UPS battery capacity calculation and battery configuration
The battery is an important part of the UPS system, and its quality is directly related to the reliability of the entire UPS system. The correct choice of UPS backup battery capacity is also vital to the normal operation of the UPS system. Excessive battery capacity selection causes a waste of investment. A small-capacity selection not only fails to meet the UPS backup time, causing safety accidents but also because the battery discharge rate is too large, which seriously affects the battery performance and life.
Battery capacity (AH) refers to the constant current (0.1C10) A and continuous discharge time (10h) H that the battery can provide at a given time (1.80V) at the end of the voltage at a standard ambient temperature (25°C) Product (I×T).
The brand of UPS and battery and the backup time of the UPS system are determined. According to the discharge performance parameters of the battery, the model and capacity of the battery are calculated and determined by calculation methods such as power method, estimation method, and power source method.
In the UPS system, when the mains power is normal, the mains is the energy source, the UPS is the energy conversion device, the battery is the energy storage, and the subsequent load is the energy consumption source. When the mains fails, the battery is the energy source and the UPS is the energy conversion For equipment, the subsequent load is still the source of consumption. If you want to calculate the UPS battery capacity, you can do the calculation according to the following methods:
Constant power method (look-up table method) to calculate UPS battery capacity:
This method is a manifestation of the law of conservation of energy, and the work provided by the battery is equal to the latter slightly greater than the work consumed by the load. W load ≤ W battery; P load ≤ P battery (P battery is equal to the constant power data of the actual battery test).
The constant power method (look-up table method) is the most commonly used method for UPS battery capacity calculation. The battery capacity and model are determined based on the actual test data of the corresponding type of battery. The battery discharge power data is limited and cannot satisfy the battery under all discharge time. Capacity calculation. Because the constant power provided by batteries of different voltage levels and batteries with different capacities of the same voltage level has no linear relationship with the battery capacity value, different voltage levels and capacities cannot be configured by simple digital conversion but must be configured strictly according to the constant power provided.
There are differences in the product performance of different brands of batteries, and the discharge parameters are quite different, so batteries of the same capacity and different brands cannot be interchanged. The constant power data of the battery comes from the test data of the new battery. The constant power method (look-up table method) does not consider the depreciation of the battery and temperature changes, so this method is suitable for the stable operating environment of the UPS battery, and the UPS load is at the rated capacity for a long time Optional when running below 80%.
Estimation method to calculate UPS battery capacity:
This method is the embodiment of the power formula and the concept of battery capacity. According to the determined UPS brand and model, everyone can know the minimum voltage Umin of the battery pack. In the UPS system, the load capacity remains unchanged in most cases, and the battery pack gradually decreases with the discharge time. According to P=U×I, the discharge current of the battery pack gradually increases. For the convenience of calculation, the maximum working current of the battery pack is selected as an example of calculation data.
The power method calculates the UPS battery capacity:
This method is the only method supported by the standard (Communication Power Equipment Installation Engineering Design Specification YD/T5040-2005) among the introduced UPS backup battery capacity calculation methods.