Change logic of state of health calculation

ESPController/include/defines.h

@@ -264,10 +264,10 @@ struct diybms_eeprom_settings
   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 - expected remaining capacity (%) at end of life/max cycles
+  uint8_t soh_eol_capacity;
   /// @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;
+  uint16_t soh_estimated_battery_cycles;  
   /// @brief Calculated percentage calculation of health 
   float soh_percent;
 };

ESPController/src/main.cpp

@@ -3220,17 +3220,16 @@ void send_ext_canbus_message(const uint32_t identifier, const uint8_t *buffer, c
 
 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->nominalbatcap / 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 batcap_mah = 1000.0F * settings->nominalbatcap;
+  float in = (float)settings->soh_total_milliamphour_in / batcap_mah;
+  float out = (float)settings->soh_total_milliamphour_out / batcap_mah;
+  // Take worst case number of cycles
   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);
 
+  settings->soh_percent = 100.0F - ((100.0F - settings->soh_eol_capacity) * (cycles / (float)settings->soh_lifetime_battery_cycles));
+
   ESP_LOGI(TAG, "State of health calc %f %, estimated cycles=%f", settings->soh_percent, cycles);
 }
 
@@ -3921,15 +3920,13 @@ ESP32 Chip model = %u, Rev %u, Cores=%u, Features=%u)",
 
       uint32_t in;
       uint32_t out;
-      if (GetStateOfCharge(&in,&out))
+      if (GetStateOfCharge(&in, &out))
       {
-        currentmon_internal.SetSOCByMilliAmpCounter(in,out);
+        currentmon_internal.SetSOCByMilliAmpCounter(in, out);
       }
 
       currentmon_internal.TakeReadings();
 
-
-
       CalculateStateOfHealth(&mysettings);
     }
     else
@@ -4242,11 +4239,15 @@ void loop()
     // Report again in 60 seconds
     heaptimer = currentMillis + 60000;
 
-    //Once per minute, store the state of charge into flash, just in case the controller is rebooted and we can restore this value
-    //on power up.
+    // Once per minute, store the state of charge into flash, just in case the controller is rebooted and we can restore this value
+    // on power up.
     if (mysettings.currentMonitoringEnabled && mysettings.currentMonitoringDevice == CurrentMonitorDevice::DIYBMS_CURRENT_MON_INTERNAL)
     {
-      SaveStateOfCharge(currentmon_internal.raw_milliamphour_in(),currentmon_internal.raw_milliamphour_out());
+      // Avoid writing zero SoC into flash
+      if (currentmon_internal.calc_state_of_charge() > 1.0F)
+      {
+        SaveStateOfCharge(currentmon_internal.raw_milliamphour_in(), currentmon_internal.raw_milliamphour_out());
+      }
     }
   }
 }

ESPController/src/settings.cpp

@@ -95,7 +95,10 @@ 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";
+
+static const char soh_eol_capacity_JSONKEY[] = "soh_eol_capacity";
+
+
 
 /* NVS KEYS
 THESE STRINGS ARE USED TO HOLD THE PARAMETER IN NVS FLASH, MAXIMUM LENGTH OF 16 CHARACTERS
@@ -192,7 +195,7 @@ 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";
+static const char soh_eol_capacity_NVSKEY[] = "soh_eol_cap";
 
 static const char soc_milliamphour_out_NVSKEY[] = "soc_mah_out";
 static const char soc_milliamphour_in_NVSKEY[] = "soc_mah_in";
@@ -523,7 +526,7 @@ 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)
+        MACRO_NVSWRITE_UINT8(soh_eol_capacity)
 
         ESP_ERROR_CHECK(nvs_commit(nvs_handle));
         nvs_close(nvs_handle);
@@ -659,8 +662,7 @@ void LoadConfiguration(diybms_eeprom_settings *settings)
         MACRO_NVSREAD(soh_total_milliamphour_out)
         MACRO_NVSREAD(soh_total_milliamphour_in)
         MACRO_NVSREAD(soh_lifetime_battery_cycles)
-        MACRO_NVSREAD_UINT8(soh_discharge_depth)
-
+        MACRO_NVSREAD_UINT8(soh_eol_capacity)
         nvs_close(nvs_handle);
     }
 
@@ -848,7 +850,7 @@ void DefaultConfiguration(diybms_eeprom_settings *_myset)
     _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_eol_capacity = 80;
     _myset->soh_percent = 100.0F;
 }
 
@@ -1064,11 +1066,6 @@ void ValidateConfiguration(diybms_eeprom_settings *settings)
     {
         settings->stateofchargeresumevalue = settings->stateofchargeresumevalue;
     }
-
-    if (settings->soh_discharge_depth == 0 || settings->soh_discharge_depth > 100)
-    {
-        settings->soh_discharge_depth = 80;
-    }
 }
 
 // Builds up a JSON document which mirrors the parameters inside "diybms_eeprom_settings"
@@ -1222,7 +1219,8 @@ void GenerateSettingsJSONDocument(JsonDocument &doc, diybms_eeprom_settings *set
     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;
+    root[soh_eol_capacity_JSONKEY] = settings->soh_eol_capacity;
+
 }
 
 void JSONToSettings(JsonDocument &doc, diybms_eeprom_settings *settings)
@@ -1319,7 +1317,8 @@ void JSONToSettings(JsonDocument &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];
+    settings->soh_eol_capacity=root[soh_eol_capacity_JSONKEY];
+
 
     strncpy(settings->homeassist_apikey, root[homeassist_apikey_JSONKEY].as<String>().c_str(), sizeof(settings->homeassist_apikey));
 

ESPController/src/webserver_json_post.cpp

@@ -579,7 +579,7 @@ esp_err_t post_savechargeconfig_json_handler(httpd_req_t *req, bool urlEncoded)
     }
 
     GetKeyValue(httpbuf, "expected_cycles", &mysettings.soh_lifetime_battery_cycles, urlEncoded);
-    GetKeyValue(httpbuf, "dischargedepth", &mysettings.soh_discharge_depth, urlEncoded);
+    GetKeyValue(httpbuf, "eol_capacity", &mysettings.soh_eol_capacity, urlEncoded);
 
     if (GetKeyValue(httpbuf, "total_ah_discharge", &mysettings.soh_total_milliamphour_out, urlEncoded))
     {

ESPController/src/webserver_json_requests.cpp

@@ -605,8 +605,8 @@ esp_err_t content_handler_chargeconfig(httpd_req_t *req)
   settings["equip_addr"] = mysettings.canbus_equipment_addr;
   settings["nominalbatcap"] = mysettings.nominalbatcap;
 
-  settings["dischargedepth"] = mysettings.soh_discharge_depth;
   settings["expectedlifetime_cycles"] = mysettings.soh_lifetime_battery_cycles;
+  settings["eol_capacity"] = mysettings.soh_eol_capacity;
   settings["total_mah_charge"] = mysettings.soh_total_milliamphour_in;
   settings["total_mah_discharge"] = mysettings.soh_total_milliamphour_out;
   settings["estimatebatterycycle"] = mysettings.soh_estimated_battery_cycles;

ESPController/web_src/default.htm

@@ -1035,13 +1035,15 @@ <h1 id="v0">Charge/Discharge configuration</h1>
             <label for="nominalbatcap">Nominal Battery Capacity (Amp-hours)</label>
             <input id="nominalbatcap" name="nominalbatcap" value="" type="number" min="1" max="9999" step="1" />
           </div>
+          <p>State of Health</p>
+
           <div>
-            <label for="expected_cycles">Expected battery lifetime/cycles (at DOD)</label>
+            <label for="expected_cycles">Expected battery lifetime/cycles</label>
             <input id="expected_cycles" name="expected_cycles" value="" type="number" min="100" max="99999" step="1" />
           </div>
           <div>
-            <label for="dischargedepth">Discharge depth %% (DOD)</label>
-            <input id="dischargedepth" name="dischargedepth" value="" type="number" min="10" max="100" step="1" />
+            <label for="eol_capacity">End of life capacity (%%)</label>
+            <input id="eol_capacity" name="eol_capacity" value="" type="number" min="10" max="100" step="1" />
           </div>
           <div>
             <label for="total_ah_charge">Lifetime amp-hours charge (in)</label>

ESPController/web_src/pagecode.js

@@ -2004,7 +2004,7 @@ $(function () {
                 $("#nominalbatcap").val(data.chargeconfig.nominalbatcap);
 
                 $("#expected_cycles").val(data.chargeconfig.expectedlifetime_cycles);
-                $("#dischargedepth").val(data.chargeconfig.dischargedepth);
+                $("#eol_capacity").val(data.chargeconfig.eol_capacity);
                 $("#total_ah_charge").val(Math.trunc(data.chargeconfig.total_mah_charge / 1000));
                 $("#total_ah_discharge").val(Math.trunc(data.chargeconfig.total_mah_discharge / 1000));
                 $("#estimate_bat_cycle").val(data.chargeconfig.estimatebatterycycle);