# Can a car battery be used to create a high power magnet?

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I know in junkyards cranes use electricity to make a magnet powerful enough to lift a car, but could a car battery be used the same way? Could it have enough juice to lift a car? Or maybe pull one?

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Possibly you could power an electromagnet capable of pulling 120 kg or 250 pounds, but not enough for a car.

Yes and no?

To make a better magnet, you mostly just need to make it bigger. In an ideal world, once the magnet is ‘turned on’ it wouldn’t use any energy to keep it running. In practice it usually does because of inefficiencies.

A car battery can dump 100 amps at 10 volts pretty easily, although not for very long. 1000 watts. A quick google indicates that a regular junkyard magnet draws closer to 10,000 watts. So, at least for a junkyard magnet, the answer is no.

However, we could make a more efficient magnet, it would just be costly. For instance, a superconductor magnet.

To lift a car? Not sure without actually calculating it, which can be done with some basic data about the battery and electromagnet coils, but I’ll wager not strong enough by a sizable margin.

Still, a car battery can put out some pretty high current for a short time, so it would still power a decent electromagnet, until it discharges.

Depends on what you mean by “lift”. If you mean generate enough force to hold a steel object in direct contact while a cable lifts the electromagnet, that’s considerably easier than pulling the steel object to the electromagnet from a distance.

The big problem is that it will be difficult to get enough of the car close to the magnet, because the force falls off with the inverse square law. A magnet stuck to a thick steel plate will pull harder than the same magnet stuck to a thin piece of sheet metal.

You mean to hypothetically erase some incriminating information off of a laptop being held in the Albuquerque PD evidence room?