What Should I Know Before Buying a Generator?
There are a lot of factors to consider when you’re planning to purchase a generator, such as cost, size and power capacity. Making the right decision based on these factors is crucial to ensure that you get the best value possible out of your generator.
We'd like to help you with some of the most commonly asked questions. If you have other things you would like to discuss, feel free to contact us so that we can help you make an informed decision about purchasing a generator.
You need to consider:
- What is the generators wattage capacity and will it support your needs?
- Does the generator have enough outlets to plug in all of the items i want to power?
- How noisy is the generator?
- Do you prefer a recoil or an electric start generator?
- Do you prefer a diesel or a petrol powered generator?
- How large is the fuel tank and how many hours of operation will it provide?
- Can the generator be easily transported?
- What accessories will you need to run the generator?
If you are unsure about any of the above, simply give us call and we will gladly assist you!
What Size Generator Do I Need?
It is very important to choose the right sized generator for your needs. If you choose a generator that is too small, you will not be able to run heavy duty items such as fridges or effectively run essential appliances during a power outage. Furthermore, overloading the generator may lead to its breakdown as well as damage to all appliances that are using its power.
On the other hand, if you choose a generator that is too big, you will be spending more on its purchase, installation, fuel, maintenance and repairs than required. Choosing a generator that is too big may lead to a huge and unnecessary initial cost. Not to mention that you will just let the extra capacity go to waste.
The size of your generator depends on the number and type of electrical appliances that you plan to run. Heating and cooling appliances like air conditioners and refrigerators consume a lot of power. You will need a bigger generator to power such appliances. On the other hand, if you want to power the lights in your house or the occasional small power tool, you can opt for a smaller generator.
Another thing to consider is the start-up wattage of your appliances. Equipments that have moving parts like fans and pumps consume a lot of electricity at start-up but do not require a lot of power to continue functioning. This is because the motor (or any moving part) needs a lot more power to move from a stationary position to their normal running position. The power consumption surge when starting up these appliances can cause your generator to fail, even when its size capacity is sufficient for all your appliances' running wattage. When electric motors form part of your appliances, you will need to multiply three times the motor horsepower (hp) to your required steady state load.
Calculating your required wattage
The first thing you need to do is work out your Total Electrical Load, using the power chart below. Then, you will need to establish your steady state load, such as lights and appliances, which you expect to operate at any one time.
| APPLIANCE | WATTS | APPLIANCE | WATTS |
|---|---|---|---|
| Clothes Dryer | 2,400 | Television Set | 75 - 200 |
| Hot Water Service | 2,500 - 3,000 | Toaster | 250 - 1,250 |
| Iron | 900 - 1,200 | Washing Machine | 500 - 3,000 |
| Kettle / Jug | 800 - 1500 | Air Conditioner (Non-inverter) | 1,000 - 2,500 |
| Lights | 25 - 200 | Domestic Water Pump | See Electric Motor below |
| Radio | 60 | Electric Motor 0.25 hp* 0.5 hp* 1 hp* 2 hp* |
187 375 750 1,500 |
| Radiator | 1,000 - 2,500 | Welder, 140 Amp(Non-inverter) | 5,000 |
| Refrigerator | 100 - 800 | 9"Angle Grinder | 2,300 |
Above chart is a guide only and some appliances will vary their watts depending on brand.
Quick conversions
To convert Watts to kVA @ 0.8pf, divide Watts by 0.8.
Example:
2000 Watts = 2.5 kVA
4800 Watts = 6 kVA
To convert kVA to kW @ 0.8 pf, multiply kVA x 0.8
Recommended generator size
1800 WATTS
Power tools rated up to 1000 watts. Portable Drill, Jigsaw, Toaster, Frypan, Lighting, Heating, TV, Small Fridge, ¼ to ½ hp Motor (depending on type). Ideal for the “Home Handyman”. Light in weight to power small appliances and for home use. Choose 2.4 kVA.
3500 WATTS
Power tools rated up to 2200 watts. Small Air Conditioner or Radial Saw, Lighting, Heating, TV, Microwave, Oven or Hotplate, Small Submersible Pump, ¾ hp Motor (depending on type). Choose 4.4 kVA.
6000 WATTS
Power tools rated up to 3400 watts. Small Air Conditioner, Radial Saw, Lighting, Heating, TV, Microwave, Oven or Hotplate, Submersible Pump, ¾ to 1 hp motor (depending on type). Choose 7 kVA.
All information above is an approximation only.
What Will Happen If I Overload My Generator?
As a rule portable generators should never be overloaded, however all Dunlite portable petrol sets can provide twice their normal output for a short period (e.g. during start-ups).
For example, a 4.4 kVA Dunlite generator can deliver up to 3500 running Watts and 7000 starting Watts.
Important to note: If a generator is running for long periods of time with an overload (i.e. that is a rating above the maximum rating of the set) there are various things that may occur:
- Overheating of the engine
- Overheating of the alternator, which will burn out the windings.
- Breakdown in oil consistency causing low oil pressure and engine failure.
- Reduced generator lifespan.