The steps to charge the battery are:

Wipe the battery case clean and remove the seals in the vent holes and dirt from the poles.

Inject the specified electrolyte to the specified liquid level, and let it stand for 6-8 hours. After the electrolyte penetrates into the electrode plate and the separator, and the temperature drops below 35 °C, open all plug covers.

Turn the charger switch to "OFF", the positive pole of the battery is connected to the positive pole of the charger, and the negative pole of the battery is connected to the negative pole of the charger. The charging current should be 10% of the battery capacity.

Turn the charger switch to "OFF", the positive pole of the battery is connected to the positive pole of the charger, and the negative pole of the battery is connected to the negative pole of the charger. The charging current should be 10% of the battery capacity.

Set the charger switch to "ON" to charge the battery. When the charging time reaches 14 hours, the electrolyte produces strong foam (the voltage and electrolyte density of the battery remain unchanged for 1.5 consecutive hours, or the value remains unchanged for 3 consecutive times, once every half an hour), which can be considered that the charging is completed.

During the charging process, if the electrolyte temperature is close to 45°C, the charging current should be reduced or the charging should be suspended until the electrolyte temperature drops below 45°C and then continue charging. When fully charged, the electrolyte will produce a lot of bubbles and the smell is suffocating. At this time, the density of the electrolyte has reached the specified value, or the single-cell voltage is about 2.3V and can remain unchanged for 2-3 hours, it means that the power is sufficient.

When disconnecting the connection between the charger and the battery, turn off the power of the charger first, otherwise sparks may be generated and hydrogen explosion may occur. When charging, it should be noted that the battery must be removed from the vehicle for charging, because hydrogen is generated by ionization during charging, and an explosion accident may occur in case of fire.

During charging, if the density and voltage of the electrolyte never reach the values when fully charged, it means that the battery plates are vulcanized, and the battery should be repaired or replaced at this time.