Self-discharge is a natural phenomenon observed in all rechargeable batteries, including lead-acid batteries. It refers to the gradual loss of stored energy when a battery is not in use. For lead-acid batteries, the self-discharge rate typically ranges from 3% to 20% per month, depending on various factors such as temperature, battery design, and manufacturing quality.
Causes of Self-Discharge
- Electrochemical Reactions: Lead-acid batteries undergo internal chemical reactions even when idle. The lead plates and sulfuric acid electrolyte react, gradually reducing the charge.
- Impurities in Materials: Impurities in the lead or electrolyte can accelerate self-discharge by promoting unwanted side reactions.
- Temperature: Higher temperatures significantly increase the rate of self-discharge. For every 10°C rise, the rate approximately doubles.
Impact of Self-Discharge
Excessive self-discharge can lead to a loss of capacity, sulfation of the plates, and reduced battery life. Proper storage and periodic recharging are essential to minimize these effects.
