Solar/consumption forecasts only refresh once per day, going stale intraday

[johanzander]

Description

Solar production and consumption forecasts are only fetched by BESS Manager twice per day: once at add-on startup, and once at 23:55 in the nightly prepare_next_day job (_fetch_predictions(), core/bess/battery_system_manager.py:965). There is no refresh on the regular 15-minute quarterly optimization job.

The underlying Home Assistant forecast sensors (e.g. Solcast, forecast.solar) do update intraday — typically every 30 minutes — as new weather/irradiance data comes in and same-day accuracy improves. BESS Manager never re-reads them until the next startup or the next 23:55 cycle, so every optimization run during the day is working off a forecast that's up to 24 hours stale, even when a materially better forecast (e.g. reflecting actual midday cloud cover) is already available from the sensor.

Evidence

• _fetch_predictions() is called from exactly two places:
  • BatterySystemManager.start() (battery_system_manager.py:548) — once at startup.
  • _handle_special_cases(), only when prepare_next_day=True (battery_system_manager.py:1442) — once daily at 23:55 (backend/app.py:344-355, CronTrigger(hour=23, minute=55)).
• The regular quarterly job (update_schedule_quarterly, backend/app.py:332-341, every :00/:15/:30/:45) calls update_battery_schedule() directly and never touches _fetch_predictions() or self._solar_predictions/self._consumption_predictions.
• Found while investigating Battery chart shows doubled/incorrect data at today/tomorrow midnight boundary #380 — not itself a cause of that bug, but noticed the prediction-refresh cadence is decoupled from the optimization cadence in a way that looks unintentional.

Impact

The DP optimizer's forecast inputs can silently lag actual conditions for most of the day. On a day where morning forecasts predicted overcast skies but it clears up by noon (or vice versa), the battery schedule computed at every quarterly tick through the afternoon still optimizes against the stale morning forecast instead of the improved same-day one, potentially charging/discharging at the wrong times.

Suggested fix direction

Refresh predictions on some intraday cadence (e.g. every quarterly job, or hourly) instead of only at startup/23:55 — to be scoped by whoever picks this up, weighing forecast-API rate limits (Solcast free tier has a daily call cap) against staleness.