Why does starting a car interrupt the radio?


Why does starting a car interrupt the radio?

In: Engineering

I think it’s because it uses all the battery power going towards the engine to start it, which is taking power from the radio which shuts it off for half a second.. but like I could be wrong

The starter motor is a car is an all electric motor and required LOTS of power. They are very powerful tiny little things. Your car needs to really concentrate to get turned on. It’ll start singing to you as soon as it gets going though.

Because to start the engine, the spark plug takes zap juice from the lightning box and the car also starts making more zap juice when the gears in the engine start moving. Both of this together messed up the zap juice flow to the radio and it starts tripping balls

Only essential electronics are active when the car is cranking. A typical new battery can output 650 amps when fully charged. But it’s fairly rare to be fully charged. Depending on that size of the motor the starter uses (I’ve measured no less than) 120 amps. If your car starts quickly this is okay, you could run entertainment systems while cranking, but if it takes a while to catch then you need to keep more power reserved for the heavy stuff.

The starter motor takes a huge amount of power, hundreds of amps. When you pull that much current out of a battery and electrical system the voltage will drop a lot due to losses of in the battery and wires. This causes the power to the radio to drop below the minimum voltage it needs to run and so it shuts off.
This is also what causes the headlights to dim while starting the car (assuming non LED lights, led ones get more complicated)

The power system on a car can be very nasty, not only does it dip when you start the car it will also have a big voltage spike when you stop using the starter motor. A lot of energy gets tied up in the magnetic fields inside the starter motor and is then released when the motor is shut off, this can cause spikes of thousands of volts. Never connect anything to a car electrical system that’s not specifically designed for use in a car.

From a technical standpoint – “How” – It’s all in the ignition switch.

When the switch is rolled over to “start”, all nonessential devices are disconnected.

As to the “why”, the other comments pretty much have that covered.