Battery capacity is the total amount of electrical energy that a battery can deliver. Note however, that this is not volume over time, because a battery’s ability to perform reduces as it ages. We discuss lead-acid battery capacity specifically in this post, although what follows generally applies to all electrochemical cells.
A Conceptual Model for Lead Acid Battery Capacity
Battery capacity refers to what each cell can deliver, and this is of great importance to a battery user. We can imagine a battery having three compartments, although this is only a conceptual example:
- The amount of active energy available right now.
- Energy we could add by recharging the battery.
- The portion that has become inactive due to aging.
A battery charge-time does not shorten because we are getting smarter at it. No not at all, it is simply evidence that the active part of the lead-acid battery’s capacity is shrinking. This reduction is a natural part of every battery’s life cycle, and we can’t undo the past. But we can learn from it and act smarter in future.
Factors Influencing Shrinking Battery Capacity
In most instances capacity fades in a straight line, as batteries age and the cumulative number of recharges stack up. Deep discharges stress a battery more than partial ones. For this reason, it makes sense to charge a battery more often. We should bear in mind that battery capacity on the label refers to its state when brand new.
Shrinking Lead Acid Battery Capacity
Lead batteries are quite unique compared to other types of cells. Their capacity gradually shrinks as sulfation accumulates on their negative lead plates, reducing the free movement of ions. This is particularly likely if we allow a lead battery to remain idle in a low state of charge. These products work best when we use them regularly.
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