fix maxu u baterky pri prodeji

backend/tests/test_planning_dispatch_milp.py

@@ -1838,6 +1838,59 @@ class SitePowerCapTests(unittest.TestCase):
         )
         self.assertGreater(r.battery_setpoint_w, 0)
 
+    def test_battery_export_respects_site_export_cap(self) -> None:
+        """SELL slot: vývoz ze site ≤ max_export; vybíjení baterie ≤ max_discharge."""
+        base = datetime(2026, 5, 22, 18, 0, tzinfo=timezone.utc)
+        slots = [
+            PlanningSlot(
+                interval_start=base,
+                buy_price=0.5,
+                sell_price=6.0,
+                pv_a_forecast_w=0,
+                pv_b_forecast_w=0,
+                load_baseline_w=2500,
+                ev1_connected=False,
+                ev2_connected=False,
+                is_predicted_price=False,
+                allow_charge=False,
+                allow_discharge_export=True,
+            )
+        ]
+        battery = _battery(uc_wh=64_000.0, min_pct=12.0, arb_pct=20.0)
+        battery.max_charge_power_w = 18_000
+        battery.max_discharge_power_w = 18_000
+        hp = SimpleNamespace(rated_heating_power_w=0, tuv_min_temp_c=45.0, tuv_target_temp_c=55.0)
+        grid = SimpleNamespace(max_import_power_w=17_000, max_export_power_w=13_500)
+        vehicles = [
+            SimpleNamespace(max_charge_power_w=0, battery_capacity_kwh=1.0, default_target_soc_pct=80.0),
+            SimpleNamespace(max_charge_power_w=0, battery_capacity_kwh=1.0, default_target_soc_pct=80.0),
+        ]
+        soc0 = 0.85 * battery.usable_capacity_wh
+        results, _, _ = solve_dispatch(
+            slots,
+            battery,
+            hp,
+            grid,
+            [None, None],
+            vehicles,
+            soc0,
+            50.0,
+            operating_mode="AUTO",
+        )
+        r = results[0]
+        self.assertLessEqual(
+            -r.grid_setpoint_w,
+            13_500,
+            msg="export ze site ≤ max_export_power_w",
+        )
+        self.assertLess(r.grid_setpoint_w, -500, msg="očekáván významný export")
+        self.assertLess(r.battery_setpoint_w, -500, msg="očekáváno vybíjení baterie")
+        self.assertLessEqual(
+            r.export_limit_w,
+            13_500,
+            msg="export_limit_w odpovídá site limitu",
+        )
+
 
 if __name__ == "__main__":
     unittest.main()