j: IEEE defines the end of battery life as the capacity is less than 80% of the nominal capacity AH. The nominal capacity and actual backup time have a nonlinear relationship. If the capacity is reduced by 20%, the corresponding backup time will be greatly reduced. Some UPS manufacturers define the end of battery life as the capacity drops to 50-60% of the nominal capacity.
k: It is strictly forbidden to mix batteries of different capacities and from different manufacturers, otherwise the battery life will be reduced
l : If two battery groups are used in parallel, the battery connection and bus impedance should be the same.
m: Maintenance-free batteries mean that there is no need to add fluid, but it is still necessary to regularly check whether the shell has cracks and whether the electrolyte has leaked.
3: Nickel-cadmium battery
Unlike lead-acid batteries, these batteries produce hydrogen and oxygen during electrolysis instead of corrosive gases, so they can be installed next to electronic equipment. They also consume very little water and generally require no maintenance. The normal life span is 20-25 years. They are much more expensive than the batteries mentioned above. The initial installation cost is about three times that of lead-acid batteries. The battery life is not affected by high ambient temperature, nor is the battery capacity affected by low ambient temperature. Generally, the voltage per cell is 1.2V, and UPS needs to be designed with a higher charger voltage because of the use of this type of battery.
Pros and Cons
1: Open lead-acid battery
Advantages: less investment, longer life than maintenance-free batteries, and lower temperature requirements.
Disadvantages: Maintenance is more complicated, a special battery room is required, corrosive gas is discharged, and initial charging must be done on site for 50-90 hours, requiring special maintenance.
Advantages: No maintenance such as adding fluid is required, it can be transported in a fully charged state, and no special maintenance is required.
Disadvantages: Failure to perform restorative charging in time will damage the battery, it is more sensitive to temperature, has a shorter lifespan, and is more expensive than lead-acid batteries.
3: Nickel-cadmium battery
Advantages: Low maintenance requirements, long life, insensitive to temperature, no harmful gas emissions.
Disadvantages: Most expensive of the three batteries.
UPS Common Batteries
Most computer centers now use maintenance-free batteries, which are more convenient to maintain, but the following work is also required
1: Discharge once every three to four months to prevent the plates from oxidation.
2: The ambient temperature should be maintained at 20-25 degrees.
3: The connection cannot be too tight or too loose and needs to be checked frequently.
4: After three years of use, it needs to be checked and replaced in time.