Your battery's settings decide how much it saves. Learn how self-use and time-of-use modes differ, how to choose a sensible backup reserve, what to adjust for winter, and when a professional optimisation review is worth it. A battery can be the right size and a quality brand and still under-deliver because of how it is set up. For most Sydney homes, self-use mode with a moderate backup reserve is a sound starting point. Time-of-use mode earns its keep when your tariff has a genuine gap between peak and cheaper periods. Seasonal changes and correct tariff windows are where fine-tuning pays off. The settings in your owner app are yours to adjust; grid protection, export limits and other installer-level settings must stay with an accredited installer.
Self-use mode: the everyday default
In self-use mode, solar supplies the home first, surplus charges the battery, and anything left over is exported. After the sun goes down, the battery discharges to cover household use until it reaches the reserve level, then the home draws from the grid.
This mode suits flat-rate tariffs and many time-of-use homes, because it simply maximises how much of your own solar you use. Its weakness shows on some time-of-use tariffs: if the battery runs empty during a cheaper overnight period, you may end up buying power in a pricier window the next morning or evening.
Your app's state-of-charge graph shows how the mode is working. If the battery reaches its reserve well before bedtime on most nights, or sits near full all evening, the settings deserve a look before you conclude the battery is the wrong size.
Time-of-use mode: aiming stored energy at expensive hours
Time-of-use mode lets you tell the battery when to hold energy and when to release it. Common approaches are keeping stored energy for the peak window, and, where the tariff gap is large enough, topping up from the grid in the cheapest window when solar will not fill the battery.
Grid charging deserves a careful look. Storing and returning energy typically loses in the order of 10% along the way, and every extra cycle counts towards the battery's warranty throughput. Charging from the grid only makes sense when the price gap clearly covers those losses.
| Mode | How it behaves | Typically suits |
|---|---|---|
| Self-use | Stores surplus solar, discharges whenever the home needs power | Flat tariffs and most solar homes |
| Time-of-use | Holds or charges energy for chosen price windows | Tariffs with a clear peak and off-peak gap |
| Backup priority | Keeps a higher reserve for outages | Storm season, outage-prone areas, homes that rely on pumps |
| VPP-controlled | The operator dispatches the battery within agreed limits | Homes enrolled in a Virtual Power Plant |
Setting a sensible backup reserve
The reserve is the share of the battery kept aside for a blackout. Set it too high and you give up usable storage every single day; set it too low and there is little left when the power goes out. As a rough guide, a 20% reserve on a 10 kWh battery holds about 2 kWh, which can keep a fridge, some LED lights and the internet running for several hours, depending on what else is switched on.
A few points worth knowing:
- A reserve only helps in an outage if your battery is wired with backup circuits. Without them, the battery shuts down with the grid, whatever the reserve setting says.
- Consider raising the reserve ahead of forecast storms and lowering it again afterwards. Some systems can do this automatically using weather alerts.
- Most homes on reliable supply do well with a modest reserve, leaving more capacity for daily savings.
- If your home relies on a water pump or someone works from home, base the reserve on those loads rather than picking a round number.
Adjusting for winter and summer
Winter brings shorter days, lower sun and higher evening use from heating, so many batteries do not fill completely. Useful adjustments include running the dishwasher, washing machine and hot water timer in the middle of the day, pre-warming the house with reverse-cycle air-conditioning while solar is available, and checking whether a small off-peak grid top-up is worthwhile on your tariff. In summer the opposite happens: the battery may be full by late morning, so that is the time to charge an EV, run the pool pump or pre-cool the house on solar. A quick settings review at the start of each season keeps the battery working for you.
Match the tariff windows on your bill
Time-of-use windows vary between networks and retailers, and some change between seasons. Check the peak, shoulder and off-peak times printed on your latest bill, and review the battery settings again whenever you change retailer, change plan or have a new meter installed. Also confirm the system clock is correct, including daylight saving changes, because a one-hour error can shift discharge out of the peak window.
Feed-in tariffs in NSW are commonly a few cents per kWh, while grid electricity commonly costs 30-45 c/kWh, so using stored solar at home is usually worth far more than exporting it. Our feed-in tariff comparison helps you see how plan choices interact with your exports.
If you join a Virtual Power Plant, the operator may control charging and discharging at certain times, so check the minimum reserve it will leave in your battery and how you can opt out of an event. In NSW, a one-off incentive of up to $1,000 applies from 1 July 2026 for connecting an existing battery to a VPP; confirm current details on the official NSW energy page before enrolling.
When to ask for an optimisation review
A professional review is worth considering when:
- your bills have not fallen as much as the proposal suggested;
- the battery is full by mid-morning and exporting heavily, or empty before the peak window ends;
- you have changed retailer, tariff or meter, or joined or left a VPP;
- you have added an EV, heat pump or pool;
- a firmware update has changed how the system behaves.
Our Battery Optimisation Service, listed in the energy market at $249 per battery system, reviews operating mode, reserve, tariff windows and VPP settings, with remote changes where the system allows. The price is indicative, and any on-site work is confirmed after a site assessment. More background on storage is on our solar batteries page.
Next steps
If you are considering a battery, or your current one is not delivering, request a quote and include a recent bill. We will look at your tariff and usage and recommend settings as part of the proposal, so the system is set up to suit your home from day one.
Frequently asked questions
Does using my battery every day shorten its life?
Daily cycling is what a home LFP battery is designed for, and its warranty, commonly 10 years, assumes regular use. Warranties usually also include an energy throughput limit or a minimum retained capacity, so avoid adding extra cycles for very small gains, such as grid charging on a narrow price gap. Keeping the battery in a shaded, ventilated location also helps it age well.
Can a firmware update change my battery settings?
Occasionally. Updates can add new operating modes, rename settings or reset some parameters to defaults. After you are notified of an update, or if the battery starts behaving differently, check the operating mode, backup reserve and tariff windows in the app. Keeping screenshots of your settings makes it easy to spot changes and restore them, or to show our support team exactly what changed.
What should I record before changing battery settings?
Take screenshots of the current mode, reserve level and tariff windows, and note the date of the change. Then compare a week or two of similar weather before and after, looking at grid imports during peak times, exports and how often the battery reaches its reserve. Changing one setting at a time makes it much clearer which change actually helped your bill.
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