How can a Tesla run for so long?

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In summary: A Tesla Model S has a power of 315 HP (234 kW) and the largest battery they come with is 100 kW*hr.This means that the car can only run for (100 kW*hr)/(234 kW) = 0.43 Hr.
  • #1
Jakeeis
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Forgive my ignorance, I really don't know a lot about this topic.

A Tesla Model S has a power of 315 HP (234 kW) and the largest battery they come with is 100 kW*hr.

So shouldn't it only be able to run for (100 kW*hr)/(234 kW) = 0.43 Hr?

I'm assuming the answer to this is the car doesn't use the full 315 HP when driving around town... The problem is when I look at dyno charts for it, the power still seems to be too high for the battery even at low rpms. Any enlightenment about this would be appreciated.
 
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  • #2
Power curves are given for WOT (wide open throttle). Do you drive a car? Try driving around with the throttle wide open all the time, it's impossible, except for maybe on an autobahn.
normal driving is mostly part throttle, which produces part power and consumes part energy consumption. This applies regardless of the engine type.
 
  • #3
In order to drive at highway speed, a sedan needs only about 15-20hp.
 
  • #4
Power consumption is a function of drag, electrical/mechanical losses, and acceleration. If you remove acceleration power consumption comes from only drag plus electrical and mechanical losses. For normal operation acceleration is usually not maximal for lengthy intervals. Power consumption is always at a much lower level that maximal output. Now if you increase drag by going faster or accelerate and decelerate maximally for long periods power consumption goes way up and run time goes way down. That's always true regardless of the energy source, electricity or internal combustion.

A big percentage of power consumption goes to drag and losses. Decreasing weight or reducing aerodynamic losses reduces drag and thereby reduces power consumption providing better run time in cruising conditions. It's a big part of efficient design in an electric car or any other motorized vehicle. If it were possible to design a car with zero drag and zero losses (which it's not) no power would be consumed in operation at a constant speed and the car could run indefinitely without refueling as long as speed remained constant.
 
  • #5
Jakeeis said:
The problem is when I look at dyno charts for it, the power still seems to be too high for the battery even at low rpms. Any enlightenment about this would be appreciated.

Dyno charts tell you how much power it can deliver at a given rpm. Not how much power is actually needed to move the car at that rpm.

For example when rolling down hill it might not consume any power or the power consumption might even be negative (regenerative braking).
 
  • #6
Another point is that for an electric - or hybrid a lot of the kenetic energy is recovered in regenerative braking, so the majority of the energy is used in the drag. In a pure combustion vehicle the energy is just lost. When the hybrid cars first came out it was surprising, but understandable. that they had better "around town" economy than highway. Stop and go driving they use much less energy, than at highway speed due to drag. And - drag increases with the square of the speed, so driving at 60 uses 4 x the energy as driving at 30.
 

1. How does a Tesla car's battery last for so long?

The battery in a Tesla car is made up of thousands of lithium-ion cells, which have a higher energy density compared to traditional lead-acid batteries. This means that they can store more energy in a smaller space, allowing the car to run for longer periods of time.

2. What is the range of a Tesla car?

The range of a Tesla car varies depending on the model, but it can range from 250 to over 400 miles on a single charge. This is due to the high energy density of the lithium-ion battery and the efficient design of the car's electric motor.

3. How often does a Tesla car need to be charged?

The frequency of charging a Tesla car depends on the individual's driving habits and the distance they travel. However, on average, a Tesla car needs to be charged every 300 miles or so, which is equivalent to about once a week for most drivers.

4. How long does it take to charge a Tesla car?

The charging time for a Tesla car also varies depending on the model and the type of charger used. On average, it takes about 30 minutes to charge a Tesla car to 80% of its battery capacity using a supercharger. A full charge can take anywhere from 8 to 12 hours using a regular home charger.

5. Can a Tesla car run on renewable energy?

Yes, a Tesla car can run on renewable energy sources such as solar or wind power. This is because the car's battery can store energy from various sources and convert it into electricity to power the vehicle. This makes Tesla cars more eco-friendly and sustainable compared to traditional gasoline-powered cars.

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