In Home Assistant, solar-surplus charging is something you build from community automations. SundialEV does it out of the box, with savings tracked against your US utility's rates. It also takes readings straight from Home Assistant, so you can keep HA as your data source. 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.
| Feature | Home Assistant | SundialEV |
|---|---|---|
| Solar-surplus charging | Build it yourself (community automations) | Yes — follows your live surplus |
| Works without a Powerwall | Yes, with any integrated inverter or meter | Yes — Tesla Solar, Enphase, SolarEdge, Solis, Growatt, Emporia Vue, Sense, or the push API |
| Savings tracked against your tariff | Not stated (the Energy dashboard tracks grid cost) | Yes — your utility's import and export rates, looked up by zip |
| Powerwall first, then the car | Build it yourself | Yes — solar goes to the car once the Powerwall reaches your priority level |
| Sell-at-peak window | Not stated | Yes — a daily window where solar exports instead of charging |
| Non-Tesla EVs | Any EV or charger with an integration (build it yourself) | 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 | Peak and off-peak prices you enter; US utility plans not stated | Yes — US utility rates, NEM 3.0 and net billing |
Every Home Assistant 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 Spotted something out of date?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.