Physics 310 Spring 2019
PROJECT INTRODUCTION
Donette Donaway owns an electrically assisted bike taxicab that she uses to transport people around San Luis Obispo CA. The “Initial component” section below summarizes the important characteristics of the bike, however arguably the most important is the bike’s weight, at 250 pounds. This weight means that the electric assist is critical to Donette’s service and due to battery limitations, this assist typically runs out after about 4 hours under normal use. Two summers ago, Cal Poly students working with Dr. Pete Schwartz installed solar panels and connected them to the bike’s battery to provided Donette with a longer period of electrical assist time. However, there were some issues with over voltage protection.
The goal of this project then is to reinstall these solar panels on the bike, and to successfully implement them with the taxi cab’s battery with proper over voltage protection.
INITIAL COMPONENT SPECIFICATIONS
Lithium Ion polymer Battery
48 V
Capacity: 11 Ah
Rectifier: 3 A (400 V)
Thin Film Solar Panel
18V MPTT operating point
54V array (18V * 3)
150 W array
1.17 m^2 of available surface area from canopy
More information is featured on the Solar System Page
RICARDO GARCIA
Hi! I'm a 4th year physics major with interests in sustainable energy. I enjoy putting my knowledge to the test and learning from failures. I am most likely outdoors or reading books about philosophy.
RYAN KIRK
Hi! I'm a 4th year physics major with interests in renewable technology and materials science. I come from the silicon valley, and in my free time I exercise, backpack, and watch hockey. Go Sharks!
LUIS MATA
I am a fourth year General Engineering major concentrating in Sustainable Energy. I am from Madera, CA and I like to mountain bike, snowboard, travel, and play soccer in my free time.
MATTHEW STEINBORN
I am a fifth year Electrical Engineeing studen with a focus on digital design. I love to climb, hike, and read, when I'm not working on my circuits.
DEMOGRAPHIC DATA
The current estimated population in San Luis Obispo is about 47,500 people. The largest group is people aged 18 to 24, which make up about 35% of the population. This is largely due to number of students who attend Cuesta and Cal Poly. Speaking of Cal Poly, it is the top employer in SLO, employing over 2,600 people. To see more about San Luis Obispo’s demographics, please visit the following site.
SLO is a very progressive city in terms of utilizing more environmentally friendly technology to produce electricity. In fact, the city of San Luis Obispo has plans to be completely carbon neutral by 2035, 10 years earlier than California's statewide goal of being carbon neutral by 2045.
SLO is also a very active town. A lot of people enjoy running, hiking, mountain biking, and other outdoor activities. The city has its fair share of traditional team sports such as soccer, baseball, and basketball, and lots of other fun, active activities. In fact, one of Donette's biggest clients is The Pad, a climbing gym that she will shuttle people to and from because it is difficult to find parking.
HOW SOLAR WORKS
Solar panels contain photovoltaic (PV) cells that take in sunlight and convert it to direct current (DC) electricity. For household use, an inverter is then used to turn the DC electricity into usable alternating current (AC) electricity. However, because our project is utilizing the solar panels to charge the battery on the bike, we do not need to convert to AC. To learn more about solar energy and how solar panels work, click here.