Quick Answer
Lead acid batteries require equalization when the electrolyte stratification becomes too severe, causing uneven charging and discharging of individual cells, which can lead to premature aging and failure. Signs include excessive sulfation, low battery capacity, and reduced charging efficiency. Equalization helps to re-balance the electrolyte distribution.
Warning Signs of Imminent Battery Failure
When lead acid batteries are not properly maintained, their internal chemistry can become severely imbalanced. This can lead to excessive sulfation, a condition where sulfuric acid crystals form on the battery plates, reducing their ability to hold a charge. Signs of sulfation include a decrease in battery capacity, increased charging time, and a noticeable decrease in the battery’s ability to hold a charge. If left unchecked, sulfation can cause a battery to fail prematurely, requiring costly replacement.
Identifying the Need for Equalization
To determine if your lead acid batteries need equalization, check the specific gravity of the electrolyte using a hydrometer. A difference of 0.030 or more between the highest and lowest readings on a single cell indicates the need for equalization. Additionally, if the batteries are old or have been stored for an extended period, equalization may be necessary to re-balance their internal chemistry.
Equalization Techniques and Best Practices
Equalization involves applying a high charge to the battery for an extended period, allowing the excess sulfuric acid to be driven off and the electrolyte to be re-distributed. The best practice is to equalize the battery at a temperature between 70°F and 90°F (21°C and 32°C), as this helps to prevent excessive gas generation and ensures a safe and efficient process. A typical equalization charge consists of a constant current of 10-20 amps for 2-4 hours, depending on the battery type and age.
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