Solar Powered Golf Cart Group 9 Jake Bettis Jacob Krueger Matthew Roland Matt Tourtelot With Support from:

Motivation ●Rapid growth in renewable energy, such as solar power, has caused a huge increase in the demand for engineers that know how to utilize these alternative sources of energy ●With our project we are able to design and create an environmentally friendly vehicle while gaining first-hand knowledge and experience in a growing industry

Goals To create an energy efficient golf cart that is capable of running on solar power and external outlet. A touch-screen display will give the user options for different energy modes, navigational help, and status of golf cart

Objectives ●Harvest energy from sunlight to power electric motor and onboard electronic systems ●Three modes of energy operations o standard, max performance, max efficiency ●Power monitoring system to display battery levels and check for battery storage defects ●User touch-screen display o Provides navigational map interface o Allows users to change cart’s operating mode o Displays cart’s current speed, current mode, and battery charge remaining.

Objectives Energy Modes ●Standard mode: A normal acceleration ramp will be used for this setting ●Max Performance: The motor controller will ramp up the speed almost instantly ●Max Efficiency: The motor controller will ramp up the speed very slowly The biggest power drain on the cart is acceleration so this was controlled to save energy

Specifications and Requirements 1.Must have a top speed of at least 15 mph 2.Must have 3 modes of operation which can be controlled by user 3.Must run off of a 36V or 48V battery storage bank 4.Batteries must be able to charge from solar panels or wall outlet 5.Must have a touch-screen display for user information 6.Must provide navigational aid to user 7.Must provide power mode options and current speed

Budget PartEstimated CostActual Cost Motor Controller$600$550 Batteries$600$550 Charge Controller$150$100 Microcontroller(s)$120$140 Touch-Screen Display$120$70 Sensors$150$50 Misc.$100$400 PCB Fabrication$0$265 Total$1,840$2,125

Power System Components ●Solar Panels and Wall Outlet o provide power for motor and onboard electronics ●Solar Charge Controller o Regulate power inputs from solar panels the batteries o Implement MPPT algorithm to keep from overcharging and damaging the batteries ●Battery Bank o provides 36V battery supply

Power System Overview Wall Outlet Solar Panels Solar Charge Controller Battery Bank Motor +36 V Power Board 3.3V DC/DC Regulator 3.3V DC/DC Regulator Motor Controller 5V DC/DC Regulator 5V DC/DC Regulator Oddroid C1 Touchscreen Display

Solar Panel Electrical Specs Project design implements two panels connected in series. UnitQuantity Maximum Power P max 250 W Voltage at maximum power point V mpp 30.7 V Current at maximum power point I mpp 8.15 A Open Circuit Voltage V oc 37.7 V Open Circuit Current I oc 8.72 A Operating Temperature-40° C to +85° C *Specs are based on single panel at standard test conditions

Battery Supply ●36V battery bank that will power motor and all onboard electronics ●Flooded lead-acid, deep cycle batteries o Able to withstand deep discharge cycles and have a long lifetime ●At 25A output batteries can last for 474 minutes, and 122 minutes at 75A

Battery Specs UnitQuantity Voltage6 V Amp hours (20 hour rate)232 Ah Minutes at 75 Amps122 min. Minutes at 56 Amps179 min. Minutes at 25 Amps474 min. Wet Weight Lbs.62 Lbs. U.S XC2 Deep Cycle Lead-Acid battery

Battery Specs ●Rate of discharge ○ Batteries need to be able to operate for as long as possible while supporting different energy modes ○ Consider current vs. discharge time

Charge Controller ●Goal is to regulate voltage and current from solar panels to the battery, to prevent overcharging ●Will implement a maximum power point tracking (MPPT) algorithm ○ Finds the maximum power point on the I/V curve and tracks that point as sunlight conditions vary ●Works as DC to DC converter ○ Outputs GPS coordinate information to the microcomputer ●Design is based off of Texas Instruments TIDA-00120

Solar Charge Controller Schematic Block diagram of Solar Charge Controller System SM72295: Photovoltaic Full Bridge Driver INA271 : voltage output, current sense amplifier

Solar Charge Controller Schematic MSP430F5132: ultra-low power mixed signal microcontroller LM5019: 100V buck regulator TLV70433: low dropout regulator (LDO)

MPPT Algorithm Perturb and Observe Method is to modify the operating voltage or current from PV panel until you obtain maximum power from it

Touchscreen Display System Objectives ●Provide users with straightforward navigation around the UCF campus via GPS location o Navigational map will be interactive and contain certain customizable features ●Display the golf cart’s current speed and operating mode ●Allow users to easily switch between available cart operating modes

Touchscreen Display System Components ●Microcomputer ○ Provides platform for Android Operating System ○ Processes GPS and display signal input and output ●GPS PCB module ○ Outputs GPS coordinate information to the microcomputer ●Touchscreen Display ○ Provides user with display of the Android Application ○ Supplies microcomputer with user input

Touchscreen Display Data Flow Chart

Microcomputer ODROID C1Raspberry Pi Market Price$38$35 CPU1500 MHz Cortex- A5 700 MHz ARM1176JZF-S Video OutputsMicro-HDMIHDMI and composite video Power Source0.8mm x 2.5mm 5V jack 5V via MicroUSB or GPIO header

ODROID C1 Features Implemented ●Android Runtime Environment compatibility o Allows for the creation of a specialized Android Application o Easy Debugging ●HDMI video signal output o Allows video signal to be sent to the touch screen display while freeing up the USB input for the touch screen’s user input signals

Touchscreen Display HDMI 4 Pi: 5” Display w/ Touch and Mini Driver - 800x480 HDMI Tekit 619AHT 7” LCD Monitor Market Price$79.95$ Screen Size4.8” x 3.0”8.23” x 5.7” Resolution800 x 480 Display Ratio16:1016:9 Contrast300:1500:1

MTK3339 GPS Module ●Sends GPS data pertaining to the current user position to the ODROID C1 ●10 Hz update frequency ●Accurate to about 3 meters

GPS Module - PCB Schematic

GPS Module - PCB Design

GPS Module - PCB

Android Application Development ●Developed within the Eclipse IDE using the latest Android SDK ●Many other inherent features of Java are used throughout the application design ●Tested for accuracy and reliability on every design prototype iteration

Android Application Class Diagram

UCF EzNAV Main Menu ●Very simple, intuitive interface ●The only screen that gives access to every created class ●Each button takes the user to a new screen within the app

Navigate Screen ●Interactive Google Maps Fragment ●“My Location” button and functionality ●Map markers for reference and building information ●License key for Google Maps API obtained through Google Inc.

Cart Status Screen ●Features updating data fields for cart information o Uses signals from the Motor Controller and GPS module to generate values ●Interface buttons that allow users to change the cart’s operating mode

Motor Controller Overview ●Pre-charge circuit prevents inrush current to motor controller ●Potentiometer pedal provides a voltage from ●Direction switch removes need for H- Bridge

Power Board

Power Board Schematic ●High current MOSFET’s ●On-Resistance of 1.45mΩ ●Capacitance ●Flyback diodes

Motor Controller Logic

Pedal ●Potentiometer over ITS

Modes of Operation ●Mode determined by user from touch screen

Progress

Questions?