Most hybrid inverters leave the factory set up to be safe, not clever. The installer hooks everything up, checks that the lights stay on when the grid drops, and leaves. Nobody goes back to tune it to the way your house uses power.
That’s a pity, because a few settings decide whether your battery pays its way or quietly costs you money. Menu names vary by brand. Sunsynk and Deye call much of this “Time of Use”. Many other inverters call it “output priority”. The ideas are the same.
1. Stop charging the battery from the grid
On a lot of systems, grid charging is switched on by default. That means when the battery runs low at night, the inverter tops it up from Eskom at full tariff, and then your solar has less room to charge it the next day.
Unless you’re expecting load shedding, turn grid charging off. Let the sun fill the battery. If outages come back, you can switch it on again for a day or two before a bad stage.
2. Put solar first
Look for a setting called something like solar first, SBU (solar, battery, utility) or load first. You want the house to run on solar, then the battery, and only then on the grid.
Some inverters ship in a utility-first mode, where the grid runs the house and the solar mostly charges the battery. It feels safe and wastes a lot of free power.
3. Set a sensible reserve
Your battery doesn’t have to empty itself every night. Many inverters let you set a minimum charge level for normal use and a lower one for outages.
A common setup is a reserve of around 30% to 40% while the grid is up, so you always have something left if it goes down, and a cut-off of 10% to 20% during an outage. Since load shedding has eased, some households drop the reserve lower to use more of their own solar in the evening. That’s a reasonable trade, as long as you know you’ve made it.
The one to leave alone
If your system isn’t registered to export power to the grid, your inverter should be set to zero export, usually with a small current sensor on the incoming supply. Don’t switch that off to “use more solar”. Exporting from an unregistered system can get your connection cut and your municipality knocking.
Check it in a week
After you change anything, watch the inverter’s app for a week. You want to see the battery reach full charge most sunny days, drop through the evening, and the grid import line stay low. If the battery is still full at sunset every day, you can afford a lower reserve. If it’s flat by 10pm, your evening load is bigger than you thought, and the battery runtime post will help you work out why.
If you’re not comfortable in the settings menu, ask your installer to make these changes on a service visit. It takes them ten minutes.
