LibreSolar · martinjaeger · Jul 29, 2024 · Jul 22, 2024 · Jul 22, 2024 · Jul 22, 2024
diff --git a/app/Kconfig b/app/Kconfig
@@ -13,37 +13,32 @@ config BAT_CAPACITY_AH
       Nominal battery capacity or sum of parallel cells capacity
 
 choice
-    prompt "Cell type"
+    prompt "Default cell type"
     default CELL_TYPE_LFP
     help
       Select the type of the single cells inside the battery
       to determine voltage set points. Total voltage set points
       are multiplied with the selected number of cells.
 
+      The default values based on this configuration can be overriden via ThingSet.
+
     config CELL_TYPE_LFP
         bool "LiFePO4, 3.3V nominal"
 
     config CELL_TYPE_NMC
         bool "NMC/Graphite, 3.7V nominal, 4.2V max"
 
-    config CELL_TYPE_NMC_HV
-        bool "NMC/Graphite High Voltage, 3.7V nominal, 4.35 max"
-
     config CELL_TYPE_LTO
         bool "NMC/Titanate, 2.4 V nominal"
 
-    config CELL_TYPE_CUSTOM
-        bool "Enable manual configuration for all customizable parameters"
 endchoice
 
 # values must match enum CellType in bms.h
 config CELL_TYPE
     int
-    default 0 if CELL_TYPE_CUSTOM
-    default 1 if CELL_TYPE_LFP
-    default 2 if CELL_TYPE_NMC
-    default 3 if CELL_TYPE_NMC_HV
-    default 4 if CELL_TYPE_LTO
+    default 0 if CELL_TYPE_LFP
+    default 1 if CELL_TYPE_NMC
+    default 2 if CELL_TYPE_LTO
 
 endmenu
 

diff --git a/app/boards/bms_16s100_sc_esp32c3.conf b/app/boards/bms_16s100_sc_esp32c3.conf
@@ -28,3 +28,4 @@ CONFIG_SHELL_CMDS_SELECT=y
 
 CONFIG_THINGSET_SHELL=y
 CONFIG_THINGSET_SHELL_REPORTING=n
+CONFIG_THINGSET_SHELL_CMD_BUF_SIZE=256
diff --git a/app/boards/bms_c1.conf b/app/boards/bms_c1.conf
@@ -38,6 +38,7 @@ CONFIG_SHELL_CMDS_SELECT=y
 
 CONFIG_THINGSET_SHELL=y
 CONFIG_THINGSET_SHELL_REPORTING=n
+CONFIG_THINGSET_SHELL_CMD_BUF_SIZE=256
 
 # DFU over CAN
 CONFIG_THINGSET_DFU=y

diff --git a/app/boards/native_sim.conf b/app/boards/native_sim.conf
@@ -28,6 +28,7 @@ CONFIG_SHELL_CMDS_SELECT=y
 
 CONFIG_THINGSET_SHELL=y
 CONFIG_THINGSET_SHELL_REPORTING=n
+CONFIG_THINGSET_SHELL_CMD_BUF_SIZE=256
 
 CONFIG_EMUL=y
 CONFIG_EEPROM=y

diff --git a/app/prj.conf b/app/prj.conf
@@ -29,5 +29,5 @@ CONFIG_THINGSET_NODE_NAME="Libre Solar BMS"
 # Change default battery nominal capacity (in Ah)
 #CONFIG_BAT_CAPACITY_AH=?
 
-# Select cell type for initial configuration: LFP (default), NMC, NMC_HV, LTO or CUSTOM
+# Select cell type for initial configuration: LFP (default), NMC or LTO
 #CONFIG_CELL_TYPE_???=y
diff --git a/app/src/bms_common.c b/app/src/bms_common.c
@@ -13,21 +13,30 @@
 
 LOG_MODULE_REGISTER(bms, CONFIG_LOG_DEFAULT_LEVEL);
 
-static float ocv_lfp[OCV_POINTS] = { 3.392F, 3.314F, 3.309F, 3.308F, 3.304F, 3.296F, 3.283F,
-                                     3.275F, 3.271F, 3.268F, 3.265F, 3.264F, 3.262F, 3.252F,
-                                     3.240F, 3.226F, 3.213F, 3.190F, 3.177F, 3.132F, 2.833F };
-
-static float ocv_nmc[OCV_POINTS] = { 4.198F, 4.135F, 4.089F, 4.056F, 4.026F, 3.993F, 3.962F,
-                                     3.924F, 3.883F, 3.858F, 3.838F, 3.819F, 3.803F, 3.787F,
-                                     3.764F, 3.745F, 3.726F, 3.702F, 3.684F, 3.588F, 2.800F };
-
-float ocv_custom[OCV_POINTS] = { 0 };
-
-static float soc_pct[OCV_POINTS] = { 100.0F, 95.0F, 90.0F, 85.0F, 80.0F, 85.0F, 70.0F,
-                                     65.0F,  60.0F, 55.0F, 50.0F, 45.0F, 40.0F, 35.0F,
-                                     30.0F,  25.0F, 20.0F, 15.0F, 10.0F, 5.0F,  0.0F };
-
-float soc_custom[OCV_POINTS] = { 0 };
+static const float ocv_lfp[NUM_OCV_POINTS] = {
+    3.392F, 3.314F, 3.309F, 3.308F, 3.304F, 3.296F, 3.283F, 3.275F, 3.271F, 3.268F, 3.265F,
+    3.264F, 3.262F, 3.252F, 3.240F, 3.226F, 3.213F, 3.190F, 3.177F, 3.132F, 2.833F,
+};
+
+static const float ocv_nmc[NUM_OCV_POINTS] = {
+    4.198F, 4.135F, 4.089F, 4.056F, 4.026F, 3.993F, 3.962F, 3.924F, 3.883F, 3.858F, 3.838F,
+    3.819F, 3.803F, 3.787F, 3.764F, 3.745F, 3.726F, 3.702F, 3.684F, 3.588F, 2.800F,
+};
+
+// Source: DOI:10.3390/batteries5010031 (https://www.mdpi.com/2313-0105/5/1/31)
+static const float ocv_lto[NUM_OCV_POINTS] = {
+    2.800F, 2.513F, 2.458F, 2.415F, 2.376F, 2.340F, 2.309F, 2.282F, 2.259F, 2.240F, 2.224F,
+    2.210F, 2.198F, 2.187F, 2.177F, 2.166F, 2.154F, 2.141F, 2.125F, 2.105F, 2.000F,
+};
+
+static const float soc_default[NUM_OCV_POINTS] = {
+    100.0F, 95.0F, 90.0F, 85.0F, 80.0F, 85.0F, 70.0F, 65.0F, 60.0F, 55.0F, 50.0F,
+    45.0F,  40.0F, 35.0F, 30.0F, 25.0F, 20.0F, 15.0F, 10.0F, 5.0F,  0.0F,
+};
+
+// actually used OCV vs. SOC curve
+float ocv_points[NUM_OCV_POINTS] = { 0 };
+float soc_points[NUM_OCV_POINTS] = { 0 };
 
 void bms_init_config(struct bms_context *bms, enum bms_cell_type type, float nominal_capacity_Ah)
 {
@@ -61,6 +70,11 @@ void bms_init_config(struct bms_context *bms, enum bms_cell_type type, float nom
     bms->ic_conf.cell_ov_delay_ms = 2000;
     bms->ic_conf.cell_uv_delay_ms = 2000;
 
+    bms->ocv_points = ocv_points;
+    bms->soc_points = soc_points;
+
+    memcpy(soc_points, soc_default, sizeof(soc_points));
+
     switch (type) {
         case CELL_TYPE_LFP:
             bms->ic_conf.cell_ov_limit = 3.80F;
@@ -74,8 +88,7 @@ void bms_init_config(struct bms_context *bms, enum bms_cell_type type, float nom
              * self-discharge
              */
             bms->ic_conf.cell_uv_limit = 2.50F;
-            bms->ocv_points = ocv_lfp;
-            bms->soc_points = soc_pct;
+            memcpy(ocv_points, ocv_lfp, sizeof(ocv_points));
             break;
         case CELL_TYPE_NMC:
             bms->ic_conf.cell_ov_limit = 4.25F;
@@ -85,8 +98,7 @@ void bms_init_config(struct bms_context *bms, enum bms_cell_type type, float nom
             bms->ic_conf.cell_uv_reset = 3.50F;
             bms->ic_conf.cell_dis_voltage_limit = 3.20F;
             bms->ic_conf.cell_uv_limit = 3.00F;
-            bms->ocv_points = ocv_nmc;
-            bms->soc_points = soc_pct;
+            memcpy(ocv_points, ocv_nmc, sizeof(ocv_points));
             break;
         case CELL_TYPE_LTO:
             bms->ic_conf.cell_ov_limit = 2.85F;
@@ -96,13 +108,7 @@ void bms_init_config(struct bms_context *bms, enum bms_cell_type type, float nom
             bms->ic_conf.cell_uv_reset = 2.10F;
             bms->ic_conf.cell_dis_voltage_limit = 2.00F;
             bms->ic_conf.cell_uv_limit = 1.90F;
-            // ToDo: Use typical OCV curve for LTO cells
-            bms->ocv_points = NULL;
-            bms->soc_points = NULL;
-            break;
-        case CELL_TYPE_CUSTOM:
-            bms->ocv_points = ocv_custom;
-            bms->soc_points = soc_custom;
+            memcpy(ocv_points, ocv_lto, sizeof(ocv_points));
             break;
     }
 

diff --git a/app/src/bms_soc.c b/app/src/bms_soc.c
@@ -14,11 +14,11 @@ void bms_soc_reset(struct bms_context *bms, int percent)
         bms->soc = percent;
     }
     else if (bms->ocv_points != NULL && bms->soc_points != NULL
-             && !is_empty((uint8_t *)bms->ocv_points, OCV_POINTS)
-             && !is_empty((uint8_t *)bms->soc_points, OCV_POINTS))
+             && !is_empty((uint8_t *)bms->ocv_points, NUM_OCV_POINTS)
+             && !is_empty((uint8_t *)bms->soc_points, NUM_OCV_POINTS))
     {
         // Executes if both OCV and SOC points are valid pointers and arrays contain non-zero data.
-        bms->soc = interpolate(bms->ocv_points, bms->soc_points, OCV_POINTS,
+        bms->soc = interpolate(bms->ocv_points, bms->soc_points, NUM_OCV_POINTS,
                                bms->ic_data.cell_voltage_avg);
     }
     else {

diff --git a/app/src/data_objects.c b/app/src/data_objects.c
@@ -20,8 +20,8 @@
 #include <stdio.h>
 
 extern struct bms_context bms;
-extern float ocv_custom[OCV_POINTS];
-extern float soc_custom[OCV_POINTS];
+extern float ocv_points[NUM_OCV_POINTS];
+extern float soc_points[NUM_OCV_POINTS];
 
 static char manufacturer[] = "Libre Solar";
 static char device_type[] = DT_PROP(DT_PATH(pcb), type);
@@ -35,9 +35,9 @@ static THINGSET_DEFINE_FLOAT_ARRAY(cell_voltages_arr, 3, bms.ic_data.cell_voltag
 static THINGSET_DEFINE_FLOAT_ARRAY(cell_temps_arr, 1, bms.ic_data.cell_temps,
                                    ARRAY_SIZE(bms.ic_data.cell_temps));
 
-static THINGSET_DEFINE_FLOAT_ARRAY(ocv_points_arr, 3, ocv_custom, ARRAY_SIZE(ocv_custom));
+static THINGSET_DEFINE_FLOAT_ARRAY(ocv_points_arr, 3, ocv_points, ARRAY_SIZE(ocv_points));
 
-static THINGSET_DEFINE_FLOAT_ARRAY(soc_points_arr, 1, soc_custom, ARRAY_SIZE(soc_custom));
+static THINGSET_DEFINE_FLOAT_ARRAY(soc_points_arr, 1, soc_points, ARRAY_SIZE(soc_points));
 
 // used for xInitConf functions
 static float new_capacity = 0;
@@ -188,6 +188,11 @@ THINGSET_ADD_FN_INT32(APP_ID_CONF, APP_ID_CONF_PRESET_LFP, "xPresetLFP", &bat_pr
 THINGSET_ADD_ITEM_FLOAT(APP_ID_CONF_PRESET_LFP, APP_ID_CONF_PRESET_LFP_CAPACITY, "fCapacity_Ah",
                         &new_capacity, 1, THINGSET_ANY_RW, 0);
 
+THINGSET_ADD_FN_INT32(APP_ID_CONF, APP_ID_CONF_PRESET_LTO, "xPresetLTO", &bat_preset_lto,
+                      THINGSET_ANY_RW);
+THINGSET_ADD_ITEM_FLOAT(APP_ID_CONF_PRESET_LTO, APP_ID_CONF_PRESET_LTO_CAPACITY, "fCapacity_Ah",
+                        &new_capacity, 1, THINGSET_ANY_RW, 0);
+
 // MEAS DATA ////////////////////////////////////////////////////////////
 
 THINGSET_ADD_GROUP(TS_ID_ROOT, APP_ID_MEAS, "Meas", THINGSET_NO_CALLBACK);
@@ -280,7 +285,9 @@ int32_t bat_preset(enum bms_cell_type type)
     }
 #endif
 
-    return ret;
+    // Always return 1 in case of success, as the flags returned by bms_ic_configure can be
+    // confusing for end users in the App. Actually applied config can be retrieved via ThingSet.
+    return ret > 0 ? 1 : ret;
 }
 
 int32_t bat_preset_nmc()
@@ -293,6 +300,11 @@ int32_t bat_preset_lfp()
     return bat_preset(CELL_TYPE_LFP);
 }
 
+int32_t bat_preset_lto()
+{
+    return bat_preset(CELL_TYPE_LTO);
+}
+
 void print_registers()
 {
     bms_ic_debug_print_mem(bms.ic_dev);

diff --git a/app/src/data_objects.h b/app/src/data_objects.h
@@ -62,6 +62,8 @@
 #define APP_ID_CONF_PRESET_NMC_CAPACITY     0xA1
 #define APP_ID_CONF_PRESET_LFP              0xA2
 #define APP_ID_CONF_PRESET_LFP_CAPACITY     0xA3
+#define APP_ID_CONF_PRESET_LTO              0xA4
+#define APP_ID_CONF_PRESET_LTO_CAPACITY     0xA5
 #define APP_ID_CONF_OCV_POINTS              0xB0
 #define APP_ID_CONF_SOC_POINTS              0xB1
 
@@ -103,6 +105,11 @@ int32_t bat_preset_nmc();
  */
 int32_t bat_preset_lfp();
 
+/**
+ * Callback function to apply preset parameters for LTO type via ThingSet
+ */
+int32_t bat_preset_lto();
+
 /**
  * Callback to read and print common BMS registers via ThingSet
  */

diff --git a/docs/src/features.rst b/docs/src/features.rst
@@ -22,7 +22,7 @@ Amongst all features inherited from underlying Zephyr, the BMS has the following
 
   - Pack layout
 
-    - Cell chemistry (LiFePO4, NMC, NCA)
+    - Cell chemistry (e.g. LiFePO4, NMC, NCA, LTO)
     - Nominal capacity
     - Number of cells
     - Thermistor type

diff --git a/include/bms/bms.h b/include/bms/bms.h
@@ -24,7 +24,7 @@ extern "C" {
 #include <stdint.h>
 
 /* fixed number of OCV vs. SOC points */
-#define OCV_POINTS 21
+#define NUM_OCV_POINTS 21
 
 /**
  * Possible BMS states
@@ -43,10 +43,9 @@ enum bms_state
  */
 enum bms_cell_type
 {
-    CELL_TYPE_CUSTOM = 0, ///< Custom settings
-    CELL_TYPE_LFP,        ///< LiFePO4 Li-ion cells (3.3 V nominal)
-    CELL_TYPE_NMC,        ///< NMC/Graphite Li-ion cells (3.7 V nominal)
-    CELL_TYPE_LTO         ///< NMC/Titanate (2.4 V nominal)
+    CELL_TYPE_LFP, ///< LiFePO4 Li-ion cells (3.3 V nominal)
+    CELL_TYPE_NMC, ///< NMC/Graphite Li-ion cells (3.7 V nominal)
+    CELL_TYPE_LTO, ///< NMC/Titanate (2.4 V nominal)
 };
 
 /**
Original file line number	Diff line number	Diff line change
Expand Up		@@ -28,3 +28,4 @@ CONFIG_SHELL_CMDS_SELECT=y

		CONFIG_THINGSET_SHELL=y
		CONFIG_THINGSET_SHELL_REPORTING=n
		CONFIG_THINGSET_SHELL_CMD_BUF_SIZE=256