As far as my understanding goes it’s possible to create power with a magnet moving around a wire coil.
Couldn’t we use this effects and charge electrical vehicles by driving over magnets (most basic idea)?
In: Physics
If you mean current EVs then we can’t do this because they do not have the necessary inductive charging components.
There are however companies that make aftermarket kits to charge your EVE wirelessly when parked in your garage, so it’s not outside the realm of possibility.
Whether you could DRIVE a car like this by surrounding entire roadways with inductive charging fields I’m not sure. I suspect not as it would be hard to provide power fast enough.
Yes, but the energy you receive is always less than the force with that the magnet slows you down (there is no free energy)
Or do you mean Wireless charging? That works with a standing car on an oscillating magnetic field.
I’m not sure the direction you are going.
Idea one:
Park your car over an area with magnetic flux. Some cell phones charge wirelessly this way.
Driving through magnetic fields, thus creating flux by moving through the field. I think the problem would be that you would spend a great deal of energy moving the car to get a pittance back.
Magnetic fields passing through a loop(s) of wire can induce current that you can use to charge a battery. The only caveat is this magnetic field has to be changing constantly or the loop has to be rotating within the magnetic field.
In either case, trying to do this on a large scale for something like an electric car would be possible but inefficient and expensive by my estimation.
The wireless chargers we use for our phones are do this by flipping the magnetic field’s direction rapidly, but even on such a small scale it’s super inefficient.
There are talks of wireless charging systems for EVs. Which this idea is very similar to, so yes.
But if you are thinking this means an electric vehicle could drive forever, no.
You don’t just create energy out of nowhere. What you do is turn kinetic energy (motion) into electrical energy. Like in generators you actually have to use energy to push against the magnetic field and produce electricity. In this case, the car now has to push against the magnets.
This means that at best the amount of energy the car would get will be exactly equal to the amount of energy it spent moving over the magnets. The laws of physics mean you can never ever do anything more than break even. And in reality, you will have a ton of losses.
It helps with the intuitive answer to this question if you experience what it’s like to move a magnet into a coil with a current running through it.
A magnet moving through/around a wire coil generates an electric field by “pushing” the insides, but the opposite is also true, an electric field from a current will also generate a magnetic field, *so it exerts a force on a magnet trying to move through*. In effect, if you try to push a magnet through by hand, you’ll feel a force pushing it back and given a strong enough current, you simply won’t have the strength to push through.
I hope you see where I’m going. No matter how much energy spend on speeding up a car, you pay it back when you try to gain back that energy in the form of electricity. Energy transformation is never 100% efficient, some is always lost to friction/heat, so you’re better off simply not spending that energy on speeding up the car in the first place.
There is one exception where you actually *want* the car to lose momentum, namely braking. Electric cars already do this, when you want to brake all you need is a magnet, it slows down the car and generates electricity, win-win.
It sounds like you have discovered the issue with driving over passive magnets. There is no reason you couldn’t expand normal wireless charging technology to work as a moving object (car) passes over. At that point though, you might just be better off using your electromagnets under the road to directly propel the cars.
No. Not in the way I think you are thinking. Moving through an EM field will take energy from the movement, not the field itself. therefore you cannot transfer energy to the car in this way. However, all electric cars can do this but they carry the magnetic field with them and they call it regenerative braking. This can only save some energy, it cannot be used to increase energy overall.
There are other wireless energy transfer methods that could be applied to electric cars on the road though.
As another poster said, the energy to charge the battery would come from the forwards motion of the car, and thus you would lose speed as you charged the battery, thus causing a net-negative kinda situation.
However, if you string overhead power lines over a train track, you can have the train touch those wires with a flexible connector and have 100% electric propulsion with theoretically infinite range and no batteries involved.
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