Short answer: A generator for a Ghana poultry farm has to carry the fans, lights, pump and vaccine fridge through an outage, and it has to start each motor on that list. Add up the running watts, divide by 0.8 to get kVA, then allow about a quarter more for start-up and headroom. Set the engine outside with its exhaust away from air inlets, wire it through a changeover switch, and keep a fuel and service log so it starts the night the power goes.
Key takeaways
- Size the set for the start-up surge of the biggest motor as well as the running watts.
- Divide running kW by 0.8 to get kVA, then add about 25 per cent for headroom.
- Run the engine outdoors, upwind, with the exhaust well away from doors and inlets.
- A licensed electrician should fit a changeover switch and a tested earth rod.
- Change the air filter through the harmattan and run the set under load once a month.
- Keep at least three days of fuel, sealed, labelled and rotated.
The pump and the fans set the size, not the lights
A generator that cannot start your water pump is a noisy box in the corner. Farmers have told us this story more than once: the set lit the house beautifully, then sat silent when the borehole motor was asked to turn over. Lights are the easy part. The fans and the pump are the loads that decide what you should buy.
A generator has two jobs. It has to carry the steady load for as long as the mains stay off, and it has to start each motor in turn without the voltage sagging so far that the motor stalls. Most farms buy for the first job and forget the second, and that is where the money gets wasted.
Think about a tunnel-ventilated house on a hot afternoon. When the fans stop, the air inside climbs fast, and birds that were settled a few minutes earlier start panting with their wings held out. A set that runs the bulbs but not the fans is not backup for a poultry house. It is a torch with an engine.
If you are still weighing solar against a generator, our notes on solar power for a poultry farm set out the same load list for a battery system.
Write the load list before you ask a dealer for a price
Dealers in Kasoa and Accra will quote a set in five minutes if you name a size. Do not name a size. Give them a list instead. Walk the farm with a pen, read the nameplate on every motor, and write down what each item draws. Nameplates give kilowatts or watts for running load. Some give amps and volts; multiply those to get volt-amps and use the result as a close enough figure for planning.
Add a column for hours per day. A feed mixer that runs for thirty minutes at feeding time counts for far less than a pump that runs for two hours, and a fan that runs all night counts for more than both. The list below is the one we would start from for a farm of this kind, with a vaccine fridge in the office, which most farms forget to count.
| Load | Qty | Watts each | Running watts | Hours per day on backup |
|---|---|---|---|---|
| Borehole submersible pump | 1 | 750 | 750 | 2 |
| Wall extractor fans | 3 | 370 | 1,110 | 6 |
| LED bulbs | 10 | 9 | 90 | 8 |
| Vaccine fridge (domestic size) | 1 | 150 | 150 | 24 |
| Total without the mixer | 2,100 | |||
| Feed mixer | 1 | 1,500 | 1,500 | 0.5 |
| Total with the mixer | 3,600 |
The fridge runs round the clock, so it is the load that keeps the vaccine cold through a long outage. The fans and the pump matter most for the birds. The mixer is the one that tempts you to buy a bigger set than you need, and that is the question to settle first.
Plan the power before the birds arrive. Our day-old chicks for Ghana farms page explains how the chicks are packed and sent to you, so the house is ready when they land.
Running load and start-up surge are two different numbers
People mix these up all the time. Running load is what a motor draws once it is turning. Start-up surge is what it draws in the first instant, while it is still stationary and the windings are pulling hard. For a motor started straight on, that surge can be several times the running figure. Three to six times is a common range in the trade, and the exact number depends on the motor and how it is started.
A set sized on running watts alone will often start a fan and stall a pump. The voltage dips, the protection trips, or the pump hums without getting up to speed, and you are left with a set that is running perfectly and a house that is still dark. The fix is not to panic and buy the biggest set in the shop. Check the surge of the single biggest motor, and start the motors one at a time.
The submersible pump is usually the worst case on a farm. It starts against a full column of water, and the head is real. If the pump is the biggest motor on your list, ask the dealer for the set's motor starting capacity, not only its name rating, and write the answer on the quote. For the wider list of what a farm needs in place before birds arrive, see our frequently asked questions.
Turning running watts into a generator size
Generators are rated in kVA, which is apparent power. Your nameplates give kW, which is real power. To move from kW to kVA, divide by the power factor. For motors and most mixed farm loads, 0.8 is the conventional planning figure. The rough sum is running kW divided by 0.8 equals kVA.
Using the list above, the house without the mixer runs at 2.1 kW. That is 2.1 divided by 0.8, or about 2.6 kVA. Add the mixer and the total becomes 3.6 kW, or about 4.5 kVA. Then add headroom. A set that runs at its full rating all night wears out faster, and it has no margin left for the moment the pump starts. We would add about 25 per cent.
- No mixer during an outage: 2.6 kVA plus 25 per cent is about 3.3 kVA, so a 4 kVA set.
- Mixer must run during an outage: 4.5 kVA plus 25 per cent is about 5.6 kVA, so a 6 kVA set.
Our advice is to decide honestly whether the mixer has to run on backup. If your feed is bagged and the mixing can wait for the mains, a 4 kVA set covers the farm for a fraction of the price. If mixing has to carry on through an outage, buy the 6 kVA set and stop going round in circles about it.
The 0.8 figure is a planning convention, not a law. Read the spec sheet for the set you are buying. If the manufacturer's sizing table disagrees, follow the manufacturer, and ask the dealer to explain the gap in writing before you pay.
When the bulbs come on and the pump stalls
Here is the sequence we hear about most. The mains go at nine at night. Somebody starts the set and switches everything on at the wall at once. The bulbs come up, the fans start, and the pump hums, drops out, and hums again. The set is not faulty. It is being asked for a short burst of current while it is already carrying the rest of the house.
There are three fixes, and they are not equally expensive. First, start the pump on its own before the fans and lights come on, and let the set settle for a minute. Second, fit a soft starter on the pump, which ramps the motor up gradually and cuts the surge. Third, move up one set size. A soft starter needs a competent electrician to fit it, and it will not rescue a set that is simply too small for the farm.
Make a rule that nobody plugs the mixer into the same run as the pump. Stagger the starts by a few seconds each, and write the order on a card beside the changeover switch so the night watchman does not have to remember it.
If the setter sits on the same circuit, read incubating through power cuts before you decide which loads go on the set.
Petrol, diesel or gas: what each costs you to run
Most small poultry farms end up choosing between petrol and diesel. Gas sets exist and suit sites with a dependable supply, but cylinder changes and gas availability are their own headache, so we will leave them aside here.
Petrol sets are cheaper to buy and easy to find in the towns. They burn more fuel for the same output, and petrol that sits for a few months goes stale and gums up the carburettor. Diesel sets cost more at the start, use less fuel per kilowatt, and keep much better in storage when they are kept clean and dry. For a farm that runs its set most nights, diesel usually works out better. For a set that only runs a few hours a month, petrol is the sensible choice.
Check the spec sheet for litres per hour at the load you will actually run. The figures at half load and at full load are very different, and most farms run well below full load most of the time. Ask the dealer to put the number in writing. If you are costing the whole farm, the start-up budget guide is a good place to set the fuel bill beside everything else.
| Type | Upfront cost | Fuel use per kW | Storage | Best for |
|---|---|---|---|---|
| Petrol, air-cooled | Lowest | Highest | Weeks to a few months before it goes off | A few hours a month |
| Diesel, air-cooled or water-cooled | Higher | Lowest | Months, if kept clean and dry | Regular nightly running |
| Gas (LPG or piped) | Varies | Depends on the cylinder and the set | Cylinder stock, no varnish problem | Sites with a dependable gas supply |
The changeover switch and the earth rod
This is the part that hurts people. A generator plugged into a wall socket, or wired into the house without a changeover switch, can push power back into the grid. Linesmen working on a fault they believe is dead can be killed by that backfeed. Never do it, not even for one night.
A changeover switch disconnects the house from the mains before it connects the house to the generator. Have a licensed electrician fit one, sized for the set and for the house circuit. Ask them to earth the generator frame to a proper earth rod, and to test the earth before they leave. An earth that has never been tested is a guess, and you cannot tell whether it works by looking at it.
A manual changeover is cheaper, and it works if somebody is awake and near the set when the power goes. An automatic transfer switch, usually called an ATS, starts the set and moves the load for you. Where fans must come back within minutes and nobody is on the farm at night, the ATS earns its price. It will not check the oil or the fuel, so someone still has to do that.
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Exhaust, carbon monoxide and where the set sits
Petrol and diesel engines both make carbon monoxide. It has no smell, it gives no warning, and it kills. Never run a generator inside a house, a store, a feed room or any space with a roof and walls around it, even with the doors wide open. The closed house next to a running set is exactly where people get caught, and the worker who sleeps in the store beside it is the one most at risk.
Stand the set on a level concrete base outside, upwind of the houses in the direction the wind usually blows at night. Point the exhaust away from air inlets, doors, windows and the feed store. A simple roof that keeps off the rain is fine, but a roof that traps the fumes is worse than no roof at all. Leave space around the set for airflow and for the service work.
Put a carbon monoxide alarm in any room where people sleep within reach of the set, and test it monthly. Keep children and dogs away from the exhaust. The wind changes overnight, so a spot that was safe at dusk can be blowing fumes into your store by midnight.
Fuel storage, and what the harmattan does to the filter
Store fuel in sealed, labelled containers made for fuel, away from the hot exhaust and anything that can spark. Keep at least three days of fuel at the set's normal running hours, and use the oldest stock first. Petrol that sits for months varnishes the carburettor. Diesel that sits in a damp tank grows a slimy layer of micro-organisms that blocks the filter. Both problems are cheap to prevent and expensive to fix on the night the power goes.
The harmattan is the season that finds the weak spots. Fine dust hangs in the air from about December into February, and it gets into the air filter, the radiator and the cooling fins. A set that ran sweetly in the rains can start to overheat in January simply because it is breathing dust. Check the air filter every week during the harmattan, and replace it sooner than the manual says if the dust is heavy. Clear the cooling fins with a dry air line, never with water sprayed on a hot engine.
Cover the set when it is idle, but do not wrap it so tightly that damp gets trapped inside. In the rains, check the fuel cap seal and keep the fuel store off the wet ground. Heat for the brooder is a separate load, and the brooder setup guide covers that side of the plan before chicks arrive.
A service calendar and the monthly test under load
A generator that has not run for three months is not backup. It is an expensive ornament. Put a service calendar on the wall beside the changeover switch and tick it off as you go. The table below is a sensible starting point, but the manual that came with the set always wins. Where your manual gives a different interval, follow the manual.
| Task | How often | Notes |
|---|---|---|
| Check oil level | Before every night on backup | Top up to the mark, not above it |
| Check fuel and top up | Every day the set is used | Keep three days in reserve |
| Clean or replace air filter | Weekly in harmattan, monthly otherwise | Dust is the usual cause of overheating |
| Change engine oil | Every 100 to 250 running hours, per the manual | Log the hour meter reading |
| Spark plug (petrol) or fuel filter (diesel) | Every six months, or per the manual | Let a mechanic handle the injectors |
| Test under load | Once a month, for 30 minutes | Pump switched on, lights and fans running |
| Check earth and changeover | Every three months | Electrician to test and sign |
The monthly test under load matters more than the rest of the table. A set that runs perfectly with nothing connected can still stall the moment the pump asks for its surge. Once a month, cut the mains at the changeover, start the set, and run the house on it for half an hour with the pump on. You will know within the first minute whether it will work on the night that counts.
A set that passes the test is one you can plan a flock around, so once the power is sorted, broiler day-old chicks can go in on schedule.
Theft, noise and the pre-outage checklist
Generators get stolen, and a farm at night is an easy target. Chain the set to a fixed point, lock the fuel cap, and keep it in sight of a room where somebody sleeps. A set left in a dark corner of the yard is the one that walks off.
Noise is the other complaint. A diesel set running at night carries a long way in still air. Put it away from neighbours' bedrooms, on a base that does not rattle, and tell the neighbours that a set will run during outages. Telling them first is cheaper than being reported for it.
Before the mains go, the person on duty should be able to tick every line on this list:
- Oil at the mark on the dipstick.
- At least three days of fuel in sealed containers.
- Air filter clean, and the hour meter written in the log.
- Changeover switch in the mains position, with the set's start switch ready.
- Pump and fan breakers on, and the mixer unplugged until the pump is running.
- Fuel cap locked, set chained, and the exhaust clear of inlets and doors.
- The start-order card in place beside the switch.
When the list is ticked and the set is ready, place your order, and we will confirm the price in writing before you pay.
Questions farmers ask
Can I run a generator inside the poultry house during a power cut?
No. A running engine in a closed house, store or feed room can kill people with carbon monoxide, and the fumes harm the birds as well. Put the set outside, upwind, with the exhaust pointing away from the air inlets and doors. Run cables from the outside into the house. A correctly sized set outside, with a changeover switch, covers the whole house without anyone breathing its exhaust.
How big a generator does a small poultry farm need?
There is no single size, because it depends on what you must run. Add up the running watts of every load you need on backup, divide by 0.8, and add about 25 per cent. The example in this article gives about 4 kVA without a feed mixer and 6 kVA with one. Give your dealer your own list and ask them to check the start-up surge of the biggest motor against the set they quote.
Should I buy a petrol or a diesel generator?
For a farm that runs its set most nights, diesel usually costs less over a year because it burns less fuel per kilowatt and keeps better in storage. For a set you will only run a few hours a month, petrol is cheaper to buy and to keep. Look at the litres per hour at your real load on the spec sheet, then work out the fuel bill for a typical outage before you decide.
How much fuel should I keep on hand?
Keep at least three days of fuel at your normal running hours. If the set runs six hours a night at roughly one litre an hour, that is about six litres a night, or 18 litres for three days. Check the burn rate on your own set, because it changes with the load. Keep the fuel in sealed, labelled containers and rotate the stock so the oldest goes first.
Why does my generator trip every time the borehole pump starts?
The set is probably being asked for the pump's start-up surge while the lights and fans are already drawing power. Start the pump on its own before anything else. If it still trips, a soft starter on the pump or a set one size up is the fix. Check the breaker rating, the cable size and every connection too, because a loose joint makes the surge worse.
Do I need an automatic transfer switch on my farm?
Not always. A manual changeover works well if someone is awake and close to the set when the power fails. An automatic transfer switch is worth the money where the fans must restart within minutes and nobody is on the farm overnight. Either way, the set still needs oil and fuel checks, because an automatic set that runs dry will stop without warning.
Can a generator run my brooder heaters as well?
Only if you size for them, and that usually means a much larger set than most small farms need. Heating loads are heavy and run for many hours, so they can use up the fuel quickly. Choose your brooding method first, then size backup power for the fans, pump, lights and fridge. Keeping the heat plan and the power plan separate stops you buying a set you cannot afford to run.
