There are many reasons for the decline in the capacity of the forklift battery during use, mainly in the following aspects
     1. After the forklift battery arrives at the user, it can be installed and used in time, resulting in long-term storage. Long-term storage will cause self-discharge to cause capacity shortage.
     2. The positive electrode of the forklift battery is corroded and the deformation causes insufficient capacity.
        The positive electrode plate of the forklift battery is the main factor affecting the working life of the battery. The capacity of the forklift battery charging and discharging cycle, especially the capacity reduction in the deep cycle is closely related to the quality deviation of the positive plate.
    2.1 The active material softens and falls off on the positive grid
        There are macropores and micropores in the microscopic active material. The large pore size exceeds 0.5cm. It is composed of many small pores. As the discharge cycle progresses, the active surface shrinks and forms a core into a coral-like structure. In the secondary discharge cycle, the accumulation of small pores is increased, so that the large pores are continuously increased, the positive electrode structure is destroyed, and the active material is detached.
        The main reason for these situations is the large current charging and discharging of the forklift battery. Avoid the occurrence of currents that should be guaranteed to be charged and discharged and avoid overcharging or overdischarging.
    2.2 Positive grid corrosion deformation
    The corrosion rate of the grid depends on the composition of the grid alloy, but the higher the storage temperature, the faster the corrosion rate, and the deeper the depth of the discharge, the more severe the corrosion.
     3. Forklift battery negative plate sulphation:
    In normal operation, the PbSO4 particles on the negative plate are small, and the discharge is easily restored to fluffy lead, but sometimes the inside of the battery generates lead sulfate which is difficult to reduce, which is called sulfation.
         There are many reasons for causing the negative salt to be salted. For example, it can not be charged in time after discharge. The battery is left on for a long time, causing serious self-discharge. The electrolyte concentration is too high, the long-term charging is insufficient, and the long-term discharge is high. This lead sulfate is difficult to be reduced by conventional methods. Thus, the reduction of active substances will inevitably affect the capacity of the forklift battery.