To start the engine, most cars with smart keys have a push button that fires up the engine before you even get in the car.

The keyless car is a marvel of engineering. But how is it that they can start even when the battery in your key fob goes dead? The answer lies in science.

If you have a newer car, you may have a battery-powered smart key with a lot of really convenient features. But what do you do if that battery dies?