How do you calculate the power supply time of UPS?
The power meter given by some manufacturers is watts/block, and the factor of 6 must be multiplied.For example: Emerson new generation rack type high-performance small capacity UPS-ITA series 20KVA, battery section 32 section (30-40 section even number section adjustable), UPS battery inversion efficiency 0.95, according to the full load 20kVA*0.9=18KW, reserves 2 hours computationW/cell = PL/ (N x 6 x ETA) =18000/ (32*6*0.95) =98.68 watts/cell
Constant power formula:W = PL / (N*6*) (watts/cell)Among them, PL is the active power UPS rated output (KW); N 12V Vf battery cell number; rated voltage for the inverter efficiency.That is to calculate the power required for a single cell, and then through the battery manufacturers to provide a constant power meter to find the battery model can meet the requirements.The termination discharge voltage is determined in accordance with 1.75V/cell. Typically, the power meter given by the battery manufacturer is the power of the monomeric 2V/Cell, defined as watts/cell.
BatteryAccording to the calculation results, the Ah number of the battery is determined, and the appropriate configuration is selected according to different brands of batteries.For example: Emerson's new generation of rack type high-performance small capacity UPS-ITA series 6KVA, battery voltage 192Vdc (16 12V Power Series), UPS inverter efficiency of 0.94, according to full load 4.8KW, backup 2 hours calculationC=4800*2/ (192*0.94*0.7) =76Ah (estimate), select the 12V85Ah battery section 16, such as C&D 12-76, LBT.
There are usually two ways to calculate a UPS battery:First, constant current mode calculation:According to the principle of conservation of energy, the following formula is used:C = (PL * T) / (Vbat * n * K)The C battery capacity, (Ah) PL uninterruptible power output power (W); T (H) - battery backup time;Vbat battery voltage (Vdc) is UPS battery inverter efficiency (0.90-0.95, according to the selected models).K - battery discharge efficiency (coefficient).
