What causes battery shedding?

Overcharging is a major cause of shedding. When a battery is overcharged, excessive current can cause the plates to heat up, leading to faster degradation of the active material. Deep discharges and frequent cycling can also accelerate shedding, especially when the battery is subjected to high loads or left discharged for long periods.

How does a lead-acid battery shed?

The shedding process occurs naturally as lead-acid batteries age. The lead dioxide material in the positive plates slowly disintegrates and flakes off. This material falls to the bottom of the battery case and begins to accumulate.

What happens when a battery is cycled?

Progressive expansion and contraction of the positive plate as the battery is cycled causes an ever-increasing amount of the active material to be lost (“shedding”) from the grid/plate wires (a process called “corrosion”).

What happens when a battery is over-discharged?

1. Over discharge. As a battery discharges, the lead sulphate which forms causes an expansion of the active material. If a battery is repeatedly over-discharged, this results in the positives shedding. In the negatives, the spongy lead is puffed out, resulting in the condition known as "bulged negatives" as illustrated in Fig 122.

What causes a battery to short?

Shedded Material Accumulation: As mentioned earlier, active material that sheds from the plates can accumulate at the bottom of the battery case. If enough material builds up, it can form a conductive bridge between the plates, leading to an internal short. Detecting internal shorts early is crucial for preventing extensive damage to the battery.

What causes a battery to age?

Stationary batteries, operated under float-charge conditions, will age typically by corrosion of the positive grids. On the other hand, service life of batteries subject to cycling regimes, will typically age by degradation of the structure of the positive active mass.