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Virtual Solar

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A Home Assistant custom integration that simulates a solar panel and battery system from sensors you already own. Point it at an ambient light (lux) sensor and a whole-house power meter, and it produces live estimated output, a virtual battery that charges and discharges over time, and a dashboard you can paste in with one service call. Built to answer “would a balcony solar setup actually be worth it?” before spending any money.

Requires Home Assistant 2024.1.0 or later. Distributed as a HACS custom repository.

Features #

  • Lux-to-Watts estimation: solar output computed live from (lux / 120) × panel_wattage × panel_count × system_efficiency.
  • Integration-owned virtual battery: a number entity that ticks every minute applying (solar − house) capped at the configured charge/discharge rates, clamped to capacity, and survives HA restarts.
  • Live-editable sliders for panel count, panel wattage, battery capacity, and system efficiency, so you can play “what if I had two panels?” from the dashboard in real time.
  • Six derived sensors: estimated output, battery status (Charging / Discharging / Full / Empty / Holding, with action-over-condition priority), charge rate (signed, with directional icon), percentage, human-readable time-to-full, and grid export (surplus that would have flowed to the grid when the battery is full or solar exceeds the charge rate).
  • Discharge control switch: toggle whether the battery discharges to cover the house or holds its charge. Automate it against a time-of-use tariff (grid overnight, battery daytime) or hold the battery while an EV is on the wall.
  • Profiles: preset configurations for Anker SOLIX SOLARBANK 3 E2700 Pro, EcoFlow DELTA 2, generic 800 W balcony kits, and generic 5 kW rooftop systems. Contributors can add more via a one-block YAML PR.
  • Asymmetric charge/discharge rates for kits like the EcoFlow DELTA 2 with separate input and output limits.
  • Multiple setups in parallel: install the integration more than once with different setup names to A/B compare configurations (e.g. 1-panel vs 3-panel) against the same real lux and house sensors.
  • Auto-generated dashboard via the virtual_solar.get_dashboard service. With multiple setups, one tab per setup in a single dashboard. Copy the response, paste into a new dashboard’s Raw configuration editor, done.
  • HACS-installable with full UI configuration, no YAML editing required.

The auto-generated Virtual Solar dashboard in Home Assistant

Installation #

  1. In HACS → Integrations → menu → Custom repositories.
  2. Add https://github.com/virtuallytd/ha-virtual-solar with category Integration.
  3. Find “Virtual Solar” in the HACS list, install it, restart Home Assistant.
  4. Settings → Devices & Services → Add Integration, search for “Virtual Solar”.

Manual #

Copy custom_components/virtual_solar/ from the latest release into your Home Assistant config/custom_components/ directory, restart HA, then add the integration via the UI.

Quick Start #

The setup wizard has four steps:

  1. Setup name + Profile: name this setup (used as the device title and entity-ID prefix), then pick a preset for a known kit, or “Custom” to fill everything in manually. Add the integration again later with a different name to run parallel setups.
  2. Sensors: choose your lux sensor (device_class: illuminance) and house power sensor (device_class: power).
  3. Solar panels: initial values for panel count (up to 60) and wattage. Edit live via the dashboard later.
  4. Virtual battery: capacity (kWh), max charge rate (W), max discharge rate (W), system efficiency (%).

After install, call Developer Tools → Actions → Virtual Solar: Get dashboard YAML, copy the entire response, and paste it into a new dashboard’s Raw configuration editor.

Under the Hood #

Pure Python, no external runtime dependencies. The integration creates one logical device with sensors driven reactively off state changes (no polling), one minute-interval timer for the battery ticker, and a single service that returns a pre-populated Lovelace YAML. State persists across HA restarts via RestoreEntity. Source is around 700 lines of straightforward HA platform code: no clever tricks, contribute-friendly.

Blog Posts #

License #

MIT.