The discharge depth of lead-acid batteries refers to the percentage of the capacity released by the lead-acid battery to its rated capacity during use, which is generally expressed as a percentage. 60% discharge depth indicates that the capacity released by the lead-acid battery reaches 60% of the rated capacity of the lead-acid battery, and at this point, the lead-acid battery still has 40% capacity left. The depth of discharge is closely related to the charging life of lead-acid batteries. The deeper the discharge depth of lead-acid batteries, the shorter their charging life, resulting in a shorter service life of lead-acid batteries. Therefore, deep discharge should be avoided as much as possible during use.