What is the consequence of sediment accumulation in the shells of a storage battery?

Sediment accumulation in the shells of a storage battery can lead to shorting of the cells. This occurs because the sediment can create conductive paths between the battery plates, which interferes with the battery's normal operation. When conductive materials accumulate, they can bridge the gap between the positive and negative plates, allowing electrical current to flow improperly and leading to a decrease in efficiency or complete failure of the battery.

Other options, while they may seem beneficial, are less accurate in this context. Enhanced efficiency and improved charge retention would actually be negatively impacted by sediment accumulation, as the presence of contaminants disrupts the electrochemical processes necessary for effective energy storage and release. Additionally, the lifespan of the battery would likely decrease due to the damage caused by the shorting effects and other related issues resulting from sediment buildup. Thus, the consequence of accumulated sediment clearly points to the risk of shorting the cells.