When the battery is seriously damaged, it is not possible to rely on the car generator to charge, portable chargers should be used to charge, such as 12V60Ah charging mode: using constant voltage current limiting mode, constant voltage 14.8V current limiting 15A charging for 16 hours, and then 3A constant current charging for 4 hours, a total of 20 hours. The battery can be fully charged according to the following phenomena to judge: 1) a large number of bubbles in the battery, both appear \"boiling\" phenomenon; 2) The terminal voltage rises to the maximum and does not rise within two hours; 3) The electrolyte rises to the highest level and does not rise again within two hours. Or observe the electric eye, the full charge state can be determined from the electric eye is green.