What are the causes of lead-acid battery plate sulfation?
2 Answers
Here are the specific reasons for lead-acid battery plate sulfation: 1. Long-term undercharging of the battery or failure to charge promptly after discharge. When temperature changes occur, lead sulfate undergoes recrystallization. If the electrolyte level is too low, the exposed part of the plates oxidizes upon contact with air. The fluctuating liquid level causes alternating wet and dry conditions on the oxidized plates, leading to recrystallization and sulfation. 2. Frequent over-discharge or deep discharge with small currents drives lead sulfate deep into the plate's inner layers, which cannot be restored during charging. Over time, this also leads to sulfation. 3. Impure electrolyte, excessively high specific gravity, and drastic temperature changes are all external factors that contribute to sulfation.
I've encountered many similar situations where the main cause of lead-acid battery sulfation is usually failing to recharge promptly after discharge. When a battery discharges, the lead and sulfuric acid inside react to form lead sulfate crystals. If left unattended after complete discharge, these crystals harden and adhere to the plates, eventually forming lumpy deposits over time. Extreme temperatures—either too high or too low—can accelerate this process. A sweltering summer garage or winter parking in freezing conditions both exacerbate the problem. High electrolyte density also contributes to sulfation. Older batteries are particularly prone to this issue, resulting in failed charging attempts and weak engine starts. I always remind people to avoid leaving deeply discharged batteries idle for extended periods—regularly driving for about half an hour to recharge can effectively prevent this.
