A blackout does not treat every piece of equipment the same way. Your fridge can handle a few minutes without power. The computer you were working on does not.
That difference is why two separate product categories exist. A UPS covers the gap. An inverter generator covers the outage. People often compare them as rivals, but they solve different failure modes, and the wrong choice is an expensive lesson.
Here is how each one works, what the specifications mean in practice, and how to match the right one to the gear you need running.
» MORE: Compare the full inverter generator range at Outbax
What Is the Difference Between an Inverter Generator and a UPS?
An inverter generator burns fuel to make electricity on demand. A UPS stores electricity in a battery and releases it the instant mains power fails.
The engine produces raw alternating current, a rectifier converts it to direct current, and an inverter module rebuilds it as clean AC with a pure sine wave output. That extra stage is why total harmonic distortion on a quality unit typically sits below 3 to 5 per cent, against the rough output of a conventional generator running its engine at fixed speed.
A UPS works from the other direction. Mains power passes through it continuously while a charged battery waits behind. When supply drops, sags or spikes, the UPS covers it before your equipment notices. Units such as the VoltX range use lithium iron phosphate, or LiFePO4 battery, cells rather than sealed lead-acid.
Three practical differences follow:
Gentrax G3500 Inverter Generator
Where the energy sits. A UPS carries a fixed amount inside the box. A generator carries none, but keeps producing as long as you feed it petrol.
How fast it takes over. A UPS transfers in milliseconds. A generator has to be started, stabilised and connected.
What it does while the grid is up. A UPS conditions incoming power all day. A generator sits idle until the grid has already failed.
Changeover Time: Why Milliseconds Decide What You Can Protect
Changeover time is the delay between mains failing and your backup carrying the load. It is the one specification that settles which category you need.
What Your Equipment Will Tolerate
One mains cycle in Australia lasts 20 milliseconds at 50 Hz. Computer power supplies built to the ATX specification are only required to hold their output for around 16 to 17 milliseconds once input is lost. Past that, the rails collapse, and anything unsaved goes with them. Network hardware, NBN equipment and EFTPOS terminals sit in the same bracket.
What a UPS Delivers
A line interactive UPS typically transfers to the battery in 2 to 10 milliseconds, comfortably inside that window. A double conversion online unit runs the load from its inverter permanently, so there is no transfer at all. The VoltX UPS 1000VA 1000W LiFePO4 Battery Backup at $1,299 is the entry point and suits a workstation, monitors, and a router.
What a Generator Realistically Delivers
Even the quickest portable inverter generator works in seconds, not milliseconds. A remote electric-start model, such as the Gentrax GTX3500 Inverter Generator, saves you the walk outside, but the engine still has to start, settle, and take load. Best case, that’s tens of seconds. With fuel checks and a changeover switch to operate, it is usually minutes.
Here’s what a customer noted about the GTX3500 Inverter Generator,
“Purchased this generator and it’s great. Easy to start, quiet and the remote is great. Would suggest that the manual points people to connect the battery, apart from that …. It’s great.”
Gentrax GT2200 Pro Inverter Generator
Runtime: Minutes of Protection Versus Hours of Power
Put both on the same scale, and the mismatch is obvious. A UPS buys minutes. A generator buys hours and keeps going while you refuel.
How Long a UPS Actually Lasts
The VoltX UPS 1000VA 1000W delivers roughly 9 to 10 minutes at a full 1,000 W draw. Drop to a typical home office load near 300W, and that stretches to around 30 to 40 minutes. Enough to save files and shut down cleanly. Not enough to run a household, including the flagship VoltX UPS 3000VA 3000W, which is built for multiple systems or a small rack.
How Long a Generator Lasts
Generator runtime is quoted against a stated load, which is the only honest way to publish it. The Gentrax GT3500 Inverter Generator runs 4.1 hours at 50 per cent load. The Gentrax GS2-7500IE 7kW Portable Inverter Generator runs 4 hours 10 minutes at its full 7 kW rated output. Refuel and the clock restarts.
Here’s what one of our customers said about the Gentrax GT3500 Inverter Generator:
“Received today, ripped out of the box, topped up the oil and fuel, 3 pulls and fired up beautifully. Runs quieter than I was expecting. Thank you Outbax for a great product.”
Reading VA Against Watts
VA is an apparent power. Watts are what your equipment actually consumes. On many units, watts work out at 60 to 70 per cent of the VA figure, so a 1,500 VA model may only carry 900 W. The VoltX units are rated one-to-one, so the number on the box is the number you can use. To size either product:
List what must stay running. You pay for protection you don’t need.
Find the real wattage. Use the rating plate or power adapter rather than peak marketing figures.
Add 20 to 25 per cent. That covers startup spikes and whatever you add next year.
Allow for motor surge. A fridge running on 600 W can pull close to 1,200 W on startup. Pumps and power tools behave the same way.
VoltX UPS 1000VA 1000W LiFePO4 Battery Backup
Brownouts, Surges, and Power Quality in Australian Homes
Outages are the obvious threat. Poor power quality quietly shortens equipment life.
Australian supply is nominally 230 V at 50 Hz under AS 60038, with a tolerance of plus 10 per cent to minus 6 per cent. That puts the legal band at roughly 216 V to 253 V. Motors then draw more current, heat rises, and the damage accumulates quietly.
A line-interactive VoltX UPS with automatic voltage regulation corrects moderate sags and swells without touching the battery and absorbs surges. An inverter generator does none of that while the grid is connected. What it contributes is clean output once running, which is why the inverter design replaced conventional generators for sensitive loads.
Neither replaces a switchboard surge diverter, and no consumer device survives a direct strike. Storm season protection works in layers.
How to Choose: Four Common Australian Scenarios
1. Home Office, NBN, and a Workstation
Buy a UPS. A generator cannot solve this at any price, because the machine has already dropped before the engine turns over. A 1,000 W class unit covers a computer, two monitors, a router and the NBN termination device.
2. Small Business with a Rack, Servers, or Point of Sale
Buy a larger UPS and monitor it. The Outbax VoltX UPS 1500VA 1500W or the 3000VA model handles multiple systems, and a UPS Network Expansion Card adds SNMP alerts and event logs.
3. Extended Outages and Whole-of-Home Backup
Buy a generator sized to your essential circuits. The Gentrax GS2-7500IE 7kW covers a fridge, freezer, lighting, communications, and a pump comfortably. A licensed electrician must connect to household wiring using a compliant changeover switch under AS/NZS 3010. Never run a lead into a power point to energise circuits. That is backfeeding; it is illegal, and it can kill a line worker.
4. Caravan, Camping, Markets, and Worksites
Buy a portable inverter generator and weigh noise as heavily as output. The Outbax Gentrax GT2000 and the Gentrax GTX4200 Pro Inverter Generator both run at 58 dB measured at 7 metres. A 3.5 kW class unit will start most caravan air conditioners. Check the rated output, not the maximum.
Running Both Together
For many households, the answer is both, in sequence. The UPS catches the failure instantly and holds the critical gear alive. The generator then takes the load and runs through the outage.
Safety and Compliance Checks Before You Buy
Carbon monoxide. Never run a generator indoors, or in a garage, shed, tent or caravan. Keep it 6 metres from windows, doors and vents.
Refuelling. Only refuel once the engine is off and cool. Store petrol in approved containers away from ignition sources.
Electrical compliance. Look for the RCM mark and AS/NZS compliance, and use outdoor-rated leads protected by an RCD.
Warranty and support. Check whether parts and service are available locally. The VoltX UPS range carries a 5 year warranty.
VoltX UPS 1500VA 1500W | LiFePO4 Battery Backup
The Bottom Line
Choose a UPS when the risk is losing data or dropping a connection. Choose an inverter generator when the risk is hours without power. Size both from real wattage, and treat any runtime claim as meaningless unless the load it was measured at is stated.
Outbax stocks both categories. If you are still weighing capacity against runtime, compare the specifications side by side or call the team about what you need to protect.
» MORE: Shop UPS systems and inverter generators at Outbax
