Lead-acid batteries can often become difficult or impossible to charge after being unused for a long time due to several factors.
- Sulfation: Over time, lead sulfate crystals can form and harden on the battery’s plates. This happens when a battery is left discharged for an extended period. These crystals can block the chemical reactions necessary for the battery to accept and hold a charge.
- Corrosion: The internal components of the battery, especially the lead plates, can corrode over time. Corrosion can lead to increased internal resistance, reducing the battery’s ability to charge and discharge effectively.
- Electrolyte Evaporation: In flooded lead-acid batteries, the electrolyte solution (a mixture of sulfuric acid and water) can evaporate over time, particularly if the battery is not maintained. Without sufficient electrolyte, the battery can’t function properly.
- Stratification: If a lead-acid battery is left unused for a long time, the heavier acid can settle at the bottom of the battery, while the water remains on top. This stratification can lead to uneven charging and discharging, damaging the battery.
- Self-Discharge: All batteries self-discharge over time, and lead-acid batteries are no exception. If the self-discharge rate is higher than expected, the battery can become completely discharged, leading to sulfation and other issues.
In some cases, specialized chargers or desulfators can help revive a lead-acid battery that has been unused for a long time, but this is not always successful. Regular maintenance, such as keeping the battery charged and checking electrolyte levels, can help prevent these issues.
