Equalization is a deliberate overcharge that corrects cell imbalances and prevents stratification in flooded lead-acid batteries. Done correctly and regularly, it extends battery life significantly.
>Why Equalization Is Needed
Over time, flooded batteries develop two problems:
1. Cell imbalance: Not all cells age at the same rate. Some self-discharge faster. Equalization brings all cells to full charge together.
2. Stratification: The sulfuric acid in electrolyte settles in layers — more concentrated at the bottom. This causes uneven plate wear. The gassing during equalization stirs the electrolyte back to uniform concentration.
When to Equalize
- Monthly: Standard flooded batteries in daily use
- After adding water: Equalize to remix electrolyte
- If specific gravity variation exceeds 0.030 between cells
- If battery seems weak or voltages are imbalanced
- Before winter (prepare batteries for cold season)
How to Equalize
- Fully charge the battery bank first
- Set charge voltage to equalization level (typically 2.4-2.5V/cell above float)
- Continue applying equalization charge for 2-4 hours
- Monitor: all cells should gas freely by the end
- Check water levels during equalization (will need topping up)
- Return to normal float charge when complete
Warning: Equalization is for flooded batteries ONLY. Do NOT equalize sealed AGM or GEL batteries — this will damage them.