $ Qcell Solar panels $ Charge Controller $ Electric Hub Motor Kit $ Batteries $ Earl's industrial
liquidation, Hawthorne High pressure tubes $ Any bicycle store Total $910.00