Emergency power reserve
With the emergency power reserve you hold back part of your battery. In normal operation your SOLIO only discharges the battery down to this limit. If the grid fails, the rest is available for your home, provided your system is designed for backup operation.
At a glance
- You set the reserve under Storage system → Settings.
- Values between 5 % and 100 % of the battery capacity are possible.
- In everyday use your SOLIO only uses the battery down to the reserve. It does not discharge any further.
- If you wish, your SOLIO also maintains the reserve with electricity from the grid.
- Whether your system can supply your home during a power cut depends on the installation. Your installer sets this up.
How the reserve works
Think of your battery as a tank whose bottom part is reserved for emergencies:
| State of charge | What your SOLIO does |
|---|---|
| Above the reserve | The battery supplies your home as normal. |
| At the reserve | The battery stops discharging. Your home then gets its electricity from the solar system or the grid. |
| Below the reserve | This can happen because the battery itself uses a little energy, for example when there is no sun for a longer time. Your SOLIO then recharges with solar power as soon as it is available. If Activate receipt of the emergency power reserve from the grid is switched on, it also recharges from the grid once the level is about 2 percentage points below the reserve. |
The reserve is also taken into account elsewhere: the estimate in the energy flow of how long your battery will last only counts down to the reserve. Apps such as Dynamic electricity tariff consider the reserve in their planning.
Setting the reserve
Expand Cockpit → Storage system in the menu and click Settings.
Turn on the switch next to Emergency power reserve. The value set in per cent is shown next to it.
Drag the slider to the value you want between 5 % and 100 %.
Decide whether Activate receipt of the emergency power reserve from the grid should be switched on. Read the notice below it.
As soon as you have changed something, a round button with a tick appears at the bottom. Click it to apply the setting.
If you have several batteries, set the reserve separately for each one. In the Storage system view, a narrow dark line in the charge level bar shows where the reserve currently is.
If the battery actively charges from the grid, the storage system must be registered for this. Grid electricity in the battery can also affect a subsidy under the German Renewable Energy Sources Act (EEG). By saving, you confirm that you have checked this. If in doubt, ask your installer.
Which value makes sense?
The higher the reserve, the longer your home can be supplied during a power cut. In return, less of the battery is available for your own solar power in everyday use, and you draw a little more electricity from the grid.
- Low reserve (e.g. 5 to 20 %): you use almost all of your battery for self-consumption and keep a small emergency reserve.
- Higher reserve: useful if a long bridging time matters to you, for example before a forecast storm. You can lower the value again afterwards.
Frequently asked questions
I cannot find “Settings” under Storage system. This item only appears if an emergency power reserve has been set up for your system. Please contact your installer.
My battery is not discharging although it is not empty. It has probably reached the emergency power reserve. Check the value under Storage system → Settings.
The state of charge is slightly below the reserve. This is normal. The battery loses some charge overnight or in dull weather. Your SOLIO recharges automatically, with solar power or, if allowed, from the grid.
Will the battery supply me automatically during a power cut? Only if your system is designed and connected for this. The emergency power reserve simply makes sure there is still energy in the battery. Your installer knows whether, and which, circuits are supplied in an emergency.