Home battery time-of-use settings: what actually controls charging and discharging?

A TOU schedule is usually more than a clock. Time window, charge/discharge direction, power limit, SOC target or reserve, and higher-priority controls can all change the result.

Charge window

A charge window tells the system when charging is allowed or requested. Depending on the platform, you may also need to set a target SOC and charging power. GoodWe's Australian TOU guidance, for example, exposes time, day/month selection, SOC cut-off and charging power.

Discharge window

A discharge window tells the battery when stored energy should be available or actively dispatched. On Fronius, time-dependent battery control can specify minimum and maximum discharge power for selected times and days.

Reserve / minimum SOC

The reserve is energy deliberately held back, commonly for backup. If reserve is high, an evening discharge rule can reach the reserve and stop even though the battery is not empty.

Grid charging permission

Some systems have a separate permission for charging from the public grid. A perfect 2am schedule cannot force grid charging if that source is disabled or restricted elsewhere in the configuration.

Power limits

Battery and inverter power limits can prevent a schedule from charging or discharging as fast as expected. Energy (kWh) and power (kW) remain different constraints.

Higher-priority controls

OEM documentation confirms that local schedules may sit below other logic. Fronius notes that battery-management rules can be influenced by self-consumption optimisation, power limits and Modbus controls. VPPs and retailer energy-management services may also charge, discharge or hold the battery for market/grid purposes.

Fronius battery scheduling → · GoodWe TOU scheduling →