fix(telemetry): dark offline PV counts as 0 W so live load stays known

.changeset/dark-offline-pv-keeps-load.md

@@ -0,0 +1,5 @@
+---
+"ftw": patch
+---
+
+Keep showing home use at night when the solar inverter goes offline after sunset. If an offline or silent solar source last reported about 0 W (within 50 W), the live view counts it as 0 W, so grid and battery still give home use instead of a blank. An inverter that drops out while producing still shows as unknown, and history and forecasts still record solar as not measured.

go/internal/api/api_history_quality.go

@@ -29,6 +29,9 @@ func (s *Server) qualifyStatusHistory(resp map[string]any, siteMeter string) {
 	}
 	if !r.Valid {
 		missing |= state.MissingLoad
+	} else if r.PVAssumedZero {
+		// Every PV source is either measured or dark and offline (0 W).
+		missing &^= state.MissingPV
 	}
 	if opts.PVInvalidReason != "" {
 		missing |= state.MissingPV

go/internal/api/api_history_quality_test.go

@@ -134,3 +134,29 @@ func TestLiveHistoryQualityConfiguredPVWithoutMeasurementIsUnknown(t *testing.T)
 		t.Fatal("unmeasured configured PV reported as zero", resp)
 	}
 }
+
+// Anders' night case: Growatt drops offline after sunset while the Pixii
+// meter and battery keep reporting. PV reads 0 and the home load stays shown.
+func TestStatusDarkOfflinePVKeepsLoad(t *testing.T) {
+	tel := telemetry.NewStore()
+	for _, name := range []string{"pixii", "growatt"} {
+		tel.EnsureDriverHealth(name)
+	}
+	tel.Update("pixii", telemetry.DerMeter, 780, nil, nil)
+	tel.Update("pixii", telemetry.DerBattery, -200, nil, nil)
+	tel.RecordDriverSuccess("pixii")
+	tel.Update("growatt", telemetry.DerPV, 0, nil, nil)
+	tel.DriverHealthMut("growatt").SetOffline()
+	srv := New(&Deps{Tel: tel})
+	resp := map[string]any{}
+	srv.qualifyStatusHistory(resp, "pixii")
+	if resp["pv_w"] != float64(0) || resp["load_w"] != float64(980) || resp["history_reason"] != "" {
+		t.Fatal(resp)
+	}
+	tel.Update("growatt", telemetry.DerPV, -3000, nil, nil)
+	tel.DriverHealthMut("growatt").SetOffline()
+	srv.qualifyStatusHistory(resp, "pixii")
+	if resp["pv_w"] != nil || resp["load_w"] != nil || resp["history_reason"] != "offline:growatt:pv" {
+		t.Fatal(resp)
+	}
+}

go/internal/telemetry/forecast.go

@@ -54,6 +54,8 @@ type ForecastSource struct {
 	Flow   ForecastFlow
 	PowerW *float64
 	SoC    *float64
+	// AssumedZero marks a dark PV source counted as 0 W while offline.
+	AssumedZero bool
 }
 
 type ForecastReading struct {
@@ -63,6 +65,8 @@ type ForecastReading struct {
 	GridW, PVW, BatteryW, EVW, V2XW, HouseholdW float64
 	Valid, PVValid                              bool
 	Reason, PVReason                            string
+	// PVAssumedZero: at least one dark, offline PV source was counted as 0 W.
+	PVAssumedZero bool
 }
 
 // ForecastMeasurement reads power and health under one lock. A command fault
@@ -114,6 +118,14 @@ func SourceFailure(reason string) bool {
 	return reason == "nonfinite_pv_sum"
 }
 
+// PVDarkThresholdW is the largest last PV output (absolute watts) for which an
+// inverter that goes offline is taken to have shut down for lack of sun.
+const PVDarkThresholdW = 50.0
+
+func pvDarkAtLastReading(w float64) bool {
+	return !math.IsNaN(w) && !math.IsInf(w, 0) && math.Abs(w) <= PVDarkThresholdW
+}
+
 func (s *Store) forecastMeasurementLocked(now time.Time, siteMeter string, opts ForecastOptions) ForecastReading {
 	return s.measurementLocked(now, siteMeter, opts, true)
 }
@@ -245,6 +257,25 @@ func (s *Store) measurementLocked(now time.Time, siteMeter string, opts Forecast
 		case pv && powerW > 0:
 			reason = "invalid_sign:"
 		}
+		// A PV inverter that drops off the bus after sunset is producing
+		// nothing. On the live path, an offline or stale PV source whose last
+		// reading was near zero counts as 0 W so the meter and battery still
+		// give a home load. Daytime outages (last reading producing) and
+		// forecast/history alignment keep failing as before.
+		if pv && !alignSources && (reason == "offline:" || reason == "stale:") && r != nil && pvDarkAtLastReading(r.RawW) {
+			zero := 0.0
+			source.PowerW = &zero
+			source.AssumedZero = true
+			out.Sources[k] = source
+			// Not measured: history and the PV model keep it unknown.
+			out.Known[DerPV] = false
+			out.PVAssumedZero = true
+			if out.PVValid {
+				out.PVValid = false
+				out.PVReason = "assumed_zero:" + k
+			}
+			continue
+		}
 		if reason != "" {
 			fail(reason+k, pv)
 			out.Known[f.DerType] = false

go/internal/telemetry/live_measurement_test.go

@@ -70,3 +70,60 @@ func TestLiveMeasurementAllowsIndependentCurrentSourceTimes(t *testing.T) {
 		})
 	}
 }
+
+func nightSite(t *testing.T, lastPV float64) *Store {
+	t.Helper()
+	s := NewStore()
+	for _, driver := range []string{"pixii", "growatt"} {
+		s.EnsureDriverHealth(driver)
+	}
+	s.Update("pixii", DerMeter, 780, nil, nil)
+	s.Update("pixii", DerBattery, 300, nil, nil)
+	s.Update("growatt", DerPV, lastPV, nil, nil)
+	s.DriverHealthMut("growatt").Status = StatusOffline
+	return s
+}
+
+func TestLiveMeasurementOfflineDarkPVCountsAsZero(t *testing.T) {
+	s := nightSite(t, -3)
+	live := s.LiveMeasurementNow("pixii", ForecastOptions{})
+	if !live.Valid || live.Known[DerPV] || !live.PVAssumedZero || live.PVW != 0 || live.HouseholdW != 480 {
+		t.Fatalf("offline dark PV hid load: valid=%t reason=%q pv=%v load=%v", live.Valid, live.Reason, live.PVW, live.HouseholdW)
+	}
+	src := live.Sources["growatt:pv"]
+	if !src.AssumedZero || src.PowerW == nil || *src.PowerW != 0 {
+		t.Fatal("assumed-zero PV source not marked")
+	}
+}
+
+func TestLiveMeasurementOfflineDarkPVWithDischargingBattery(t *testing.T) {
+	s := nightSite(t, 0)
+	s.Update("pixii", DerBattery, -500, nil, nil)
+	live := s.LiveMeasurementNow("pixii", ForecastOptions{})
+	if !live.Valid || live.HouseholdW != 1280 {
+		t.Fatalf("want load 1280, got valid=%t reason=%q load=%v", live.Valid, live.Reason, live.HouseholdW)
+	}
+}
+
+func TestLiveMeasurementOfflineProducingPVStaysUnknown(t *testing.T) {
+	s := nightSite(t, -2500)
+	live := s.LiveMeasurementNow("pixii", ForecastOptions{})
+	if live.Valid || live.Known[DerPV] || live.Reason != "offline:growatt:pv" {
+		t.Fatalf("daytime PV outage was guessed: valid=%t reason=%q", live.Valid, live.Reason)
+	}
+}
+
+func TestForecastOfflineDarkPVStaysUnknown(t *testing.T) {
+	s := nightSite(t, 0)
+	if r := s.ForecastMeasurementNow("pixii", ForecastOptions{}); r.Valid || r.Known[DerPV] {
+		t.Fatal("forecast/history path accepted an assumed PV value")
+	}
+}
+
+func TestLiveMeasurementOfflineMeterStillFails(t *testing.T) {
+	s := nightSite(t, 0)
+	s.DriverHealthMut("pixii").Status = StatusOffline
+	if live := s.LiveMeasurementNow("pixii", ForecastOptions{}); live.Valid || live.Known[DerMeter] {
+		t.Fatal("offline site meter produced a load")
+	}
+}