Why Does a Car Battery Get Hot?

[StGenevieve]

Here are the reasons why a car battery gets hot: 1. Battery issues: Aging of the battery, increased internal resistance, dried-out electrolyte, or internal short circuits can cause overheating. As the battery is used more frequently, including during discharge and charge cycles, water molecules within the battery gradually deplete, leading to gas emission and water loss. This results in heat generation during electrochemical reactions. 2. Battery aging problem: If the battery has been in use for two years or more, thermal runaway may occur due to the battery's inherent quality or usage conditions. A specific symptom is the charger not switching to a green light even after overnight charging. The battery, suffering from water loss, enters thermal runaway, which severely damages the battery. If the battery has been in use for over 18 months, it is generally advisable to replace it, as adding water for repair has limited effectiveness. 3. Charger problem: Standard chargers lack pulse functionality and do not have negative pulse depolarization features. Such chargers often fail to maintain a constant voltage in the later stages of charging, causing the battery voltage to exceed permissible limits. This leads to excessive gas emission, water loss, and overheating.