What Causes Inconsistent Voltage Among 4 Batteries?
2 Answers
After prolonged use of an electric vehicle, the voltage of the four batteries may become inconsistent, resulting in shorter travel distances. In such cases, it is necessary to replace the batteries to ensure uniform voltage across all batteries. If one battery has a significantly lower voltage than the other three, it indicates a problem with that specific battery. Replacing only the faulty battery is sufficient, as long as its voltage matches the other three. The resulting circuit will remain relatively durable without significant adverse effects. Regular battery maintenance is essential. Below is relevant information about battery voltage: Normal Battery Voltage: The normal voltage range for a battery is between 11.8V and 12.8V. After starting, the battery voltage should range from 13.2V to 14.8V. As long as the voltage during startup does not fall below 11V, it is considered normal. Both excessively high and low battery voltages can have adverse effects. Battery Voltage Precautions: When charging lead-acid batteries, wear protective clothing. Ensure there are no sparks near the battery during charging, and smoking is strictly prohibited. When charging one or multiple batteries in parallel, the charger voltage should not exceed 16V. Connect the charger's positive lead to the battery's positive terminal and the negative lead to the negative terminal. Start the charger at the lowest current setting and gradually increase it until the battery begins to accept current. For deeply discharged or cold batteries, this process may take several minutes. If acid mist is emitted from the battery's vent or the battery temperature exceeds 52°C, stop charging immediately, as these signs indicate battery damage requiring replacement. Charging is complete when the current drops below 1A or after 24 hours of charging, at which point charging can be stopped.
I've noticed that many car owners have inconsistent battery voltages, which is common in older vehicles or those used frequently. The voltage differences are mainly due to uneven battery aging—some batteries develop higher internal resistance over a few years and can't hold a charge well. Charging system issues also play a big role, such as unstable alternator output, leaving some batteries undercharged. Connection problems are frequent too, like corroded terminals or loose bolts increasing resistance and causing uneven current distribution. When adding aftermarket electronics like high-power audio systems, the battery under heavier load faces more stress and tends to age prematurely. It's recommended to check each battery's voltage monthly with a multimeter—a difference within 0.2V is acceptable, but exceeding 0.5V is risky, requiring charger inspection or immediate battery replacement to avoid startup failure and vehicle damage. Parking in shaded areas can slow aging. Overall, while this seems minor, neglecting it may damage vehicle components, costing both money and peace of mind.
