**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 **

- DC amps to watts
- AC single phase amps to watts
- AC three phase amps to watts

**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

**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

**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