The cycle of a battery is determined by the number full charge and discharge cycles. This is before its functional capacity falls to below 80% of its original capacity. A battery’s life cycle takes into consideration the number of charges and discharges before it becomes obsolete.
There are many factors that determine the number of cycles that a battery undergoes before it makes its final bow; these include the discharge rate and depth of discharge. The battery’s operating temperature and charging methods are also key considerations.
Self-discharge occurs when the electrical capacity of the battery is lost, mostly because the cell is sitting on the shelf and not active at all. Electrical and internal chemical reactions within the cell are what initiates self-discharge, in what looks like the exertion of a small external load. This automatically reduces the stored charge of the battery.
Self- discharge is one key reason for the decrease in the shelf life of a battery. When in use, the battery tends to function at less than full charge simply because of self-discharge.
Also known as lazy battery effect, memory effect occurs when there’s a reduction in the durability of a battery’s charge. This is a consequence of repeated recharging after incomplete discharge in earlier usages. The frequent recharging in effect causes the crystalline structure of the electrodes to manifest differently.
The capacity of the charging system is also gradually reduced. In this case, the battery tries to remember and function on the small capacity. There are several causes of memory effect/ these include:
1.Repeated partial charges
2.The make of the battery; there are some models that develop memory effect in cases of incomplete discharge before recharging.
3.High or low rates of discharge
4.When the charging time is limited and inadequate
5.The charger is itself is poorly designed or malfunctioning
Different designs and models react differently to the memory effect. Some of them do not experience memory effect at all, while others undergo significant levels of the same.
Basically, Voltage in a battery signifies the difference in electric potential between the positive and negative terminals of a battery. One terminal is positively charged, and the other is negatively charged. If there is a big difference in the potential, it leads to a greater voltage. In essence, voltage is what determines the amount of energy a battery can discharge at one single time.
Charging a battery makes the voltage rise while discharging makes the voltage to fall low. It is like stretching and releasing a rubber band. There is an increase in both temperature and pressure during charge, hence increasing the voltage. Over-exertion and uncontrolled increase of the same can easily lead to rupture and explosion of the battery. In the same way, discharging the battery below the recommended capacity’s lower voltage can also lead to permanent damage to the battery.
Battery capacity is determined and measured in ampere-hours. As such, Ah is the discharge current that a battery delivers over a period of time. It is possible to install with a higher Ah, than specified, to allow for longer runtime; at the same time, using a smaller pack than specified, allows for shorter runtime.
As is expected, chargers often have some tolerance when it comes to Ah. This then allows larger batteries to take a longer time to charge, as compared to a smaller pack.