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Building an Electric Vehicle: Components and Construction Part 1: Volkswagen Conversion Part 2: Electric Go-Kart Race. Michael D. Kane, PhD (1) Associate Professor of Bioinformatics (2) University Faculty Scholar (3) Chair of Graduate Education
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Building an Electric Vehicle: Components and Construction Part 1: Volkswagen Conversion Part 2: Electric Go-Kart Race Michael D. Kane, PhD (1) Associate Professor of Bioinformatics (2) University Faculty Scholar (3) Chair of Graduate Education Department of Computer and Information Technology (4) Lead Genomic Scientist Bindley Bioscience Center at Discovery Park Purdue University West Lafayette, Indiana, USA evw.tech.purdue.edu
Problems with EV propulsion 1. range: function of energy density of the battery. Compare gasoline @ 12,000 (theo.) / 2600 Wh/kg with the lead-acid battery @ 175 (theo.) / 35 Wh/kg 2. time to refuel: charge 40 kWh in 5 minutes? 220 V × 2200 A!!! When you pump gasoline @ 20 /min, your energy transfer rate is about 10 MW! (Hint: energy density of gasoline is 10 kWhth/.) 3. cost: (a) light but safe means higher materials costs, e.g., less steel, more aluminum; and higher processing costs, e.g., fewer castings, more forgings... (b) to reduce load on the battery requires high efficiency appliances = costly (c) low cycle life — batteries priced @ $4,000 to $8,000 lasting about 2 years
Specific Energies of Battery Chemistries (Wh/kg) (MJ/kg) lead acid 35 0.13 NiCd 45 0.16 NaS 80 0.28 NiMH 90 0.32 Li ion 150 0.54 gasoline 12,000 43 NOTE: 1 Wh/kg storage capacity equals about 1 mile driving range
Specifications & Performance: http://evw.tech.purdue.edu Drive system: 72 volts (lead acid) Top Speed: 40 mph Distance: 25 miles Cost: $5,000 (total) Vehicle: $1,500 Batteries: $700 Electronics: $2,000 Batt Chargers: $500 Mechanical: $300
Original VW Motor: 150 pounds (70 kg) 55 hp Conversion to Electric Motor: 70 pounds (30 kg) 27 hp* 200 pounds (90 kg) in batteries. Conversion is +120 pounds (55 kg) * The electric motor used in the conversion is rated at 15 hp (peak), but calculating horse-power in an electric motor is different than an internal combustion engine.
Contactor: A relay that closes the “drive batteries” circuit (i.e. turns the vehicle “on”) Throttle Box Shunt Controller
Batteries : 6 x 12V lead-acid deep-cycle AND 1 x 12V for accessories
Controller Used in the EV Go-Kart Used in the VW conversion
TESLA $110,000 270 hp EV-Bug $5,000 27 hp
Tesla Battery The pack weighs 990 pounds, stores 56 kWh of electric energy, and delivers up to 215 kW of electric power, 375 volts. Battery cost is about $30,000 Each cell is 18mm in diameter by 65mm length, The small cell size enables efficient heat transfer, allows for precise charge management, improves reliability, and extends battery pack life. Each cell is enclosed in a steel case which effectively transfers heat away from the cell. The small size makes the cell essentially isothermal, and its large surface area allows it to shed heat to the ambient environment. Sixty-nine cells are wired in parallel to create bricks. Ninety-nine bricks are connected in series to create sheets, and 11 sheets are inserted into the pack casing. In total, this creates a pack made up of 6,831 cells.
Chassis Motor mount added to rear Battery mounts added to sides of cart.
Contactor Fuses Controller Power Switches
60V system with top speed of about 40 mph, endurance at about 40 laps.
Technology and Innovation Wireless • Remote desktop to cart PC • Alter power settings during the race to optimize power/performance • Video feed sent to Jumbotron (entertainment) • Audio communications with driver On-board Camera GPS (speed) Lap-top to controller Blue-tooth helmet