Car battery cabling

stranger12

Hi guys

How is car battery cabled?

On positive lead, i can see it is going to alternator and starter but how other systems such as light work?

Re negative, it is connected to chassis which means all of the car body is grounded. Isn't that dangerous in any ways?

Many thanks

molerat

stranger12 wrote: »

Hi guys

How is car battery cabled?

On positive lead, i can see it is going to alternator and starter but how other systems such as light work?

Re negative, it is connected to chassis which means all of the car body is grounded. Isn't that dangerous in any ways?

Many thanks

Only if you connect the battery positive to the body :eek:

https://www.howacarworks.com/basics/how-car-electrical-systems-work

stranger12

So with dc can you get electricuted using one leg either negative or positive?

molerat

stranger12 wrote: »

So with dc can you get electricuted using one leg either negative or positive?

Not with 12v ........ but you will get a big spark and possibly an exploding battery. The link in my post shows how car electrics work in a very basic way.

thescouselander

Stranger12 - why don't you use the motoring forum for questions about cars?

robatwork

Car batteries work at 12V so even though they do pump out high currents, the electricity isn't going to kill you. However the exploding battery might, not to mention toxic acid everywhere.

So don't mess with it.

The car body is negative - the current finds its way from the positive, through your lights, alternator and everything else back to the negative terminal generally through the wiring.

thescouselander

robatwork wrote: »

Car batteries work at 12V so even though they do pump out high currents, the electricity isn't going to kill you. However the exploding battery might, not to mention toxic acid everywhere.

So don't mess with it.

The car body is negative - the current finds its way from the positive, through your lights, alternator and everything else back to the negative terminal generally through the wiring.

At least that's the simple explanation and how older cars work. Modern cars often have a more complicated setup with a switched ground going back to an ECU somewhere. Either way automative electrics can be a bit of a black art at times.

Biggles

thescouselander wrote: »

Stranger12 - why don't you use the motoring forum for questions about cars?

It's not because he's a stranger. Maybe it's because he's 12?

Rain_Shadow

thescouselander wrote: »

Stranger12 - why don't you use the motoring forum for questions about cars?

I can just see the responses now. :rotfl:

Nile

Hi, we move threads if we think they’ll get more help elsewhere (please read the forum rule) so this post/thread has been moved to another board. If you have any questions about this policy please email forumteam@moneysavingexpert.com.

I’ve moved your thread from the ‘In my home’ board to the ‘Motoring’ board, where it is better suited.

Regards

Nile

AdrianC

stranger12 wrote: »

How is car battery cabled?

On positive lead, i can see it is going to alternator and starter but how other systems such as light work?

There's also a connection to the main fusebox, which then distributes the +ve around the rest of the car. It may well be off the starter or alternator, but it's often straight from the +ve battery clamp. The starter and alternator connections see much, much larger currents than the rest of the car.

Re negative, it is connected to chassis which means all of the car body is grounded. Isn't that dangerous in any ways?

No. Just don't short between a +ve and the bodywork.

Older cars had +ve earth. Some cars, especially Japanese, have permanent +ve to lights etc, and switch the earths.

Some cars - with fibreglass bodies - don't use the body as earth, so need extra cabling instead. They often have electrical problems caused by poor connection between lights etc and battery -ve.