Learn about how to calculate the battery size for applications like Uninterrupted Power Supply (UPS), solar PV system, telecommunications, and other auxiliary services in power system along with solved example.
To calculate the battery capacity in Ah, use the following formula: Final Size = [Uncorrected Size x (1+Design Margin) x Aging Factor x Temperature Correction factor] / System Efficiency. Then, the total battery capacity is Final Size x Nominal System Voltage / 1000. For example, the battery capacity required for an application is 21.7Ah, and the next available standard size of the battery is 24Ah.
The total load to be supported by the UPS is the sum of all these individual device power requirements. DC Bus (V) – Is the voltage required by the inverter to operate. DC buses range from 12V (1 x battery) to 180V (40 x batteries). Battery capacity determines how long does a UPS last under load.
Step 1: Collect the Total Connected Loads The first step is the determination of the total connected loads that the battery needs to supply. This is mostly particular to the battery application like UPS system or solar PV system. Step 2: Develop the Load Profile
When will the Battery sizing calculations be initiated?
The battery sizing calculations are initiated as soon as we have the subsequent data. The calculations are based on the "Recommended Practice for Sizing Lead-Acid Batteries for Stationary Applications" and "Recommended Practice for Sizing Nickel-Cadmium Batteries for Stationary Applications" IEEE standards.
If you had a UPS with a 12V battery, battery capacity of 2.9AH and Watts Power Rating of 300W. We know that that the Uninterruptible Power Supply can support the load demand of 270W since it's less than the Watts Power Rating of 300W. We can calculate the amperage of the load on the UPS from formula (3). 270W / 12V = 22.5A.
The very latest generation of on-line UPS have inverter efficiencies of up to 97%, producing longer battery autonomies than could previously be achieved from the same battery connected to a UPS with a less efficient inverter. A 1500VA UPS with a 12V 100Ah battery, and the total wattage of your load is 800W, calculate the backup time?