What to Do When a Car Battery Cannot Be Charged?
1 Answers
When this situation occurs, you should go to a local 4S shop for maintenance and battery activation. If you do not use the car frequently, you should still charge the battery regularly. Otherwise, the battery may remain in a discharged state, which can lead to reduced performance and lifespan, and may even result in the inability to charge the battery. Aging of the battery can cause discharge: Batteries have a limited lifespan. If a battery exceeds its service life, it may fail to start. This situation is more common in older vehicles. Nowadays, some maintenance-free batteries also have an observation window to check their lifespan. DCDC malfunction: The DCDC, essentially the generator in a fuel-powered vehicle, is the device that charges the small battery. Under normal conditions, when the vehicle's high voltage is activated, the DCDC starts charging the small battery while also providing low-voltage power to the entire vehicle. However, if the DCDC malfunctions, it cannot charge the battery. Consequently, when the battery's power is depleted, the vehicle will experience a discharge situation. Therefore, if your car shows signs of discharge during driving or charging, you should check whether the DCDC is functioning properly. Additionally, the depth of discharge (DoD) also has an impact. DoD refers to how much the battery is discharged before stopping during use. A 100% DoD means all capacity is discharged. The lifespan of lead-acid batteries is greatly affected by the DoD. Design considerations focus on whether the battery is used for deep cycling, shallow cycling, or float charging. If a battery designed for shallow cycling is used for deep cycling, the lead-acid battery will fail quickly. This is because the positive active material, lead dioxide, does not bond strongly with itself. During discharge, it generates lead sulfate, and during charging, it reverts to lead dioxide. The molar volume of lead sulfate is larger than that of lead oxide, causing the active material to expand during discharge. If one mole of lead oxide converts to one mole of lead sulfate, the volume increases by 95%. Repeated contraction and expansion loosen the bonds between lead dioxide particles, making them prone to detachment. If only 20% of the active material in one mole of lead dioxide is discharged, the degree of contraction and expansion is significantly reduced, slowing the damage to the bonding force. Therefore, the deeper the discharge, the shorter the cycle life.
