diff --git a/backend/services/planning_engine.py b/backend/services/planning_engine.py
index 906258a..1d22ad4 100644
--- a/backend/services/planning_engine.py
+++ b/backend/services/planning_engine.py
@@ -71,7 +71,7 @@ NEG_BUY_CHARGE_SHORTFALL_PENALTY_CZK_KWH = 100.0
 PRE_NEG_CHARGE_PENALTY_CZK_KWH = 400.0
 PRE_NEG_BATT_EXPORT_SHORTFALL_PENALTY_CZK_KWH = 80.0
 PRE_NEG_BATT_EXPORT_MIN_SELL_CZK_KWH = 1.0
-PLANNER_BUILD_TAG = "2026-06-01-spot-grid-charge-at-acq-buy-v61"
+PLANNER_BUILD_TAG = "2026-06-01-kv1-fixed-night-self-consume-v62"
 # Ranní slabá FVE: neaplikovat pv_store ge_pv=0 (jinak curtail při sell < večerní peak).
 DAWN_LOW_PV_NO_CURTAIL_W = 1500
 # BA81/KV1: PV→bat jen v těsné blízkosti nejnižšího sell v horizontu (≈ poledne), ne při ~3 Kč ráno.
@@ -1833,10 +1833,12 @@ def _night_self_consume_discourage_import_indices(
     evening_push_ts: set[int],
     charge_acquisition_czk_kwh: float,
     min_spread: float,
+    purchase_fixed: bool = False,
 ) -> set[int]:
     """
     Noční sloty mimo evening_push: penalizace importu pro dům (preferovat bd).
     v45: celé noční okno, ne jen evening_early_export_ban subset.
+    KV1: buy ≈ acq (konstantní ~6,35) — jinak prázdná množina, síť místo baterie v noci.
     """
     out: set[int] = set()
     for t, s in enumerate(slots):
@@ -1844,11 +1846,15 @@ def _night_self_consume_discourage_import_indices(
             continue
         if not _in_night_battery_export_window(s):
             continue
-        buy_t = float(s.buy_price)
-        if buy_t <= float(charge_acquisition_czk_kwh) + float(min_spread):
-            continue
         if float(s.load_baseline_w) <= 0:
             continue
+        buy_t = float(s.buy_price)
+        if purchase_fixed:
+            if buy_t >= 0.0:
+                out.add(t)
+            continue
+        if buy_t <= float(charge_acquisition_czk_kwh) + float(min_spread):
+            continue
         out.add(t)
     return out
 
@@ -2836,6 +2842,7 @@ def solve_dispatch(
             evening_push_ts=evening_push_ts,
             charge_acquisition_czk_kwh=charge_acquisition_czk_kwh,
             min_spread=float(degradation_cost_effective),
+            purchase_fixed=purchase_fixed_pre,
         )
         post_evening_push_night_ts = _post_evening_push_night_self_consume_indices(
             slots, evening_push_ts
@@ -4123,7 +4130,10 @@ def solve_dispatch(
             # Spot (home-01): buy > min ne-záporného buy v horizontu.
             # Fixní tarif (KV1): navíc buy > charge_acquisition (konstantní buy ≈ ref).
             expensive_import_slot = buy_t > ref_buy_horizon + min_spread
-            if fixed_tariff_like_pre:
+            if purchase_fixed_pre and buy_t >= 0.0:
+                # KV1/BA81: buy skoro konstantní — buy > acq nikdy neplatí, jinak v noci import za 6 Kč.
+                expensive_import_slot = True
+            elif fixed_tariff_like_pre:
                 expensive_import_slot = expensive_import_slot or (
                     buy_t > charge_acquisition_czk_kwh + min_spread
                 )
diff --git a/backend/tests/test_planning_dispatch_milp.py b/backend/tests/test_planning_dispatch_milp.py
index 80d53a8..d3334cb 100644
--- a/backend/tests/test_planning_dispatch_milp.py
+++ b/backend/tests/test_planning_dispatch_milp.py
@@ -1833,6 +1833,88 @@ class NegativeSellPvChargeTests(unittest.TestCase):
             "sell nad min horizontu: žádné grid nabíjení",
         )
 
+    def test_kv1_fixed_night_uses_battery_not_grid_import(self) -> None:
+        """v62: po večerním push nocí bd≥load, ne import za fixní buy."""
+        prague = ZoneInfo("Europe/Prague")
+        push = PlanningSlot(
+            interval_start=datetime(2026, 6, 1, 18, 45, tzinfo=prague).astimezone(
+                timezone.utc
+            ),
+            buy_price=6.353,
+            sell_price=9.61,
+            pv_a_forecast_w=0,
+            pv_b_forecast_w=0,
+            load_baseline_w=400,
+            ev1_connected=False,
+            ev2_connected=False,
+            allow_charge=False,
+            allow_discharge_export=True,
+            charge_acquisition_buy_czk_kwh=6.353,
+        )
+        night = PlanningSlot(
+            interval_start=datetime(2026, 6, 1, 23, 0, tzinfo=prague).astimezone(
+                timezone.utc
+            ),
+            buy_price=6.353,
+            sell_price=3.09,
+            pv_a_forecast_w=0,
+            pv_b_forecast_w=0,
+            load_baseline_w=800,
+            ev1_connected=False,
+            ev2_connected=False,
+            allow_charge=False,
+            allow_discharge_export=False,
+            charge_acquisition_buy_czk_kwh=6.353,
+        )
+        battery = _battery(uc_wh=12_500.0, min_pct=10.0, arb_pct=30.0)
+        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=17_000,
+            max_export_power_w=8000,
+            block_export_on_negative_sell=True,
+            purchase_pricing_mode="fixed",
+        )
+        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 = 0.35 * battery.usable_capacity_wh
+        results, _, _ = solve_dispatch(
+            [push, night],
+            battery,
+            hp,
+            grid,
+            [None, None],
+            vehicles,
+            soc0,
+            50.0,
+            operating_mode="AUTO",
+        )
+        r_night = results[1]
+        self.assertLess(
+            r_night.battery_setpoint_w,
+            -200,
+            "noc po push: výdej z baterie na dům",
+        )
+        self.assertLessEqual(
+            r_night.grid_setpoint_w,
+            400,
+            "noc: ne plný import za 6,35 Kč",
+        )
+
     def test_fixed_evening_push_no_charge_at_peak_sell(self) -> None:
         """v59: večerní push — při sell>buy ne nabíjet, jen vybíjet."""
         prague = ZoneInfo("Europe/Prague")
diff --git a/docs/planning-changelog.md b/docs/planning-changelog.md
index 8493def..0638c60 100644
--- a/docs/planning-changelog.md
+++ b/docs/planning-changelog.md
@@ -5,6 +5,16 @@ Formát: **datum (ISO)** · stručný důvod · soubory · chování / ověřen
 
 ---
 
+## 2026-06-01 — KV1: noc z baterie, ne import za 6,35 Kč (v62)
+
+**Problém:** Po večerním vývozu (~32 % SoC) plán **22:00–06:00** krmil dům ze **sítě** (`grid ~260 W`, `bat 0`) místo z baterie. Fixní **buy ≈ charge_acquisition ≈ 6,35** → `expensive_import_slot` nikdy true → neplatilo `bd ≥ load` ani noční penalizace importu (`buy > acq` je false).
+
+**Změna (v62):** u **`purchase_pricing_mode=fixed`**: `expensive_import_slot = true` (buy ≥ 0); `_night_self_consume_discourage_import_indices` zahrne noční sloty i při **buy = acq**.
+
+Tag **`2026-06-01-kv1-fixed-night-self-consume-v62`**.
+
+---
+
 ## 2026-06-01 — home-01: grid jen při buy ≤ acquisition (v61, zrušeno v60)
 
 **Problém:** **19:00** nabíjení za **buy ~5,5** při **`charge_acquisition ~3,25`** z rána → falešně ziskový večerní export. **v60** (`sell < buy` ve slotu) bylo **špatně**: u spotu (a často u fixního tarifu) je **`sell < buy` normální** (marže distributora) — arbitráž je **mezi sloty**, ne v jedné čtvrthodině.