In the first stage, the battery is

In the first stage, the battery is charged at a proper constant current. After the battery is charged to a certain capacity, the battery is charged at a constant voltage. The charging current decreases until it is sufficient. In this way, the battery will not appear in the early charge of a large current, in the late will not appear too high voltage, so that the battery gas generation.After charging in two stages, the capacity of the battery can reach the rated capacity under the current environmental conditions. However, due to the battery self-discharge will lose a part of capacity, so many charging controllers continue to charge with a small current after the battery is full, to make up for the battery's self-discharge, this way of charging with a small current is also known as floating charge or trickle charge. This is the third stage on a two-stage basis, but with a lower charging voltage than the constant-voltage stage.