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How Solar Charging Works

Updated

If your app offers solar charging, smart charging can charge your car from your own solar panels. This lowers what you pay for grid electricity and uses more of your own solar power.

How to set it up

  1. Link your solar inverter in the app.
  2. Set a solar start threshold: the solar surplus at which charging from solar starts.

Inverter login tips

  • Huawei (FusionSolar): log in with your username, not your email address.
  • SolarEdge: you need admin rights and the 32-character API key.

How it works

Smart charging reads your inverter in real time. It always plans for the cheapest hours of your energy tariff first. When there is surplus solar, charging from solar takes priority.

Below the solar start threshold, smart charging falls back to the plan based on the cheapest hours.

With a smart meter connected to your inverter

The app reads your real-time solar export: the power your home is not using. Charging starts when the export reaches your threshold and stops when it drops below. If your car supports it, the charging power is adjusted to the available solar.

Without a smart meter

The app asks for your typical home electricity use. It then estimates the surplus as your total solar production minus that estimated use.

Solar forecast

If your app offers solar forecast, smart charging forecasts tomorrow's solar production. It keeps the sunny hours free for solar and charges only the rest overnight in the cheapest hours. Without a forecast, the car is often already full before the sun comes up, and most of the day's solar goes unused.

The forecast needs a few details about your panels: the peak power of your system, the direction the panels face and their tilt. Your ready-by time, maximum price and minimum charge level still apply.

Charging power by brand

Some cars can adjust their charging power to match your solar output:

  • Tesla: full adjustment. The charging power follows your solar surplus as closely as possible.
  • Volkswagen ID. and Škoda: two steps. The car switches between full and half power (roughly 16A and 8A per phase), depending on the available solar.
  • Mercedes-Benz: start and stop only. Smart charging starts and stops charging without adjusting the charging power.
  • Other brands: start and stop only. The car charges at full power when solar is above the threshold and stops when it drops below.

Does charging stop when clouds pass?

Yes. If the solar output drops below your threshold, charging pauses. It resumes when the sun comes back. For cars that can adjust their power, the power goes down gradually first.

Does it take my home use into account?

Yes, if you have a smart meter connected to your inverter. Without one, the app uses your estimated home use.

How to charge from solar only

You can charge almost only from solar with two settings:

  • Maximum price: set it to zero. The car then only charges from the grid when energy is free, and otherwise waits for surplus solar.
  • Minimum charge level: set it to your safety buffer, for example 40%. The battery always reaches that level by your ready-by time, in the cheapest hours available, even if those hours are above your maximum price. Everything above 40% is left for solar or free energy.

This way you always have a safe minimum, and the rest comes from the sun. See Smart Charging Settings Explained.

Solar locations

Solar charging works at any location your inverter is assigned to when you link it.

Supported inverter brands

Huawei, SolarEdge, Growatt, Fronius, SMA, Sungrow, Enphase, Sofar, Deye, Solarman Pro, Solax, Solis, GoodWe, Ferroamp, AlphaESS, Kostal, and more.

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Need help?

Contact the support team of your app. If your app comes from your energy supplier, that is your energy supplier's customer service. Tell them your car brand and model, your inverter brand, and when it happened. A screenshot of the app helps.