Annual Battery Test, Analysis, Cleaning, Documentation and Reporting

Accumulated dirt, salt, grime, and corrosion on top of the battery can create a conductive path between the terminals, causing a slow, constant electrical drain known as a voltage leak. This leakage can discharge the battery even while powered off or disconnected. For best longevity, a battery should never run below 50% of its capacity. Running a lead-acid battery down (deep discharging) is very bad for it and significantly reduces its lifespan. Consistently discharging below 50% causes premature sulfation—where hardened lead sulfate crystals form on plates—lowering capacity, accelerating corrosion, and potentially causing permanent total failure.

Impact of Deep Discharging;

Reduced Cycle Life: Draining a battery completely (<20% charge) allows the polarity of weaker cells to reverse, causing irreversible damage. 

Irreversible Sulfation: Excessive lead sulfate accumulates and hardens on plates, making it impossible for the battery to hold a charge. 

Physical Damage: Deep discharges can cause plate shedding, where active material breaks off, resulting in internal short circuits. 

Recommended Storage for Longevity;

Optimum Limit: Aim to avoid discharging below 50% depth of discharge (DoD) for best longevity.

Resting Voltage: For a 12-volt battery, avoid letting it drop below 11.8 volts (rested) or 10.5 volts (under load).

Maintenance: Recharge immediately after use to prevent sulfation.