Feature: add SoC & voltage thresholds for battery current limit

This changes the custom current limit so the custom limit is only
applied when any of:

- SoC is valid and not ignored and SoC < threshold
- Voltage is valid and Voltage < threshold
- Voltage is invalid

Independently, if "Use Battery-Reported limit" is enabled and valid, it
is applied (unless a lower custom limit already was applied).

include/Configuration.h

@@ -145,6 +145,8 @@ struct BATTERY_CONFIG_T {
     BatteryVoltageUnit MqttVoltageUnit;
     bool EnableDischargeCurrentLimit;
     float DischargeCurrentLimit;
+    float DischargeCurrentLimitBelowSoc;
+    float DischargeCurrentLimitBelowVoltage;
     bool UseBatteryReportedDischargeCurrentLimit;
     char MqttDischargeCurrentTopic[MQTT_MAX_TOPIC_STRLEN + 1];
     char MqttDischargeCurrentJsonPath[BATTERY_JSON_MAX_PATH_STRLEN + 1];

include/defaults.h

@@ -156,6 +156,8 @@
 #define BATTERY_JKBMS_POLLING_INTERVAL 5
 #define BATTERY_ENABLE_DISCHARGE_CURRENT_LIMIT false
 #define BATTERY_DISCHARGE_CURRENT_LIMIT 0.0
+#define BATTERY_DISCHARGE_CURRENT_LIMIT_BELOW_SOC 100.0
+#define BATTERY_DISCHARGE_CURRENT_LIMIT_BELOW_VOLTAGE 60.0
 #define BATTERY_USE_BATTERY_REPORTED_DISCHARGE_CURRENT_LIMIT false
 
 #define HUAWEI_ENABLED false

src/Battery.cpp

@@ -91,14 +91,26 @@ float BatteryClass::getDischargeCurrentLimit()
     if (!config.Battery.EnableDischargeCurrentLimit) { return FLT_MAX; }
 
     auto dischargeCurrentLimit = config.Battery.DischargeCurrentLimit;
-    auto dischargeCurrentValid = dischargeCurrentLimit > 0.0f;
+    auto dischargeCurrentLimitValid = dischargeCurrentLimit > 0.0f;
-
+    auto dischargeCurrentLimitBelowSoc = config.Battery.DischargeCurrentLimitBelowSoc;
+    auto dischargeCurrentLimitBelowVoltage = config.Battery.DischargeCurrentLimitBelowVoltage;
+    auto statsSoCValid = getStats()->getSoCAgeSeconds() <= 60 && !config.PowerLimiter.IgnoreSoc;
+    auto statsSoC = statsSoCValid ? getStats()->getSoC() : 100.0; // fail open so we use voltage instead
+    auto statsVoltageValid = getStats()->getVoltageAgeSeconds() <= 60;
+    auto statsVoltage = statsVoltageValid ? getStats()->getVoltage() : 0.0; // fail closed
     auto statsCurrentLimit = getStats()->getDischargeCurrentLimit();
     auto statsLimitValid = config.Battery.UseBatteryReportedDischargeCurrentLimit
         && statsCurrentLimit >= 0.0f
         && getStats()->getDischargeCurrentLimitAgeSeconds() <= 60;
 
-    if (statsLimitValid && dischargeCurrentValid) {
+
+    if (statsSoC > dischargeCurrentLimitBelowSoc && statsVoltage > dischargeCurrentLimitBelowVoltage) {
+        // Above SoC and Voltage thresholds, ignore custom limit.
+        // Battery-provided limit will still be applied.
+        dischargeCurrentLimitValid = false;
+    }
+
+    if (statsLimitValid && dischargeCurrentLimitValid) {
         // take the lowest limit
         return min(statsCurrentLimit, dischargeCurrentLimit);
     }
@@ -107,7 +119,7 @@ float BatteryClass::getDischargeCurrentLimit()
         return statsCurrentLimit;
     }
 
-    if (dischargeCurrentValid) {
+    if (dischargeCurrentLimitValid) {
         return dischargeCurrentLimit;
     }
 

src/Configuration.cpp

@@ -88,6 +88,8 @@ void ConfigurationClass::serializeBatteryConfig(BatteryConfig const& source, Jso
     target["mqtt_voltage_unit"] = config.Battery.MqttVoltageUnit;
     target["enable_discharge_current_limit"] = config.Battery.EnableDischargeCurrentLimit;
     target["discharge_current_limit"] = config.Battery.DischargeCurrentLimit;
+    target["discharge_current_limit_below_soc"] = config.Battery.DischargeCurrentLimitBelowSoc;
+    target["discharge_current_limit_below_voltage"] = config.Battery.DischargeCurrentLimitBelowVoltage;
     target["use_battery_reported_discharge_current_limit"] = config.Battery.UseBatteryReportedDischargeCurrentLimit;
     target["mqtt_discharge_current_topic"] = config.Battery.MqttDischargeCurrentTopic;
     target["mqtt_discharge_current_json_path"] = config.Battery.MqttDischargeCurrentJsonPath;
@@ -383,6 +385,8 @@ void ConfigurationClass::deserializeBatteryConfig(JsonObject const& source, Batt
     target.MqttVoltageUnit = source["mqtt_voltage_unit"] | BatteryVoltageUnit::Volts;
     target.EnableDischargeCurrentLimit = source["enable_discharge_current_limit"] | BATTERY_ENABLE_DISCHARGE_CURRENT_LIMIT;
     target.DischargeCurrentLimit = source["discharge_current_limit"] | BATTERY_DISCHARGE_CURRENT_LIMIT;
+    target.DischargeCurrentLimitBelowSoc = source["discharge_current_limit_below_soc"] | BATTERY_DISCHARGE_CURRENT_LIMIT_BELOW_SOC;
+    target.DischargeCurrentLimitBelowVoltage = source["discharge_current_limit_below_voltage"] | BATTERY_DISCHARGE_CURRENT_LIMIT_BELOW_VOLTAGE;
     target.UseBatteryReportedDischargeCurrentLimit = source["use_battery_reported_discharge_current_limit"] | BATTERY_USE_BATTERY_REPORTED_DISCHARGE_CURRENT_LIMIT;
     strlcpy(target.MqttDischargeCurrentTopic, source["mqtt_discharge_current_topic"] | "", sizeof(config.Battery.MqttDischargeCurrentTopic));
     strlcpy(target.MqttDischargeCurrentJsonPath, source["mqtt_discharge_current_json_path"] | "", sizeof(config.Battery.MqttDischargeCurrentJsonPath));

webapp/src/locales/de.json

@@ -724,6 +724,10 @@
         "DischargeCurrentLimitConfiguration": "Einstellungen Entladestromlimit",
         "LimitDischargeCurrent": "Entladestrom limitieren",
         "DischargeCurrentLimit": "max. Entladestrom",
+        "DischargeCurrentLimitBelowSoc": "Limitieren unter SoC",
+        "DischargeCurrentLimitBelowSocInfo": "Das Entladestromlimit wird nur unter dieser SoC-Schwelle angewendet (nicht verwendet falls 'Batterie SoC ignorieren' aktiviert ist).",
+        "DischargeCurrentLimitBelowVoltage": "Limitieren unter Spannung",
+        "DischargeCurrentLimitBelowVoltageInfo": "Das Entladestromlimit wird nur unter dieser Spannungs-Schwelle angewendet (wenn SoC ignoriert oder nicht verfügbar).",
         "UseBatteryReportedDischargeCurrentLimit": "Von der Batterie übermitteltes Limit verwenden",
         "BatteryReportedDischargeCurrentLimitInfo": "<b>Hinweis:</b> Das niedrigste Limit wird angewendet, wobei das von der Batterie übermittelte Entladestromlimit nur verwendet wird, wenn in der letzten Minute ein Update eingegangen ist; andernfalls dient das zuvor festgelegte Limit als Fallback.",
         "MqttDischargeCurrentTopic": "Topic für Entladestromlimit",

webapp/src/locales/en.json

@@ -727,6 +727,10 @@
         "DischargeCurrentLimitConfiguration": "Discharge Current Limit Settings",
         "LimitDischargeCurrent": "Limit Discharge Current",
         "DischargeCurrentLimit": "max. Discharge Current",
+        "DischargeCurrentLimitBelowSoc": "Apply limit below SoC",
+        "DischargeCurrentLimitBelowSocInfo": "The discharge current limit is not applied above this SoC (not used if 'Ignore Battery SoC' is enabled).",
+        "DischargeCurrentLimitBelowVoltage": "Apply limit below voltage",
+        "DischargeCurrentLimitBelowVoltageInfo": "The discharge current limit is not applied above this voltage (used if SoC ignored or unavailable).",
         "UseBatteryReportedDischargeCurrentLimit": "Use Battery-Reported limit",
         "BatteryReportedDischargeCurrentLimitInfo": "<b>Hint:</b> The lowest limit will be applied, with the battery-reported discharge current limit used only if an update was received in the last minute; otherwise, the previously specified limit will act as a fallback.",
         "MqttDischargeCurrentTopic": "Discharge Current Limit Value Topic",

webapp/src/types/BatteryConfig.ts

@@ -11,6 +11,8 @@ export interface BatteryConfig {
     mqtt_voltage_unit: number;
     enable_discharge_current_limit: boolean;
     discharge_current_limit: number;
+    discharge_current_limit_below_soc: number;
+    discharge_current_limit_below_voltage: number;
     use_battery_reported_discharge_current_limit: boolean;
     mqtt_discharge_current_topic: string;
     mqtt_discharge_current_json_path: string;

webapp/src/views/BatteryAdminView.vue

@@ -141,6 +141,28 @@
                         postfix="A"
                     />
 
+                    <InputElement
+                        :label="$t('batteryadmin.DischargeCurrentLimitBelowSoc')"
+                        v-model="batteryConfigList.discharge_current_limit_below_soc"
+                        type="number"
+                        min="0"
+                        max="100"
+                        step="0.1"
+                        postfix="%"
+                        :tooltip="$t('batteryadmin.DischargeCurrentLimitBelowSocInfo')"
+                    />
+
+                    <InputElement
+                        :label="$t('batteryadmin.DischargeCurrentLimitBelowVoltage')"
+                        v-model="batteryConfigList.discharge_current_limit_below_voltage"
+                        type="number"
+                        min="0"
+                        max="60"
+                        step="0.01"
+                        postfix="V"
+                        :tooltip="$t('batteryadmin.DischargeCurrentLimitBelowVoltageInfo')"
+                    />
+
                     <InputElement
                         :label="$t('batteryadmin.UseBatteryReportedDischargeCurrentLimit')"
                         v-model="batteryConfigList.use_battery_reported_discharge_current_limit"