About SunHarvest

SunHarvest is an independent companion for Tesla Powerwall owners. It makes the battery work around the price of electricity and the weather, rather than a fixed schedule.

Why it exists

A home battery earns its keep by being in the right state at the right time: full before the expensive evening, empty enough to soak up tomorrow's sun, and exporting when export pays. On a flat tariff that barely matters. On a smart tariff like Octopus Agile, Flux or Go, where prices change every half hour and tomorrow's weather decides whether overnight charging is worth it, it matters every day.

The Powerwall's own app gives you a few modes and a backup reserve. It does not know your real half-hourly prices, it cannot react to the forecast the way you would, and it does not tell you what a day actually cost. SunHarvest fills that gap. It was built on, and runs every day against, a real Powerwall 3 with solar.

What it believes

• You should be able to see what happened. Every settings change is logged with who made it: you, a rule, the AI, or something outside SunHarvest, such as the Tesla app. Every AI plan is kept, with exactly what the planner was given and why it chose each rule.
• Automation should read like English. A rule is a sentence: when this, only if that, then do these things. No scripting, no YAML.
• Your data is yours. It is not sold or used for advertising. You can delete a date range or your whole account yourself, at once. The privacy policy is short and specific.
• AI should be optional and yours. AI mode runs on the provider and key you choose, and your own rules take over whenever it stops.

How it is paid for

Hosting, Tesla API access, forecasts and price feeds all cost money every month. Monitoring and your own rules are free. Free accounts see a small ad inside the app, which helps cover those costs. Pro is a monthly subscription for AI mode, faster updates and the savings figures, and removes the ads. The public pages of this site, including this one, carry no ads.

How it is built

SunHarvest is a .NET service that talks to Tesla's Fleet API on your behalf, records your system every few minutes, and runs your rules. The web app and the Android app share the same screens. Weather and solar-radiation forecasts come from Open-Meteo and are run through your own roof arrays. Prices come from Octopus Energy's public feeds or the rates you enter.

Independence

SunHarvest is not affiliated with, endorsed by or sponsored by Tesla, Inc. or Octopus Energy. It uses Tesla's official Fleet API, with your consent, and you can revoke its access from your Tesla account at any time.