What is the charging current for starting a car battery?
3 Answers
Car battery starting charging current is 6A. When the car engine is running, it drives the generator to operate. The electricity generated by the generator can power the car's electrical devices, while another portion of the electrical energy can charge the battery through a transformer. The car battery is an important component of a vehicle, providing power to the ignition system and storing electrical energy for the car. Also known as a storage battery, the car battery is a type of battery that works by converting chemical energy into electrical energy. Typically, the battery referred to is a lead-acid battery, which is mainly made of lead and its oxides, with an electrolyte of sulfuric acid solution. The normal service life ranges from 1 to 8 years, largely depending on the condition of the vehicle.
It depends on the engine displacement and temperature. Last time I helped my neighbor measure his 1.6L sedan, the starting current instantly surged to over 200 amps, which was quite startling like a welding machine. Actually, the charging current stabilizes after normal startup. At idle, the alternator outputs about 15-20A, and it can go above 30A when driving on the highway. Just a reminder, for older cars with aging wiring, the charging current may decrease. My friend's decade-old car was only charging at 8A, and it ended up breaking down halfway.
With twenty years of experience in car repair, the starting current mainly depends on the battery capacity. A standard 55Ah battery typically has a starting current ranging from 150-300A, especially higher during cold starts in winter. The key lies in the battery terminals. Once, a customer complained about starting difficulties, and upon testing, it was found that terminal oxidation increased resistance, causing the actual current to be 40% lower than normal. Charging is more critical regarding alternator output: idle speed generates about 10-30A, while pressing the accelerator deeply can reach up to 50A. However, cars modified with high-power audio systems are prone to excessive power drain.
