ohAnd · ohAnd · Aug 25, 2026 · Aug 25, 2026 · Aug 25, 2026 · Aug 25, 2026
diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
@@ -466,7 +466,7 @@ These need more than a simple attribute swap:
 | Group              | Fields                                                                                                           | Interface           | Change Required                                  |
 | ------------------ | ---------------------------------------------------------------------------------------------------------------- | ------------------- | ------------------------------------------------ |
 | Battery capacity   | `battery.capacity_wh`, `battery.charge_efficiency`, `battery.discharge_efficiency`, `battery.max_charge_power_w` | BatteryInterface    | Update battery_data dict + recalc charging curve |
-| Battery price calc | `battery.price_update_interval`, `battery.price_history_lookback_hours`, `battery.price_euro_per_wh_accu`        | BatteryPriceHandler | Restart timer or update interval                 |
+| Battery price calc | `battery.price_update_interval`, `battery.price_history_lookback_hours`, `battery.price_ct_kwh_accu`             | BatteryPriceHandler | Restart timer or update interval                 |
 | Price fixed array  | `price.fixed_24h_array`                                                                                          | PriceInterface      | Re-parse array + recalc prices                   |
 | EOS time slot      | `eos.time_frame` (see Priority 1.5)                                                                              | Multiple            | Debounced reload with cache clear                |
 

diff --git a/docs/assets/data/config_schema.json b/docs/assets/data/config_schema.json
@@ -1169,12 +1169,12 @@
       "display_group": "Sensors"
     },
     {
-      "key": "battery.price_euro_per_wh_accu",
+      "key": "battery.price_ct_kwh_accu",
       "type": "float",
       "default": 0.0,
       "section": "battery",
       "level": "standard",
-      "description": "Static battery price in €/Wh (0 = use dynamic or ignore)",
+      "description": "Static battery price in ct/kWh (0 = use dynamic or ignore)",
       "labels": [
         "restart_required"
       ],

diff --git a/docs/user-guide/configuration.html b/docs/user-guide/configuration.html
@@ -1676,19 +1676,19 @@ <h3>battery.sensor_battery_temperature</h3>
                         </tr>
                     </table>
 
-                    <h3>battery.price_euro_per_wh_accu</h3>
+                    <h3>battery.price_ct_kwh_accu</h3>
                     <table>
                         <tr>
                             <th>Parameter</th>
-                            <td><code>battery.price_euro_per_wh_accu</code></td>
+                            <td><code>battery.price_ct_kwh_accu</code></td>
                         </tr>
                         <tr>
                             <th>Description</th>
                             <td>Static price for battery energy storage</td>
                         </tr>
                         <tr>
                             <th>Unit</th>
-                            <td>Euro per Wh (€/Wh)</td>
+                            <td>Cents per kWh (ct/kWh)</td>
                         </tr>
                         <tr>
                             <th>Default</th>
@@ -1770,7 +1770,7 @@ <h3>battery.price_euro_per_wh_sensor</h3>
                         </tr>
                         <tr>
                             <th>Notes</th>
-                            <td>If configured, overrides static <code>price_euro_per_wh_accu</code> value. Leave empty
+                            <td>If configured, overrides static <code>price_ct_kwh_accu</code> value. Leave empty
                                 to use static price.</td>
                         </tr>
                     </table>
@@ -2015,7 +2015,7 @@ <h3>battery.battery_price_include_feedin</h3>
                             <td>
                                 <code>false</code> - PV-sourced energy costs €0 (default, free solar energy)<br>
                                 <code>true</code> - PV-sourced energy is valued at <code>price.feed_in_price</code>
-                                (€/kWh) as opportunity cost
+                                (ct/kWh, converted internally to €/kWh) as opportunity cost
                             </td>
                         </tr>
                         <tr>
@@ -3013,7 +3013,7 @@ <h4>Example Configuration</h4>
   source: tibber
   token: "YOUR_TIBBER_TOKEN"
   feed_in_source: fixed
-  feed_in_price: 0.08
+  feed_in_price: 8  # 8 ct/kWh
   feed_in_negative_price_switch: true
 
   # Smart price prediction with energyforecast.de

diff --git a/docs/user-guide/index.html b/docs/user-guide/index.html
@@ -510,9 +510,9 @@ <h2><i class="fas fa-coins"></i> Battery Energy Pricing</h2>
             <h4>Three Battery Pricing Modes</h4>
             <p><strong>Mode 1: Fixed Static Price</strong> (Default)</p>
             <ul>
-                <li>Battery energy cost set to a single fixed value (€/Wh)</li>
+                <li>Battery energy cost set to a single fixed value (ct/kWh)</li>
                 <li>Simple but inaccurate - doesn't reflect actual charging sources</li>
-                <li>Configuration: <code>battery.price_euro_per_wh_accu: 0.00004</code> (default)</li>
+                <li>Configuration: <code>battery.price_ct_kwh_accu: 4</code> (4 ct/kWh; <code>0</code> is the default, meaning "unused")</li>
                 <li>Use case: Quick setup when you don't have sensor data available</li>
             </ul>
 
@@ -671,9 +671,10 @@ <h4>Example Configuration</h4>
   # Thresholds
   charging_threshold_w: 50
   grid_charge_threshold_w: 100
-
-  # Feed-in price (for valuing PV surplus energy)
-  feed_in_price: 0.04  # €0.04/kWh when not charging from grid</code></pre>
+
+  # To value PV surplus at the feed-in tariff instead of €0, also set:
+  # battery_price_include_feedin: true
+  # and configure price.feed_in_price (in the price: section, in ct/kWh)</code></pre>
         </div>
 
         <!-- Battery Overview -->

diff --git a/src/config_web/__init__.py b/src/config_web/__init__.py
@@ -31,7 +31,11 @@
 
 from .schema import ConfigSchema
 from .store import ConfigStore
-from .migration import migrate_yaml_to_store, migrate_ha_options_to_store
+from .migration import (
+    migrate_yaml_to_store,
+    migrate_ha_options_to_store,
+    migrate_battery_price_unit_to_ct_kwh,
+)
 from .merger import build_merged_config
 from .api import config_bp, init_api
 from .backup import backup_bp, init_backup
@@ -124,6 +128,9 @@ def start_db(self):
             self._schema,
         )
 
+        # One-time migration: battery.price_euro_per_wh_accu (€/Wh) -> battery.price_ct_kwh_accu (ct/kWh)
+        migrate_battery_price_unit_to_ct_kwh(self._store)
+
         # Build the merged config dict
         self.rebuild_config()
 

diff --git a/src/config_web/hot_reload.py b/src/config_web/hot_reload.py
@@ -383,7 +383,11 @@ def _sync_feed_in_negative_price_switch(self, negative_price_switch):
                 e)
 
     def _apply_battery_feedin_price(self, feedin_price):
-        """Apply live feed-in price updates to the battery price handler."""
+        """Apply live feed-in price updates to the battery price handler.
+
+        feedin_price arrives as ct/kWh (price.feed_in_price); pv_cost_euro_per_kwh
+        expects €/kWh.
+        """
         if self._battery is None:
             return
 
@@ -392,12 +396,13 @@ def _apply_battery_feedin_price(self, feedin_price):
             return
 
         old_val = getattr(price_handler, "pv_cost_euro_per_kwh", "?")
-        price_handler.pv_cost_euro_per_kwh = feedin_price
+        new_val = feedin_price / 100.0
+        price_handler.pv_cost_euro_per_kwh = new_val
         # Force a fresh historical calculation on next battery update cycle.
         price_handler.last_price_calculation = None
         logger.info(
-            "[HotReload] Updated battery price feed-in cost = %s (was %s)",
-            feedin_price,
+            "[HotReload] Updated battery price feed-in cost = %s €/kWh (was %s)",
+            new_val,
             old_val,
         )
 

diff --git a/src/config_web/migration.py b/src/config_web/migration.py
@@ -194,6 +194,45 @@ def migrate_ha_options_to_store(
     return True
 
 
+_BATTERY_PRICE_UNIT_MIGRATION_KEY = "_migrated_battery_price_unit_v2"
+
+
+def migrate_battery_price_unit_to_ct_kwh(store: ConfigStore) -> bool:
+    """
+    One-time migration: ``battery.price_euro_per_wh_accu`` (€/Wh) becomes
+    ``battery.price_ct_kwh_accu`` (ct/kWh).
+
+    The old key name no longer matched its unit once the field was switched
+    to ct/kWh, so the field itself is renamed. Existing installations with a
+    nonzero value configured have it rescaled (×100000, €/Wh → ct/kWh) and
+    moved to the new key, so the real-world price they configured is
+    preserved across the change. Runs exactly once, guarded by a marker key.
+
+    Args:
+        store: An opened ConfigStore instance.
+
+    Returns:
+        True if the migration ran (first time), False if it was already done.
+    """
+    if store.get(_BATTERY_PRICE_UNIT_MIGRATION_KEY, False):
+        return False
+
+    old_value = store.get("battery.price_euro_per_wh_accu")
+    if old_value:
+        new_value = old_value * 100000
+        store.set("battery.price_ct_kwh_accu", new_value)
+        logger.info(
+            "[Migration] Moved battery.price_euro_per_wh_accu (%s €/Wh) to "
+            "battery.price_ct_kwh_accu (%s ct/kWh)",
+            old_value,
+            new_value,
+        )
+    store.delete("battery.price_euro_per_wh_accu")
+
+    store.set(_BATTERY_PRICE_UNIT_MIGRATION_KEY, True)
+    return True
+
+
 def _has_user_configured_values(config_dict: dict) -> bool:
     """
     Detect whether a config dict contains real user-configured values or just

diff --git a/src/config_web/schema.py b/src/config_web/schema.py
@@ -973,12 +973,12 @@ def defaults_dict(self) -> dict:
         display_group="Sensors",
     ),
     FieldDef(
-        key="battery.price_euro_per_wh_accu",
+        key="battery.price_ct_kwh_accu",
         field_type="float",
         default=0.0,
         section="battery",
         level="standard",
-        description="Static battery price in €/Wh (0 = use dynamic or ignore)",
+        description="Static battery price in ct/kWh (0 = use dynamic or ignore)",
         labels=["restart_required"],
         help_url="configuration.html#battery",
         validation={"min": 0.0},

diff --git a/src/eos_connect.py b/src/eos_connect.py
@@ -200,8 +200,16 @@ def formatTime(self, record, datefmt=None):
 )
 
 battery_config = dict(config_manager.config["battery"])
-battery_config["feed_in_price"] = config_manager.config.get("price", {}).get(
-    "feed_in_price", 0.0
+# price.feed_in_price is ct/kWh; BatteryPriceHandler.pv_cost_euro_per_kwh expects €/kWh
+battery_config["feed_in_price"] = (
+    config_manager.config.get("price", {}).get("feed_in_price", 0.0) / 100.0
+)
+# battery.price_ct_kwh_accu is ct/kWh (user-facing); BatteryInterface/
+# BatteryPriceHandler expect price_euro_per_wh_accu in €/Wh internally
+battery_config.pop("price_ct_kwh_accu", None)
+battery_config["price_euro_per_wh_accu"] = (
+    config_manager.config.get("battery", {}).get("price_ct_kwh_accu", 0.0)
+    / 100000.0
 )
 
 battery_interface = interface_factory.create_battery_interface(

diff --git a/src/interfaces/feed_in_price_interface.py b/src/interfaces/feed_in_price_interface.py
@@ -97,10 +97,6 @@ def __init__(self, config, time_frame_base, timezone="UTC", evcc_interface=None)
         # Also try legacy key
         if fixed_price_ct_kwh == 0.0 and "fixed_price" in config:
             fixed_price_ct_kwh = config.get("fixed_price", 0.0)
-        # If value is suspiciously small (e.g., EUR instead of ct), convert it
-        if fixed_price_ct_kwh < 0.1 and fixed_price_ct_kwh > 0:
-            # Looks like EUR/kWh, convert to ct/kWh
-            fixed_price_ct_kwh = fixed_price_ct_kwh * 100
         self.fixed_price_ct_kwh = fixed_price_ct_kwh
 
         # Negative price switching: if True, clamps negative market prices to 0

diff --git a/src/web/js/chart.js b/src/web/js/chart.js
@@ -228,7 +228,7 @@ class ChartManager {
 
         // Electricity Price - with segment styling for forecast data
         const priceRawData = data_response["result"]["Electricity_price"];
-        const priceData = priceRawData.map(value => value * 1000);
+        const priceData = priceRawData.map(value => value * 100000);
 
         // Apply segment styling if forecast data is available
         if (priceInfo && priceInfo.forecast_start_index !== null && priceInfo.forecast_type !== "all_real") {
@@ -268,7 +268,7 @@ class ChartManager {
 
             // Set dataset 10 (real prices) - solid orange
             this.chartInstance.data.datasets[10].data = dataset10Data;
-            this.chartInstance.data.datasets[10].label = `Electricity Price (${localization.currency_symbol}/kWh)`;
+            this.chartInstance.data.datasets[10].label = `Electricity Price (${localization.currency_minor_unit}/kWh)`;
             this.chartInstance.data.datasets[10].borderColor = 'rgba(255, 69, 0, 0.8)';
             this.chartInstance.data.datasets[10].borderDash = [];
 
@@ -277,7 +277,7 @@ class ChartManager {
                 console.warn('[ChartManager] Dataset 11 does not exist for forecast visualization');
             } else {
                 this.chartInstance.data.datasets[11].data = dataset11Data;
-                this.chartInstance.data.datasets[11].label = `Electricity Price Forecast - ${priceInfo.forecast_type.replace(/_/g, ' ')} (${localization.currency_symbol}/kWh)`;
+                this.chartInstance.data.datasets[11].label = `Electricity Price Forecast - ${priceInfo.forecast_type.replace(/_/g, ' ')} (${localization.currency_minor_unit}/kWh)`;
                 this.chartInstance.data.datasets[11].borderColor = 'rgba(167, 167, 167, 0.7)';
                 // this.chartInstance.data.datasets[11].borderDash = [5, 5];  // Dotted pattern
                 this.chartInstance.data.datasets[11].borderWidth = 2;  // Thicker to see dashing
@@ -290,11 +290,11 @@ class ChartManager {
                 this.chartInstance.data.datasets[11].hidden = false;
             }
 
-            this.chartInstance.options.scales.y1.title.text = `Price (${localization.currency_symbol}/kWh)`;
+            this.chartInstance.options.scales.y1.title.text = `Price (${localization.currency_minor_unit}/kWh)`;
         } else {
             // No forecasting - all real prices
             this.chartInstance.data.datasets[10].data = priceData;
-            this.chartInstance.data.datasets[10].label = `Electricity Price (${localization.currency_symbol}/kWh)`;
+            this.chartInstance.data.datasets[10].label = `Electricity Price (${localization.currency_minor_unit}/kWh)`;
             this.chartInstance.data.datasets[10].borderColor = 'rgba(255, 69, 0, 0.8)';
             this.chartInstance.data.datasets[10].borderDash = [];
 
@@ -304,7 +304,7 @@ class ChartManager {
                 this.chartInstance.data.datasets[11].hidden = true;
             }
 
-            this.chartInstance.options.scales.y1.title.text = `Price (${localization.currency_symbol}/kWh)`;
+            this.chartInstance.options.scales.y1.title.text = `Price (${localization.currency_minor_unit}/kWh)`;
         }
 
         this.chartInstance.update('none'); // Update without animation
@@ -330,7 +330,7 @@ class ChartManager {
                     { label: 'Income', data: [], type: 'line', borderColor: 'lightyellow', backgroundColor: 'yellow', borderWidth: 1, yAxisID: 'y1', stepped: true, hidden: true, pointRadius: 1, pointHoverRadius: 4 },
                     { label: 'Discharge Allowed', data: [], type: 'line', borderColor: 'rgba(144, 238, 144, 0.3)', backgroundColor: 'rgba(144, 238, 144, 0.05)', borderWidth: 1, fill: true, yAxisID: 'y3', pointRadius: 1, pointHoverRadius: 4, stepped: true },
                     { label: 'Dynamic Discharge Allowed (PV > Load)', data: [], type: 'line', borderColor: 'rgba(50, 205, 50, 0.6)', backgroundColor: 'rgba(50, 205, 50, 0.1)', borderWidth: 1, fill: true, yAxisID: 'y3', pointRadius: 1, pointHoverRadius: 4, stepped: true, hidden: false },
-                    { label: `Electricity Price (${localization.currency_symbol}/kWh)`, data: [], type: 'line', borderColor: 'rgba(255, 69, 0, 0.8)', backgroundColor: 'rgba(255, 165, 0, 0.2)', borderWidth: 1, yAxisID: 'y1', stepped: true, pointRadius: 1, pointHoverRadius: 4 },
+                    { label: `Electricity Price (${localization.currency_minor_unit}/kWh)`, data: [], type: 'line', borderColor: 'rgba(255, 69, 0, 0.8)', backgroundColor: 'rgba(255, 165, 0, 0.2)', borderWidth: 1, yAxisID: 'y1', stepped: true, pointRadius: 1, pointHoverRadius: 4 },
                     { label: 'Electricity Price - Forecast', data: [], type: 'line', borderColor: 'rgba(167, 167, 167, 0.7)', backgroundColor: 'rgba(220, 20, 60, 0.05)', borderWidth: 2, yAxisID: 'y1', stepped: true, pointRadius: 1, pointHoverRadius: 4, fill: false, hidden: true },
                     { label: 'PV Charge Planned', data: [], type: 'line', borderColor: 'transparent', backgroundColor: 'transparent', borderWidth: 0, fill: false, yAxisID: 'y3', pointRadius: 0, pointHoverRadius: 0, stepped: true, hidden: true }
                 ]
@@ -340,7 +340,7 @@ class ChartManager {
                 maintainAspectRatio: false,
                 scales: {
                     y: { beginAtZero: true, title: { display: true, text: 'Energy (kWh)', color: 'lightgray' }, grid: { color: 'rgb(54, 54, 54)' }, ticks: { color: 'lightgray' } },
-                    y1: { beginAtZero: true, position: 'right', title: { display: true, text: `Price (${localization.currency_symbol}/kWh)`, color: 'lightgray' }, grid: { drawOnChartArea: false }, ticks: { color: 'lightgray', callback: value => value.toFixed(2) } },
+                    y1: { beginAtZero: true, position: 'right', title: { display: true, text: `Price (${localization.currency_minor_unit}/kWh)`, color: 'lightgray' }, grid: { drawOnChartArea: false }, ticks: { color: 'lightgray', callback: value => value.toFixed(1) } },
                     y2: { beginAtZero: true, position: 'right', title: { display: true, text: 'Battery SOC (%)', color: 'darkgray' }, grid: { drawOnChartArea: false }, ticks: { color: 'darkgray', callback: value => value.toFixed(0) } },
                     y3: { beginAtZero: true, position: 'right', display: false, title: { display: true, text: 'AC Charge', color: 'darkgray' }, grid: { drawOnChartArea: false }, ticks: { color: 'darkgray', callback: value => value.toFixed(2) } },
                     x: { grid: { color: 'rgb(54, 54, 54)' }, ticks: { color: 'lightgray', font: { size: 10 } } }
@@ -393,7 +393,7 @@ class ChartManager {
                                 else if (label === 'Income')
                                     return `${label}: ${value} ${localization.currency_symbol}`;
                                 else if (label.startsWith('Electricity Price'))
-                                    return `${label}: ${value.toFixed(3)} ${localization.currency_symbol}/kWh`;
+                                    return `${label}: ${value.toFixed(2)} ${localization.currency_minor_unit}/kWh`;
                                 else if (label === 'Discharge Allowed')
                                     return `${label}: ${value}`;
                                 else if (label === 'PV Charge Planned')

diff --git a/tests/config_web/test_api.py b/tests/config_web/test_api.py
@@ -39,7 +39,7 @@ def _sample_config():
             "charge_efficiency": 0.88, "discharge_efficiency": 0.88,
             "max_charge_power_w": 5000, "min_soc_percentage": 5,
             "max_soc_percentage": 100, "charging_curve_enabled": True,
-            "sensor_battery_temperature": "", "price_euro_per_wh_accu": 0.0,
+            "sensor_battery_temperature": "", "price_ct_kwh_accu": 0.0,
             "price_euro_per_wh_sensor": "", "price_calculation_enabled": False,
             "price_update_interval": 900, "price_history_lookback_hours": 96,
             "battery_power_sensor": "", "pv_power_sensor": "", "grid_power_sensor": "",