What is the normal current for a car battery?
3 Answers
Car battery current is considered normal when it reaches 300-400A. Factors determining current size: The current size depends on the number of electrical appliances in use. For example, just turning on an interior light might consume about 0.3A. Factors affecting battery working current: The working current of a battery depends on its model, i.e., capacity, which is usually labeled on the casing. The higher the working current, the shorter the duration. For instance, a 20Ah battery discharging at 2 amps can last for 10 hours before needing a recharge. The instantaneous maximum current can reach 70 to 100 amps or even higher. However, it's important to note that excessively high currents can lead to problems, including the risk of battery explosion.
Having driven for so many years, the topic of a car battery's normal current is worth discussing. Generally speaking, after turning off the engine and removing the key, the battery's leakage current should be below 50 milliamps, approximately 0.05 amps. During startup, the current surges to several hundred amps, commonly ranging from 350 to 600 amps, depending on your vehicle's size—smaller sedans may be on the lower end, while SUVs could be higher. The current itself isn't a fixed value and depends on the battery's health and temperature. If the leakage current exceeds 50 milliamps, there might be wiring issues such as a short circuit, leading to difficulty starting the car or rapid battery depletion. It's advisable to check the voltage with a multimeter every few months; a normal reading is around 12.6 volts. During maintenance, clean the battery terminals to prevent corrosion. If the battery is old and its output weakens, replace it promptly to avoid getting stranded on the roadside in winter.
As a car enthusiast, I often measure the battery current myself. The normal values are divided into two parts: the leakage current when the engine is off should be below 50 milliamps; the current during startup is very high, around 400 amps. These aren't numbers you need to focus on daily. The key is the battery's CCA (Cold Cranking Amps) standard, which is indicated in the new car's manual. If the current is too high after parking, it might be due to the audio or navigation system drawing power. Buy a simple multimeter to check for leakage—a stable reading below 0.05 amps is considered normal. Battery life generally lasts 2-5 years. Pay attention to slow starter response when the battery is low; regularly check the alternator's charging performance to ensure smooth driving and avoid unexpected delays in your trip.
