SOH calculations

ESPController/include/defines.h

@@ -161,6 +161,7 @@ struct diybms_eeprom_settings
 
   uint16_t currentMonitoring_shuntmv;
   uint16_t currentMonitoring_shuntmaxcur;
+  /// @brief Amp-hours battery capacity
   uint16_t currentMonitoring_batterycapacity;
   uint16_t currentMonitoring_fullchargevolt;
   uint16_t currentMonitoring_tailcurrent;
@@ -255,9 +256,18 @@ struct diybms_eeprom_settings
   uint8_t canbus_equipment_addr;  // battery index on the same canbus for PYLONFORCE, 0 - 15, default 0
   char homeassist_apikey[24+1];
 
-  // State of health variables
+  /// @brief State of health variables - total lifetime mAh output (discharge)
   uint32_t soh_total_milliamphour_out;
+  /// @brief State of health variables - total lifetime mAh input (charge)
   uint32_t soh_total_milliamphour_in;
+  /// @brief State of health variables - total expected lifetime cycles of battery (6000)
+  uint16_t soh_lifetime_battery_cycles;
+  /// @brief State of health variables - estimated number of cycles
+  uint16_t soh_estimated_battery_cycles;
+  /// @brief State of health variables - discharge depth (80%)  
+  uint8_t soh_discharge_depth;
+  /// @brief Calculated percentage calculation of health 
+  float soh_percent;
 };
 
 typedef union

ESPController/src/Rules.cpp

@@ -667,7 +667,7 @@ void Rules::CalculateDynamicChargeVoltage(const diybms_eeprom_settings *mysettin
 /// @return SoC is rounded down to nearest integer and limits output range between 0 and 100.
 uint16_t Rules::StateOfChargeWithRulesApplied(const diybms_eeprom_settings *mysettings, float realSOC) const
 {
-    uint16_t value = floor(realSOC);
+    auto value = (uint16_t)floor(realSOC);
 
     // Deliberately force SoC to be reported as 2%, to trick external CANBUS devices into trickle charging (if they support it)
     if (mysettings->socforcelow)

ESPController/src/main.cpp

@@ -2821,11 +2821,11 @@ void send_ext_canbus_message(const uint32_t identifier, const uint8_t *buffer, c
     if (res == ESP_OK)
     {
       canbus_messages_received++;
-      ESP_LOGD(TAG, "CANBUS received message ID: %0x, DLC: %d, flags: %0x",
-               message.identifier, message.data_length_code, message.flags);
+      // ESP_LOGD(TAG, "CANBUS received message ID: %0x, DLC: %d, flags: %0x",message.identifier, message.data_length_code, message.flags);
+
       if (!(message.flags & TWAI_MSG_FLAG_RTR)) // we do not answer to Remote-Transmission-Requests
       {
-        //        ESP_LOG_BUFFER_HEXDUMP(TAG, message.data, message.data_length_code, ESP_LOG_DEBUG);
+        // ESP_LOG_BUFFER_HEXDUMP(TAG, message.data, message.data_length_code, ESP_LOG_DEBUG);
         if (mysettings.canbusprotocol == CanBusProtocolEmulation::CANBUS_PYLONFORCEH2)
         {
           pylonforce_handle_rx(&message);
@@ -3195,10 +3195,25 @@ void send_ext_canbus_message(const uint32_t identifier, const uint8_t *buffer, c
       // Screen off
       tftsleep();
     }
-
   }
 }
 
+void CalculateStateOfHealth(diybms_eeprom_settings *settings)
+{
+  // Value indicating what a typical discharge cycle looks like in amp-hours (normally 80% of cell for LFP)
+  float depth = 1000.0F * ((float)settings->currentMonitoring_batterycapacity/100.0F * (float)settings->soh_discharge_depth);
+  float in = (float)settings->soh_total_milliamphour_in / depth;
+  float out = (float)settings->soh_total_milliamphour_out / depth;
+  //Take worst case
+  float cycles = max(in, out);
+
+  settings->soh_percent =100-((cycles / (float)settings->soh_lifetime_battery_cycles) * 100.0F);
+
+  settings->soh_estimated_battery_cycles=(uint16_t)round(cycles);
+
+  ESP_LOGI(TAG, "State of health calc %f %, estimated cycles=%f", settings->soh_percent, cycles);
+}
+
 // Do activities which are not critical to the system like background loading of config, or updating timing results etc.
 [[noreturn]] void lazy_tasks(void *)
 {
@@ -3240,6 +3255,8 @@ void send_ext_canbus_message(const uint32_t identifier, const uint8_t *buffer, c
 
           SaveConfiguration(&mysettings);
 
+          CalculateStateOfHealth(&mysettings);
+
           // Reset the current monitor at midnight (ish)
           CurrentMonitorResetDailyAmpHourCounters();
 
@@ -3840,7 +3857,6 @@ ESP32 Chip model = %u, Rev %u, Cores=%u, Features=%u)",
   LoadConfiguration(&mysettings);
   ValidateConfiguration(&mysettings);
 
-
   if (strlen(mysettings.homeassist_apikey) == 0)
   {
     // Generate new key
@@ -3883,6 +3899,8 @@ ESP32 Chip model = %u, Rev %u, Cores=%u, Features=%u)",
       currentmon_internal.GuessSOC();
 
       currentmon_internal.TakeReadings();
+
+      CalculateStateOfHealth(&mysettings);
     }
     else
     {

ESPController/src/pylon_canbus.cpp

@@ -94,8 +94,7 @@ void pylon_message_355()
     data.stateofchargevalue = rules.StateOfChargeWithRulesApplied(&mysettings, currentMonitor.stateofcharge);
 
     //  2 SOH value un16 1 %
-    // TODO: Need to determine this based on age of battery/cycles etc.
-    data.stateofhealthvalue = 100;
+    data.stateofhealthvalue = (uint16_t)(trunc(mysettings.soh_percent));
 
     send_canbus_message(0x355, (uint8_t *)&data, sizeof(data355));
   }

ESPController/src/settings.cpp

@@ -94,6 +94,9 @@ static const char homeassist_apikey_JSONKEY[] = "homeassistapikey";
 static const char soh_total_milliamphour_out_JSONKEY[] = "soh_mah_out";
 static const char soh_total_milliamphour_in_JSONKEY[] = "soh_mah_in";
 
+static const char soh_lifetime_battery_cycles_JSONKEY[] = "soh_batcycle";
+static const char soh_discharge_depth_JSONKEY[] = "soh_disdepth";
+
 /* NVS KEYS
 THESE STRINGS ARE USED TO HOLD THE PARAMETER IN NVS FLASH, MAXIMUM LENGTH OF 16 CHARACTERS
 */
@@ -188,7 +191,8 @@ static const char homeassist_apikey_NVSKEY[] = "haapikey";
 
 static const char soh_total_milliamphour_out_NVSKEY[] = "soh_mah_out";
 static const char soh_total_milliamphour_in_NVSKEY[] = "soh_mah_in";
-
+static const char soh_lifetime_battery_cycles_NVSKEY[] = "soh_batcycle";
+static const char soh_discharge_depth_NVSKEY[] = "soh_disdepth";
 
 #define MACRO_NVSWRITE(VARNAME) writeSetting(nvs_handle, VARNAME##_NVSKEY, settings->VARNAME);
 #define MACRO_NVSWRITE_UINT8(VARNAME) writeSetting(nvs_handle, VARNAME##_NVSKEY, (uint8_t)settings->VARNAME);
@@ -455,6 +459,8 @@ void SaveConfiguration(const diybms_eeprom_settings *settings)
 
         MACRO_NVSWRITE(soh_total_milliamphour_out)
         MACRO_NVSWRITE(soh_total_milliamphour_in)
+        MACRO_NVSWRITE(soh_lifetime_battery_cycles)
+        MACRO_NVSWRITE_UINT8(soh_discharge_depth)
 
         ESP_ERROR_CHECK(nvs_commit(nvs_handle));
         nvs_close(nvs_handle);
@@ -585,8 +591,10 @@ void LoadConfiguration(diybms_eeprom_settings *settings)
 
         MACRO_NVSREADSTRING(homeassist_apikey);
 
-        MACRO_NVSREAD(soh_total_milliamphour_out);
-        MACRO_NVSREAD(soh_total_milliamphour_in);
+        MACRO_NVSREAD(soh_total_milliamphour_out)
+        MACRO_NVSREAD(soh_total_milliamphour_in)
+        MACRO_NVSREAD(soh_lifetime_battery_cycles)
+        MACRO_NVSREAD_UINT8(soh_discharge_depth)
 
         nvs_close(nvs_handle);
     }
@@ -774,6 +782,9 @@ void DefaultConfiguration(diybms_eeprom_settings *_myset)
     // State of health
     _myset->soh_total_milliamphour_out = 0;
     _myset->soh_total_milliamphour_in = 0;
+    _myset->soh_lifetime_battery_cycles = 6000;
+    _myset->soh_discharge_depth = 80;
+    _myset->soh_percent = 100.0F;
 }
 
 /// @brief Save WIFI settings into FLASH NVS
@@ -1137,6 +1148,8 @@ void GenerateSettingsJSONDocument(DynamicJsonDocument *doc, diybms_eeprom_settin
 
     root[soh_total_milliamphour_out_JSONKEY] = settings->soh_total_milliamphour_out;
     root[soh_total_milliamphour_in_JSONKEY] = settings->soh_total_milliamphour_in;
+    root[soh_lifetime_battery_cycles_JSONKEY] = settings->soh_lifetime_battery_cycles;
+    root[soh_discharge_depth_JSONKEY] = settings->soh_discharge_depth;
 }
 
 void JSONToSettings(DynamicJsonDocument &doc, diybms_eeprom_settings *settings)
@@ -1232,6 +1245,8 @@ void JSONToSettings(DynamicJsonDocument &doc, diybms_eeprom_settings *settings)
 
     settings->soh_total_milliamphour_out = root[soh_total_milliamphour_out_JSONKEY];
     settings->soh_total_milliamphour_in = root[soh_total_milliamphour_in_JSONKEY];
+    settings->soh_lifetime_battery_cycles = root[soh_lifetime_battery_cycles_JSONKEY];
+    settings->soh_discharge_depth = root[soh_discharge_depth_JSONKEY];
 
     strncpy(settings->homeassist_apikey, root[homeassist_apikey_JSONKEY].as<String>().c_str(), sizeof(settings->homeassist_apikey));
 

ESPController/src/victron_canbus.cpp

@@ -183,7 +183,7 @@ void victron_message_355()
   struct data355
   {
     uint16_t stateofchargevalue;
-    // uint16_t stateofhealthvalue;
+    uint16_t stateofhealthvalue;
     // uint16_t highresolutionsoc;
   };
 
@@ -193,7 +193,7 @@ void victron_message_355()
     // 0 SOC value un16 1 %
     data.stateofchargevalue = rules.StateOfChargeWithRulesApplied(&mysettings, currentMonitor.stateofcharge);
     // 2 SOH value un16 1 %
-    // data.stateofhealthvalue = 100;
+    data.stateofhealthvalue = (uint16_t)(trunc(mysettings.soh_percent));
 
     send_canbus_message(0x355, (uint8_t *)&data, sizeof(data355));
   }