What Causes False Voltage in Car Batteries?
2 Answers
The following are the reasons for false voltage in car batteries:1. Display Issue: Electric vehicles display battery level based on the corresponding relationship between load current and voltage. When the vehicle starts or climbs a slope, the load current increases, causing the voltage to drop, which results in a sudden decrease in the displayed battery level. This is why the battery level may drop by 1-2 bars instantly when climbing a slope. Once the slope is finished and the load current returns to normal, the voltage also recovers to its normal level, making the battery level appear to return.2. Cadmium-Free Batteries/Cadmium-free batteries have lower initial voltage and are prone to sudden power drops during acceleration: Older batteries contained cadmium, which enhanced conductivity, reduced internal resistance, improved discharge voltage, and provided better performance in extreme temperatures and during charge-discharge cycles. After 2014, due to environmental protection initiatives, cadmium-free batteries were promoted, which slightly affected battery performance. The initial voltage became lower, leading to sudden power drops during acceleration.
I've been driving for over a decade, and the most common cause of weak battery voltage is battery aging. Over time, the internal plates become sulfated and crystallized, which is equivalent to increased resistance. The voltage may appear high on the surface, but the actual available energy is very low. Another factor is insufficient charging, such as frequent short-distance driving where the alternator never gets a chance to fully charge the battery, or when the alternator itself malfunctions. Extreme weather also plays a role—cold winter temperatures can drastically reduce battery performance, while summer heat accelerates internal aging. I've also noticed that if the battery lacks water or gets contaminated, its internal condition becomes even more unstable. It's important to regularly check battery health, ideally using a multimeter every six months to measure the actual voltage or getting a professional diagnosis at a repair shop. Don't wait until you have trouble starting the car to regret it—timely replacement can save a lot of hassle.
