The memory effect is well known for their inconvenience. NiCd batteries in loading procedures should be performed with care. Typically, if the battery is recharged still containing 30% load, will be able to use only the remaining 70% capacity. If it is overloaded with 60%, capacity is reduced to 40%. Why is this happening?
In a NiCd battery, the active elements, nickel and cadmium, are in the form of crystals. When the batteries are recharged before fully downloaded, the memory effect occurs and the crystals grow and accumulate in training, making the battery gradually loses its capacity. Strictly not the memory effect (which makes the crystals more), but the effect of crystallization (which produces clumps of crystals) the real problem of the batteries. In a state of advanced degradation, the formation of crystals separator may even rupture the insulation causing high levels of self-discharge or short circuit.
In fact, the problem is not so worrying. There is a need for iron discipline and only recharge the battery when fully discharged. Usually, it suffices that the first load is longa (around 15 hours) and then the battery is completely discharged. After the battery is fully recharged at least once a week. This operation should be enough to keep the crystals in activity and not allow them to create formations.
NiMH batteries and lithium have no problems of crystallization, then, do not suffer the memory effect.
Self-discharge
The batteries also suffer from an effect of self-discharge, or lose some energy when not in use.
Usually, the batteries fail to maintain all energy. A NiCd battery can lose about 10% of energy in the first 24 hours (but continue to lose just 10% per month) and NiMH batteries have a self-discharge rate even higher, because atoms Hydrogen leak. If the self-discharge is very high, the battery may be danificados. One problem may be a separator danificados, which is irreparable. Typically, a battery with a self-discharge rate exceeding 30% per day will be recycled.
Excess Burden
The excess charge can also be detrimental. Batteries should be charged just enough, especially NiMH batteries. A charge of one night when just a few hours would suffice, can significantly pickling life of a battery. According to Jerry Wiles, of Batteries Plus, "there are more batteries damaged by excessive burden by abuse of another order."
What already exists
In fact, lithium polymer batteries are now a reality. Used initially by Ericsson and now widely used by other manufacturers, are very similar to those already known lithium batteries, with the flexibility its main advantage, promising to revolutionize not just the battery market but also the future design of mobile phones, and that these new "pearls" will be produced in pliable sheets with the thickness of a millimeter, thus resulting possibly in cell phones with a most innovative design. They have also a cycle of loading / unloading rigid than its congener, or less space, less weight and more autonomy.
