The widespread use of cell phones and various gadgets, along with noticeable advantages, has also generated certain problems for their owners. One of them is connected with the fact that in the overwhelming majority of cases a battery is used for power supply in normal operation mode, for some types of which the so-called memory effect is characteristic.
The essence of the effect is that when recharging an incompletely discharged battery multiple times, the latter is due to the crystallization of the working mass “Remembers” the initial level, Figure 1 and then discharges only to the corresponding value, refusing to give the remaining load to the load unused charge. In this case, the indicator of the gadget indicates that there is no charge left in the battery, which is equivalent to a decrease in capacity.
What type of batteries is characterized by memory effect
The positive point, if you can call it that, in this case is that the memory effect is characteristic only for nickel-based batteries (widespread nickel-cadmium cells and somewhat lesser known nickel metal hydride).
For its effective suppression, it was recommended to follow two basic rules:
- do not allow the capacity to drop less than 10% of the manufacturer's recommended level;
- charge the battery to a maximum of 90% of the rated value.
It is clear that the overwhelming majority of ordinary users find it difficult to follow these recommendations. Taking this feature into account, gadget manufacturers began to install additional charge level controller, which forcibly stopped the charging current when the charge level reached 0.9 from nominal. The same controller turned off the device when it reached a 10% charge level.
In modern lithium batteries, Figure 2, the memory effect is absent simply due to the peculiarities of the chemical processes taking place in its working material. Moreover, these elements will last much longer if the charge is maintained in them at the maximum level, i.e. put on recharge as soon as possible. It is this feature, combined with the fact that, in terms of other parameters, these elements are at least not inferior to nickel ones, has led to their widespread use.
Recovering capacity
With a certain patience and punctuality, the actual capacity of an obsolete nickel battery can be restored almost completely by performing the so-called. training. This procedure is based on the destruction of crystalline formations in the working medium. To do this, it is enough to fully charge and discharge the cell several times. The number of such cycles depends on the battery life and the level of crystallization of its working mass.
In order to suppress the memory effect preventively, it is recommended to repeat the complete discharge procedure:
- once a month for nickel-cadmium cells
- once every two - a maximum of three months for nickel metal hydride.
Effective preventive maintenance for batteries in finger form factor is achieved by selecting the refresh mode, which is supported by older models of the corresponding chargers, Figure 3.
A good preventive measure is compliance with the temperature regime of operation, i.e. preventing the device from heating and cooling too much.