A portable power station for home backup is a battery and inverter in a box that switches on the moment the grid drops out, keeping your fridge, lights, router and phone chargers running without a generator, fuel or extension cords through a window. The right size depends on what you actually need powered and for how long, not on the biggest number on the shelf.
Below is a quick way to match your situation to a unit, a sizing method that holds up to a calculator, and what to check before you run one indoors during an outage.
| What you need | What to look at |
|---|---|
| Fridge, lights and devices through an evening blackout, one unit, easy to wheel around the house | BLUETTI Elite 320 |
| Whole-house essentials through a 24-hour-plus outage, with room to add batteries later | BLUETTI AC300 & B300 |
| A larger property, multiple fridges or future expansion toward whole-home backup | BLUETTI Apex 300 |
If you want to run your own numbers against your actual appliances, use the calculator below.
Power station size calculator
Start from a preset, then tick what you'll run and change the numbers to match your own gear. Watts are on the rating plate or charger.
| Appliance | Qty | Watts | Hours | Wh/day |
|---|
Estimates only. Capacity allows 20% for inverter losses and battery you shouldn't use. Fridge watts are while the compressor runs, and hours are how long it runs in a day, which climbs in hot weather. Check the manufacturer's specs before you buy.
What actually needs power in a blackout
Most Australian blackouts are measured in hours, not days, but the 2019-20 bushfire season and recent east coast storms showed that some last well beyond that. Work out what matters before you shop:
- The fridge and freezer. Food safety is usually the first worry. A compressor fridge cycles on and off rather than drawing power constantly, which matters for sizing.
- Lighting. A few LED lights cost very little power compared with everything else on this list.
- Communications. Your modem, router and phone and laptop charging keep you in contact and let you check outage updates.
- Medical devices. A CPAP machine or similar needs to stay running. Check the device's own manual for its power draw and whether it needs a particular inverter type, and build in extra capacity rather than cutting it fine.
- Anything load-heavy. Air conditioners, electric kettles, washing machines and electric cooktops draw far more than the above and are usually the first things to leave off a blackout plan unless you have a much larger system.
Where a device can run from a 12V DC outlet instead of the inverter's 240V AC output, such as some fridges, lighting or camp gear, it skips the conversion step entirely and gets more out of the same battery. That's worth checking before you assume everything has to run through the AC outlets.
How UPS switchover keeps things running without a flicker
A power station with uninterruptible power supply (UPS) function sits between the wall and your appliances, passing grid power straight through while it's available and switching to its own battery the instant the grid drops. The gap between the two is the switchover time, and it's short enough on these units to stop a router rebooting or a laptop losing its charge state.
The BLUETTI Elite 320 switches to battery power in as little as 10ms, which helps protect sensitive electronics like computers, routers and medical devices during a blackout. The BLUETTI Apex 300 uses an instant 20ms UPS switchover so critical devices don't lose power during an outage.
BLUETTI's own user guide for the AC300 and B300 states there's no delay for online UPS and 20ms for off-line UPS, and the BLUETTI AC300 & B300 run a 24/7 UPS home backup mode that keeps loads powered from the grid until it fails, then takes over from the batteries. None of this is designed to protect equipment with zero tolerance for any interruption, such as some servers, so if you run anything that sensitive, check its own UPS requirements separately.
Sizing for a 24-hour blackout: a worked example
This example assumes a standard two-door fridge/freezer, LED lighting, a home router and typical phone and laptop charging, no air conditioning or electric cooking, and an inverter losing about 20 percent of what it draws from the battery converting DC to 240V AC.
| Appliance | Draw | Run time | Energy used |
|---|---|---|---|
| Fridge/freezer | 150W when running | 8h compressor run time in 24h | 1,200Wh |
| LED lighting (4 bulbs) | 40W | 5h | 200Wh |
| Router/modem | 15W | 24h | 360Wh |
| Phone + laptop charging | 75W | 3h | 225Wh |
| Total AC load | 1,985Wh |
Run that 1,985Wh of AC loads through an inverter losing 20 percent and you need 1,985 ÷ 0.8, or about 2,481Wh, out of the battery over the day. Allow a further 10 percent for usable capacity and standby drain, which is normal for any lithium battery, and compare that 2,481Wh figure against each unit's usable capacity rather than its rated number:
- Elite 320: 3,200Wh rated, about 2,880Wh usable. Covers this load with some capacity left over.
- AC300 & B300 (one B300 fitted): 3,072Wh rated, about 2,765Wh usable. Also covers it, with a smaller buffer.
- Apex 300 base unit: 2,764.8Wh rated, about 2,488Wh usable. Right on the line for this exact load.
Summer changes the maths. On a 40-degree day a fridge's compressor can run closer to 10 to 12 hours of the 24 instead of 8, which pushes that single line item up to 1,500 to 1,800Wh and the whole day's battery draw past 3,000Wh. That's the point where a single base unit runs out before the grid comes back, and it's why the expandable options matter if you want a buffer rather than a knife-edge calculation. For the full method behind this kind of sum, see our guide to working out runtime from amp hours, or read more on matching power station size to your needs.
Adding capacity when one unit isn't enough
The BLUETTI AC300 & B300 starts at 3,072Wh with one B300 battery fitted and is 100% modular, supporting up to 4×B300 battery modules for a capacity of 12,288Wh, while the AC300's own inverter still delivers 3,000W continuous output (6,000W surge) regardless of how many batteries are attached. That means you can start with one battery for a typical blackout and add a second ahead of storm season without replacing the whole system, charging through AC, solar, a car, a generator or a lead-acid battery depending on what you've got on hand.
The BLUETTI Apex 300 goes further again, scaling from 2,764.8Wh up to 58kWh and output from 3,840W up to 11.52kW as modules are added, built around automotive-grade LiFePO₄ cells rated for over 17 years of daily use. That range suits a larger property with more than one fridge, a bore pump, or plans to build toward broader off-grid coverage over time rather than a single blackout night. Charging tops out at up to 11.52kW from a generator or 19.2kW of solar with the separate SolarX 4K controller; check the spec sheet for the standard AC wall charging figure if that's your main charging method.
Comparing the three for home backup
| Model | Battery capacity | Continuous AC output | Expandable to | UPS switchover |
|---|---|---|---|---|
| Elite 320 | 3,200Wh | 1,800W (3,600W surge) | Single unit | 10ms |
| AC300 & B300 | 3,072Wh with one B300 | 3,000W (6,000W surge) | 12,288Wh with 4×B300 | 20ms |
| Apex 300 | 2,764.8Wh | 3,840W | Up to 58kWh / 11.52kW | 20ms |
Surge figures cover brief startup spikes from motors and compressors, not sustained output. None of these use Power Lifting Mode as extra continuous capacity, and it isn't suited to motors or compressors in any case, so size against the continuous figure, not a lifted one.
Using one safely indoors
Unlike a petrol or diesel generator, a battery power station produces no exhaust fumes, so there's no carbon monoxide risk running one inside the house. That said, follow the same basic precautions as any mains-connected appliance: keep it clear of water, don't cover the vents while it's under load, and keep it out of direct summer sun given the operating range most lithium units are rated to (typically -20°C to 40°C for these BLUETTI models).
If you want backup wired into your switchboard to cover specific circuits automatically, that's a job for a licensed electrician fitting a proper transfer switch or sub panel. Never backfeed a power station into a wall socket to power house wiring, which is both unsafe and illegal in every Australian state. For broader off-grid planning beyond a single blackout, our guide to going off the power grid covers the next steps, and you can read more on how BLUETTI power stations are built if you're comparing the wider range.
Frequently asked questions
Can I run a power station indoors during a blackout?
Yes. These are sealed lithium battery systems with no exhaust, so there's no fume risk like a petrol generator. Still keep the unit ventilated, away from water and out of direct heat, and follow the manufacturer's manual for placement.
How long will a power station run my fridge in a blackout?
It depends on the fridge's wattage and how long its compressor actually runs, not a flat 24-hour draw. In the worked example above, a typical fridge, lighting, router and device charging together need about 2,481Wh from the battery over a day once inverter losses are included, which fits within the usable capacity of the Elite 320 or AC300 & B300 base unit but sits right at the edge of the Apex 300 base unit.
What about CPAP machines and other medical devices?
Check your device's own manual for its power draw and inverter compatibility before relying on any power station for it, and build in extra capacity rather than sizing to the exact figure. Medical devices are not the place to cut sizing close.
Can solar charging keep a power station going through a multi-day outage?
It can extend runtime considerably if you have working panels and daylight, since the AC300 accepts up to 2,400W of solar input and the Apex 300 up to 19.2kW with the separate SolarX 4K controller. Actual output depends on panel size, angle and cloud cover, so treat solar as a top-up during an outage rather than a guaranteed full recharge.
Still not sure which one suits you?
Tell us what you need to keep running and for how long, and whether you're after a single portable unit or something you can expand over time, and we'll help you match it to a model. Get in touch or browse the full Portable Power range to compare specs side by side.
