Generator sizing calculator for poultry farms & hatcheries.
Enter your poultry load breakdown and the largest motor. We return standby kVA in three scenarios so you can specify a genset that actually restarts fans after a brownout.
Scenario cards, ATS ampacity and UPS sizing update to match. kW view converts via power factor pf = 0.8.
Loads (kW)
All loads on. DOL inrush 7×. +15% margin. Hot-day worst case.
85% diversity. 5× inrush. +10% margin.
Soft-starters / VFDs. 70% diversity. +5% margin.
Indicative only. Confirm final kVA with your supplier or electrical consultant against the single-line diagram and worst-case ambient temperature. Standby rating assumed.
Fuel-tank runtime
How long the generator runs on one tank at Expected running load (87.5 kW).
Battery kWh sizing
Battery bank to keep hatchery / SCADA / critical fans alive during ATS transfer or short outages.
ATS ampacity
Automatic Transfer Switch rating from the Expected genset (197 kVA) at 400 V, 3-phase, with a 25% continuous-duty margin, rounded up to the next standard frame.
UPS sizing (hatchery-critical)
Bridges the ATS transfer window and protects incubation controls / SCADA / alarms.
First-pass sizing only. ATS frames, UPS topology (line-interactive vs online double-conversion) and battery chemistry (lithium vs VRLA) affect the final specification and should be confirmed by the supplier against your single-line diagram and site conditions.
Sensitivity — what changes the number most?
Drag the sliders — the tables below recompute instantly so you can see how DoD, inverter efficiency, autonomy, UPS pf and ATS margin move the recommended sizing.
Battery kWh — DoD × Autonomy
Nominal battery bank for a 20 kW critical load at inverter η = 0.94.
Longer autonomy scales battery kWh linearly.
Lithium ~0.9, VRLA ~0.5. Halving DoD doubles the bank.
Modern hybrid inverters: 0.92–0.96.
| DoD ↓ / Autonomy → | 0.5 h | 1 h | 2 h | 4 h |
|---|---|---|---|---|
| 0.50 | 21 kWh | 43 kWh | 85 kWh | 170 kWh |
| 0.70 | 15 kWh | 30 kWh | 61 kWh | 122 kWh |
| 0.80 | 13 kWh | 27 kWh | 53 kWh | 106 kWh |
| 0.90← current | 12 kWh | 24 kWh | 47 kWh | 95 kWh |
UPS & ATS sensitivity
How UPS kVA / hold-up energy and ATS frame move with your assumptions.
0.9 typical, 1.0 for unity-pf online double-conversion.
Bridges ATS transfer + genset failure-to-start.
| UPS pf | 0.75 | 0.85 | 0.9 | 1 |
|---|---|---|---|---|
| Apparent power | 26.7 kVA | 23.5 kVA | 22.2 kVA | 20.0 kVA |
| Minutes | 5 min | 10 min | 15 min | 30 min |
|---|---|---|---|---|
| Battery energy | 1.67 kWh | 3.33 kWh | 5.00 kWh | 10.00 kWh |
| Margin | ×1.00 | ×1.15 | ×1.25 | ×1.40 |
|---|---|---|---|---|
| Frame | 400 A | 400 A | 400 A | 400 A |
Default ×1.25 = NEC continuous-duty; current sizing draws 354 A → 400 A frame.
Turn a size into a shortlist
Send these numbers straight to a backup-power RFQ. Genset kVA, fuel-tank runtime, battery kWh, ATS frame and UPS kVA are prefilled into the buyer notes so suppliers quote against the same sizing brief.
Generator sizing — FAQ
How is generator kVA calculated for a poultry farm?＋
Take the total running kW of continuous loads (fans, cooling, lighting, feeders, drinkers, controllers), add starting inrush for the largest motor (typically 5–7× rated kW for direct-on-line fans), divide by generator power factor (~0.8), then add a diversity and safety margin. This calculator applies that logic across three scenarios.
Why three scenarios (Conservative / Expected / Optimistic)?＋
Conservative assumes all loads run simultaneously with full motor inrush (worst-case hot day). Expected uses a realistic diversity factor. Optimistic uses staggered fan start-up and soft-starters. Serious buyers order Conservative; Optimistic requires proven soft-start hardware.
Does this replace an electrical engineer's sizing?＋
No. This is a first-pass sizing tool for RFQ preparation. The final genset kVA must be confirmed by the supplier or an electrical consultant against your single-line diagram, VSD/soft-start strategy and worst-case ambient temperature.
What kVA does a 100,000-bird broiler farm typically need?＋
As an order-of-magnitude reference, a 100,000-bird tunnel-ventilated broiler complex generally sits between 250–500 kVA once fans, cooling, lighting, feeders and starting inrush are covered. Hatcheries scale with setter and hatcher count.
How do I estimate diesel generator runtime from fuel-tank size?＋
Diesel gensets burn roughly 0.25–0.30 L/kWh at 50–75% load. Runtime hours ≈ tank litres ÷ (running kW × 0.28). This calculator uses 0.28 L/kWh at the Expected running load; hot ambient, low load and old engines all increase specific fuel consumption.
How do I size a battery bank in kWh for a poultry farm?＋
Battery kWh ≈ critical load kW × autonomy hours ÷ (depth-of-discharge × inverter efficiency). For lithium at 90% DoD and 94% inverter efficiency, a 20 kW critical load needing 2 hours of ride-through works out to ~47 kWh nominal. Hatcheries typically size for 30–120 minutes; broilers for 15–60 minutes to cover ATS transfer plus fan restart.
How is ATS ampacity chosen?＋
The Automatic Transfer Switch must be rated at or above the generator's full-load amps at the site voltage. For 3-phase, A = kVA × 1000 ÷ (√3 × V). We add a 25% NEC-style continuous-duty margin and round up to the next standard frame (100/160/250/400/630/800/1250/1600/2000 A).
Do I need a UPS on top of a standby generator?＋
Yes for hatchery-critical loads (setter/hatcher controls, incubation ventilation, alarm and SCADA). A UPS bridges the 8–15 seconds an ATS needs to detect mains loss and transfer to genset, and protects electronics from switch-over transients. Broiler farms with tolerant controls can skip UPS on non-critical circuits.