What is the starting current of a vehicle?
2 Answers
Generally, the starting current of a sedan ranges between 100 to 300 amperes. The principle of starting current is as follows: 1. At the moment the motor is energized and remains stationary, with the rotor speed at 0, the synchronous rotating magnetic field cuts the rotor windings at the maximum speed. 2. This induces the highest electromotive force in the rotor windings, generating a large current that counteracts the magnetic flux of the stator field. To maintain the original magnetic flux compatible with the power supply voltage, the stator windings automatically increase the current. 3. Since the rotor current is very large at this time, the stator current of the motor also increases significantly, reaching 5 to 7 times the rated current, which explains why the motor has a high starting current.
I've driven several cars, especially during winter when starting difficulties are common, often requiring attention to the starting current. Simply put, most gasoline cars have a starting current ranging between 200 to 500 amps, depending on the vehicle size and ambient temperature. For example, my compact sedan draws about 300 amps during a cold start, while an SUV or truck might surge above 400 amps. The current magnitude mainly comes from the starter motor needing to instantly rotate the engine, so the battery must be sufficiently powerful—otherwise, you'll hear clicking sounds or no rotation after attempting to start. When choosing a battery, it's advisable to check the CCA value (Cold Cranking Amps), typically matching between 350 to 700 amps, which can extend battery life. Regularly inspecting terminals for corrosion is also crucial to avoid increased resistance causing poor starts. Real-world experience has taught me that neglecting this significantly raises the risk of roadside breakdowns, particularly in cold regions.
