Build an Electric Vehicle : A Beginner's Course

Compute the power requirement for an electric motor in two wheelers by analyzing resistance, speed, and acceleration, and explore motor type selection, including the bldc motor and its specification sheet.

This lecture uses aerodynamic, rolling, and gradient resistances to calculate power for electric two-wheeler, targeting 80 km/h and a 10° grade at 30 km/h, concluding a 3 kW motor suffices.

finalize the motor type selection for Dhruva by choosing a three kilowatt BLDC motor among four options.

Explain the working of a BLDC motor, with a stator electromagnet and rotor permanent magnet, and six-step commutation controlled by hall effect sensors and PWM to set speed.

Explore how motor specification sheets define rated and peak power, current, torque, and IP67 protection; using a 3 kW BLDC example to design a 48V system with 90 Nm torque.

Explore how to size an electric motor for a vehicle, apply a basic motor-type selection framework, and understand BLDC motor operation and motor specification sheets—guided by practical hands-on and self-reflection.

Explore how a torque map in the motor controller converts throttle input and motor speed into torque values, creating eco and power modes with different acceleration and range.

Explore key battery parameters such as voltage, resistance, current, charge and energy capacity, specific energy, and specific power, and see how they guide lithium battery selection.

Lead-acid chemistry has lower specific energy, heavier mass, shorter cycle life, and poorer discharge efficiency under large loads due to Peukert's effect, making lithium-ion the preferred technology for electric vehicles.

Compare lfp and nmc batteries for electric two-wheelers, noting nmc's higher specific energy and lfp's superior specific power, cycle durability, and safety against thermal runaway.

Understand the lithium ion battery's operation through electrochemical potential, lithium cell structure (cathode, anode, electrolyte, separator), charging and discharging, and graphite intercalation with NMC and lithium ferro phosphate chemistries.

Collect motor and vehicle data to size the battery; calculate energy per kilometer; determine the energy needed for a 100 km range; and outline the cell arrangement.

Explore the emerging trend of sodium ion batteries as a cheaper, safer, more abundant alternative to lithium chemistries. Compare their construction and operation and note drawbacks.

Explore battery parameters and Peukert's law to size lithium-ion packs for electric vehicles. Compare chemistries like lead acid, lif, and NMC, and outline a 4.2 kWh lithium ferro phosphate pack.

Learn how electric vehicle charging works, including AC to DC conversion by the battery charger, and the constant current and constant voltage stages that protect the battery.

Explore the three EV charging levels—level one, level two, and level three—classified by power output. Learn how home AC charging contrasts with off-board DC fast charging at public stations.

Explore the charging process of electric vehicles, including level one to level three charging, constant current and constant voltage, quick charging, and charger selection for the Dhruva 750-watt onboard charger.

Understand why an electric two-wheeler needs a transmission system to connect a mid-drive motor to the wheel via chain or belt drives and meet torque demands.

Size the transmission by calculating wheel torque from resistance forces and tyre radius, adopt a 1990/12 tyre, and estimate a fivefold transmission ratio for typical performance.

Understand why a transmission is needed to connect motor to wheel and size it for torque, noting EVs favor a belt drive over CVT or gear drive for simplicity.

Learn to model an electric vehicle chassis that minimizes the center of gravity and remains compact by prioritizing battery and motor placement.

This lecture extends the chassis of an electric two-wheeler to seat two passengers and applies Riba analysis to optimize driver ergonomics, adjusting the seat and handle based on ergonomic scores.

Explore self-reflection on virtual vehicle modeling of Dhruva, including ergonomic rebar analysis, battery placement, and assembly of major parts, while reviewing performance targets and upcoming safety regulations.

Uncover why electric vehicle fires stem from thermal runaway, not hot summers, as batteries self-heat uncontrollably after a short circuit, with safety regulations guiding prevention.

Explore real reasons batteries catch fire in electric vehicles, including poor cell quality, design flaws, faulty BMS, and mechanical impacts, and see how short circuits cause high temperatures.

Explore how international safety regulations govern electric vehicles, focusing on UN regulation 136 for category L and its relation to regulation 100, and India's A156 standard.

Explore mechanical abuse tests for electric vehicle batteries under United Nations regulation 136 part two, including vibration, thermal shock and cycling, mechanical drop, mechanical shock, and fire resistance.

Explore why electric vehicles catch fire and explain how international regulations, including regulation 136, ensure safety through battery tests such as mechanical abusive testing and electrical abusive testing.