Why do electric cars accelerate faster than most gas-powered cars, even though they have less horsepower?
In: Technology
Power is force times speed, so if you can push harder and are going faster you are pushing with more power. Pushing at low speed requires little power, and pushing super fast against little resistance requires little power.
In a gas car the engine spins the wheels with tiny explosions, like if you imagine an old sail boat steering wheel with all the handles and you can slap the handles. Imagine you can only slap the wheel with one kind of slap, no strong and weak slap. The max power is when you are slapping as fast as you can, each slap is the same strength and you are fishing them out as fast as you can, any faster and the slaps become weaker. So overall a gas car has zero power at zero speed, power increases as speed increases until you reach the max power speed, and then as you go faster it drops off. Changing gears is like making the wheel bigger or smaller and you have the same handle spacing, so bigger wheels turn slower and take more slaps to go all the way around.
An electric car is generally current limited, the battery could source a lot more but the switches that connect the battery to the motor can only handle so much before they melt. Current times voltage is power, and the batter has a roughly constant voltage. Also current is proportional to torque. The voltage needed to spin a motor slowly increases with speed. So an electric car has full torque at zero speed, and at every speed up to the point where the motor voltage needed is close to the battery voltage minus losses, or you hit the power limit of the switches. This is a bit like having a water hose to push up a kite, you have a lot of pressure when the hose is close to the kite, and within a certain distance it is basically full power, and the you get to a point where the water stream spreads out and pushes less hard, and eventually there is some maximum height where you can just barely keep the kite aloft
Latest Answers