The alternator works by charging up the battery to power the starter motor, ignition and all other electrical components.
If this fails as a result your car’s electronics will follow.
If your car starts to die – the lights dim; the radio stops – chances are it’s at fault, not the battery itself as people usually assume.
If the charging voltage is too low, the charging system could fail therefore causing the car to break down.
Drained batteries or worn/loose cables are factors that might affect the charging voltage
It’s always best to check out the whole charging system first of all the battery, voltage regulator and finally the alternator.