This is a problem that is usually found in older vehicles, but it can certainly be a problem for new BMWs as well. If you find that your BMW’s starting a bit rougher, it doesn’t seem to have the same amount of power, or you’ve had to jumpstart it with a coworker’s vehicle recently, you may also notice that the battery is simply not holding a charge like it used to.
It could very well be an old or defective battery or one that needs to have more water added to the cells. It could also be something more than just the battery. It could be the alternator.
In every car there is a battery and alternator. The alternator is designed to take over for the battery once the engine is operational. The alternator functions along the serpentine belt. When the engine is running, it is turning the serpentine belt which turns the mechanisms in the alternator and also the air conditioning compressor.
The engine relies on the battery to turn the starter motor and fire the spark plugs to get it going. That requires a great deal of amperage and if the battery is not strong enough to supply the necessary amperage, the engine likely won’t start, thus requiring a jumpstart. If you find that you have to jumpstart your battery, but it doesn’t seem to charge up, and you replace the battery, it could very well be the alternator.
It could also be a short in the system.
If you have SRS braking on your BMW, for example, there could be a short in the system that is draining the battery while the vehicle sits idle for extended periods of time.
Any time you notice a potential problem with your battery, electrical system, or are having to jumpstart it more than once in the past month, it’s time to call on an experienced technician to diagnose the problem. Relying on a BMW certified auto service center is the best option. These technicians can quickly diagnose the problem, repair it, and get you back on the road enjoying your BMW.