If ever asked from where does the headlamps, flash bulbs, stereo, air-conditioner and the other electrical devices get the electricity to run? For sure your answer is battery. Actually you are partially correct as the battery supplies the stored power when needed which is charged by the BMW alternator. BMW alternator is a small and light weighted device.
Basically, a BMW alternator is an electromechanical device which converts the mechanical energy from car's engine to electrical energy in the form of alternating current by electro-magnetic induction to power the car's electrical systems. BMW alternator delivers power to charge the electric battery and to the other power hungry components in order to work together for the generation of a précised voltage and amperage. Few major power hungry components are a rotating magnet or a rotor, an iron core or a stator, a set of rectifiers or a diode bridge, slip rings and brushes, and a small pulley. Efficiency of a BMW alternator depends on its size; gets altered with the speed of an alternator and is limited by fan cooling loss, bearing loss, iron loss, copper loss and the voltage drop in the diode bridges. BMW alternator is an assembly of moving parts, which may get dirty or bruised or stressed due to huge temperature variations causing them to eventually fail.
Symptoms of a bad BMW Alternator
- The car's light may badly lit.
- A failed bearing inside your alternator may produce a large grinding sound.
- A faulty BMW alternator may let your ride to stall.
- Power supply can be cut due to a dead battery. Irrespective of the age of your BMW battery it may become dead because of a faulty BMW alternator.
- If in case the connectors had lost its footing over the battery terminal, then due to a bad or loose connection there will be no power supply throughout the circuit.
- Deposition of dirt around the battery terminal may also badly affect the battery connection.
Easy to do diagnostic test for BMW Alternator:
***Almost every vehicle on the road is a 12 volt DC (direct current) electrical system.
- Take a voltmeter, set it to DC instead of AC and connect it to the battery (red lead or wire to the positive terminal and the black to the negative).
- Turn-off every electrical component in your car and raise the RPM to 1,000.
- The voltmeter should register 14 volts; any reading less than 12 volts indicate trouble.
- Now turn-on every electrical component including the headlamps, AC, radio, flash bulbs, stereo, air-conditioner and other electronic devices. Again raise the RPM to 1,000.
- This time also the voltmeter should register 14 volts, any reading less than 14 volts clearly indicates serious trouble with your BMW alternator.
It is quiet difficult to check whether your BMW alternator is still working or not because even they are about to die or are malfunctioning for quite a long time they will still run to few miles by consuming the stored power of the battery. So, it is suggested that you should always check the tension in the drive belt of your BMW alternator especially whenever you are changing the oil.