VE.Direct: use float rather than double

double precision floating point numbers are not needed to handle
VE.Direct values. handling double is implemented in software and hence
*much* more resource intensive.

include/VictronMppt.h

@@ -34,13 +34,13 @@ public:
     int32_t getPanelPowerWatts() const;
 
     // sum of total yield of all MPPT charge controllers in kWh
-    double getYieldTotal() const;
+    float getYieldTotal() const;
 
     // sum of today's yield of all MPPT charge controllers in kWh
-    double getYieldDay() const;
+    float getYieldDay() const;
 
     // minimum of all MPPT charge controllers' output voltages in V
-    double getOutputVoltage() const;
+    float getOutputVoltage() const;
 
 private:
     void loop();

lib/VeDirectFrameHandler/VeDirectData.h

@@ -10,9 +10,9 @@ typedef struct {
     uint16_t PID = 0;               // product id
     char SER[VE_MAX_VALUE_LEN];     // serial number
     char FW[VE_MAX_VALUE_LEN];      // firmware release number
-    double V = 0;                   // battery voltage in V
-    double I = 0;                   // battery current in A
-    double E = 0;                   // efficiency in percent (calculated, moving average)
+    float V = 0;                    // battery voltage in V
+    float I = 0;                    // battery current in A
+    float E = 0;                    // efficiency in percent (calculated, moving average)
 
     frozen::string const& getPidAsString() const; // product ID as string
 } veStruct;
@@ -21,17 +21,17 @@ struct veMpptStruct : veStruct {
     uint8_t MPPT;                   // state of MPP tracker
     int32_t PPV;                    // panel power in W
     int32_t P;                      // battery output power in W (calculated)
-    double VPV;                     // panel voltage in V
-    double IPV;                     // panel current in A (calculated)
+    float VPV;                      // panel voltage in V
+    float IPV;                      // panel current in A (calculated)
     bool LOAD;                      // virtual load output state (on if battery voltage reaches upper limit, off if battery reaches lower limit)
     uint8_t CS;                     // current state of operation e.g. OFF or Bulk
     uint8_t ERR;                    // error code
     uint32_t OR;                    // off reason
     uint32_t HSDS;                  // day sequence number 1...365
-    double H19;                     // yield total kWh
-    double H20;                     // yield today kWh
+    float H19;                      // yield total kWh
+    float H20;                      // yield today kWh
     int32_t H21;                    // maximum power today W
-    double H22;                     // yield yesterday kWh
+    float H22;                      // yield yesterday kWh
     int32_t H23;                    // maximum power yesterday W
 
     frozen::string const& getMpptAsString() const; // state of mppt as string

lib/VeDirectFrameHandler/VeDirectMpptController.cpp

@@ -76,7 +76,7 @@ void VeDirectMpptController::frameValidEvent() {
 	}
 
 	if (_tmpFrame.PPV > 0) {
-		_efficiency.addNumber(static_cast<double>(_tmpFrame.P * 100) / _tmpFrame.PPV);
+		_efficiency.addNumber(static_cast<float>(_tmpFrame.P * 100) / _tmpFrame.PPV);
 		_tmpFrame.E = _efficiency.getAverage();
 	}
 }

lib/VeDirectFrameHandler/VeDirectMpptController.h

@@ -24,9 +24,9 @@ public:
         _index = (_index + 1) % WINDOW_SIZE;
     }
 
-    double getAverage() const {
+    float getAverage() const {
         if (_count == 0) { return 0.0; }
-        return static_cast<double>(_sum) / _count;
+        return static_cast<float>(_sum) / _count;
     }
 
 private:
@@ -47,5 +47,5 @@ public:
 private:
     bool processTextDataDerived(std::string const& name, std::string const& value) final;
     void frameValidEvent() final;
-    MovingAverage<double, 5> _efficiency;
+    MovingAverage<float, 5> _efficiency;
 };

src/VictronMppt.cpp

@@ -158,9 +158,9 @@ int32_t VictronMpptClass::getPanelPowerWatts() const
     return sum;
 }
 
-double VictronMpptClass::getYieldTotal() const
+float VictronMpptClass::getYieldTotal() const
 {
-    double sum = 0;
+    float sum = 0;
 
     for (const auto& upController : _controllers) {
         if (!upController->isDataValid()) { continue; }
@@ -170,9 +170,9 @@ double VictronMpptClass::getYieldTotal() const
     return sum;
 }
 
-double VictronMpptClass::getYieldDay() const
+float VictronMpptClass::getYieldDay() const
 {
-    double sum = 0;
+    float sum = 0;
 
     for (const auto& upController : _controllers) {
         if (!upController->isDataValid()) { continue; }
@@ -182,13 +182,13 @@ double VictronMpptClass::getYieldDay() const
     return sum;
 }
 
-double VictronMpptClass::getOutputVoltage() const
+float VictronMpptClass::getOutputVoltage() const
 {
-    double min = -1;
+    float min = -1;
 
     for (const auto& upController : _controllers) {
         if (!upController->isDataValid()) { continue; }
-        double volts = upController->getData().V;
+        float volts = upController->getData().V;
         if (min == -1) { min = volts; }
         min = std::min(min, volts);
     }