Move the battery power calculation part to the BatteryMonitor class

Author: m-RNA

components/CommandManager/CommandManager/commands/device_commands.cpp

@@ -1,6 +1,4 @@
 #include "device_commands.hpp"
-#include <algorithm>
-#include <array>
 #include "LEDManager.hpp"
 #include "MonitoringManager.hpp"
 #include "esp_mac.h"
@@ -230,53 +228,15 @@ CommandResult getBatteryStatusCommand(std::shared_ptr<DependencyRegistry> regist
         return CommandResult::getErrorResult("MonitoringManager unavailable");
     }
 
-    const float volts = mon->getBatteryVoltageMilliVolts();
-    if (volts <= 0.0f)
+    const auto status = mon->getBatteryStatus();
+    if (!status.valid)
     {
         return CommandResult::getErrorResult("Battery voltage unavailable");
     }
 
-    struct VoltageSOC
-    {
-        float voltage_mv;
-        float soc;
-    };
-
-    constexpr std::array<VoltageSOC, 12> lookup = {
-        VoltageSOC{4200.0f, 100.0f}, VoltageSOC{4060.0f, 90.0f}, VoltageSOC{3980.0f, 80.0f}, VoltageSOC{3920.0f, 70.0f},
-        VoltageSOC{3870.0f, 60.0f},  VoltageSOC{3820.0f, 50.0f}, VoltageSOC{3790.0f, 40.0f}, VoltageSOC{3770.0f, 30.0f},
-        VoltageSOC{3740.0f, 20.0f},  VoltageSOC{3680.0f, 10.0f}, VoltageSOC{3450.0f, 5.0f},  VoltageSOC{3300.0f, 0.0f},
-    };
-
-    float percent = 0.0f;
-    if (volts >= lookup.front().voltage_mv)
-    {
-        percent = lookup.front().soc;
-    }
-    else if (volts <= lookup.back().voltage_mv)
-    {
-        percent = lookup.back().soc;
-    }
-    else
-    {
-        for (size_t index = 0; index < lookup.size() - 1; ++index)
-        {
-            const auto high = lookup[index];
-            const auto low = lookup[index + 1];
-            if (volts <= high.voltage_mv && volts >= low.voltage_mv)
-            {
-                const float span = high.voltage_mv - low.voltage_mv;
-                const float ratio = (volts - low.voltage_mv) / (span > 0.0f ? span : 1.0f);
-                percent = low.soc + ratio * (high.soc - low.soc);
-                break;
-            }
-        }
-    }
-    percent = std::clamp(percent, 0.0f, 100.0f);
-
     const auto json = nlohmann::json{
-        {"voltage_mv", std::format("{:.2f}", static_cast<double>(volts))},
-        {"percentage", std::format("{:.1f}", static_cast<double>(percent))},
+        {"voltage_mv", std::format("{:.2f}", static_cast<double>(status.voltage_mv))},
+        {"percentage", std::format("{:.1f}", static_cast<double>(status.percentage))},
     };
     return CommandResult::getSuccessResult(json);
 #else

components/Monitoring/Monitoring/BatteryMonitor.cpp

@@ -71,3 +71,52 @@ int BatteryMonitor::getBatteryMilliVolts() const
     return 0;
 #endif
 }
+
+float BatteryMonitor::voltageToPercentage(int voltage_mv)
+{
+    const float volts = static_cast<float>(voltage_mv);
+
+    // Handle boundary conditions
+    if (volts >= soc_lookup_.front().voltage_mv)
+        return soc_lookup_.front().soc;
+
+    if (volts <= soc_lookup_.back().voltage_mv)
+        return soc_lookup_.back().soc;
+
+    // Linear interpolation between lookup table points
+    for (size_t i = 0; i < soc_lookup_.size() - 1; ++i)
+    {
+        const auto &high = soc_lookup_[i];
+        const auto &low = soc_lookup_[i + 1];
+
+        if (volts <= high.voltage_mv && volts >= low.voltage_mv)
+        {
+            const float voltage_span = high.voltage_mv - low.voltage_mv;
+            if (voltage_span <= 0.0f)
+            {
+                return low.soc;
+            }
+            const float ratio = (volts - low.voltage_mv) / voltage_span;
+            return low.soc + ratio * (high.soc - low.soc);
+        }
+    }
+
+    return 0.0f;
+}
+
+BatteryStatus BatteryMonitor::getBatteryStatus() const
+{
+    BatteryStatus status = {0, 0.0f, false};
+
+#if CONFIG_MONITORING_BATTERY_ENABLE
+    const int mv = getBatteryMilliVolts();
+    if (mv <= 0)
+        return status;
+
+    status.voltage_mv = mv;
+    status.percentage = std::clamp(voltageToPercentage(mv), 0.0f, 100.0f);
+    status.valid = true;
+#endif
+
+    return status;
+}

components/Monitoring/Monitoring/BatteryMonitor.hpp

@@ -14,15 +14,31 @@
  * +-----------------------+
  */
 
+#include <algorithm>
+#include <array>
+#include <cmath>
 #include "AdcSampler.hpp"
 #include "sdkconfig.h"
-#include <cmath>
+
+
+/**
+ * @struct BatteryStatus
+ * @brief Battery status information
+ */
+struct BatteryStatus
+{
+    int voltage_mv;    // Battery voltage in millivolts
+    float percentage;  // State of charge percentage (0-100%)
+    bool valid;        // Whether the reading is valid
+};
 
 /**
  * @class BatteryMonitor
- * @brief Monitors battery voltage through a resistor divider
+ * @brief Monitors battery voltage and calculates state of charge for Li-ion batteries
  *
  * Uses AdcSampler (BSP layer) for hardware abstraction.
+ * Includes voltage-to-SOC lookup table for typical Li-ion/Li-Po batteries.
+ *
  * Configuration is done via Kconfig options:
  * - CONFIG_MONITORING_BATTERY_ENABLE
  * - CONFIG_MONITORING_BATTERY_ADC_GPIO
@@ -39,10 +55,29 @@ class BatteryMonitor
     // Initialize battery monitoring hardware
     bool setup();
 
-    // Read once, update filter, and return battery voltage in mV (after divider compensation), 0 on failure
+    /**
+     * @brief Read battery voltage (with divider compensation)
+     * @return Battery voltage in millivolts, 0 on failure
+     */
     int getBatteryMilliVolts() const;
 
-    // Whether monitoring is enabled by Kconfig and supported by BSP
+    /**
+     * @brief Calculate battery state of charge from voltage
+     * @param voltage_mv Battery voltage in millivolts
+     * @return State of charge percentage (0-100%)
+     */
+    static float voltageToPercentage(int voltage_mv);
+
+    /**
+     * @brief Get complete battery status (voltage + percentage)
+     * @return BatteryStatus struct with voltage, percentage, and validity
+     */
+    BatteryStatus getBatteryStatus() const;
+
+    /**
+     * @brief Check if battery monitoring is enabled and supported
+     * @return true if enabled and ADC is supported
+     */
     static constexpr bool isEnabled()
     {
 #ifdef CONFIG_MONITORING_BATTERY_ENABLE
@@ -53,6 +88,34 @@ class BatteryMonitor
     }
 
 private:
-    float scale_{1.0f}; // Voltage divider scaling factor
+    /**
+     * @brief Li-ion/Li-Po voltage to SOC lookup table entry
+     */
+    struct VoltageSOC
+    {
+        float voltage_mv;
+        float soc;
+    };
+
+    /**
+     * @brief Typical Li-ion single cell discharge curve lookup table
+     * Based on typical 3.7V nominal Li-ion/Li-Po cell characteristics
+     */
+    static constexpr std::array<VoltageSOC, 12> soc_lookup_ = {{
+        {4200.0f, 100.0f}, // Fully charged
+        {4060.0f, 90.0f},
+        {3980.0f, 80.0f},
+        {3920.0f, 70.0f},
+        {3870.0f, 60.0f},
+        {3820.0f, 50.0f},
+        {3790.0f, 40.0f},
+        {3770.0f, 30.0f},
+        {3740.0f, 20.0f},
+        {3680.0f, 10.0f},
+        {3450.0f, 5.0f}, // Low battery warning
+        {3300.0f, 0.0f}, // Empty / cutoff voltage
+    }};
+
+    float scale_{1.0f};      // Voltage divider scaling factor
     mutable AdcSampler adc_; // ADC sampler instance (BSP layer)
 };

components/Monitoring/Monitoring/MonitoringManager.cpp

@@ -127,10 +127,11 @@ void MonitoringManager::run()
 #if CONFIG_MONITORING_BATTERY_ENABLE
         if (BatteryMonitor::isEnabled() && now_tick >= next_tick_bat)
         {
-            const int mv = bm_.getBatteryMilliVolts();
-            if (mv > 0)
+            const auto status = bm_.getBatteryStatus();
+            if (status.valid)
             {
-                last_battery_mv_.store(mv);
+                std::lock_guard<std::mutex> lock(battery_mutex_);
+                last_battery_status_ = status;
             }
             next_tick_bat = now_tick + batt_period;
         }
@@ -161,11 +162,14 @@ float MonitoringManager::getCurrentMilliAmps() const
     return 0.0f;
 }
 
-float MonitoringManager::getBatteryVoltageMilliVolts() const
+BatteryStatus MonitoringManager::getBatteryStatus() const
 {
 #if CONFIG_MONITORING_BATTERY_ENABLE
     if (BatteryMonitor::isEnabled())
-        return static_cast<float>(last_battery_mv_.load());
+    {
+        std::lock_guard<std::mutex> lock(battery_mutex_);
+        return last_battery_status_;
+    }
 #endif
-    return 0.0f;
+    return {0, 0.0f, false};
 }

components/Monitoring/Monitoring/MonitoringManager.hpp

@@ -19,6 +19,7 @@
 #include <freertos/FreeRTOS.h>
 #include <freertos/task.h>
 #include <atomic>
+#include <mutex>
 #include "BatteryMonitor.hpp"
 #include "CurrentMonitor.hpp"
 
@@ -47,8 +48,8 @@ class MonitoringManager
 
     // Latest filtered current in mA
     float getCurrentMilliAmps() const;
-    // Latest battery voltage in mV
-    float getBatteryVoltageMilliVolts() const;
+    // Get complete battery status (voltage + percentage + validity)
+    BatteryStatus getBatteryStatus() const;
 
     // Check if any monitoring feature is enabled
     static constexpr bool isEnabled()
@@ -62,7 +63,8 @@ class MonitoringManager
 
     TaskHandle_t task_{nullptr};
     std::atomic<float> last_current_ma_{0.0f};
-    std::atomic<int> last_battery_mv_{0};
+    BatteryStatus last_battery_status_{0, 0.0f, false};
+    mutable std::mutex battery_mutex_;  // Protect non-atomic BatteryStatus
 
     CurrentMonitor cm_;
     BatteryMonitor bm_;