What does the Smart Charging feature do?

Prerequisites

  • Smappee Genius (EV Box: Smart Charging Plus package)
  • Solar measurements
  • Car Charger Submetering
  • Car Charger Smart device in the App linked to the Car Charger Submetering
  • Plausible Solar Forecast (can be viewed in the Electricity Usage Graph in the Dashboard on 5 minute intervals)

What does it do?

The user can set a desired target time and range each day of the week using the Smappee app.

The optimizer running inside the genius uses this information to start scheduling optimized charging sessions.

 

  • The optimizer looks if there is a schedule within the coming 24 hours.

  • If a schedule is found the optimizer will calculate an optimal planning each 5 minutes, given the updated actuals, the forecasted solar energy, forecasted consumption and configured tariffs.

    • The required kWh to be charged are simple calculated by using the 20kWh/100km ratio.

    • In a first step the optimizer will use the forecasted solar minus forecasted consumption to have an idea of the available current and future excess energy, this will be used first to assign in a consecutive way charging buckets per 5 minutes where excess solar is available.

    • If the total energy of the previous step does not cover the left over part to be charged, we need to fall back on drawing extra energy from the grid, in this second phase the tariffs are used to find the periods within the given timeframe that have the cheapest price and these 5 minute buckets will be filled consecutive until the desired total kWh is reached.

    • If the previous planned steps still result in a leftover kWh amount because the planned schedule could not be followed due to some other uncontrollable reason, that surplus amount will be replanned every 5 minutes together with the rest of the volume to be charged.

  • Special handling of the first (or current 5min interval), solar (and load) available for the current 5 min interval are calculated using a blend of the forecast and the actual values. If we are T seconds in the 5 min window, for these T seconds the actual measured solar is used and the exponential smoothed value of the T seconds measurements is projected until the end of the window. That way the current 5 mins gives in the beginning an expectation of available solar that gets corrected by the actual solar as we move further in the interval. Same for expected consumption within the current 5 min window.

  • When the charging target is reached, the car should stop charging possibly way in front of the time that has been set, there can be a deviation between the actual charged volume and the target that has been set, as this will depend on the brand and driving style. So it may look as the target has been reached in km, the charging may still continue according to the 20kWh/100km ratio that is used.

  • Additionally, if the charging time has elapsed and the car is still connected with no charging schedule ahead in the coming 24h, the optimizer will be disabled and the normal overload charging will resume until the system enters a new optimizer window with a target 24h ahead. So this may result in the car starting to charge again, because there is no current target in sight.