UPS and Battery sizing

⚡

UPS & BATTERY SIZING CALC

● LIVE CALC

Load Inventory

Desktop PCs

400

Watts per unit: W

Emergency Lights (28W)

50

Fixed @ 28W each

BLDC Fans

25

Watts per unit: W

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Configuration

UPS Phase Type

3-Phase (Recommended) 1-Phase

⚠ LOAD EXCEEDS 20 kVA — 3-Phase mandatory. 1-Phase not feasible.

Power Factor

?

Power Factor (PF)
Ratio of real power (kW) to apparent power (kVA). Computer SMPS loads have PF ~0.8–0.9. Lower PF means a larger kVA UPS is needed for the same kW load. Most online UPS are rated at PF 0.8 or 0.9.

0.80

Backup Time Required

Enter value in minutes

Battery Bank DC Voltage

?

DC Bus Voltage
Large UPS systems use a series-connected battery bank at higher DC voltages (240V, 360V, 480V) to reduce current and cable size. Higher voltage = lower current = thinner cables. 480V DC = 40 × 12V batteries in series.

240V DC (20 × 12V batteries) 360V DC (30 × 12V batteries) 480V DC (40 × 12V batteries) 600V DC (50 × 12V batteries)

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Total Connected Load

74.3

kilo-Watts (kW)

kW

Apparent Load

92.8

kilo-Volt-Amperes (kVA)

kVA

Recommended UPS Rating

100

kVA (Next Standard Size)

UPS

UPS Phase Requirement

3-Phase

Required for load > 20 kVA

Φ

Battery Sizing Results

Total Load Power

74,275 W

DC Bus Voltage

480 V

Required Battery Current

155 A

Backup Duration

15 min (0.25 hrs)

Inverter Efficiency Factor

90%

Required Battery Capacity (C10)

43 Ah

Connect 40 Nos of 12V batteries in series
to achieve 480V DC Bus Voltage.
Each battery rated: 43 Ah (C10 rating recommended).

Load Breakdown

PC Load

72,000 W

Emergency Lights

1,400 W

BLDC Fans

875 W

LOAD vs HEADROOM 74%

3-PHASE LOAD DISTRIBUTION

R

33.3 kVA

Y

33.3 kVA

B

33.3 kVA

Top Indian UPS Brands

Numerical

Microtek

Luminous

Su-Kam

Vertiv

Delta

★ NUMERICAL (Murugappa Group) — Top pick for institutes in India with best after-sales network.
★ VERTIV — Premium option if budget permits.