Solar Manager — BYD battery + SMA inverter¶
A community-built TinyC project that turns a Waveshare ESP32-S3-ETH into a full-featured energy management controller for a residential solar installation.
Hardware: Waveshare ESP32-S3-ETH · BYD HVS 10.24 battery · SMA Tripower 10.0 SE inverter · SMA Home Manager 2.0 · Wallbox Warp3 · Shelly switches.
Software: pure TinyC, no Berry / Scripter — uses Modbus/TCP, HTTP webUI
hooks, forecast.solar API, Energy Charts day-ahead price API, multi-device
orchestration.
Status display¶
A built-in TFT displays live battery state — SOC, SoH, charge/discharge power, lifetime energy throughput, AC/DC efficiency, and the next astronomical events (sunrise / solar noon / sunset).
Main webUI — battery control rules¶
The browser-served control panel. Operators can switch the battery between
Normal, Blockiert (blocked) and Erzwungen (forced) for charge and
discharge independently. Below, an arbitrary number of charge / discharge
rules can be defined, each combining time windows, SOC thresholds, electricity
price, PV forecast, and current PV output as AND-conditions.
SOC history¶
A rolling daily plot of the battery's state-of-charge with colour-coded operating modes (grid charge / grid feed-in / normal / PV surplus / own use / blocked). Below the chart: self-consumption ratio, autarky percentage, and battery cycle counter.
PV yield forecast¶
Pulled from the api.forecast.solar service for two roof orientations
(NW and SE), with the actual measured DC power overlaid for accuracy
calibration. Today's and tomorrow's totals are shown at the top.
Electricity pricing — fixed / dynamic / time-of-use¶
Three pricing models can be selected. The fixed-tariff calculator breaks down the consumer price into its regulatory components (Netzentgelt, Abgaben, Steuern) per the German 14a EnWG framework.
Flexible grid tariffs (HT / NT / Hochlast)¶
Per-window time-of-use tariffs with up to three windows for low / standard / high-load periods, and a fully editable list of grid surcharges and levies.
Net price calculation¶
Reverse calculation from gross consumer price down to the energy-component base price (used by the rule engine for break-even decisions).
Day-ahead exchange price¶
When the dynamic-price model is selected, the Boersenstrompreis page pulls the day-ahead spot price (EPEX) and visualises it as a coloured bar chart — green for cheap, orange for premium hours.
Shelly orchestration¶
Up to N Shelly devices (Plug S 1PM, Plug EM, Mini relays …) are auto-discovered or manually configured by IP. Each device has its own rule list with the same combinators as the battery rules, so loads can be switched on PV surplus, cheap-grid windows, or SOC thresholds.
Settings — inverter & PV plant¶
Modbus/TCP address of the SMA inverter, max charge/discharge power, plant location (lat / lon) and per-roof orientation (tilt + azimuth + kWp). A forecast correction factor calibrates the model to measured reality.
Settings — network devices & efficiency reference¶
All connected devices grouped on one page (Home Manager, inverter, BMU, Wallbox), plus the monthly / yearly / lifetime AC and DC throughput counters used to compute round-trip efficiency.
Want to build something similar?
The complete TinyC source is not yet bundled with the standard examples — contact the author or watch the Releases page for a future drop.