How the free window works with a home battery

From 1 July 2026, NSW has a regulated plan called the Solar Sharer Offer. Most people just call it the free window.

In NSW that window is 11am to 2pm, every day. Same time all year. It does not move for daylight saving. You need a smart meter, and you have to opt in. They will not put you on it. You do not need solar on the roof. If you are in an embedded network, you cannot get it.

The reason it exists is pretty straightforward. There is a heap of solar on the grid in the middle of the day. This plan makes that power free for a few hours so you can use it then, instead of at dinner when everyone else wants it.

Solar Sharer is not for everyone, because the rest of the day is still time-of-use, and those rates can be higher than a normal plan. The daily supply charge still applies. Hot water on a controlled load does not get the free rate. You have to look at the whole plan, not just the free hours.

The 24 kWh cap

On the government plan, the first 24 kWh in that window is free. That is roughly what a five-person house uses in a whole day. Go over 24 kWh in those three hours and the extra is charged at the cheapest remaining rate on the plan.

24 kWh is a lot if you are just running the house. It is not a lot if you are also filling a battery, or charging a car, in the same window.

The government plan is not the only free window. Retailers have their own versions, and they do not all use that 24 kWh cap.

OVO’s Free 4 is one of those. It is their own plan, not the government one. Free power is 11am to 3pm, so you get an extra hour, and they do not publish a daily kWh cap. They still have a fair use policy. If they think you are using it well beyond a normal house, they can move you onto their standard contract.

Using it with a battery

We use the free window to charge the battery on a rainy day, or in winter, when the solar production is lower. We then charge the battery from that window. So even if it is raining, we will still fill the battery for the evening.

We have been doing this for about 18 months with OVO and our customers’ batteries. Well before the government plan existed. Same idea. Use the free window to top the battery up when the roof is quiet. To be candid with you, the results have been great. Houses still go into the evening with a full battery through winter and wet stretches.

The roof fills it when it can. The free window tops it up when the roof cannot. Keep in mind the free window applies to the whole house, not just the battery.

Whether you actually hit 100% in one session depends on the size of the battery and how empty it is. The inverter size matters as well. That governs the charge rate, which determines how quickly we can charge the battery. A typical home battery can take a full charge in a few hours. A much bigger stack may need more than one window, or a longer retailer plan like OVO’s four hours.

If anyone has questions about these plans, or how to get the battery to charge in the free window, give us a shout.