The capacity of lead-acid batteries can decrease significantly in winter due to lower temperatures. Here are some reasons why this happens.
- Electrochemical Reaction Rate: The chemical reactions inside a battery slow down at lower temperatures, reducing its ability to deliver power.
- Increased Viscosity of Electrolyte: Cold temperatures can increase the viscosity of the electrolyte, which makes it harder for ions to move between the plates, reducing the battery’s efficiency.
- Higher Internal Resistance: The internal resistance of a battery increases as the temperature drops, leading to reduced capacity and performance.
- Self-discharge: While self-discharge rates are generally lower in cold temperatures, any capacity that is lost due to self-discharge is harder to recover in the cold, making the battery appear weaker.
Lead-acid batteries can lose as much as 20-50% of their capacity at freezing temperatures (0°C or 32°F) compared to their capacity at room temperature (25°C or 77°F). To mitigate this, it’s important to keep lead-acid batteries charged and, if possible, insulated or warmed in cold weather conditions.