Learn about low-capacity cells, cell matching, balancing, shorted cells and loss of electrolyte
Battery users and entrepreneurs often ask, “Can batteries be restored?” The answer is, “It depends.” Most battery failures are permanent and cannot be repaired, but there are exceptions. Sulfation on lead acid batteries can be removed if caught in time (See BU-804b: Sulfation and How to Prevent it); crystalline formation, also known as “memory,” on nickel-based batteries can be dissolved through deep-cycling (See BU-807: How to Restore Nickel-based Batteries); and “sleeping” lithium-ion packs can be boosted back to life if they have been over-discharged. (See BU-808a, How to Awaken Sleeping Li-ion)
Permanent battery defects include high internal resistance, elevated self-discharge, electrical short and capacity fade. Poorly designed chargers, exposure to excess heat, harsh charge and discharge cycles, and inappropriate storage contribute to early aging. Let’s examine the cause of these non-correctable battery problems and explore what can be done to minimize them.
A manufacturer cannot predict the exact capacity when a battery comes off the production line, and this is especially true with lead acid batteries that involve manual assembly. Fully automated cell production in “clean rooms” also causes performance differences, and as part of quality control, each cell is measured and segregated into categories according to their inherent capacity levels. The high-capacity A-cells may be reserved for special applications and sold at premium prices; the large mid-range B-group may go to commercial and industrial markets; and the low-grade C-cells may end up in a consumer product or in a department store. Cycling will not significantly improve the capacity of the low-end cell, and the buyer must be aware of differences in capacity and quality, which often translate into life expectancy.
Last updated 2015-04-21
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