How can conducted noise from an automobile battery charging system be suppressed?

The alternating current generated by a vehicle's alternator is converted to DC by rectifiers, which can generate high-frequency RF 'whine' that travels along the vehicle's wiring. This is known as conducted noise. Installing ferrite chokes on the alternator and charging system leads acts as a high-impedance barrier to these high-frequency RF currents. This safely suppresses the noise without disrupting the DC power flow. Filter capacitors placed in series would incorrectly block the DC power entirely.