The typical car electrical system
So, Apart from the main charging, starting and ignition circuits, there are other circuits as well.
These Circuits Power:
- Electric motors
- Gauges of electrical instruments
- Heating elements
- Magnetically operated locks
- The radio and so on
All Circuits are opened and closed either by switches or by relays – remote switches operated by electromagnets.
So, Current flows along a single cable from the battery to the component being powered, and back to the battery through the car’s metal body. Also, The body is connected to the ground terminal of the battery by a thick cable.
In a negative (-) ground system, the current flows from the positive (+) terminal to the component being operated. The component is grounded to the car body, which is grounded to the negative (-) terminal of the battery.
This type of circuit is called an ground return system. Any part of it connected to the car body is said to be grounded.
Also, The strength of the current is measured in amperes (amps); the pressure that drives it round the circuit is called voltage (volts). Modern cars have a 12 volt battery. Finally, Its capacity is measured in amp/hours. A 56 amp/hour battery should be able to deliver a current of 1 amp for 56 hours, or 2 amps for 28 hours.
If the battery voltage drops, less current flows, and eventually there is not enough to make the components work.