How much is the starting current of an engine starter?
3 Answers
When a gasoline engine starts, the battery output current can reach 200 to 600 amps, while for a diesel engine, it can reach up to 1000 amps. Introduction to starting current: The starting current (CCA) index refers to the minimum current obtainable under specific conditions at -17.8°C and -28.9°C. This index links the starting capability of the battery with important variables such as engine displacement, compression ratio, temperature, starting time, the technical state of the engine and electrical system, and the minimum operating voltage for starting and ignition. Starting current vs. operating current: Generally, the starting current is 20 times the operating current. This occurs when the battery is weak or not fully charged, or possibly when the under-voltage indicator is damaged. It is recommended to test the battery voltage after 25 kilometers. For a 48V battery, a reading around 50V is considered normal.
The starting current of an engine starter generally ranges between 300 to 800 amps, depending on the vehicle size and engine type. For small cars, the starting current is typically around 300 to 400 amps, while mid-size SUVs or pickup trucks may require 500 to 600 amps. Large trucks or diesel-engine vehicles can reach up to 800 amps or more. This is mainly because high torque is needed to crank the engine during startup, and the current increases further in cold weather due to higher oil viscosity. Prolonged high current draw can rapidly deplete the battery, leading to shortened battery life or electrical system failures. If the battery is aged or has insufficient charge, the starting current may increase. It is recommended to regularly check battery health and use high-quality batteries to avoid unexpected breakdowns. Ensuring the starter and wiring connections are secure can also prevent risks associated with excessive current.
Anyone who has driven a car knows that the starting current is quite substantial, typically around 400 amps, but the exact value depends on your vehicle model. My compact car measured about 300 amps during startup, while my neighbor’s SUV jumped to 500 amps when starting. Why so high? Because the starter motor has to rotate the entire engine within seconds, requiring high instantaneous power. The battery’s condition plays a big role—when the charge is low, current fluctuations intensify, which can easily blow fuses or damage wiring. I recommend parking in a garage during winter to reduce cold-start stress and using a multimeter to check if the current is normal. Excessive current not only drains the battery faster but may also cause the motor to overheat, so avoid frequent starts to extend battery life. Regularly checking for loose connections is also crucial.
