Table of Contents
Power and Energy
Units of power are HP or KW. 1 HP = 747 kW. Voltage x Current = Watts (V x I = W). Energy is power over time or kWh. We average one kilowatt of power in a one hour race for a total of 1 kWh.
Voltage and Current
Electrical shock can be dangerous, so working with lower voltages is a big safety benefit. Electric vehicles can use 400 - 800 volt systems, most homebuilt cars are in the range of 200 volts, but lighter/smaller vehicles can get by with 24 - 48 volts. Electric bicycles use 36V, 48V, 60V and even 72V packs.
Wires and Connectors
Wire gauge (size) is sized according to the maximum amount of current that it will carry. There are sizing charts (here). Wire is heavy and expensive so the lightest gauge should be used for those reasons. Welding cable is commonly used for the drive system cabling. Wire quality varies with strand count (higher strand count is more flexible and more suitable for shock/vibration environments) and also wire insulation.
Connector pins and wire terminals can be crimped or soldered. Both are reliable methods if done properly, and the most important thing is strain relief (making sure the wire will not pull on the connection). Heat shrink is typically used on all terminations, and wire sheathing can be used to protect wire bundles (here). Here are some sources for various connectors and terminals. Some connectors require special crimping tools and pin extraction tools, but many use common standard crimping tools
Batteries and Charging
Electrathon cars usually use lead acid batteries. They are heavy but cheap and readily available, and do not require a Battery Management System (BMS) which keeps the designs simpler and also safer. Some lithium chemistries are very volatile and can be a fire risk if poor quality or if not used properly.
Physics (Forces, Energy, Losses, Friction, Aerodynamics)
Materials (Steel, Aluminum, Composites)
Most vehicles use steel tubing welded together. Some have used steel tubing with fittings bolted together. Aluminum is lighter but more expensive. Aluminum square tubing can be bolted or riveted together and some use round tubing welded together. Few cars are made from composites (fiberglass, carbon fiber or wood (the "natural . Bamboo has been used as a sustainable material.
Fasteners (Welding, Rivets, Bolts, Adhesives)