fix max sell z baterky

backend/tests/test_planning_dispatch_milp.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 import unittest
 from datetime import datetime, timedelta, timezone
 from types import SimpleNamespace
+from zoneinfo import ZoneInfo
 
 from services.planning_engine import (
     DispatchResult,
@@ -2198,6 +2199,60 @@ class SpreadGuardHome01EconomicsTests(unittest.TestCase):
 class ChargeAcquisitionArbitrageTests(unittest.TestCase):
     """Mezi-slotová arbitráž: večerní export při nízké charge_acquisition z SQL."""
 
+    def test_evening_peak_battery_export_at_site_cap(self) -> None:
+        """Nejvyšší večerní sell: výrazný export; levnější večerní sloty bez předčasného vývozu."""
+        prague = ZoneInfo("Europe/Prague")
+        base = datetime(2026, 5, 25, 17, 0, tzinfo=prague)
+        sells = [3.5, 3.7, 4.04, 3.75, 3.8, 3.6]
+        slots = [
+            PlanningSlot(
+                interval_start=base + timedelta(minutes=15 * i),
+                buy_price=0.8,
+                sell_price=sell,
+                pv_a_forecast_w=6000,
+                pv_b_forecast_w=0,
+                load_baseline_w=800,
+                ev1_connected=False,
+                ev2_connected=False,
+                allow_charge=False,
+                allow_discharge_export=True,
+                charge_acquisition_buy_czk_kwh=0.8,
+            )
+            for i, sell in enumerate(sells)
+        ]
+        battery = _battery(uc_wh=64_000.0, terminal_soc_value_factor=0.0)
+        battery.max_discharge_power_w = 6250
+        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=16_000, max_export_power_w=16_000)
+        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),
+        ]
+        results, _ms, snap = solve_dispatch(
+            slots,
+            battery,
+            hp,
+            grid,
+            [None, None],
+            vehicles,
+            0.85 * battery.soc_max_wh,
+            50.0,
+            operating_mode="AUTO",
+        )
+        self.assertEqual(snap["planner_build_tag"], "2026-05-28-evening-peak-full-export-v26")
+        peak_idx = sells.index(4.04)
+        peak = results[peak_idx]
+        self.assertIn(peak.export_mode, ("BATTERY_SELL", "PV_SURPLUS"))
+        self.assertGreater(abs(peak.grid_setpoint_w), 5000)
+        for i, r in enumerate(results):
+            if i == peak_idx or sells[i] >= 4.04 - 0.05:
+                continue
+            self.assertNotEqual(
+                r.export_mode,
+                "BATTERY_SELL",
+                msg=f"slot {i} sell={sells[i]} must not battery-export before peak",
+            )
+
     def test_evening_battery_export_when_sell_above_acquisition(self) -> None:
         base = datetime(2026, 5, 21, 10, 0, tzinfo=timezone.utc)
         cheap = (0.75, 0.25)