The battery capacity is usually expressed in kV · A or kW for power supply equipment. However, as a VRLA battery used as a power source, it is more accurate to use ampere hours (A · h) to represent its capacity. The battery capacity is defined as Δ t0tdt, and theoretically t can tend to infinity. However, in reality, when the battery is discharged below the termination voltage and still continues to discharge, it may damage the battery. Therefore, the t value is limited. In the battery industry, the hour (h) represents the sustainable discharge time of the battery, which can be perceived as C24, C20, C10, C8, C3 C1 and other nominal capacity values. The nominal capacity of small batteries is measured in milliampere hours (mA · h), while the nominal capacity of large batteries is measured in ampere hours (A · h) and kiloampere hours (kA · h). The telecommunications industry often takes nominal capacity values such as C10 and C8. For example, the common Deka battery 12AVR100SH is a 12V single unit with a capacity of 100 A · h, which can continuously discharge for 10 hours with a current of 10A. The total discharge ampere hour is 10 * 10=100 A · h. (In actual testing, to maintain a constant current value, when the voltage changes, the external circuit load should be adjusted for measurement). The capacity of electric vehicle batteries is represented by the following conditions: electrolyte ratio 1.280/20 ℃, discharge current for 5 hours, discharge termination voltage 1.70V/Cell, electrolyte temperature during discharge 30 ± 2 ℃. 1. Voltage drop during discharge, terminal voltage lower than unloaded voltage (open circuit voltage) before discharge, The reasons are as follows: 1. V=E-I.RV: Terminal voltage (V) I: Discharge current (A) E: Open circuit voltage (V) R: Internal impedance (Ω) 2. During discharge, the specific gravity of the electrolyte decreases and the voltage also decreases. 3. When discharging, the internal impedance of the battery increases accordingly. If it is 1 time when fully charged, it will increase by 2-3 times when fully discharged. The reason why the voltage of the battery used for lifting is lower than that used for walking is because the power of the hydraulic motor used for lifting is higher than that of the driving motor used for walking. Therefore, if the discharge current is higher, the I.R. of the above formula will also increase. The capacity of a battery is represented by the relationship between discharge rate and capacity in a capacity test as follows: 5HR 1.7V/cell3HR... 1.65V/cell1HR... 1.55V/cell It is strictly prohibited to continue discharging when the above voltage is reached. The deeper the discharge, the higher the internal temperature of the battery, and the more severe the degradation of active substances, thereby shortening the battery life. Therefore, if the battery voltage of the stacker without load lifting has reached 1.75v/cell (42v for 24cells and 21v for 12cells), it should be stopped and charged immediately. Battery temperature and capacity: When the battery temperature decreases, its capacity will also significantly decrease due to the following reasons. (A) The electrolyte is not easy to diffuse, and the chemical reaction rate of polar active substances slows down. (B) The impedance of the electrolyte increases, the battery voltage decreases, and the 5HR capacity of the battery decreases as the battery temperature decreases. Therefore, the usage time in winter is shorter than that in summer. Especially for batteries used in freezers, due to their high discharge capacity, the actual usage time of the day is significantly reduced. If you want to extend the usage time, you should first increase the temperature in winter or before entering the freezer. When repeatedly charging and discharging daily for use, the battery life will be affected by the depth of discharge. The discharge amount and specific gravity of the electrolyte in a battery are almost proportional to the discharge amount. Therefore, based on the specific gravity of the battery when fully discharged and the specific gravity of the battery when discharged at 10%, the discharge capacity of the battery can be calculated. The best way to determine the discharge capacity is to determine the specific gravity of the electrolyte in a lead-acid battery. Therefore, regularly measure the specific gravity after use to avoid excessive discharge. While measuring the specific gravity, also measure the temperature of the electrolyte. The specific gravity calculated at 20 ℃ should not be reduced below the value of 80% discharge. The discharge state and internal impedance will increase with the increase of discharge amount, especially at the discharge end point, where the impedance is the highest. The main reason is that the discharge process causes the poor conductor producing current in the electrode plate - lead sulfate and the decrease in the specific gravity of the electrolyte, which leads to an increase in internal impedance. Therefore, after discharge, it is necessary to charge immediately. If the discharge state is allowed to continue, the lead sulfate will form a stable white crystal (this is the sulfurization phenomenon mentioned in the literature), Even if charged, the active substances in the electrode cannot be restored to their original state, which will shorten the service life of the battery. When a white lead sulfate battery is discharged, both the cathode and anode plates produce lead sulfate (PbS04) simultaneously. If it is allowed to continue discharging and not charged, stable white lead sulfate crystals will eventually form (even if recharged, it is difficult to restore the original active substance). This state is called white sulfurization phenomenon. The temperature during discharge: When the battery is excessively discharged, the internal impedance significantly increases, so the battery temperature also increases. The high temperature during discharge will increase the temperature at the completion of charging. Therefore, controlling the temperature at the end of discharge below 40 ℃ is the most ideal. Theoretical capacity, also known as calculated capacity, is determined by the amount of active substance contained in the battery plate. The electrochemical equivalent of a lead-acid battery is 0.517 A · h/g for Pb, 0.259 A · h/g for Pb, 0.488 A · h/g for Pb, and 0.224 A · h/g for Pb. The capacity calculated based on the amount of electrochemical equivalent and active substance is called the theoretical capacity of the battery