evcc is excellent, open source and local. SundialEV is the better fit if you'd rather not host anything: it runs in the cloud, looks up your US utility's rates by zip, and controls a Tesla without a developer account or command proxy. If your solar was interconnected after April 15, 2023 (NEM 3.0), exports earn a fraction of retail — 4.5¢ per kWh against about 35¢ to import on PG&E (rates as of July 2026), so every kWh your car absorbs instead is worth far more.
Open source, running locally on your own hardware — your data stays with you.
Very broad hardware support: 200+ chargers, 50+ vehicles, 200+ solar and storage systems.
Deep energy logic: home-battery priority, dynamic tariffs, and Dynamic Feed-In that pauses charging when export pays more.
evcc's Tesla docs describe the setup for controlling a Tesla's charging:
Source: evcc's own page, checked September 26, 2026.
SundialEV connects with your Tesla sign-in and a virtual key approved on the car.
| Feature | evcc | SundialEV |
|---|---|---|
| Solar-surplus charging | Yes | Yes — follows your live surplus |
| Works without a Powerwall | Yes | Yes — Tesla Solar, Enphase, SolarEdge, Solis, Growatt, Emporia Vue, Sense, or the push API |
| Savings tracked against your tariff | Yes | Yes — your utility's import and export rates, looked up by zip |
| Powerwall first, then the car | Yes — home battery priority level | Yes — solar goes to the car once the Powerwall reaches your priority level |
| Sell-at-peak window | Yes — Dynamic Feed-In | Yes — a daily window where solar exports instead of charging |
| Non-Tesla EVs | Yes — 200+ chargers, 50+ vehicles | Any EV on a Wallbox Pulsar Plus (OCPP) or Emporia charger; Ford battery level (beta) |
| Cloud or self-hosted | Self-hosted | Cloud — iOS, Android and web apps |
| US utility rates | Fixed or time-based tariffs you enter; US utility plans not stated | Yes — US utility rates, NEM 3.0 and net billing |
Every evcc cell links to the page it came from, checked September 26, 2026. “Not stated” means their pages don't say either way. Spotted something out of date? Email support@sundialev.com and we'll fix it.
Enter your zip and the calculator uses your utility's real rates.
7 countries · See the fleet map
Works to utilize my solar to charge my car! I have it set up so I don't draw from the grid to charge my car (free fuel!)
ChronoVII · App Store
Provides an amazing amount of control for how and when you charge your vehicle. Support is also very responsive.
Mark A. Hartman · App Store
This app makes charging for the most part easier especially if you only want to charge on excess solar
ecyka2000 · App Store
SundialEV charges from your solar surplus automatically.