Initial charging. The new or long-term stock battery needs to be discharged for the first time before use, and the steps are as follows:

① Firstly, screw out the water filling cover and remove the seal of the small hole on the cover to make it air free.

②Add the prepared electrolyte with a density of 1.285 (note that when preparing the electrolyte, sulfuric acid should be injected into distilled water slowly), and add it to 10~15mm above the partition.

③After the electrolyte is added, the battery can be left to stand for 2~3h to connect the positive and negative terminals of the battery with the positive and negative terminals of the power supply and prepare for discharge.

④ Preliminary charging is carried out according to the current and time specified in Table 2-59. The first stage of current charging so that the terminal voltage of each small cell rises to 2.4V, then switch to the second stage of current charging until the voltage and electrolyte ratio in 3h basically no longer change. 

Frequent charging method. Regular charging of acid battery is carried out in two stages, the charging current and time are shown in Table 2-59. The first stage of charging makes the battery voltage rise to about 2.4V for each cell, then switch to the second stage of charging until the electrolyte density reaches 1.285 and the top and bottom are uniform, then the charging is finished.