From 0018c4349c7a1cadea4ff6a9c2dea37ad9ae7b46 Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Sat, 21 Feb 2026 15:34:41 -0600
Subject: [PATCH 01/12] Handle BMS cell probe disconnects and sanitize temps

Detect and handle disconnected BMS cell temperature probes by treating known disconnected sentinel values as NaN. Add helpers (isBmsCellTempValidC, sanitizeBmsCellTempC) and constants to inc/sp140/bms.h, update telemetry struct comments to indicate NaN semantics, and sanitize raw cell temps in updateBMSData. Recompute highest/lowest temperature extrema from valid readings and log probe connection/disconnection transitions. Update BLE temperature characteristic to include a valid-sensor bitmap and send 0 for invalid sensors. Update LVGL main screen to compute battery temperature using only valid cell probes and only display it when a valid reading exists.
---
 inc/sp140/bms.h                 | 12 +++++
 inc/sp140/structs.h             | 12 ++---
 src/sp140/ble/bms_service.cpp   | 30 ++++++++----
 src/sp140/bms.cpp               | 87 ++++++++++++++++++++++++++++++---
 src/sp140/lvgl/lvgl_updates.cpp | 26 +++++++---
 5 files changed, 137 insertions(+), 30 deletions(-)

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index fcde6e9a..9da4145a 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -10,6 +10,18 @@
 #define MCP_CS 5        // MCP2515 CS pin
 #define MCP_BAUDRATE 250000
 
+// BMS cell probe disconnect handling
+constexpr float BMS_CELL_TEMP_DISCONNECTED_C = -40.0f;
+constexpr float BMS_CELL_TEMP_DISCONNECT_THRESHOLD_C = BMS_CELL_TEMP_DISCONNECTED_C + 0.5f;
+
+inline bool isBmsCellTempValidC(float tempC) {
+  return !isnan(tempC) && tempC > BMS_CELL_TEMP_DISCONNECT_THRESHOLD_C;
+}
+
+inline float sanitizeBmsCellTempC(float tempC) {
+  return isBmsCellTempValidC(tempC) ? tempC : NAN;
+}
+
 // External declarations
 extern STR_BMS_TELEMETRY_140 bmsTelemetryData;
 extern BMS_CAN* bms_can;
diff --git a/inc/sp140/structs.h b/inc/sp140/structs.h
index 29715c09..043ac821 100644
--- a/inc/sp140/structs.h
+++ b/inc/sp140/structs.h
@@ -76,8 +76,8 @@ typedef struct {
   float power;                  // Power (kW)
   float highest_cell_voltage;   // Highest individual cell voltage (V)
   float lowest_cell_voltage;    // Lowest individual cell voltage (V)
-  float highest_temperature;    // Highest temperature reading (°C)
-  float lowest_temperature;     // Lowest temperature reading (°C)
+  float highest_temperature;    // Highest valid temperature reading (°C), NaN if unavailable
+  float lowest_temperature;     // Lowest valid temperature reading (°C), NaN if unavailable
   float energy_cycle;          // Energy per cycle (kWh)
   uint32_t battery_cycle;      // Battery cycle count
   uint8_t battery_fail_level;  // Battery failure status
@@ -92,10 +92,10 @@ typedef struct {
   // Individual temperature sensors
   float mos_temperature;        // BMS MOSFET temperature (°C) - index 0
   float balance_temperature;    // BMS balance resistor temperature (°C) - index 1
-  float t1_temperature;         // T1 cell temperature sensor (°C) - index 2
-  float t2_temperature;         // T2 cell temperature sensor (°C) - index 3
-  float t3_temperature;         // T3 cell temperature sensor (°C) - index 4
-  float t4_temperature;         // T4 cell temperature sensor (°C) - index 5
+  float t1_temperature;         // T1 cell temperature sensor (°C), NaN if disconnected - index 2
+  float t2_temperature;         // T2 cell temperature sensor (°C), NaN if disconnected - index 3
+  float t3_temperature;         // T3 cell temperature sensor (°C), NaN if disconnected - index 4
+  float t4_temperature;         // T4 cell temperature sensor (°C), NaN if disconnected - index 5
 } STR_BMS_TELEMETRY_140;
 #pragma pack(pop)
 
diff --git a/src/sp140/ble/bms_service.cpp b/src/sp140/ble/bms_service.cpp
index 4478473f..7929db10 100644
--- a/src/sp140/ble/bms_service.cpp
+++ b/src/sp140/ble/bms_service.cpp
@@ -199,19 +199,29 @@ void updateBMSTelemetry(const STR_BMS_TELEMETRY_140& telemetry) {
   // Sensor mapping: [0]=MOS, [1]=Balance, [2]=T1, [3]=T2, [4]=T3, [5]=T4, [6-7]=Reserved
   if (pBMSTemperatures) {
     uint8_t temp_buffer[17];
-
-    // Byte 0: Valid sensor bitmap (bit N = sensor N is valid)
-    // 0b00111111 = sensors 0-5 valid (6 temperature sensors)
-    temp_buffer[0] = 0b00111111;
+    uint8_t validBitmap = 0;
 
     // Bytes 1-16: 8×int16_t temperatures in deci-degrees C (0.1°C resolution)
     int16_t* temps = reinterpret_cast<int16_t*>(&temp_buffer[1]);
-    temps[0] = static_cast<int16_t>(telemetry.mos_temperature * 10.0f);      // [0] MOS
-    temps[1] = static_cast<int16_t>(telemetry.balance_temperature * 10.0f);  // [1] Balance
-    temps[2] = static_cast<int16_t>(telemetry.t1_temperature * 10.0f);       // [2] T1
-    temps[3] = static_cast<int16_t>(telemetry.t2_temperature * 10.0f);       // [3] T2
-    temps[4] = static_cast<int16_t>(telemetry.t3_temperature * 10.0f);       // [4] T3
-    temps[5] = static_cast<int16_t>(telemetry.t4_temperature * 10.0f);       // [5] T4
+    const float sensorTemps[6] = {
+      telemetry.mos_temperature,
+      telemetry.balance_temperature,
+      telemetry.t1_temperature,
+      telemetry.t2_temperature,
+      telemetry.t3_temperature,
+      telemetry.t4_temperature
+    };
+
+    for (uint8_t i = 0; i < 6; i++) {
+      bool isValid = !isnan(sensorTemps[i]);
+
+      if (isValid) {
+        validBitmap |= static_cast<uint8_t>(1U << i);
+      }
+      temps[i] = isValid ? static_cast<int16_t>(sensorTemps[i] * 10.0f) : 0;
+    }
+
+    temp_buffer[0] = validBitmap;
     temps[6] = 0;  // [6] Reserved
     temps[7] = 0;  // [7] Reserved
 
diff --git a/src/sp140/bms.cpp b/src/sp140/bms.cpp
index 768bf71a..0b660471 100644
--- a/src/sp140/bms.cpp
+++ b/src/sp140/bms.cpp
@@ -3,6 +3,70 @@
 #include "sp140/globals.h"
 #include "sp140/lvgl/lvgl_core.h"  // for spiBusMutex
 
+namespace {
+
+constexpr uint8_t kBmsCellProbeCount = 4;
+
+void logBmsCellProbeConnectionTransitions(const float rawCellTemps[kBmsCellProbeCount]) {
+  static bool hasPreviousState = false;
+  static bool wasConnected[kBmsCellProbeCount] = {false, false, false, false};
+
+  for (uint8_t i = 0; i < kBmsCellProbeCount; i++) {
+    const bool connected = isBmsCellTempValidC(rawCellTemps[i]);
+
+    if (!hasPreviousState) {
+      wasConnected[i] = connected;
+      continue;
+    }
+
+    if (connected != wasConnected[i]) {
+      USBSerial.printf("[BMS] T%u sensor %s (raw=%.1fC)\n",
+                       i + 1,
+                       connected ? "reconnected" : "disconnected",
+                       rawCellTemps[i]);
+      wasConnected[i] = connected;
+    }
+  }
+
+  hasPreviousState = true;
+}
+
+void recomputeBmsTemperatureExtrema(STR_BMS_TELEMETRY_140& telemetry) {  // NOLINT(runtime/references)
+  const float allTemps[] = {
+    telemetry.mos_temperature,
+    telemetry.balance_temperature,
+    telemetry.t1_temperature,
+    telemetry.t2_temperature,
+    telemetry.t3_temperature,
+    telemetry.t4_temperature
+  };
+
+  bool hasValidReading = false;
+  float highest = NAN;
+  float lowest = NAN;
+
+  for (float temp : allTemps) {
+    if (isnan(temp)) {
+      continue;
+    }
+
+    if (!hasValidReading) {
+      highest = temp;
+      lowest = temp;
+      hasValidReading = true;
+      continue;
+    }
+
+    if (temp > highest) highest = temp;
+    if (temp < lowest) lowest = temp;
+  }
+
+  telemetry.highest_temperature = highest;
+  telemetry.lowest_temperature = lowest;
+}
+
+}  // namespace
+
 STR_BMS_TELEMETRY_140 bmsTelemetryData = {
   .bmsState = TelemetryState::NOT_CONNECTED
 };
@@ -51,10 +115,6 @@ void updateBMSData() {
   // Calculated highest cell minus lowest cell voltage
   bmsTelemetryData.voltage_differential = bms_can->getHighestCellVoltage() - bms_can->getLowestCellVoltage();
 
-  // Temperature readings
-  bmsTelemetryData.highest_temperature = bms_can->getHighestTemperature();
-  bmsTelemetryData.lowest_temperature = bms_can->getLowestTemperature();
-
   // Battery statistics
   bmsTelemetryData.battery_cycle = bms_can->getBatteryCycle();
   bmsTelemetryData.energy_cycle = bms_can->getEnergyCycle();
@@ -73,10 +133,21 @@ void updateBMSData() {
   // Populate individual temperature sensors
   bmsTelemetryData.mos_temperature = bms_can->getTemperature(0);      // BMS MOSFET
   bmsTelemetryData.balance_temperature = bms_can->getTemperature(1);  // BMS Balance resistors
-  bmsTelemetryData.t1_temperature = bms_can->getTemperature(2);       // Cell probe 1
-  bmsTelemetryData.t2_temperature = bms_can->getTemperature(3);       // Cell probe 2
-  bmsTelemetryData.t3_temperature = bms_can->getTemperature(4);       // Cell probe 3
-  bmsTelemetryData.t4_temperature = bms_can->getTemperature(5);       // Cell probe 4
+
+  const float rawCellTemps[kBmsCellProbeCount] = {
+    bms_can->getTemperature(2),
+    bms_can->getTemperature(3),
+    bms_can->getTemperature(4),
+    bms_can->getTemperature(5)
+  };
+
+  bmsTelemetryData.t1_temperature = sanitizeBmsCellTempC(rawCellTemps[0]);  // Cell probe 1
+  bmsTelemetryData.t2_temperature = sanitizeBmsCellTempC(rawCellTemps[1]);  // Cell probe 2
+  bmsTelemetryData.t3_temperature = sanitizeBmsCellTempC(rawCellTemps[2]);  // Cell probe 3
+  bmsTelemetryData.t4_temperature = sanitizeBmsCellTempC(rawCellTemps[3]);  // Cell probe 4
+
+  logBmsCellProbeConnectionTransitions(rawCellTemps);
+  recomputeBmsTemperatureExtrema(bmsTelemetryData);
 
   bmsTelemetryData.lastUpdateMs = millis();
   unsigned long dur = bmsTelemetryData.lastUpdateMs - tStart;
diff --git a/src/sp140/lvgl/lvgl_updates.cpp b/src/sp140/lvgl/lvgl_updates.cpp
index 8897c670..35e3eada 100644
--- a/src/sp140/lvgl/lvgl_updates.cpp
+++ b/src/sp140/lvgl/lvgl_updates.cpp
@@ -334,11 +334,25 @@ void updateLvglMainScreen(
   float batteryPercent = unifiedBatteryData.soc;
   float totalVolts = unifiedBatteryData.volts;
   float lowestCellV = bmsTelemetry.lowest_cell_voltage;
-  // Calculate highest cell temperature from T1-T4 only (excluding MOSFET and balance temps)
-  float batteryTemp = bmsTelemetry.t1_temperature;
-  if (bmsTelemetry.t2_temperature > batteryTemp) batteryTemp = bmsTelemetry.t2_temperature;
-  if (bmsTelemetry.t3_temperature > batteryTemp) batteryTemp = bmsTelemetry.t3_temperature;
-  if (bmsTelemetry.t4_temperature > batteryTemp) batteryTemp = bmsTelemetry.t4_temperature;
+  // Calculate battery temp from connected T1-T4 cell probes only.
+  const float cellTemps[] = {
+    bmsTelemetry.t1_temperature,
+    bmsTelemetry.t2_temperature,
+    bmsTelemetry.t3_temperature,
+    bmsTelemetry.t4_temperature
+  };
+  float batteryTemp = NAN;
+  bool hasValidBatteryTemp = false;
+  for (float cellTemp : cellTemps) {
+    if (!isBmsCellTempValidC(cellTemp)) {
+      continue;
+    }
+
+    if (!hasValidBatteryTemp || cellTemp > batteryTemp) {
+      batteryTemp = cellTemp;
+      hasValidBatteryTemp = true;
+    }
+  }
   float escTemp = escTelemetry.cap_temp;
   float motorTemp = escTelemetry.motor_temp;
   // Check if BMS or ESC is connected
@@ -660,7 +674,7 @@ void updateLvglMainScreen(
     lv_obj_remove_style(batt_temp_bg, &style_warning, 0);
     lv_obj_remove_style(batt_temp_bg, &style_critical, 0);
 
-    if (bmsTelemetry.bmsState == TelemetryState::CONNECTED) {
+    if (bmsTelemetry.bmsState == TelemetryState::CONNECTED && hasValidBatteryTemp) {
       lv_label_set_text_fmt(batt_temp_label, "%d", static_cast<int>(batteryTemp));
       if (batteryTemp >= bmsCellTempThresholds.critHigh) {
         lv_obj_add_style(batt_temp_bg, &style_critical, 0);

From ba0883874395881a7f053108754d876827430e4c Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Sat, 21 Feb 2026 15:41:41 -0600
Subject: [PATCH 02/12] Sanitize BMS cell temps; add tests and stubs

Inline BMS cell temperature validity into sanitizeBmsCellTempC and update call sites to use the sanitizer (and isnan checks) to treat disconnected probes as NaN. Update lvgl and bms logic to rely on sanitized values. Add unit tests covering sanitizer behavior and monitor handling of disconnected BMS probes, and include native test stubs for BMS_CAN and SPI. This centralizes validity logic and ensures disconnected readings are ignored consistently.
---
 inc/sp140/bms.h                               |  7 +--
 src/sp140/bms.cpp                             |  2 +-
 src/sp140/lvgl/lvgl_updates.cpp               |  7 ++-
 test/native_stubs/BMS_CAN.h                   |  3 +
 test/native_stubs/SPI.h                       |  3 +
 .../test_simplemonitor/test_simplemonitor.cpp | 62 +++++++++++++++++++
 6 files changed, 74 insertions(+), 10 deletions(-)
 create mode 100644 test/native_stubs/BMS_CAN.h
 create mode 100644 test/native_stubs/SPI.h

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index 9da4145a..a861af43 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -12,14 +12,9 @@
 
 // BMS cell probe disconnect handling
 constexpr float BMS_CELL_TEMP_DISCONNECTED_C = -40.0f;
-constexpr float BMS_CELL_TEMP_DISCONNECT_THRESHOLD_C = BMS_CELL_TEMP_DISCONNECTED_C + 0.5f;
-
-inline bool isBmsCellTempValidC(float tempC) {
-  return !isnan(tempC) && tempC > BMS_CELL_TEMP_DISCONNECT_THRESHOLD_C;
-}
 
 inline float sanitizeBmsCellTempC(float tempC) {
-  return isBmsCellTempValidC(tempC) ? tempC : NAN;
+  return (!isnan(tempC) && tempC > BMS_CELL_TEMP_DISCONNECTED_C) ? tempC : NAN;
 }
 
 // External declarations
diff --git a/src/sp140/bms.cpp b/src/sp140/bms.cpp
index 0b660471..7d2319f6 100644
--- a/src/sp140/bms.cpp
+++ b/src/sp140/bms.cpp
@@ -12,7 +12,7 @@ void logBmsCellProbeConnectionTransitions(const float rawCellTemps[kBmsCellProbe
   static bool wasConnected[kBmsCellProbeCount] = {false, false, false, false};
 
   for (uint8_t i = 0; i < kBmsCellProbeCount; i++) {
-    const bool connected = isBmsCellTempValidC(rawCellTemps[i]);
+    const bool connected = !isnan(sanitizeBmsCellTempC(rawCellTemps[i]));
 
     if (!hasPreviousState) {
       wasConnected[i] = connected;
diff --git a/src/sp140/lvgl/lvgl_updates.cpp b/src/sp140/lvgl/lvgl_updates.cpp
index 35e3eada..93c66afa 100644
--- a/src/sp140/lvgl/lvgl_updates.cpp
+++ b/src/sp140/lvgl/lvgl_updates.cpp
@@ -344,12 +344,13 @@ void updateLvglMainScreen(
   float batteryTemp = NAN;
   bool hasValidBatteryTemp = false;
   for (float cellTemp : cellTemps) {
-    if (!isBmsCellTempValidC(cellTemp)) {
+    const float sanitizedCellTemp = sanitizeBmsCellTempC(cellTemp);
+    if (isnan(sanitizedCellTemp)) {
       continue;
     }
 
-    if (!hasValidBatteryTemp || cellTemp > batteryTemp) {
-      batteryTemp = cellTemp;
+    if (!hasValidBatteryTemp || sanitizedCellTemp > batteryTemp) {
+      batteryTemp = sanitizedCellTemp;
       hasValidBatteryTemp = true;
     }
   }
diff --git a/test/native_stubs/BMS_CAN.h b/test/native_stubs/BMS_CAN.h
new file mode 100644
index 00000000..473c7ddd
--- /dev/null
+++ b/test/native_stubs/BMS_CAN.h
@@ -0,0 +1,3 @@
+#pragma once
+
+class BMS_CAN {};
diff --git a/test/native_stubs/SPI.h b/test/native_stubs/SPI.h
new file mode 100644
index 00000000..f74ca657
--- /dev/null
+++ b/test/native_stubs/SPI.h
@@ -0,0 +1,3 @@
+#pragma once
+
+class SPIClass {};
diff --git a/test/test_simplemonitor/test_simplemonitor.cpp b/test/test_simplemonitor/test_simplemonitor.cpp
index f3d6ed8f..85381df5 100644
--- a/test/test_simplemonitor/test_simplemonitor.cpp
+++ b/test/test_simplemonitor/test_simplemonitor.cpp
@@ -1,4 +1,5 @@
 #include <gtest/gtest.h>
+#include "sp140/bms.h"
 #include "sp140/simple_monitor.h"
 #include "sp140/monitor_config.h"
 
@@ -237,6 +238,67 @@ TEST(SimpleMonitor, BMSTemperatureAlerts) {
     EXPECT_EQ(logger.entries.back().lvl, AlertLevel::CRIT_HIGH);
 }
 
+TEST(SimpleMonitor, BMSCellTemperatureDisconnectedIsIgnored) {
+  FakeLogger logger;
+  float fakeTemp = 30.0f;
+
+  SensorMonitor cellTempMon(
+    SensorID::BMS_T1_Temp,
+    SensorCategory::BMS,
+    bmsCellTempThresholds,
+    [&]() { return fakeTemp; },
+    &logger);
+
+  cellTempMon.check();  // Baseline OK
+  EXPECT_TRUE(logger.entries.empty());
+
+  // Disconnected probe reading should be treated as invalid (sanitized to NaN upstream).
+  fakeTemp = NAN;
+  cellTempMon.check();
+  EXPECT_TRUE(logger.entries.empty());
+
+  // Remaining connected probes still report alerts normally.
+  fakeTemp = 54.0f;
+  cellTempMon.check();
+  ASSERT_EQ(logger.entries.size(), 1u);
+  EXPECT_EQ(logger.entries.back().lvl, AlertLevel::WARN_HIGH);
+}
+
+TEST(SimpleMonitor, BMSCellTemperatureDisconnectClearsActiveAlert) {
+  FakeLogger logger;
+  float fakeTemp = 55.0f;
+
+  SensorMonitor cellTempMon(
+    SensorID::BMS_T2_Temp,
+    SensorCategory::BMS,
+    bmsCellTempThresholds,
+    [&]() { return fakeTemp; },
+    &logger);
+
+  // Enter warning state first.
+  cellTempMon.check();
+  ASSERT_EQ(logger.entries.size(), 1u);
+  EXPECT_EQ(logger.entries.back().lvl, AlertLevel::WARN_HIGH);
+
+  // Disconnect should clear the active alert.
+  fakeTemp = NAN;
+  cellTempMon.check();
+  ASSERT_EQ(logger.entries.size(), 2u);
+  EXPECT_EQ(logger.entries.back().lvl, AlertLevel::OK);
+}
+
+TEST(SimpleMonitor, BMSCellTempSanitizerDisconnectThreshold) {
+  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(-40.0f)));
+  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(-41.0f)));
+  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(-39.5f), -39.5f);
+}
+
+TEST(SimpleMonitor, BMSCellTempSanitizerPreservesValidValues) {
+  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(0.0f), 0.0f);
+  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(25.0f), 25.0f);
+  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(NAN)));
+}
+
 TEST(SimpleMonitor, MonitorIDAccess) {
     FakeLogger logger;
 

From b5fb582df9a3f5f026b5f57a05311b339a5a9c88 Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Sat, 21 Feb 2026 15:43:28 -0600
Subject: [PATCH 03/12] Treat -40C cell reading as disconnected
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Unify handling of BMS cell probes by treating a raw -40.0°C as a disconnected probe and converting such readings to NaN.

Changes:
- inc/sp140/bms.h: add BMS_CELL_TEMP_DISCONNECTED_C constant and update sanitizeBmsCellTempC to return NaN for disconnected/invalid readings (use strict > to exclude -40.0).
- src/sp140/bms.cpp: reuse sanitizer for connection detection and logging, exclude NaN values from extrema computation, and recompute extrema after sanitization so published high/low temps match stored values.
- src/sp140/lvgl/lvgl_updates.cpp: sanitize cell temps before UI logic and show "-" when no valid battery temperature is available.

Reason: ensures consistent telemetry, logging and UI behavior for disconnected probes and helps field-debug intermittent wiring issues.
---
 inc/sp140/bms.h                 | 6 +++++-
 src/sp140/bms.cpp               | 5 +++++
 src/sp140/lvgl/lvgl_updates.cpp | 2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index a861af43..37516efa 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -10,10 +10,14 @@
 #define MCP_CS 5        // MCP2515 CS pin
 #define MCP_BAUDRATE 250000
 
-// BMS cell probe disconnect handling
+// BMS cell probe disconnect handling.
+// Requirement: a raw value of exactly -40C indicates a disconnected probe.
+// Use strict '>' so -40.0 is treated as disconnected, not valid.
 constexpr float BMS_CELL_TEMP_DISCONNECTED_C = -40.0f;
 
 inline float sanitizeBmsCellTempC(float tempC) {
+  // Return NaN for disconnected/invalid readings so monitor/UI logic can skip
+  // this probe the same way we handle disconnected ESC motor temp.
   return (!isnan(tempC) && tempC > BMS_CELL_TEMP_DISCONNECTED_C) ? tempC : NAN;
 }
 
diff --git a/src/sp140/bms.cpp b/src/sp140/bms.cpp
index 7d2319f6..ae80c28e 100644
--- a/src/sp140/bms.cpp
+++ b/src/sp140/bms.cpp
@@ -12,6 +12,8 @@ void logBmsCellProbeConnectionTransitions(const float rawCellTemps[kBmsCellProbe
   static bool wasConnected[kBmsCellProbeCount] = {false, false, false, false};
 
   for (uint8_t i = 0; i < kBmsCellProbeCount; i++) {
+    // Reuse the same sanitizer used for telemetry storage so detection and
+    // downstream behavior stay consistent.
     const bool connected = !isnan(sanitizeBmsCellTempC(rawCellTemps[i]));
 
     if (!hasPreviousState) {
@@ -46,6 +48,7 @@ void recomputeBmsTemperatureExtrema(STR_BMS_TELEMETRY_140& telemetry) {  // NOLI
   float lowest = NAN;
 
   for (float temp : allTemps) {
+    // Disconnected probes are stored as NaN; exclude them from extrema.
     if (isnan(temp)) {
       continue;
     }
@@ -146,7 +149,9 @@ void updateBMSData() {
   bmsTelemetryData.t3_temperature = sanitizeBmsCellTempC(rawCellTemps[2]);  // Cell probe 3
   bmsTelemetryData.t4_temperature = sanitizeBmsCellTempC(rawCellTemps[3]);  // Cell probe 4
 
+  // Emit transition logs to help field-debug intermittent probe wiring issues.
   logBmsCellProbeConnectionTransitions(rawCellTemps);
+  // Keep published high/low temperatures aligned with sanitized probe values.
   recomputeBmsTemperatureExtrema(bmsTelemetryData);
 
   bmsTelemetryData.lastUpdateMs = millis();
diff --git a/src/sp140/lvgl/lvgl_updates.cpp b/src/sp140/lvgl/lvgl_updates.cpp
index 93c66afa..86b9e36e 100644
--- a/src/sp140/lvgl/lvgl_updates.cpp
+++ b/src/sp140/lvgl/lvgl_updates.cpp
@@ -344,6 +344,7 @@ void updateLvglMainScreen(
   float batteryTemp = NAN;
   bool hasValidBatteryTemp = false;
   for (float cellTemp : cellTemps) {
+    // sanitizeBmsCellTempC() converts disconnected probes (-40C) to NaN.
     const float sanitizedCellTemp = sanitizeBmsCellTempC(cellTemp);
     if (isnan(sanitizedCellTemp)) {
       continue;
@@ -687,6 +688,7 @@ void updateLvglMainScreen(
         lv_obj_add_flag(batt_temp_bg, LV_OBJ_FLAG_HIDDEN);
       }
     } else {
+      // No valid cell probe connected: show "-" instead of a fake low reading.
       lv_label_set_text(batt_temp_label, "-");
       lv_obj_add_flag(batt_temp_bg, LV_OBJ_FLAG_HIDDEN);
     }

From 313f19870e546aa30b34a018d2e9a60e998cdf5b Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Sat, 21 Feb 2026 15:50:44 -0600
Subject: [PATCH 04/12] fix include

CI fix
---
 inc/sp140/bms.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index 37516efa..feb375dd 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -3,6 +3,7 @@
 #include <Arduino.h>
 #include <SPI.h>
 #include <BMS_CAN.h>
+#include <math.h>
 
 #include "sp140/structs.h"
 

From 4c1d543eec88e9d80b156d05115c234857a95070 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 25 Feb 2026 20:08:44 +0000
Subject: [PATCH 05/12] Initial plan


From 0fcb5738053e88ca03207288cf72fb240522dd7e Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 25 Feb 2026 20:23:44 +0000
Subject: [PATCH 06/12] fix: keep last two BMS cell probes active at -40C

Co-authored-by: zjwhitehead <4623792+zjwhitehead@users.noreply.github.com>
---
 inc/sp140/bms.h                                | 11 +++++++----
 src/sp140/bms.cpp                              | 15 ++++++++++-----
 test/test_simplemonitor/test_simplemonitor.cpp |  5 +++++
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index feb375dd..09e9d19e 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -12,14 +12,17 @@
 #define MCP_BAUDRATE 250000
 
 // BMS cell probe disconnect handling.
-// Requirement: a raw value of exactly -40C indicates a disconnected probe.
-// Use strict '>' so -40.0 is treated as disconnected, not valid.
+// Requirement: a raw value of exactly -40C indicates a disconnected probe
+// unless explicitly kept as a valid reading.
 constexpr float BMS_CELL_TEMP_DISCONNECTED_C = -40.0f;
 
-inline float sanitizeBmsCellTempC(float tempC) {
+inline float sanitizeBmsCellTempC(float tempC, bool treatDisconnectedAsInvalid = true) {
   // Return NaN for disconnected/invalid readings so monitor/UI logic can skip
   // this probe the same way we handle disconnected ESC motor temp.
-  return (!isnan(tempC) && tempC > BMS_CELL_TEMP_DISCONNECTED_C) ? tempC : NAN;
+  return (!isnan(tempC) &&
+          (treatDisconnectedAsInvalid ? tempC > BMS_CELL_TEMP_DISCONNECTED_C : tempC >= BMS_CELL_TEMP_DISCONNECTED_C))
+           ? tempC
+           : NAN;
 }
 
 // External declarations
diff --git a/src/sp140/bms.cpp b/src/sp140/bms.cpp
index ae80c28e..834ca35e 100644
--- a/src/sp140/bms.cpp
+++ b/src/sp140/bms.cpp
@@ -6,6 +6,11 @@
 namespace {
 
 constexpr uint8_t kBmsCellProbeCount = 4;
+constexpr uint8_t kBmsMinRequiredProbeCount = 2;
+
+float sanitizeBmsCellProbeTempC(float tempC, uint8_t probeIndex) {
+  return sanitizeBmsCellTempC(tempC, probeIndex < kBmsMinRequiredProbeCount);
+}
 
 void logBmsCellProbeConnectionTransitions(const float rawCellTemps[kBmsCellProbeCount]) {
   static bool hasPreviousState = false;
@@ -14,7 +19,7 @@ void logBmsCellProbeConnectionTransitions(const float rawCellTemps[kBmsCellProbe
   for (uint8_t i = 0; i < kBmsCellProbeCount; i++) {
     // Reuse the same sanitizer used for telemetry storage so detection and
     // downstream behavior stay consistent.
-    const bool connected = !isnan(sanitizeBmsCellTempC(rawCellTemps[i]));
+    const bool connected = !isnan(sanitizeBmsCellProbeTempC(rawCellTemps[i], i));
 
     if (!hasPreviousState) {
       wasConnected[i] = connected;
@@ -144,10 +149,10 @@ void updateBMSData() {
     bms_can->getTemperature(5)
   };
 
-  bmsTelemetryData.t1_temperature = sanitizeBmsCellTempC(rawCellTemps[0]);  // Cell probe 1
-  bmsTelemetryData.t2_temperature = sanitizeBmsCellTempC(rawCellTemps[1]);  // Cell probe 2
-  bmsTelemetryData.t3_temperature = sanitizeBmsCellTempC(rawCellTemps[2]);  // Cell probe 3
-  bmsTelemetryData.t4_temperature = sanitizeBmsCellTempC(rawCellTemps[3]);  // Cell probe 4
+  bmsTelemetryData.t1_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[0], 0);  // Cell probe 1
+  bmsTelemetryData.t2_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[1], 1);  // Cell probe 2
+  bmsTelemetryData.t3_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[2], 2);  // Cell probe 3
+  bmsTelemetryData.t4_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[3], 3);  // Cell probe 4
 
   // Emit transition logs to help field-debug intermittent probe wiring issues.
   logBmsCellProbeConnectionTransitions(rawCellTemps);
diff --git a/test/test_simplemonitor/test_simplemonitor.cpp b/test/test_simplemonitor/test_simplemonitor.cpp
index 85381df5..08cabe1c 100644
--- a/test/test_simplemonitor/test_simplemonitor.cpp
+++ b/test/test_simplemonitor/test_simplemonitor.cpp
@@ -293,6 +293,11 @@ TEST(SimpleMonitor, BMSCellTempSanitizerDisconnectThreshold) {
   EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(-39.5f), -39.5f);
 }
 
+TEST(SimpleMonitor, BMSCellTempSanitizerCanKeepDisconnectedValueWhenRequired) {
+  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(-40.0f, false), -40.0f);
+  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(-41.0f, false)));
+}
+
 TEST(SimpleMonitor, BMSCellTempSanitizerPreservesValidValues) {
   EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(0.0f), 0.0f);
   EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(25.0f), 25.0f);

From 41a957dbf38b854fd9553236f95494420735856c Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Wed, 25 Feb 2026 22:16:34 -0600
Subject: [PATCH 07/12] Clean up the sanitize logic
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Introduce BMS_CELL_PROBE_COUNT and BMS_MAX_IGNORED_DISCONNECTED_PROBES and replace the single-value sanitizer with sanitizeCellProbeTemps(), which converts disconnected sentinel (-40°C) probes to NaN while ignoring up to two such sentinels before treating further -40°C readings as real temperatures. Update bms.cpp to produce and log using sanitized probe arrays and adjust LVGL code to assume probe values are pre-sanitized. Remove the old sanitizeBmsCellTempC overload that accepted a keep-disconnected flag and expand tests to cover the new multi-probe sanitization and alert transition behavior.
---
 inc/sp140/bms.h                               |  38 +++++-
 src/sp140/bms.cpp                             |  35 +++---
 src/sp140/lvgl/lvgl_updates.cpp               |   8 +-
 .../test_simplemonitor/test_simplemonitor.cpp | 109 +++++++++++++++++-
 4 files changed, 154 insertions(+), 36 deletions(-)

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index 09e9d19e..94342f8c 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -13,16 +13,42 @@
 
 // BMS cell probe disconnect handling.
 // Requirement: a raw value of exactly -40C indicates a disconnected probe
-// unless explicitly kept as a valid reading.
+// for single-value sanitization.
 constexpr float BMS_CELL_TEMP_DISCONNECTED_C = -40.0f;
+constexpr uint8_t BMS_CELL_PROBE_COUNT = 4;
+constexpr uint8_t BMS_MAX_IGNORED_DISCONNECTED_PROBES = 2;
 
-inline float sanitizeBmsCellTempC(float tempC, bool treatDisconnectedAsInvalid = true) {
+inline float sanitizeBmsCellTempC(float tempC) {
   // Return NaN for disconnected/invalid readings so monitor/UI logic can skip
   // this probe the same way we handle disconnected ESC motor temp.
-  return (!isnan(tempC) &&
-          (treatDisconnectedAsInvalid ? tempC > BMS_CELL_TEMP_DISCONNECTED_C : tempC >= BMS_CELL_TEMP_DISCONNECTED_C))
-           ? tempC
-           : NAN;
+  return (!isnan(tempC) && tempC > BMS_CELL_TEMP_DISCONNECTED_C) ? tempC : NAN;
+}
+
+inline void sanitizeCellProbeTemps(
+    const float rawTemps[BMS_CELL_PROBE_COUNT],
+    float sanitizedTemps[BMS_CELL_PROBE_COUNT]) {
+  uint8_t ignoredDisconnectedProbeCount = 0;
+
+  for (uint8_t i = 0; i < BMS_CELL_PROBE_COUNT; i++) {
+    const float tempC = rawTemps[i];
+
+    if (isnan(tempC) || tempC < BMS_CELL_TEMP_DISCONNECTED_C) {
+      sanitizedTemps[i] = NAN;
+      continue;
+    }
+
+    if (tempC == BMS_CELL_TEMP_DISCONNECTED_C) {
+      if (ignoredDisconnectedProbeCount < BMS_MAX_IGNORED_DISCONNECTED_PROBES) {
+        sanitizedTemps[i] = NAN;
+        ignoredDisconnectedProbeCount++;
+      } else {
+        sanitizedTemps[i] = tempC;
+      }
+      continue;
+    }
+
+    sanitizedTemps[i] = tempC;
+  }
 }
 
 // External declarations
diff --git a/src/sp140/bms.cpp b/src/sp140/bms.cpp
index 834ca35e..46302989 100644
--- a/src/sp140/bms.cpp
+++ b/src/sp140/bms.cpp
@@ -5,21 +5,14 @@
 
 namespace {
 
-constexpr uint8_t kBmsCellProbeCount = 4;
-constexpr uint8_t kBmsMinRequiredProbeCount = 2;
-
-float sanitizeBmsCellProbeTempC(float tempC, uint8_t probeIndex) {
-  return sanitizeBmsCellTempC(tempC, probeIndex < kBmsMinRequiredProbeCount);
-}
-
-void logBmsCellProbeConnectionTransitions(const float rawCellTemps[kBmsCellProbeCount]) {
+void logBmsCellProbeConnectionTransitions(const float sanitizedCellTemps[BMS_CELL_PROBE_COUNT]) {
   static bool hasPreviousState = false;
-  static bool wasConnected[kBmsCellProbeCount] = {false, false, false, false};
+  static bool wasConnected[BMS_CELL_PROBE_COUNT] = {false, false, false, false};
 
-  for (uint8_t i = 0; i < kBmsCellProbeCount; i++) {
-    // Reuse the same sanitizer used for telemetry storage so detection and
+  for (uint8_t i = 0; i < BMS_CELL_PROBE_COUNT; i++) {
+    // Use already-sanitized telemetry values so connection detection and
     // downstream behavior stay consistent.
-    const bool connected = !isnan(sanitizeBmsCellProbeTempC(rawCellTemps[i], i));
+    const bool connected = !isnan(sanitizedCellTemps[i]);
 
     if (!hasPreviousState) {
       wasConnected[i] = connected;
@@ -27,10 +20,10 @@ void logBmsCellProbeConnectionTransitions(const float rawCellTemps[kBmsCellProbe
     }
 
     if (connected != wasConnected[i]) {
-      USBSerial.printf("[BMS] T%u sensor %s (raw=%.1fC)\n",
+      USBSerial.printf("[BMS] T%u sensor %s (sanitized=%.1fC)\n",
                        i + 1,
                        connected ? "reconnected" : "disconnected",
-                       rawCellTemps[i]);
+                       sanitizedCellTemps[i]);
       wasConnected[i] = connected;
     }
   }
@@ -142,20 +135,22 @@ void updateBMSData() {
   bmsTelemetryData.mos_temperature = bms_can->getTemperature(0);      // BMS MOSFET
   bmsTelemetryData.balance_temperature = bms_can->getTemperature(1);  // BMS Balance resistors
 
-  const float rawCellTemps[kBmsCellProbeCount] = {
+  const float rawCellTemps[BMS_CELL_PROBE_COUNT] = {
     bms_can->getTemperature(2),
     bms_can->getTemperature(3),
     bms_can->getTemperature(4),
     bms_can->getTemperature(5)
   };
+  float sanitizedCellTemps[BMS_CELL_PROBE_COUNT];
 
-  bmsTelemetryData.t1_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[0], 0);  // Cell probe 1
-  bmsTelemetryData.t2_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[1], 1);  // Cell probe 2
-  bmsTelemetryData.t3_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[2], 2);  // Cell probe 3
-  bmsTelemetryData.t4_temperature = sanitizeBmsCellProbeTempC(rawCellTemps[3], 3);  // Cell probe 4
+  sanitizeCellProbeTemps(rawCellTemps, sanitizedCellTemps);
+  bmsTelemetryData.t1_temperature = sanitizedCellTemps[0];  // Cell probe 1
+  bmsTelemetryData.t2_temperature = sanitizedCellTemps[1];  // Cell probe 2
+  bmsTelemetryData.t3_temperature = sanitizedCellTemps[2];  // Cell probe 3
+  bmsTelemetryData.t4_temperature = sanitizedCellTemps[3];  // Cell probe 4
 
   // Emit transition logs to help field-debug intermittent probe wiring issues.
-  logBmsCellProbeConnectionTransitions(rawCellTemps);
+  logBmsCellProbeConnectionTransitions(sanitizedCellTemps);
   // Keep published high/low temperatures aligned with sanitized probe values.
   recomputeBmsTemperatureExtrema(bmsTelemetryData);
 
diff --git a/src/sp140/lvgl/lvgl_updates.cpp b/src/sp140/lvgl/lvgl_updates.cpp
index 86b9e36e..5b22fe55 100644
--- a/src/sp140/lvgl/lvgl_updates.cpp
+++ b/src/sp140/lvgl/lvgl_updates.cpp
@@ -344,14 +344,12 @@ void updateLvglMainScreen(
   float batteryTemp = NAN;
   bool hasValidBatteryTemp = false;
   for (float cellTemp : cellTemps) {
-    // sanitizeBmsCellTempC() converts disconnected probes (-40C) to NaN.
-    const float sanitizedCellTemp = sanitizeBmsCellTempC(cellTemp);
-    if (isnan(sanitizedCellTemp)) {
+    if (isnan(cellTemp)) {
       continue;
     }
 
-    if (!hasValidBatteryTemp || sanitizedCellTemp > batteryTemp) {
-      batteryTemp = sanitizedCellTemp;
+    if (!hasValidBatteryTemp || cellTemp > batteryTemp) {
+      batteryTemp = cellTemp;
       hasValidBatteryTemp = true;
     }
   }
diff --git a/test/test_simplemonitor/test_simplemonitor.cpp b/test/test_simplemonitor/test_simplemonitor.cpp
index 08cabe1c..f42060d8 100644
--- a/test/test_simplemonitor/test_simplemonitor.cpp
+++ b/test/test_simplemonitor/test_simplemonitor.cpp
@@ -293,17 +293,116 @@ TEST(SimpleMonitor, BMSCellTempSanitizerDisconnectThreshold) {
   EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(-39.5f), -39.5f);
 }
 
-TEST(SimpleMonitor, BMSCellTempSanitizerCanKeepDisconnectedValueWhenRequired) {
-  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(-40.0f, false), -40.0f);
-  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(-41.0f, false)));
-}
-
 TEST(SimpleMonitor, BMSCellTempSanitizerPreservesValidValues) {
   EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(0.0f), 0.0f);
   EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(25.0f), 25.0f);
   EXPECT_TRUE(isnan(sanitizeBmsCellTempC(NAN)));
 }
 
+TEST(SimpleMonitor, BMSCellProbeSanitizerIgnoresUpToTwoDisconnectedSentinels) {
+  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-40.0f, -39.0f, -40.0f, 12.0f};
+  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+
+  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+
+  EXPECT_TRUE(isnan(sanitizedTemps[0]));
+  EXPECT_FLOAT_EQ(sanitizedTemps[1], -39.0f);
+  EXPECT_TRUE(isnan(sanitizedTemps[2]));
+  EXPECT_FLOAT_EQ(sanitizedTemps[3], 12.0f);
+}
+
+TEST(SimpleMonitor, BMSCellProbeSanitizerKeepsThirdDisconnectedSentinelAsValidTemp) {
+  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, -40.0f, 25.0f};
+  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+
+  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+
+  EXPECT_TRUE(isnan(sanitizedTemps[0]));
+  EXPECT_TRUE(isnan(sanitizedTemps[1]));
+  EXPECT_FLOAT_EQ(sanitizedTemps[2], -40.0f);
+  EXPECT_FLOAT_EQ(sanitizedTemps[3], 25.0f);
+}
+
+TEST(SimpleMonitor, BMSCellProbeSanitizerKeepsThirdAndFourthDisconnectedSentinelsAsValidTemps) {
+  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, -40.0f, -40.0f};
+  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+
+  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+
+  EXPECT_TRUE(isnan(sanitizedTemps[0]));
+  EXPECT_TRUE(isnan(sanitizedTemps[1]));
+  EXPECT_FLOAT_EQ(sanitizedTemps[2], -40.0f);
+  EXPECT_FLOAT_EQ(sanitizedTemps[3], -40.0f);
+}
+
+TEST(SimpleMonitor, BMSCellProbeSanitizerTreatsBelowDisconnectedAndNaNAsInvalid) {
+  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-41.0f, -39.0f, -40.0f, NAN};
+  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+
+  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+
+  EXPECT_TRUE(isnan(sanitizedTemps[0]));
+  EXPECT_FLOAT_EQ(sanitizedTemps[1], -39.0f);
+  EXPECT_TRUE(isnan(sanitizedTemps[2]));
+  EXPECT_TRUE(isnan(sanitizedTemps[3]));
+}
+
+TEST(SimpleMonitor, BMSCellProbeSentinelTransitionFromTwoToThreeToTwoTriggersAndClearsAlert) {
+  FakeLogger logger;
+  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {NAN, NAN, NAN, NAN};
+
+  SensorMonitor t1Mon(
+    SensorID::BMS_T1_Temp,
+    SensorCategory::BMS,
+    bmsCellTempThresholds,
+    [&]() { return sanitizedTemps[0]; },
+    &logger);
+  SensorMonitor t2Mon(
+    SensorID::BMS_T2_Temp,
+    SensorCategory::BMS,
+    bmsCellTempThresholds,
+    [&]() { return sanitizedTemps[1]; },
+    &logger);
+  SensorMonitor t3Mon(
+    SensorID::BMS_T3_Temp,
+    SensorCategory::BMS,
+    bmsCellTempThresholds,
+    [&]() { return sanitizedTemps[2]; },
+    &logger);
+  SensorMonitor t4Mon(
+    SensorID::BMS_T4_Temp,
+    SensorCategory::BMS,
+    bmsCellTempThresholds,
+    [&]() { return sanitizedTemps[3]; },
+    &logger);
+
+  const auto evaluateCycle = [&](const float rawTemps[BMS_CELL_PROBE_COUNT]) {
+    sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+    t1Mon.check();
+    t2Mon.check();
+    t3Mon.check();
+    t4Mon.check();
+  };
+
+  // Two disconnected sentinels are ignored - no low-temp alert.
+  const float twoSentinels[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, 5.0f, 6.0f};
+  evaluateCycle(twoSentinels);
+  EXPECT_TRUE(logger.entries.empty());
+
+  // Third sentinel becomes a real temperature and must trigger a low-temp alert.
+  const float threeSentinels[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, -40.0f, 6.0f};
+  evaluateCycle(threeSentinels);
+  ASSERT_EQ(logger.entries.size(), 1u);
+  EXPECT_EQ(logger.entries[0].id, SensorID::BMS_T3_Temp);
+  EXPECT_EQ(logger.entries[0].lvl, AlertLevel::CRIT_LOW);
+
+  // Returning to only two sentinels clears that low-temp alert cleanly.
+  evaluateCycle(twoSentinels);
+  ASSERT_EQ(logger.entries.size(), 2u);
+  EXPECT_EQ(logger.entries[1].id, SensorID::BMS_T3_Temp);
+  EXPECT_EQ(logger.entries[1].lvl, AlertLevel::OK);
+}
+
 TEST(SimpleMonitor, MonitorIDAccess) {
     FakeLogger logger;
 

From 37d733551aa306b3dafdfb12cbed4741126706b2 Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Tue, 10 Mar 2026 14:46:40 -0500
Subject: [PATCH 08/12] Use BMS_CAN TEMP_PROBE_DISCONNECTED constant

Replace the local BMS_CELL_TEMP_DISCONNECTED_C sentinel with the canonical TEMP_PROBE_DISCONNECTED constant from BMS_CAN. Update sanitizeBmsCellTempC and sanitizeCellProbeTemps to reference BMS_CAN::TEMP_PROBE_DISCONNECTED, and remove the duplicate local constant. Add a native test stub for BMS_CAN exposing the constexpr TEMP_PROBE_DISCONNECTED so tests compile. Also bump the ANT-BMS-CAN dependency reference in platformio.ini to the commit that contains this change. This centralizes the probe-disconnected sentinel in the BMS_CAN library while keeping application-level policy (max ignored disconnected probes) in the app.
---
 inc/sp140/bms.h             | 12 ++++++------
 platformio.ini              |  2 +-
 test/native_stubs/BMS_CAN.h |  8 +++++++-
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index 94342f8c..087ce3d7 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -12,16 +12,16 @@
 #define MCP_BAUDRATE 250000
 
 // BMS cell probe disconnect handling.
-// Requirement: a raw value of exactly -40C indicates a disconnected probe
-// for single-value sanitization.
-constexpr float BMS_CELL_TEMP_DISCONNECTED_C = -40.0f;
+// The BMS reports TEMP_PROBE_DISCONNECTED (-40C) for unplugged probes.
+// Detection is handled by the BMS_CAN library; policy (how many disconnected
+// probes to tolerate) lives here in the application.
 constexpr uint8_t BMS_CELL_PROBE_COUNT = 4;
 constexpr uint8_t BMS_MAX_IGNORED_DISCONNECTED_PROBES = 2;
 
 inline float sanitizeBmsCellTempC(float tempC) {
   // Return NaN for disconnected/invalid readings so monitor/UI logic can skip
   // this probe the same way we handle disconnected ESC motor temp.
-  return (!isnan(tempC) && tempC > BMS_CELL_TEMP_DISCONNECTED_C) ? tempC : NAN;
+  return (!isnan(tempC) && tempC > BMS_CAN::TEMP_PROBE_DISCONNECTED) ? tempC : NAN;
 }
 
 inline void sanitizeCellProbeTemps(
@@ -32,12 +32,12 @@ inline void sanitizeCellProbeTemps(
   for (uint8_t i = 0; i < BMS_CELL_PROBE_COUNT; i++) {
     const float tempC = rawTemps[i];
 
-    if (isnan(tempC) || tempC < BMS_CELL_TEMP_DISCONNECTED_C) {
+    if (isnan(tempC) || tempC < BMS_CAN::TEMP_PROBE_DISCONNECTED) {
       sanitizedTemps[i] = NAN;
       continue;
     }
 
-    if (tempC == BMS_CELL_TEMP_DISCONNECTED_C) {
+    if (tempC == BMS_CAN::TEMP_PROBE_DISCONNECTED) {
       if (ignoredDisconnectedProbeCount < BMS_MAX_IGNORED_DISCONNECTED_PROBES) {
         sanitizedTemps[i] = NAN;
         ignoredDisconnectedProbeCount++;
diff --git a/platformio.ini b/platformio.ini
index 7ed8fb27..0365c02d 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -55,7 +55,7 @@ lib_deps =
 	adafruit/Adafruit MCP2515@0.2.1
 	https://github.com/rlogiacco/CircularBuffer@1.4.0
 	https://github.com/openppg/SINE-ESC-CAN#8caa93996b5d000fe10ca5265bd1c472dfdf885b
-	https://github.com/openppg/ANT-BMS-CAN#da685ce2a0e87e23df625f33ad751203ad6a4f8f
+	https://github.com/openppg/ANT-BMS-CAN#99f4c075871bff41109ed1e578c00ba9178450ba
 	lvgl/lvgl@^8.4.0
 	h2zero/NimBLE-Arduino@^2.3.5
 lib_ignore =
diff --git a/test/native_stubs/BMS_CAN.h b/test/native_stubs/BMS_CAN.h
index 473c7ddd..7eb11067 100644
--- a/test/native_stubs/BMS_CAN.h
+++ b/test/native_stubs/BMS_CAN.h
@@ -1,3 +1,9 @@
 #pragma once
 
-class BMS_CAN {};
+#include <cmath>
+#include <cstdint>
+
+class BMS_CAN {
+public:
+  static constexpr float TEMP_PROBE_DISCONNECTED = -40.0f;
+};

From 536e847e541e938366332c29dc4296094e94729e Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Tue, 10 Mar 2026 14:56:43 -0500
Subject: [PATCH 09/12] BMS: use library NaN policy for temp probes

Sanitize BMS cell probe handling to accept NaN from the BMS library and apply an app-level tolerance: allow up to BMS_MAX_IGNORED_DISCONNECTED_PROBES NaNs to pass through, but replace any additional NaNs with the TEMP_PROBE_DISCONNECTED sentinel so monitors alert. Removed the old single-value sanitizer, made sanitizeCellProbeTemps a two-pass routine that counts NaNs and writes either NaN, the original temp, or the sentinel. Updated bms.cpp to consume the new API (pass-through NaNs from library, call sanitizeCellProbeTemps, and use library-provided highest/lowest temps), removed recomputeBmsTemperatureExtrema, and adjusted connection-logging comments. Tests were updated to feed NaN for disconnected probes and to reflect the new alerting/tolerance behavior. Also updated the ANT-BMS-CAN dependency reference in platformio.ini.
---
 inc/sp140/bms.h                               |  51 ++++-----
 platformio.ini                                |   2 +-
 src/sp140/bms.cpp                             |  60 +++-------
 .../test_simplemonitor/test_simplemonitor.cpp | 103 +++++++++---------
 4 files changed, 85 insertions(+), 131 deletions(-)

diff --git a/inc/sp140/bms.h b/inc/sp140/bms.h
index 087ce3d7..ed5d2005 100644
--- a/inc/sp140/bms.h
+++ b/inc/sp140/bms.h
@@ -11,43 +11,36 @@
 #define MCP_CS 5        // MCP2515 CS pin
 #define MCP_BAUDRATE 250000
 
-// BMS cell probe disconnect handling.
-// The BMS reports TEMP_PROBE_DISCONNECTED (-40C) for unplugged probes.
-// Detection is handled by the BMS_CAN library; policy (how many disconnected
-// probes to tolerate) lives here in the application.
+// BMS cell probe disconnect policy.
+// The library returns NaN for disconnected probes. This app tolerates up to
+// BMS_MAX_IGNORED_DISCONNECTED_PROBES disconnected; beyond that the NaN is
+// replaced with the sentinel value so downstream temp monitors fire an alert.
 constexpr uint8_t BMS_CELL_PROBE_COUNT = 4;
 constexpr uint8_t BMS_MAX_IGNORED_DISCONNECTED_PROBES = 2;
 
-inline float sanitizeBmsCellTempC(float tempC) {
-  // Return NaN for disconnected/invalid readings so monitor/UI logic can skip
-  // this probe the same way we handle disconnected ESC motor temp.
-  return (!isnan(tempC) && tempC > BMS_CAN::TEMP_PROBE_DISCONNECTED) ? tempC : NAN;
-}
-
 inline void sanitizeCellProbeTemps(
-    const float rawTemps[BMS_CELL_PROBE_COUNT],
-    float sanitizedTemps[BMS_CELL_PROBE_COUNT]) {
-  uint8_t ignoredDisconnectedProbeCount = 0;
+    const float temps[BMS_CELL_PROBE_COUNT],
+    float out[BMS_CELL_PROBE_COUNT]) {
+  uint8_t disconnectedCount = 0;
 
+  // First pass: count disconnected probes (NaN from library)
   for (uint8_t i = 0; i < BMS_CELL_PROBE_COUNT; i++) {
-    const float tempC = rawTemps[i];
-
-    if (isnan(tempC) || tempC < BMS_CAN::TEMP_PROBE_DISCONNECTED) {
-      sanitizedTemps[i] = NAN;
-      continue;
-    }
+    if (isnan(temps[i])) disconnectedCount++;
+  }
 
-    if (tempC == BMS_CAN::TEMP_PROBE_DISCONNECTED) {
-      if (ignoredDisconnectedProbeCount < BMS_MAX_IGNORED_DISCONNECTED_PROBES) {
-        sanitizedTemps[i] = NAN;
-        ignoredDisconnectedProbeCount++;
-      } else {
-        sanitizedTemps[i] = tempC;
-      }
-      continue;
+  // Second pass: if within tolerance, pass NaN through (silently ignored).
+  // If too many are disconnected, replace excess NaN with the sentinel value
+  // so temperature monitors fire a CRIT_LOW alert.
+  uint8_t ignoredCount = 0;
+  for (uint8_t i = 0; i < BMS_CELL_PROBE_COUNT; i++) {
+    if (!isnan(temps[i])) {
+      out[i] = temps[i];
+    } else if (ignoredCount < BMS_MAX_IGNORED_DISCONNECTED_PROBES) {
+      out[i] = NAN;
+      ignoredCount++;
+    } else {
+      out[i] = BMS_CAN::TEMP_PROBE_DISCONNECTED;
     }
-
-    sanitizedTemps[i] = tempC;
   }
 }
 
diff --git a/platformio.ini b/platformio.ini
index 0365c02d..3615f9c2 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -55,7 +55,7 @@ lib_deps =
 	adafruit/Adafruit MCP2515@0.2.1
 	https://github.com/rlogiacco/CircularBuffer@1.4.0
 	https://github.com/openppg/SINE-ESC-CAN#8caa93996b5d000fe10ca5265bd1c472dfdf885b
-	https://github.com/openppg/ANT-BMS-CAN#99f4c075871bff41109ed1e578c00ba9178450ba
+	https://github.com/openppg/ANT-BMS-CAN#567aca5b2fc4e4c9e9d315457324b97147613f37
 	lvgl/lvgl@^8.4.0
 	h2zero/NimBLE-Arduino@^2.3.5
 lib_ignore =
diff --git a/src/sp140/bms.cpp b/src/sp140/bms.cpp
index 46302989..9541ad1c 100644
--- a/src/sp140/bms.cpp
+++ b/src/sp140/bms.cpp
@@ -10,8 +10,6 @@ void logBmsCellProbeConnectionTransitions(const float sanitizedCellTemps[BMS_CEL
   static bool wasConnected[BMS_CELL_PROBE_COUNT] = {false, false, false, false};
 
   for (uint8_t i = 0; i < BMS_CELL_PROBE_COUNT; i++) {
-    // Use already-sanitized telemetry values so connection detection and
-    // downstream behavior stay consistent.
     const bool connected = !isnan(sanitizedCellTemps[i]);
 
     if (!hasPreviousState) {
@@ -31,41 +29,6 @@ void logBmsCellProbeConnectionTransitions(const float sanitizedCellTemps[BMS_CEL
   hasPreviousState = true;
 }
 
-void recomputeBmsTemperatureExtrema(STR_BMS_TELEMETRY_140& telemetry) {  // NOLINT(runtime/references)
-  const float allTemps[] = {
-    telemetry.mos_temperature,
-    telemetry.balance_temperature,
-    telemetry.t1_temperature,
-    telemetry.t2_temperature,
-    telemetry.t3_temperature,
-    telemetry.t4_temperature
-  };
-
-  bool hasValidReading = false;
-  float highest = NAN;
-  float lowest = NAN;
-
-  for (float temp : allTemps) {
-    // Disconnected probes are stored as NaN; exclude them from extrema.
-    if (isnan(temp)) {
-      continue;
-    }
-
-    if (!hasValidReading) {
-      highest = temp;
-      lowest = temp;
-      hasValidReading = true;
-      continue;
-    }
-
-    if (temp > highest) highest = temp;
-    if (temp < lowest) lowest = temp;
-  }
-
-  telemetry.highest_temperature = highest;
-  telemetry.lowest_temperature = lowest;
-}
-
 }  // namespace
 
 STR_BMS_TELEMETRY_140 bmsTelemetryData = {
@@ -131,28 +94,31 @@ void updateBMSData() {
     bmsTelemetryData.cell_voltages[i] = bms_can->getCellVoltage(i);
   }
 
-  // Populate individual temperature sensors
+  // Populate temperature sensors (library returns NaN for disconnected probes)
   bmsTelemetryData.mos_temperature = bms_can->getTemperature(0);      // BMS MOSFET
   bmsTelemetryData.balance_temperature = bms_can->getTemperature(1);  // BMS Balance resistors
 
-  const float rawCellTemps[BMS_CELL_PROBE_COUNT] = {
+  // Cell probes: library already returns NaN for disconnected. Apply app-level
+  // policy (tolerate up to N disconnected before alerting).
+  const float cellTemps[BMS_CELL_PROBE_COUNT] = {
     bms_can->getTemperature(2),
     bms_can->getTemperature(3),
     bms_can->getTemperature(4),
     bms_can->getTemperature(5)
   };
   float sanitizedCellTemps[BMS_CELL_PROBE_COUNT];
-
-  sanitizeCellProbeTemps(rawCellTemps, sanitizedCellTemps);
-  bmsTelemetryData.t1_temperature = sanitizedCellTemps[0];  // Cell probe 1
-  bmsTelemetryData.t2_temperature = sanitizedCellTemps[1];  // Cell probe 2
-  bmsTelemetryData.t3_temperature = sanitizedCellTemps[2];  // Cell probe 3
-  bmsTelemetryData.t4_temperature = sanitizedCellTemps[3];  // Cell probe 4
+  sanitizeCellProbeTemps(cellTemps, sanitizedCellTemps);
+  bmsTelemetryData.t1_temperature = sanitizedCellTemps[0];
+  bmsTelemetryData.t2_temperature = sanitizedCellTemps[1];
+  bmsTelemetryData.t3_temperature = sanitizedCellTemps[2];
+  bmsTelemetryData.t4_temperature = sanitizedCellTemps[3];
 
   // Emit transition logs to help field-debug intermittent probe wiring issues.
   logBmsCellProbeConnectionTransitions(sanitizedCellTemps);
-  // Keep published high/low temperatures aligned with sanitized probe values.
-  recomputeBmsTemperatureExtrema(bmsTelemetryData);
+
+  // Library already excludes disconnected probes from high/low temps
+  bmsTelemetryData.highest_temperature = bms_can->getHighestTemperature();
+  bmsTelemetryData.lowest_temperature = bms_can->getLowestTemperature();
 
   bmsTelemetryData.lastUpdateMs = millis();
   unsigned long dur = bmsTelemetryData.lastUpdateMs - tStart;
diff --git a/test/test_simplemonitor/test_simplemonitor.cpp b/test/test_simplemonitor/test_simplemonitor.cpp
index f42060d8..380f5538 100644
--- a/test/test_simplemonitor/test_simplemonitor.cpp
+++ b/test/test_simplemonitor/test_simplemonitor.cpp
@@ -287,67 +287,62 @@ TEST(SimpleMonitor, BMSCellTemperatureDisconnectClearsActiveAlert) {
   EXPECT_EQ(logger.entries.back().lvl, AlertLevel::OK);
 }
 
-TEST(SimpleMonitor, BMSCellTempSanitizerDisconnectThreshold) {
-  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(-40.0f)));
-  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(-41.0f)));
-  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(-39.5f), -39.5f);
-}
-
-TEST(SimpleMonitor, BMSCellTempSanitizerPreservesValidValues) {
-  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(0.0f), 0.0f);
-  EXPECT_FLOAT_EQ(sanitizeBmsCellTempC(25.0f), 25.0f);
-  EXPECT_TRUE(isnan(sanitizeBmsCellTempC(NAN)));
-}
+// sanitizeCellProbeTemps now receives NaN from the library for disconnected
+// probes. It applies app policy: up to 2 NaN are passed through silently;
+// beyond that, NaN is replaced with the sentinel so temp monitors alert.
 
-TEST(SimpleMonitor, BMSCellProbeSanitizerIgnoresUpToTwoDisconnectedSentinels) {
-  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-40.0f, -39.0f, -40.0f, 12.0f};
-  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+TEST(SimpleMonitor, BMSCellProbeSanitizerIgnoresUpToTwoDisconnected) {
+  // Two disconnected (NaN from library), two connected
+  const float temps[BMS_CELL_PROBE_COUNT] = {NAN, -39.0f, NAN, 12.0f};
+  float out[BMS_CELL_PROBE_COUNT] = {};
 
-  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+  sanitizeCellProbeTemps(temps, out);
 
-  EXPECT_TRUE(isnan(sanitizedTemps[0]));
-  EXPECT_FLOAT_EQ(sanitizedTemps[1], -39.0f);
-  EXPECT_TRUE(isnan(sanitizedTemps[2]));
-  EXPECT_FLOAT_EQ(sanitizedTemps[3], 12.0f);
+  EXPECT_TRUE(isnan(out[0]));
+  EXPECT_FLOAT_EQ(out[1], -39.0f);
+  EXPECT_TRUE(isnan(out[2]));
+  EXPECT_FLOAT_EQ(out[3], 12.0f);
 }
 
-TEST(SimpleMonitor, BMSCellProbeSanitizerKeepsThirdDisconnectedSentinelAsValidTemp) {
-  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, -40.0f, 25.0f};
-  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+TEST(SimpleMonitor, BMSCellProbeSanitizerAlertsOnThirdDisconnected) {
+  // Three disconnected: first two become NaN, third becomes sentinel for alert
+  const float temps[BMS_CELL_PROBE_COUNT] = {NAN, NAN, NAN, 25.0f};
+  float out[BMS_CELL_PROBE_COUNT] = {};
 
-  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+  sanitizeCellProbeTemps(temps, out);
 
-  EXPECT_TRUE(isnan(sanitizedTemps[0]));
-  EXPECT_TRUE(isnan(sanitizedTemps[1]));
-  EXPECT_FLOAT_EQ(sanitizedTemps[2], -40.0f);
-  EXPECT_FLOAT_EQ(sanitizedTemps[3], 25.0f);
+  EXPECT_TRUE(isnan(out[0]));
+  EXPECT_TRUE(isnan(out[1]));
+  EXPECT_FLOAT_EQ(out[2], BMS_CAN::TEMP_PROBE_DISCONNECTED);
+  EXPECT_FLOAT_EQ(out[3], 25.0f);
 }
 
-TEST(SimpleMonitor, BMSCellProbeSanitizerKeepsThirdAndFourthDisconnectedSentinelsAsValidTemps) {
-  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, -40.0f, -40.0f};
-  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+TEST(SimpleMonitor, BMSCellProbeSanitizerAlertsOnThirdAndFourthDisconnected) {
+  // All four disconnected: first two NaN, third and fourth become sentinel
+  const float temps[BMS_CELL_PROBE_COUNT] = {NAN, NAN, NAN, NAN};
+  float out[BMS_CELL_PROBE_COUNT] = {};
 
-  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+  sanitizeCellProbeTemps(temps, out);
 
-  EXPECT_TRUE(isnan(sanitizedTemps[0]));
-  EXPECT_TRUE(isnan(sanitizedTemps[1]));
-  EXPECT_FLOAT_EQ(sanitizedTemps[2], -40.0f);
-  EXPECT_FLOAT_EQ(sanitizedTemps[3], -40.0f);
+  EXPECT_TRUE(isnan(out[0]));
+  EXPECT_TRUE(isnan(out[1]));
+  EXPECT_FLOAT_EQ(out[2], BMS_CAN::TEMP_PROBE_DISCONNECTED);
+  EXPECT_FLOAT_EQ(out[3], BMS_CAN::TEMP_PROBE_DISCONNECTED);
 }
 
-TEST(SimpleMonitor, BMSCellProbeSanitizerTreatsBelowDisconnectedAndNaNAsInvalid) {
-  const float rawTemps[BMS_CELL_PROBE_COUNT] = {-41.0f, -39.0f, -40.0f, NAN};
-  float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {};
+TEST(SimpleMonitor, BMSCellProbeSanitizerPassesThroughValidTemps) {
+  const float temps[BMS_CELL_PROBE_COUNT] = {10.0f, 20.0f, 30.0f, 40.0f};
+  float out[BMS_CELL_PROBE_COUNT] = {};
 
-  sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+  sanitizeCellProbeTemps(temps, out);
 
-  EXPECT_TRUE(isnan(sanitizedTemps[0]));
-  EXPECT_FLOAT_EQ(sanitizedTemps[1], -39.0f);
-  EXPECT_TRUE(isnan(sanitizedTemps[2]));
-  EXPECT_TRUE(isnan(sanitizedTemps[3]));
+  EXPECT_FLOAT_EQ(out[0], 10.0f);
+  EXPECT_FLOAT_EQ(out[1], 20.0f);
+  EXPECT_FLOAT_EQ(out[2], 30.0f);
+  EXPECT_FLOAT_EQ(out[3], 40.0f);
 }
 
-TEST(SimpleMonitor, BMSCellProbeSentinelTransitionFromTwoToThreeToTwoTriggersAndClearsAlert) {
+TEST(SimpleMonitor, BMSCellProbeDisconnectTransitionTriggersAndClearsAlert) {
   FakeLogger logger;
   float sanitizedTemps[BMS_CELL_PROBE_COUNT] = {NAN, NAN, NAN, NAN};
 
@@ -376,28 +371,28 @@ TEST(SimpleMonitor, BMSCellProbeSentinelTransitionFromTwoToThreeToTwoTriggersAnd
     [&]() { return sanitizedTemps[3]; },
     &logger);
 
-  const auto evaluateCycle = [&](const float rawTemps[BMS_CELL_PROBE_COUNT]) {
-    sanitizeCellProbeTemps(rawTemps, sanitizedTemps);
+  const auto evaluateCycle = [&](const float temps[BMS_CELL_PROBE_COUNT]) {
+    sanitizeCellProbeTemps(temps, sanitizedTemps);
     t1Mon.check();
     t2Mon.check();
     t3Mon.check();
     t4Mon.check();
   };
 
-  // Two disconnected sentinels are ignored - no low-temp alert.
-  const float twoSentinels[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, 5.0f, 6.0f};
-  evaluateCycle(twoSentinels);
+  // Two disconnected probes (NaN) are within tolerance - no alert.
+  const float twoDisconnected[BMS_CELL_PROBE_COUNT] = {NAN, NAN, 5.0f, 6.0f};
+  evaluateCycle(twoDisconnected);
   EXPECT_TRUE(logger.entries.empty());
 
-  // Third sentinel becomes a real temperature and must trigger a low-temp alert.
-  const float threeSentinels[BMS_CELL_PROBE_COUNT] = {-40.0f, -40.0f, -40.0f, 6.0f};
-  evaluateCycle(threeSentinels);
+  // Third disconnect exceeds tolerance - sentinel triggers CRIT_LOW alert.
+  const float threeDisconnected[BMS_CELL_PROBE_COUNT] = {NAN, NAN, NAN, 6.0f};
+  evaluateCycle(threeDisconnected);
   ASSERT_EQ(logger.entries.size(), 1u);
   EXPECT_EQ(logger.entries[0].id, SensorID::BMS_T3_Temp);
   EXPECT_EQ(logger.entries[0].lvl, AlertLevel::CRIT_LOW);
 
-  // Returning to only two sentinels clears that low-temp alert cleanly.
-  evaluateCycle(twoSentinels);
+  // Returning to two disconnected clears the alert.
+  evaluateCycle(twoDisconnected);
   ASSERT_EQ(logger.entries.size(), 2u);
   EXPECT_EQ(logger.entries[1].id, SensorID::BMS_T3_Temp);
   EXPECT_EQ(logger.entries[1].lvl, AlertLevel::OK);

From ed07a2c4a80316fbb400c3490cd6e354682adb7d Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Wed, 11 Mar 2026 13:28:45 -0500
Subject: [PATCH 10/12] Bump espressif32 and Adafruit libs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Update platformio.ini to use espressif32@6.13.0 and bump several Adafruit libraries: Adafruit BusIO 1.17.2→1.17.4, Adafruit NeoPixel 1.15.2→1.15.4, and Adafruit CAN 0.2.1→0.2.3. These dependency updates improve compatibility and include upstream fixes for the OpenPPG-CESP32S3-CAN-SP140 environment.
---
 platformio.ini | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/platformio.ini b/platformio.ini
index 3d8bc0e3..f5f21ae4 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -21,7 +21,7 @@ lib_ignore =
 
 
 [env:OpenPPG-CESP32S3-CAN-SP140]
-platform = espressif32@6.12.0
+platform = espressif32@6.13.0
 board = m5stack-stamps3
 framework = arduino
 src_folder = sp140
@@ -45,11 +45,11 @@ lib_deps =
 	SPI
 	ArduinoJson@7.3.1
 	Time@1.6.1
-	adafruit/Adafruit BusIO@1.17.2
+	adafruit/Adafruit BusIO@1.17.4
 	adafruit/Adafruit BMP3XX Library@2.1.6
 	adafruit/Adafruit ST7735 and ST7789 Library@1.11.0
-	adafruit/Adafruit NeoPixel@1.15.2
-	adafruit/Adafruit CAN@0.2.1
+	adafruit/Adafruit NeoPixel@1.15.4
+	adafruit/Adafruit CAN@0.2.3
 	adafruit/Adafruit MCP2515@0.2.1
 	https://github.com/rlogiacco/CircularBuffer@1.4.0
 	https://github.com/openppg/SINE-ESC-CAN#8caa93996b5d000fe10ca5265bd1c472dfdf885b

From e86c551d58d32dc3b797d7fce39fe8bd19e00b00 Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Wed, 11 Mar 2026 13:31:04 -0500
Subject: [PATCH 11/12] use merged in cell temp detection update in bms lib

---
 platformio.ini | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/platformio.ini b/platformio.ini
index f5f21ae4..0beb5bcf 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -53,7 +53,7 @@ lib_deps =
 	adafruit/Adafruit MCP2515@0.2.1
 	https://github.com/rlogiacco/CircularBuffer@1.4.0
 	https://github.com/openppg/SINE-ESC-CAN#8caa93996b5d000fe10ca5265bd1c472dfdf885b
-	https://github.com/openppg/ANT-BMS-CAN#567aca5b2fc4e4c9e9d315457324b97147613f37
+	https://github.com/openppg/ANT-BMS-CAN#fd54852bc6f1c9608e37af9ca7c13ea4135c095b
 	lvgl/lvgl@^8.4.0
 	h2zero/NimBLE-Arduino@^2.3.5
 lib_ignore =

From 7549747cc64c50d7dd2a4a59eb1243a7478df8f0 Mon Sep 17 00:00:00 2001
From: Zach Whitehead <zjwhitehead@users.noreply.github.com>
Date: Wed, 11 Mar 2026 14:09:23 -0500
Subject: [PATCH 12/12] Bump ArduinoJson and NimBLE-Arduino deps

Update platformio.ini to use ArduinoJson@7.4.3 (from 7.3.1) and h2zero/NimBLE-Arduino@^2.3.9 (from ^2.3.5). This brings in upstream fixes and improvements for JSON handling and BLE stack compatibility.
---
 platformio.ini | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/platformio.ini b/platformio.ini
index 0beb5bcf..7749a8b7 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -43,7 +43,7 @@ debug_tool = esp-builtin
 lib_deps =
 	Wire
 	SPI
-	ArduinoJson@7.3.1
+	ArduinoJson@7.4.3
 	Time@1.6.1
 	adafruit/Adafruit BusIO@1.17.4
 	adafruit/Adafruit BMP3XX Library@2.1.6
@@ -55,7 +55,7 @@ lib_deps =
 	https://github.com/openppg/SINE-ESC-CAN#8caa93996b5d000fe10ca5265bd1c472dfdf885b
 	https://github.com/openppg/ANT-BMS-CAN#fd54852bc6f1c9608e37af9ca7c13ea4135c095b
 	lvgl/lvgl@^8.4.0
-	h2zero/NimBLE-Arduino@^2.3.5
+	h2zero/NimBLE-Arduino@^2.3.9
 lib_ignore =
 	Adafruit SleepyDog Library
 	${extra.lib_ignore}