Energy Energy is the ability or capacity something has to affect change in another thing Forms of Energy heat electromagnetic radiation (light, radio waves etc) energy stored in chemical bonds mechanical energy (potential and kinetic) electrical mass

Quantifying Energy The Unit of Energy is the joule (J) One joule is roughly the amount of energy needed to lift one apple one meter from the floor It is the amount of energy it takes to lift an object one meter using one Newton of force. Sometimes it is expressed as Newton Meters where 1 joule = 1 Nm or Newton-meter

Quantifying Energy – Watt Hour Watt hours (Wh) Are very useful to use when calculating the amount of Energy each of the systems in our vehicles are each going to need and how much the entire vehicle will need. Therefore Watt Hours will be the most commonly used unit of Energy 1Wh = 3600 joules (an easy way to remember this is that an hour has 60 x 60 seconds and therefore 3600 seconds, why this is relevant will become clear when we talk about Units of Power)

Kilowatt hours (KWh) 1kWh = 1000 Wh = 3.6 million joules Kilowatt hours are typically how building electricity usage is measured when purchased from a power plant ft-lbs is the imperial equivalent 1 ft-lb = joules Notice how the ft-lb is a combination of distance and force, just like the Newton-meter calorie The amount of energy required to raise the temperature of one milliliter of water one degree Celsius BTU The standard by which natural gas is measured Quantifying Energy – Other common units

Power = The rate at which electrical energy is transferred in an electronic circuit Notice that the power is a rate, which means that it forms a ratio over time therefore the formula for power is: Power = Power

Energy and Power: What’s the difference? When applied non-scientifically, these words seem to have similar meaning, but they have a constituent relationship, they are part of one another. One way to imagine the difference is in a car. The Energy of the car is represented by the amount of fuel in the car. The Power of the car is the ability of its engine to convert the fuel into movement. How well it does this determines how powerful is it.

Quantifying Power Watt - The watt is the most often encountered metric unit of power 1 Watt = 1 joule/second. (remember that power is a rate of energy consumed over time, joule is a unit for energy and second is obviously a unit of time) Kilowatt – A higher order unit of power 1 kW = 1000 W Horsepower - An often used imperial unit of power. 1 Horsepower = 746 Watts

Criteria for determining a power system What are the considerations that we need to make when deciding which kind of Power To understand how all of this is going to work together, we need to know a little bit about how we talk, think and work with electronics