Car Batteries, and how they're connected

[dhong089]

This is an automotive-related question, but I’m sure any of you guys can answer it.

The car battery is a significant part that supplies lots of power to various components of the car.

I always thought that the battery would be connected to various connectors in order to supply the power. Basically I thought there would be lots of wires running from the battery to the components. However, the negative terminal of the battery is simply attached to the frame of the car itself. Thus when the battery begins to let the electrons flow, I presume the car-components (radio, blower motor, fan, etc) receive their power from the frame, via the battery.

How wild! I never imagined that cars operated like this! Ever! I would've never guessed that the "frame" of the car would act like a conductor wire. Can someone explain how this works? Shouldn't there be an insulator to prevent the electrons from escaping, just like wires using insulators? I mean, if water or something touches the frame, wouldn’t it be dangerous? The process just seems so “primitive,” yet advanced at the same time. I had a bit of a mind explosion today when I removed my battery from my car today.

 

[Jiggy-Ninja]

This is an automotive-related question, but I’m sure any of you guys can answer it.

The car battery is a significant part that supplies lots of power to various components of the car.

I always thought that the battery would be connected to various connectors in order to supply the power. Basically I thought there would be lots of wires running from the battery to the components. However, the negative terminal of the battery is simply attached to the frame of the car itself. Thus when the battery begins to let the electrons flow, I presume the car-components (radio, blower motor, fan, etc) receive their power from the frame, via the battery.

How wild! I never imagined that cars operated like this! Ever! I would've never guessed that the "frame" of the car would act like a conductor wire. Can someone explain how this works? Shouldn't there be an insulator to prevent the electrons from escaping, just like wires using insulators? I mean, if water or something touches the frame, wouldn’t it be dangerous? The process just seems so “primitive,” yet advanced at the same time. I had a bit of a mind explosion today when I removed my battery from my car today.

The frame is metal. Metal conducts. That answers one of the frame questions.

Electrons don't "leak" out of wires very easily. There are three mains reasons (that I can think of off the top of my head) for wires to have insulation:

1) Protect the conductor from damage/corrosion/other negative effects.

2) Prevent bare wires from touching each other and shorting out

3) Protect you from being hurt by shock.

With a few exceptions (things get really weird at really high frequencies), electricity needs a complete path from one end of the source to the other in order to flow.

Water or trees outside of the car are not part of the electrical circuit, so just touching the car won't affect it at all.

Having the frame as a common connecting point for all the electronics cuts down on the amount of wires that need to be run around it. All of the electronics need to be connected to the + and - of the battery in some way, and connecting the - to the frame and having everything else connect to that cuts the amount of wires that need to be run to the battery in half. They still need to the connected to the + side though.

And before you ask, connecting the + side to the frame would work just as well, if the car was designed for that setup. The only reason the - side is connected is because that is what is commonly connected to "ground" in electrical schematics, and it's a really good idea to keep the setup the same in all cars.

 

[Zryn]

Shouldn't there be an insulator to prevent the electrons from escaping, just like wires using insulators?

You mean like a colored insulating chemical sprayed on the outside surface of the chassis?

 

[Jiggy-Ninja]

You mean like a colored insulating chemical sprayed on the outside surface of the chassis?

Ha ha, that's a good point, I didn't even catch that. Funny how you miss the obvious sometimes.