Three Free Hours: A Tale Of Three Batteries

Free power windows arrive for most Australians on July 1. If you own a battery, you probably want to configure it to take advantage, and fill it for free, from the grid.

But your battery will not do this on its own. Out of the box, it has no clue your free window exists. Somebody has to open the app and tell it, and that somebody is you.

How Do You Configure A Battery To Use Free Electricity?

How hard is it to configure? Depends entirely on your brand. To show you the range you might be walking into, I’ve looked into how to set it up on the three batteries I own: a Powerwall 2 on the family home, a Sungrow on the Airbnb, and an iStore on the shed. Same job for all three, fill as fast as you can during the free window. Three completely different fights, from a two-minute job to a swearing fit.

The Tesla Powerwall: Easiest To Set Up, Hardest To Boss Around

At home with my Powerwall 2.

I run the Powerwall 2 on the family home, so this is the one I know best.

Configuring it for the free window takes about two minutes. Open the Tesla app, go to Settings -> Operational Mode, and choose Time-Based Control. Then go Settings -> Utility Rate Plan and tell it when your free window is. Done. Tesla’s app is the only one of the three my mum could drive. And that’s important, because most battery owners are not tech nerds.

Now the catch.

You don’t tell a Powerwall to charge from the grid. You drop a price hint and let it decide. And it fancies itself. The system runs its own solar forecast, and if it reckons tomorrow will be sunny, it’ll skip your cheap window and wait for free sun instead.

Which is the most Elon thing imaginable: a battery so full of hubris, it thinks it knows better than you.

Sungrow: The App Is A Disaster

My Sungrow setup on my rental property.

To configure a Sungrow battery for free charging, you need to open their app: iSolarCloud, go to Settings -> Operation Mode, then select Forced Mode. Select Charge/discharge settings, select Charge. Confirm…

And then the iSolarCloud app refuses to let you continue. And you go down a rabbit hole of workarounds proposed in 17 different online forums by Sungrow owners who have had the same issue. Then you give up and call your installer.

Sungrow hardware is great. Sungrow installer support in Australia is fantastic. Unfortunately, for anything other than the most basic configuration, the Sungrow app is shit.

So my Sungrow battery will not be taking advantage of 3 free hours until I get around to calling my installer – unfortunately, that won’t happen before this post is published. But I’m assured by random forum posters that it will eventually work.

iStore: Good Luck

The iStore in my shed.

The iStore battery runs the shed. Lift the badge, and it’s a Huawei Luna2000. iStore signed an OEM deal with Huawei in 2024, then moved Australian customers off Huawei’s FusionSolar and onto their own app, Univers EMS. So Univers is what a typical iStore owner gets handed.

This is where I nearly lost it. I opened Univers hunting for the battery settings and found none. No charge schedule, no time-of-use, nothing on the home screen. They are in there, filed where no sane person would look: tap Me -> My Plant -> Quick Setting, and up come Battery TOU and the charge and discharge limits. Battery controls, buried under “Me.” Whoever signed off on that menu owes me twenty minutes.

Once you’re in, set a TOU charge window of 11:00 to 14:00, add discharge windows covering the rest of the day so the battery actually hands its charge back, and check that charge-from-grid is switched on. Cross your fingers and hope it all works come July 1.

So the iStore hands you the most detailed settings of the three but a hell of a clumsy tool to reach it. If Univers won’t play ball, your fallbacks are the installer’s back end (the HiSolar app) or going full nerd with third-party software like Home Assistant.

Now Go And Do Yours

Whatever battery is bolted to your wall, it will not charge from the free window until you make it, and the making-it ranges from two taps to a brawl with a non-intuitive app. So open the app today, not the afternoon your free plan kicks in.

A few things to brace for on the way. The friendliest app might be the one that second-guesses you. The most capable might bury a trap that makes no sense until it’s bitten you. And some settings hide behind an installer login, or a grid-charge permission set at commissioning, so you may not be able to finish the job without installer help.

Go looking, and if your brand has its own special way of making this miserable, or your installer’s gone to ground, or your retailer’s blocking the grid charge, tell me in the comments.

Phase Shift is a weekly opinion column by SolarQuotes founder Finn Peacock. Subscribe to SolarQuotes’ free newsletter to get it emailed to your inbox along with our other home electrification coverage.