Use chargeTotalImport for /Ac/Energy/Forward with monotonic guard

Prefer EVCC chargeTotalImport (kWh meter) over chargedEnergy for /Ac/Energy/Forward — required for IntegratedDevice loadpoints (heat pump, sgready-relay, …) where chargedEnergy stays 0. Guarded with max(candidate, previous) so transient EVCC drops (chargeTotalImport: null) cannot roll the VRM counter backwards. Cumulative counter also published when disconnected. Tests: source-switch, disconnected+total_import.

Co-authored-by: Franz Bettag <franz@bettag.net>

Author: fbettag

dbus_service.py

@@ -150,11 +150,27 @@ def update(self, lp: Loadpoint) -> None:
             s["/Status"] = status
             s["/Connected"] = 1
 
-            # Cumulative counters only refreshed while connected. UNVERIFIED:
-            # chargedEnergy is treated as Wh (-> /1000 = kWh). Must be confirmed
-            # against a real EVCC /api/state sample before deploy.
+            # chargeTotalImport is EVCC's cumulative kWh meter value. It keeps
+            # increasing for IntegratedDevice loadpoints (heatpump, sgready-
+            # relay, …) where chargedEnergy stays at 0 because EVCC has no
+            # session semantics for "always connected" chargers. Fall back to
+            # chargedEnergy / 1000 when the meter value is missing.
+            total_import = float(lp.charge_total_import or 0.0)
+            if total_import > 0:
+                candidate = total_import
+            elif status != STATUS_DISCONNECTED:
+                candidate = float(lp.charged_energy) / 1000.0
+            else:
+                candidate = None
+
+            if candidate is not None:
+                # /Ac/Energy/Forward must be monotonic for VRM. Guard against
+                # transient source switches (e.g. EVCC briefly returning
+                # chargeTotalImport: null) rolling the counter backwards.
+                previous = float(s["/Ac/Energy/Forward"] or 0.0)
+                s["/Ac/Energy/Forward"] = max(candidate, previous)
+
             if status != STATUS_DISCONNECTED:
-                s["/Ac/Energy/Forward"] = float(lp.charged_energy) / 1000.0
                 s["/ChargingTime"] = int(lp.charge_duration_ns) // 1_000_000_000
 
             idx = (int(s["/UpdateIndex"]) + 1) % 256

evcc_api.py

@@ -26,6 +26,7 @@ class Loadpoint:
     charge_voltages: List[float] = field(default_factory=lambda: [230.0, 230.0, 230.0])
     effective_max_current: int = 16
     charged_energy: float = 0.0
+    charge_total_import: float = 0.0
     charge_duration_ns: int = 0
 
 
@@ -61,6 +62,7 @@ def _parse_loadpoints(state: dict) -> List[Loadpoint]:
             charge_voltages=_normalize_triple(raw.get("chargeVoltages"), 230.0),
             effective_max_current=int(raw.get("effectiveMaxCurrent") or 16),
             charged_energy=float(raw.get("chargedEnergy") or 0.0),
+            charge_total_import=float(raw.get("chargeTotalImport") or 0.0),
             charge_duration_ns=int(raw.get("chargeDuration") or 0),
         ))
     return out

tests/fixtures/evcc_state_1lp.json

@@ -10,6 +10,7 @@
       "chargeVoltages": [230, 230, 230],
       "effectiveMaxCurrent": 20,
       "chargedEnergy": 250.0,
+      "chargeTotalImport": 12.345,
       "chargeDuration": 600000000000
     }
   ]

tests/fixtures/evcc_state_3lp.json

@@ -10,6 +10,7 @@
       "chargeVoltages": [230, 230, 230],
       "effectiveMaxCurrent": 16,
       "chargedEnergy": 0.0,
+      "chargeTotalImport": 1.234,
       "chargeDuration": 0
     },
     {
@@ -22,6 +23,7 @@
       "chargeVoltages": [230, 230, 230],
       "effectiveMaxCurrent": 20,
       "chargedEnergy": 1800.0,
+      "chargeTotalImport": 98.765,
       "chargeDuration": 3600000000000
     },
     {
@@ -34,6 +36,7 @@
       "chargeVoltages": [230, 230, 230],
       "effectiveMaxCurrent": 16,
       "chargedEnergy": 0.0,
+      "chargeTotalImport": 19341.908,
       "chargeDuration": 0
     }
   ]

tests/test_dbus_service.py

@@ -111,7 +111,8 @@ def test_update_connected_not_charging(monkeypatch):
 
 def test_update_charging_uses_per_phase_voltages(monkeypatch):
     svc, vedbus, _ = _make_svc(monkeypatch)
-    vedbus.__getitem__.return_value = 5
+    # /UpdateIndex starts at 5 (wraps to 6); other paths are uninitialised.
+    vedbus.__getitem__.side_effect = lambda k: 5 if k == "/UpdateIndex" else 0
     lp = Loadpoint(
         title="HeatingElement", connected=True, charging=True, mode="pv",
         charge_power=4500.0,
@@ -132,13 +133,81 @@ def test_update_charging_uses_per_phase_voltages(monkeypatch):
     assert sets["/Current"] == 19.5
     assert sets["/MaxCurrent"] == 20
     assert sets["/Mode"] == MODE_AUTO
-    # UNVERIFIED unit: chargedEnergy treated as Wh; must confirm against
-    # a live EVCC /api/state sample before merging the deploy.
+    # Fallback for EVCC payloads without chargeTotalImport.
     assert sets["/Ac/Energy/Forward"] == 1.8
     assert sets["/ChargingTime"] == 3600
     assert sets["/UpdateIndex"] == 6
 
 
+def test_update_prefers_charge_total_import_for_cumulative_energy(monkeypatch):
+    svc, vedbus, _ = _make_svc(monkeypatch)
+    vedbus.__getitem__.return_value = 0
+    lp = Loadpoint(
+        title="Heatpump", connected=True, charging=False, mode="off",
+        charge_power=90.25,
+        charge_currents=[0.93, 0.49, 0.5],
+        charge_voltages=[237.5, 236.9, 236.9],
+        charged_energy=0.0,
+        charge_total_import=19341.908,
+    )
+    svc.update(lp)
+    sets = dict(c.args for c in vedbus.__setitem__.call_args_list)
+    assert sets["/Ac/Energy/Forward"] == 19341.908
+
+
+def test_update_energy_forward_is_monotonic_across_source_switch(monkeypatch):
+    """EVCC may transiently return chargeTotalImport: null / 0 (e.g. on a
+    loadpoint without a meter). The fallback to chargedEnergy/1000 must not
+    roll /Ac/Energy/Forward backwards for VRM.
+    """
+    svc, vedbus, _ = _make_svc(monkeypatch)
+
+    state = {"/Ac/Energy/Forward": 0.0, "/UpdateIndex": 0}
+    vedbus.__getitem__.side_effect = lambda k: state.get(k, 0)
+    vedbus.__setitem__.side_effect = lambda k, v: state.__setitem__(k, v)
+
+    lp_high = Loadpoint(
+        title="Heatpump", connected=True, charging=True, mode="pv",
+        charged_energy=0.0, charge_total_import=19341.908,
+    )
+    svc.update(lp_high)
+    assert state["/Ac/Energy/Forward"] == 19341.908
+
+    # EVCC transiently drops the meter value; chargedEnergy is 0 on a heating LP
+    lp_drop = Loadpoint(
+        title="Heatpump", connected=True, charging=True, mode="pv",
+        charged_energy=0.0, charge_total_import=0.0,
+    )
+    svc.update(lp_drop)
+    assert state["/Ac/Energy/Forward"] == 19341.908  # held, no regression
+
+    # Meter value comes back and grows
+    lp_resume = Loadpoint(
+        title="Heatpump", connected=True, charging=True, mode="pv",
+        charged_energy=0.0, charge_total_import=19500.0,
+    )
+    svc.update(lp_resume)
+    assert state["/Ac/Energy/Forward"] == 19500.0
+
+
+def test_update_disconnected_with_total_import_still_publishes_cumulative(monkeypatch):
+    """A disconnected loadpoint with a positive chargeTotalImport (e.g. an
+    EV that just unplugged) should still publish the lifetime counter so
+    VRM history doesn't stall on disconnect. /ChargingTime stays unpublished.
+    """
+    svc, vedbus, _ = _make_svc(monkeypatch)
+    vedbus.__getitem__.return_value = 0
+    lp = Loadpoint(
+        title="Carport", connected=False, charging=False, mode="pv",
+        charged_energy=0.0, charge_total_import=15303.908,
+    )
+    svc.update(lp)
+    sets = dict(c.args for c in vedbus.__setitem__.call_args_list)
+    assert sets["/Status"] == STATUS_DISCONNECTED
+    assert sets["/Ac/Energy/Forward"] == 15303.908
+    assert "/ChargingTime" not in sets
+
+
 def test_update_index_wraps_at_255(monkeypatch):
     svc, vedbus, _ = _make_svc(monkeypatch)
     vedbus.__getitem__.return_value = 255

tests/test_evcc_api.py

@@ -30,6 +30,7 @@ def test_fetch_state_returns_loadpoints_1lp(requests_mock):
     assert lp.charge_currents == [6.5, 0, 0]
     assert lp.effective_max_current == 20
     assert lp.mode == "pv"
+    assert lp.charge_total_import == 12.345
 
 
 def test_fetch_state_returns_loadpoints_3lp(requests_mock):
@@ -90,6 +91,7 @@ def test_missing_optional_fields_use_defaults():
     assert lps[0].charge_currents == [0, 0, 0]
     assert lps[0].connected is False
     assert lps[0].charge_power == 0.0
+    assert lps[0].charge_total_import == 0.0
     assert lps[0].effective_max_current == 16