Electricity has arguably never been cheaper in the middle of the day or more expensive at 6 pm, yet the two barely overlap. An off-peak power station closes that gap: it charges from a suitable wall socket while electricity is cheapest for use later, when grid rates are more expensive.
No solar, no switchboard work, no electrician, nothing fixed to the building—so it suits a rental or an apartment, too. Here’s how it works, what it can realistically run, and how to tell whether it suits your place.
When Electricity Is Cheapest
Electricity costs less during quiet hours and most during the 6 to 10 pm peak, when everyone’s cooking, washing, and streaming at once. Midday became the cheapest slot for a simple reason: there’s plenty of generation, and with most people out, little demand to soak it up.
The free electricity window is the extreme end of that same trend. Eligible customers can charge up during a set midday block at no cost—3 hours of free electricity, capped at up to 24 kWh a day:
- NSW and South East Queensland: 11 am to 2 pm
- South Australia: 12 pm to 3 pm
- Victoria: from 1 October 2026
There are conditions. You’ll generally need to be an eligible residential customer on a qualifying retailer’s plan, with a smart NMI meter, on a non-embedded network, and you’ll have to opt in. Charges outside the window still apply, and the terms vary and can change. It’s best to check the details with your own retailer first.
Off-peak pricing is also spreading across WA, Tasmania, the ACT and the NT, so even outside those regions, most people have a cheaper window to aim at. The catch is this: the window is fixed; it opens late morning while people are usually out.
Meet the VoltX Indevolt PowerFlex
The VotlX Indevolt PowerFlex 3000 charges from an AC outlet on a schedule you set. In three steps, it charges when electricity is cheapest, holds that charge for you, and runs your selected low-draw loads at night, when electricity is more expensive.
It’s a plug-in power station in the most practical sense: you don’t need an electrician or complex installation job to make it work. One limitation stated plainly: it’s AC-only. Solar panels can’t be connected. If you specifically want a solar-paired product, this isn’t it. Physically, it’s about the size of a small kitchen appliance (roughly 425 x 195 x 260 mm per module, around 21.5 kg). As an off-peak power station, it’s built to stay in one place plugged in, with the schedule set once and repeating every day.
Not the Power You Take Camping
Say “power station” and most people picture the carry-handle unit that lives in a cupboard between camping trips. This is a different unit.
It Stays Put and Runs Itself
A portable unit gets plugged and unplugged by hand; the VoltX Indevolt PowerFlex runs several charge, standby and supply windows a day without anyone touching it. For an 11 am weekday while you’re at work, that’s the entire point.
It’s Built for Daily Cycling
The cells carry a stated rating of up to 8,000 cycles, whereas portable units are designed for occasional use and wear out far faster if cycled every day. Overlooking it at purchase is the mistake that costs the most later.
It Grows
From roughly 2 kWh to around 12 kWh, with output rising alongside—where most portable units are fixed. The trade-offs, honestly: no portability and no solar input. If what you actually need is electricity at a campsite, buy a portable power station instead.
One Day, Set Once
Here’s a single weekday. Overnight and through the morning, the unit sits on standby. At 11 am, it starts charging and stops at 2 pm. It holds that charge through the afternoon, then supplies your appliances from around 6 pm—straight through the evening peak. The idea is simple: charge during off-peak electricity, then draw on it after six.
You set this in the app as a series of daily windows. An example:
| 11 am to 3 pm | Charge |
| 2 pm to 6 pm | Standby |
| 6 pm to 10 pm | Supply |
The standby block matters: it stops the unit handing back electricity during hours when grid power is already cheap, saving it for when it counts. Two honest caveats:
- A scheduled charging window doesn’t guarantee a full charge—how much it takes on depends on the starting level, your settings and what’s drawing power at the time.
- The schedule should match your own plan, not copy the example. You can check the charge level from your phone or from your desk at work.
Works If You Rent or Live in an Apartment
Fixed batteries have always needed a roof, switchboard work, the owner’s permission, and often strata sign-off—usually where the conversation ended for renters and apartment residents. Plugging in an appliance changes that. Nothing is fixed to the building, nothing’s modified, no approval is needed, and it comes with you when the lease ends. That’s what makes it a realistic power station for renters and a genuine power station for an apartment.
Units and apartments also tend to have lower evening use, so a smaller configuration covers a larger share of what you get through. Apartment dwellers have one thing to check: whether the building sits on an embedded network, since embedded-network customers usually aren’t eligible for the free-electricity offers (though off-peak rates may still apply). Your strata manager or a recent bill will tell you. The same logic serves a small business—time-of-use pricing, plus keeping select appliances running during an outage. If riding out a power outage is a priority, our guide to keeping the fridge, Wi-Fi, and CPAP running through a blackout is worth a read.
Start at 2 kWh, Expand as You Need
Don’t overthink kWh: 2 kWh is roughly what a typical fridge gets through in a day. Start there and add capacity later if you need it. It’s what makes it a genuinely expandable power station.
| Configuration | Capacity | Output |
|---|---|---|
| Main unit | ~2 kWh | 1 kW |
| Main unit + 1 module | ~4 kWh | 2 kW |
| Main unit + 2–5 modules | 6–12 kWh | Up to 3 kW |
Notice output climbs with capacity, so a bigger configuration runs more things at once, not just for longer—the part people miss. Think of it as a tank and a tap: capacity is how much water is in the tank; output is how wide the tap opens. At 1 kW you can run a fridge, lights, the TV, laptops, phone charging, and a fan—but not an electric kettle, oven, or ducted air conditioning.
There are two ways to come up short, with different fixes. Running out before bed is a capacity problem; not being able to run things at the same time is an output problem. Adding modules helps both. As a steer, a couple in a unit sits happily at the smaller end, while a family wanting most of the evening covered moves up. One limit people forget? A larger configuration won’t necessarily fill completely inside a three-hour window, so your available charging time is part of the sizing decision. Our rundown on sizing a lithium battery bank walks through the maths.
Safety and Long-Term Use
Because it sits indoors and cycles daily, chemistry matters. VoltX Indevolt PowerFlex uses LiFePO4—lithium iron phosphate—the chemistry generally chosen for units that live inside and charge every day, because it’s more thermally stable than the lithium used in phones and laptops. That’s what makes it a sensible LiFePO4 power station rather than a repurposed gadget.
Built-in electronics monitor the cells and shut things down if voltage, current, or temperature drift outside safe limits. The stated rating of up to 8,000 cycles is a product specification, not a guaranteed number of years—but it does mean the unit is designed for daily cycling rather than occasional use. It carries an advertised 10-year Australian warranty, subject to the applicable terms; read the warranty and the operating instructions before you buy, not after. Plugging into a standard outlet involves no licensed electrical work, but a faulty outlet or a unit behaving oddly is a job for a qualified electrician. Keep it indoors on a flat surface, with clear space around it and away from heat sources.
Check Your Electricity Plan Before You Choose
Three quick checks decide whether this makes sense for you.
Your Window
Pull up a recent bill and find your actual cheaper hours—whether there’s a free window you’re eligible for or simply separate peak and off-peak rates, how far apart those rates sit, and how many hours the cheap period runs.
The Full Picture
What you save depends on the gap between charging cost and the evening electricity you no longer buy, how much of the charge you actually use, and small losses along the way. Keep two questions separate: cutting what you spend on electricity, and recovering the purchase price; they run on different timelines.
The Fit
Which appliances you want running after six, roughly how much you'll get through on a normal evening, and whether the main unit covers it or you need a larger configuration.
The Window Is Fixed. Your Day Doesn’t Have to Be.
Electricity is cheapest—sometimes free—during the hours most of us are out, rearranging your life around that isn't realistic. Moving the electricity is. Three things decide your setup: the gap between cheap and peak rates on your plan, what your evenings actually look like, and the size you start with. Starting small is a sound decision, because the configuration expands whenever your needs do.
Find Your Configuration Today
Have a look at the VoltX Indevolt PowerFlex 3000 and compare the main unit against the expandable configurations to find the setup that matches your appliances and electricity plan. Start at 2 kWh, then add modules toward 12 kWh whenever you’re ready—no solar, electrician, or rearranging your day around the meter.
