The capacity of lead-acid batteries is significantly affected by temperature.
- Low Temperatures:
- Reduced Capacity: At low temperatures, the chemical reactions within the battery slow down, which reduces the battery’s capacity. For instance, at 0°C (32°F), the capacity can drop to about 50-70% of its rated capacity at 25°C (77°F).
- Increased Internal Resistance: Low temperatures increase the battery’s internal resistance, which can reduce the efficiency of energy delivery and make it harder for the battery to deliver high currents.
- Potential for Freezing: If a lead-acid battery is discharged and exposed to very low temperatures, the electrolyte (sulfuric acid and water mixture) can freeze, potentially causing physical damage to the battery.
- High Temperatures:
- Increased Capacity: Higher temperatures can increase the battery’s capacity temporarily because the chemical reactions occur more rapidly. At 40°C (104°F), a battery might deliver about 105-110% of its rated capacity.
- Accelerated Degradation: Prolonged exposure to high temperatures accelerates the degradation of the battery. This includes increased corrosion of the positive plate, loss of water from the electrolyte due to evaporation, and general aging of the battery materials.
- Thermal Runaway: In extreme cases, high temperatures can lead to thermal runaway, where the battery heats up uncontrollably, potentially leading to failure or even safety hazards.
- Optimal Operating Temperature:
- Ideal Range: Lead-acid batteries perform best around 20-25°C (68-77°F). Within this range, they can deliver their rated capacity and have a reasonable lifespan.
- Temperature Management: To ensure optimal performance and longevity, it is important to manage the operating temperature of lead-acid batteries, especially in applications where they are exposed to extreme conditions.
