How to calculate UPS Battery Backup Time:

Backup (In hours)= (No. of Batteries X Battery AmpH X Volts of each Battery) / (Load in VA/Power Factor shorty p.f.)

Assume you have 10KVA UPS (Online or Off Line) UPS and installed with 16 PCS Battery and each of 12 Volt and 65AmpH; then what is the maximum backup time it will deliver? You can consider 0.8 is P.F is a standard.

Backup (In Hours)=(16 x 65 x 12)/((10X1000)/0.8)=0.9984 Hour

 

Calculating electric power from electric current

  1. DC amps to watts
  2. AC single phase amps to watts
  3. AC three phase amps to watts

 

  1. DC amps to watts calculation formula:

The power P in watts (W) is equal to the current I in amps (A), times the voltage V in volts (V):
P(W) = I(A)× V(V)
So watts are equal to amps times volts:
watt = amp × volt
or
W = A × V
Example:
What is power consumption in watts when the current is 3A and the voltage supply is 220V?
Answer: The power P is equal to current of 3 amps times the voltage of 220 volts.
P = 3A × 220V = 660W

  1. AC single phase amps to watts calculation formula:

The real power P in watts (W) is equal to the power factor PF times the phase current I in amps (A), times the RMS voltage V in volts (V):
P(W) = PF × I(A)× V(V)
So watts are equal to power factor times amps times volts:

watt = PF ×amp × volt
or
W = PF ×A × V
Example:
What is power consumption in watts when the power factor is 0.8 and the phase current is 3A and the RMS voltage supply is 220V?
Answer: The power P is equal to power factor of 0.8 times current of 3 amps times voltage of 110 volts.
P = 0.8 × 3A × 220V = 528W

  1. AC three phase amps to watts calculation formula:

Watts calculation with line to line voltage;
The real power P in watts (W) is equal to square root of 3 times the power factor PF times the phase current I in amps (A), times the line to line RMS voltage VL-L in volts (V):
P(W) = √3 × PF × I(A)× VL-L(V)
So watts are equal to square root of 3 times power factor PF times amps times volts:
watt = √3 × PF ×amp × volt
or
W = √3 × PF ×A × V
Example;

What is power consumption in watts when the power factor is 0.8 and the phase current is 3A and the RMS voltage supply is 220V?
Answer: the power P is equal to power factor of 0.8 times current of 3 amps times the voltage of 110 volts.
P = √3 × 0.8 × 3A × 220V = 914W

Watts calculation with line to neutral voltage:
The calculation assumes the loads are balanced.
The real power P in watts (W) is equal to 3 times the power factor PF times the phase current I in amps (A), times the line to neutral RMS voltage VL-0 in volts (V):
P(W) = 3 × PF × I(A)× VL-0(V)
So watts are equal to 3 times power factor PF times amps times volts:
watt = 3 × PF ×amp × volt
or
W = 3 × PF ×A × V