Understanding the Power Output of Inverter Generators
G’day readers! Nathan here from Generator Warehouse to provide insight into one of the most critical specifications to understand when selecting an inverter generator - the power output. As an engineer with over ten years of experience working with diesel and generator systems, I’ve helped customers navigate this critical metric to ensure they choose the right generator for their needs. Stick with me as I break down the vital aspects of inverter generator power output in this comprehensive guide.
Why Consider an Inverter Generator?
Before diving into power output, it’s worth understanding why inverter generators are ideal for sensitive electronics in the first place. Unlike traditional generators, which produce “dirty” power with fluctuations in voltage and frequency, inverter generators convert the raw energy into clean sine wave power. This makes them suitable for safely running sensitive devices like phones, laptops, medical equipment, power tools, and so on without the risk of damage.
Some of the main benefits of inverter generators include:
- Clean, consistent power output protects sensitive electronics
- Increased fuel efficiency compared to traditional generators
- Quieter operation due to advanced engine and alternator design
- More portable and lighter-weight
If you need backup power for delicate equipment or want a quieter, more eco-friendly generator option, an inverter model is likely the best fit.
Watts, Volts, and Amps - Simplified
The power output is typically listed in watts when looking at generator specifications. But what does that mean? And how does it relate to volts and amps?
Here’s a simple analogy that demystifies these concepts:
- Watts - The “amount” of power. Similar to the quantity of water flowing through a pipe.
- Volts - The “pressure” at which electricity flows. Similar to water pressure in a pipe.
- Amps - The “rate of flow” of electric current. Similar to the flow rate of water.
To determine a generator's wattage (power output), you can multiply the volts by the amps. For example, a generator producing 240 volts at 7.5 amps would have an output of 240 x 7.5 = 1,800 watts.
Peak vs Running Power Output
Another key specification to understand is peak power output vs running power output:
- Peak Output - The maximum wattage a generator can produce quickly, usually when starting devices with motors or compressors that require a temporary power surge.
- Running Output - The generator's continuous, reliable output can safely be used over extended periods.
Most manufacturers list both numbers, with the running output consistently lower than the peak. Knowing the running watts is essential to size your generator and prevent overload properly.
Calculating Your Power Requirements
How do you determine what size generator you need? It comes down to adding up the running wattages of the items you plan to power simultaneously. Here are the key steps:
- Make a list of all devices and appliances you want to connect
- Determine the rated (running) wattage for each from manuals or spec labels
- Add together the running watts for the items that will operate simultaneously
- Choose a generator with a running wattage output at least 20% to 30% higher than your total
That 20% to 30% buffer allows room for appliance power surges on startup and avoids overload. You should also check the peak output to ensure it can handle motor starting surges without voltage drops.
For example, say you want to power a 700W microwave, 1000W coffee maker, and 300W TV simultaneously - that’s a total of 2000W running watts. Multiply by 1.2 gives a recommended generator output of at least 2400 running watts, with an even higher peak output.
Types of Inverter Generators
Hyundai Inverter Generators Welling & Crossley Inverter Generators
Briggs & Stratton Inverter Generators
Inverter generators fall into three main categories based on power output:
1. Compact/Portable
- Output: Less than 3000 running watts
- Applications: Camping, RV travel, outdoor events, power outages
- Benefits: Extremely portable, quiet operation, fuel efficiency
- Limitations: Can only handle a few small devices/appliances
This category includes ultra-lightweight models under 1000W, ideal for charging phones and laptops on camping trips, and up to mid-sized 2000-3000W units capable of providing elemental backup power during blackouts.
2. Home Backup
- Output: 3000 to 10000 running watts
- Applications: Whole house backup, off-grid living, outdoor kitchens
- Benefits: Provide extended backup time, can power most household circuits
- Limitations: Bulkier, higher fuel consumption than portable models
These systems are powerful enough to deliver backup power to an entire home, running the refrigerator, lights, TV and other essentials during prolonged outages.
3. Commercial/Industrial
- Output: Over 10000 running watts
- Applications: Construction sites, events, data centers, manufacturing
- Benefits: Heavy-duty power output, highly configurable, sustainable option
- Limitations: Large size, specialised installation, higher upfront and maintenance costs
On the top end of the spectrum, commercial-grade inverter generators offer robust power delivery for heavy-duty applications while still providing the clean electricity that sensitive equipment requires.
Critical Factors Affecting Power Output
The engine, alternator winding, and inverter technology contribute to a generator’s power potential. Here are some of the critical factors:
- Engine Size: Larger engine displacements produce more rotational torque to turn the alternator and generate electricity.
- Alternator Design: The winding, efficiency, and voltage regulation impact power delivery.
- Inverter Technology: The quality of the inverter components that convert the power also affects output.
- Fuel Type: Petrol generators provide peak power output, while diesel generators offer superior runtimes.
- Voltage Regulation: Maintaining consistent, clean electricity is critical and requires advanced inverter and voltage regulation technologies.
Higher-grade commercial systems often come with paralleling capability, allowing two or more units to be linked to combine their output for even greater capacity. Careful load balancing is crucial in this configuration.
Real-World Power Output
It’s essential to recognise that just because a generator is rated for a specific running wattage, the actual power it can deliver depends on external factors as well:
Altitude
Generator output declines approximately 3.5% for every 1000 ft (300 m) above sea level due to the drop in atmospheric pressure.
Temperature
In very hot or cold weather, the engine efficiency and, thus, the output capacity is reduced. Cold temperatures are incredibly impactful on start-up performance.
Maintenance
Lack of routine maintenance like air filter/oil changes will degrade performance over time. Well-maintained units see less variation between rated and actual capability.
Load Fluctuations
Despite having a higher-rated capacity, the generator can only deliver as much power as the connected load draws. However, sudden demand spikes can impact voltage stability.
While natural derating does occur, following the 20% capacity buffer in your initial sizing calculations helps compensate for real-world variations.
Inverter Generator Buyer’s Guide
If you’ve done the power calculations and decided an inverter generator is the right fit, keep these key factors in mind while comparing specific models:
Intended Use
Match the generator size, weight, runtime and outlets to your needs - residential backup, RV, construction site, etc. Don’t over or under-buy!
Power Quality
Look for generators with pure sine wave inverters, low total harmonic distortion (THD) and solid voltage/frequency regulation for sensitive device compatibility.
Sound Level
Inverter generators run remarkably quieter than traditional models. If low noise is essential for your location, compare ratings.
Ease of Use
Consider the control panel layout, automatic features like low oil shutdown, fuel gauge and outlets provided, including AC, USB, etc.
Warranties & Support
Aim for a consumer warranty and confirm the components covered. Local dealer backup is also helpful for maintenance and service.
Let Us Help You Select the Ideal Model
Hyundai Inverter Generators Welling & Crossley Inverter Generators
Briggs & Stratton Inverter Generators
This overview has helped demystify generator power output specifications and given some guidance in choosing the correct inverter generator for your needs. With over ten years in the power equipment industry, the team here at Generator Warehouse can provide personalised advice and recommend models suited to your budget and requirements. Please contact us anytime or visit a showroom to see our range - we’re always happy to help!