Where the setting is
On the inverter display, open System Work Mode and tick Time Of Use. The table has six time periods. Each period starts at its time and lasts until the next period starts.
Each period has a power limit, a battery target in percent and a Grid tick. With Grid ticked, the inverter may charge the battery from the grid during that period, up to the target. Menu names can differ slightly between models and firmware, so check the manual for your model.
Set a night window
Start one period when your night tariff starts, tick Grid and set the target. Start the next period when the night tariff ends and leave Grid unticked there, so the inverter stops buying power from the grid in the morning.
Our own test home uses a period from 00:00 with Grid ticked, and the next period from 06:00. Use the night hours of your own supplier.
- Time Of Use ticked
- Night period: Grid ticked, target set
- Morning period: Grid unticked
How high to set the target
The battery only needs what tomorrow's daytime use will take beyond the solar you can count on, plus a reserve you never want to go below.
Example: a 10 kWh battery, a 20% reserve, 18 kWh of daytime use, and a forecast of 16 kWh of solar. Counting on three quarters of the forecast leaves 12 kWh of solar, so the home is short 6 kWh, which is 60% of the battery. With the reserve, the target is 80%.
Why one fixed target costs money
A fixed 100% fills the battery from the grid even before a sunny day, so the free solar has nowhere to go. A fixed low target leaves you buying day-rate power on a cloudy winter day.
The right target changes every night with the weather and with how much your home uses. Changing it by hand every evening is possible, but few people keep it up.
What Solsidus does
The Solsidus box sits beside the inverter and talks to it on your home network. Every night it learns your home's use, checks tomorrow's solar forecast and sets the night period's battery target.
It changes only that target, reads it back to confirm the inverter accepted it, and pauses if a safety check fails. It does not change the time periods, the charging power or current, or the discharge floor.