Features Of Maintenance-free Batteries


Also known as valve-controlled sealed lead-acid battery, observe the following principles during use and maintenance:

A: The sealed battery is allowed to operate in a range of 15-50 degrees, but the battery life can be extended if the battery is used in a range of 5-35 degrees. Below minus 15 degrees Celsius, battery chemistry changes and the battery cannot be recharged. Maximum life will be obtained when used in the range of 20 degrees to 25 degrees. The battery will have a long life but low capacity at low temperature, and a high capacity but short life at high temperature.

B: For the relationship between battery life and temperature, refer to the following rules. When the temperature exceeds 25 degrees Celsius, the battery life will be reduced by half for every 8.3 degrees Celsius.

C: The design floating charging voltage of maintenance-free battery is 2.3V/knot. The 12V battery is 13.8V. CSB recommends 2.25-2.3V per section. In the case of 120 batteries in series, when the temperature is higher than 25 degrees Celsius, the floating charging voltage should be reduced by 3MV for each degree of temperature increase. Similarly, the voltage should be increased by 3MV for every degree increase in temperature to prevent insufficient charging. Discharge termination voltage at full load (<30 min) is 1.67V per section. In the case of low discharge rate (low current discharge for a long time) to increase to 1.7V-1.8V per section, ApCSYMMETRA can adjust the charging voltage according to the load.

D: If the battery is not recharged within 72 hours after discharge. The sulfate will attach to the plate and insulate it, damaging the battery.

E: When the battery is floating or equalized, the gas in the battery is electrolyzed into water on the negative plate, so as to maintain the capacity of the battery and do not need to add water. However, corrosion of the battery plate will reduce the battery capacity.

F: The battery separator life is only 5-6 months when the ambient temperature is 30-40 degrees. Batteries that have been stored for a long time must be charged every six months. Batteries must be stored in a dry and cool environment. Maintenance-free batteries at 20 degrees have a self-discharge rate of 3-4% per month and vary with temperature.

G: Maintenance-free batteries are equipped with a safety valve. When the internal pressure of the battery rises to a certain extent, the safety valve can automatically remove excess gas, and the safety valve will automatically recover when the internal pressure is restored.

H: The cycle life of a battery depends on the discharge rate, discharge depth, and recovery charging mode. The most important factor is the discharge depth. At discharge rate and time, the shallower the discharge depth, the longer the battery cycle life. The cycle life of a maintenance-free battery is about 200 times under the condition of 25 degrees 100% deep discharge.

I: When the battery reaches its life, it exhibits capacity decay, internal short circuit, shell deformation, plate corrosion, and open-circuit voltage reduction.

J: IEEE means that the capacity at the end of battery life is less than 80% of the nominal capacity AH. Nominal capacity has a nonlinear relationship with actual backup time. If capacity is reduced by 20%, backup time will be greatly reduced. Some UpS manufacturers mean that the battery life is terminated when the capacity is reduced to 50-60% of the nominal capacity.

K: Do not mix batteries of different capacities and manufacturers. Otherwise, battery life will be reduced.

L: If two batteries are connected in parallel, ensure that the batteries are connected and the busbar impedance is the same.

M: Maintenance-free battery means that you can not add liquid, but it is still necessary to check the shell regularly for cracks and leakage of electrolyte.