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The Backup Reserve setting determines how much battery capacity is saved for a blackout. A high reserve increases outage protection but reduces bill savings. A low reserve maximises savings but limits backup time. Most households find a 30 to 50 percent reserve provides a practical balance between energy security and financial benefit.
What Is the Backup Reserve Setting?
The most important setting for blackout protection is commonly called Backup Reserve or Minimum State of Charge. This setting tells your battery to hold back a percentage of stored energy exclusively for a power outage.
Think of it like a fuel reserve in your car. Your battery will not discharge below this percentage during normal daily use. That reserved energy stays untouched unless the grid fails. You can usually find this setting in your battery’s mobile app under energy management or system settings.
What Happens If the Reserve Is Set Too High or Too Low?
The reserve setting directly affects the balance between bill savings and blackout protection.
A very high reserve, such as 80 to 100 percent, keeps most or all of the battery ready for an outage. This maximises backup duration but significantly reduces daily savings because the stored solar energy is not used at night.
A very low reserve, such as 10 to 20 percent, maximises self-consumption and bill reduction. However, if a blackout occurs late in the evening after most stored energy has been used, only a small amount of backup power will remain.
For most households, the setting is a trade-off between energy security and financial return.
What Is a Practical Setting for Most Homes?
For many Australian households, a reserve between 30 and 50 percent provides a balanced outcome. This level often supplies enough energy to run essential appliances for several hours while still allowing meaningful daily savings.
For example:
• A 13 kWh battery with a 30 percent reserve keeps about 4 kWh aside for emergencies.
• A 10 kWh battery with a 40 percent reserve holds 4 kWh in backup.
The actual runtime depends on what you are powering. Essential loads such as refrigeration, lighting and internet use far less energy than air conditioning or electric ovens.
What Should You Check Before Adjusting the Setting?
Before changing your reserve percentage, confirm how your system is wired. Most homes are configured for essential circuit backup rather than whole-home supply. High-demand appliances are typically excluded from the backup circuit.
You should also consider your local reliability of supply. If outages are rare, you may prefer a lower reserve for greater savings. If you live in an area with frequent or extended blackouts, a higher reserve may provide greater peace of mind.
Adjusting the backup reserve in the app is safe, but any electrical modifications should always be handled by a licensed installer.
