In many cases, your solar production will be different from the charge power of your car. Since we are not able to modulate the charge power of your car (yet), tado° Smart Charging App will calculate the share of power that has to be drawn from the grid to charge your EV. From this, tado° will calculate the average price per kWh to charge your EV. The calculated price is taken into account in the optimization.

This means that we will not charge your car if the share we have to draw from the grid during a peak moment is more expensive than charging during the off-peak rate.

An example

Your EV charges with a charge power of 10 kW and your PV panels produce 5 kW. This means that 5kW (50%) of the charge power has to come from the grid. We assume a peak rate of €0.50/kWh, an off-peak rate of €0.30/kWh, and that the solar energy is free. The average price for charging your EV becomes (5 * 0.50 + 5 * 0)/10 = €0.25/kWh. This is lower than the off-peak tariff of €0.30/kWh, meaning that the optimization will try to charge the EV.

If the PV production becomes less than 40% of the charge power, the combined price will not be lower than the off-peak tariff. This means that we will not charge the EV during these moments.