Feature: DPL: support overscaling on all inverters (#1286)

this change allows to support overscaling for all inverters, as the configuration of
inputs (which one is part of a particular MPPT) is now provided from withing the
code. this information is used to implement overscaling for any of the inverters
(which are generally compatible with OpenDTU(-OnBattery)).

lib/Hoymiles/src/inverters/HERF_1CH.cpp

@@ -29,6 +29,10 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A }
+};
+
 HERF_1CH::HERF_1CH(HoymilesRadio* radio, const uint64_t serial)
     : HM_Abstract(radio, serial) {};
 
@@ -53,3 +57,13 @@ uint8_t HERF_1CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HERF_1CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HERF_1CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HERF_1CH.h

@@ -10,4 +10,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
 };

lib/Hoymiles/src/inverters/HERF_2CH.cpp

@@ -36,6 +36,11 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A },
+    { CH1, MPPT_B }
+};
+
 HERF_2CH::HERF_2CH(HoymilesRadio* radio, const uint64_t serial)
     : HM_Abstract(radio, serial) {};
 
@@ -60,3 +65,13 @@ uint8_t HERF_2CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HERF_2CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HERF_2CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HERF_2CH.h

@@ -10,4 +10,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
 };

lib/Hoymiles/src/inverters/HMS_1CH.cpp

@@ -28,6 +28,10 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A }
+};
+
 HMS_1CH::HMS_1CH(HoymilesRadio* radio, const uint64_t serial)
     : HMS_Abstract(radio, serial) {};
 
@@ -52,3 +56,13 @@ uint8_t HMS_1CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HMS_1CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HMS_1CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HMS_1CH.h

@@ -11,4 +11,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HMS_1CHv2.cpp

@@ -28,6 +28,10 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A }
+};
+
 HMS_1CHv2::HMS_1CHv2(HoymilesRadio* radio, const uint64_t serial)
     : HMS_Abstract(radio, serial) {};
 
@@ -52,3 +56,13 @@ uint8_t HMS_1CHv2::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HMS_1CHv2::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HMS_1CHv2::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HMS_1CHv2.h

@@ -11,4 +11,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HMS_2CH.cpp

@@ -35,6 +35,11 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A },
+    { CH1, MPPT_B }
+};
+
 HMS_2CH::HMS_2CH(HoymilesRadio* radio, const uint64_t serial)
     : HMS_Abstract(radio, serial) {};
 
@@ -59,3 +64,13 @@ uint8_t HMS_2CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HMS_2CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HMS_2CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HMS_2CH.h

@@ -11,4 +11,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HMS_4CH.cpp

@@ -49,6 +49,13 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A },
+    { CH1, MPPT_B },
+    { CH2, MPPT_C },
+    { CH3, MPPT_D }
+};
+
 HMS_4CH::HMS_4CH(HoymilesRadio* radio, const uint64_t serial)
     : HMS_Abstract(radio, serial) {};
 
@@ -73,3 +80,13 @@ uint8_t HMS_4CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HMS_4CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HMS_4CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HMS_4CH.h

@@ -10,4 +10,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HMT_4CH.cpp

@@ -58,6 +58,13 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A },
+    { CH1, MPPT_A },
+    { CH2, MPPT_B },
+    { CH3, MPPT_B }
+};
+
 HMT_4CH::HMT_4CH(HoymilesRadio* radio, const uint64_t serial)
     : HMT_Abstract(radio, serial) {};
 
@@ -82,3 +89,13 @@ uint8_t HMT_4CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HMT_4CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HMT_4CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HMT_4CH.h

@@ -10,4 +10,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HMT_6CH.cpp

@@ -72,6 +72,15 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A },
+    { CH1, MPPT_A },
+    { CH2, MPPT_B },
+    { CH3, MPPT_B },
+    { CH4, MPPT_C },
+    { CH5, MPPT_C }
+};
+
 HMT_6CH::HMT_6CH(HoymilesRadio* radio, const uint64_t serial)
     : HMT_Abstract(radio, serial) {};
 
@@ -96,3 +105,13 @@ uint8_t HMT_6CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HMT_6CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HMT_6CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HMT_6CH.h

@@ -10,4 +10,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HM_1CH.cpp

@@ -28,6 +28,10 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A }
+};
+
 HM_1CH::HM_1CH(HoymilesRadio* radio, const uint64_t serial)
     : HM_Abstract(radio, serial) {};
 
@@ -65,3 +69,13 @@ uint8_t HM_1CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HM_1CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HM_1CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HM_1CH.h

@@ -11,4 +11,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HM_2CH.cpp

@@ -36,6 +36,11 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A },
+    { CH1, MPPT_B }
+};
+
 HM_2CH::HM_2CH(HoymilesRadio* radio, const uint64_t serial)
     : HM_Abstract(radio, serial) {};
 
@@ -73,3 +78,13 @@ uint8_t HM_2CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HM_2CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HM_2CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HM_2CH.h

@@ -10,4 +10,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/HM_4CH.cpp

@@ -49,6 +49,13 @@ static const byteAssign_t byteAssignment[] = {
     { TYPE_INV, CH0, FLD_EFF, UNIT_PCT, CALC_TOTAL_EFF, 0, CMD_CALC, false, 3 }
 };
 
+static const channelMetaData_t channelMetaData[] = {
+    { CH0, MPPT_A },
+    { CH1, MPPT_A },
+    { CH2, MPPT_B },
+    { CH3, MPPT_B }
+};
+
 HM_4CH::HM_4CH(HoymilesRadio* radio, const uint64_t serial)
     : HM_Abstract(radio, serial) {};
 
@@ -86,3 +93,13 @@ uint8_t HM_4CH::getByteAssignmentSize() const
 {
     return sizeof(byteAssignment) / sizeof(byteAssignment[0]);
 }
+
+const channelMetaData_t* HM_4CH::getChannelMetaData() const
+{
+    return channelMetaData;
+}
+
+uint8_t HM_4CH::getChannelMetaDataSize() const
+{
+    return sizeof(channelMetaData) / sizeof(channelMetaData[0]);
+}

lib/Hoymiles/src/inverters/HM_4CH.h

@@ -10,4 +10,6 @@ public:
     String typeName() const;
     const byteAssign_t* getByteAssignment() const;
     uint8_t getByteAssignmentSize() const;
-};
+    const channelMetaData_t* getChannelMetaData() const;
+    uint8_t getChannelMetaDataSize() const;
+};

lib/Hoymiles/src/inverters/InverterAbstract.cpp

@@ -298,3 +298,35 @@ void InverterAbstract::resetRadioStats()
 {
     RadioStats = {};
 }
+
+std::vector<ChannelNum_t> InverterAbstract::getChannelsDC() const
+{
+    std::vector<ChannelNum_t> l;
+    for (uint8_t i = 0; i < getChannelMetaDataSize(); i++) {
+        l.push_back(getChannelMetaData()[i].ch);
+    }
+    return l;
+}
+
+std::vector<MpptNum_t> InverterAbstract::getMppts() const
+{
+    std::vector<MpptNum_t> l;
+    for (uint8_t i = 0; i < getChannelMetaDataSize(); i++) {
+        auto m = getChannelMetaData()[i].mppt;
+        if (l.end() == std::find(l.begin(), l.end(), m)){
+            l.push_back(m);
+        }
+    }
+    return l;
+}
+
+std::vector<ChannelNum_t> InverterAbstract::getChannelsDCByMppt(const MpptNum_t mppt) const
+{
+    std::vector<ChannelNum_t> l;
+    for (uint8_t i = 0; i < getChannelMetaDataSize(); i++) {
+        if (getChannelMetaData()[i].mppt == mppt) {
+            l.push_back(getChannelMetaData()[i].ch);
+        }
+    }
+    return l;
+}

lib/Hoymiles/src/inverters/InverterAbstract.h

@@ -24,6 +24,20 @@ enum {
     FRAGMENT_OK = 0
 };
 
+enum MpptNum_t {
+    MPPT_A = 0,
+    MPPT_B,
+    MPPT_C,
+    MPPT_D,
+    MPPT_CNT
+};
+
+// additional meta data per input channel
+typedef struct {
+    ChannelNum_t ch; // channel 0 - 5
+    MpptNum_t mppt; // mppt a - d (0 - 3)
+} channelMetaData_t;
+
 #define MAX_RF_FRAGMENT_COUNT 13
 
 class CommandAbstract;
@@ -40,6 +54,9 @@ public:
     virtual const byteAssign_t* getByteAssignment() const = 0;
     virtual uint8_t getByteAssignmentSize() const = 0;
 
+    virtual const channelMetaData_t* getChannelMetaData() const = 0;
+    virtual uint8_t getChannelMetaDataSize() const = 0;
+
     bool isProducing();
     bool isReachable();
 
@@ -112,6 +129,10 @@ public:
     StatisticsParser* Statistics();
     SystemConfigParaParser* SystemConfigPara();
 
+    std::vector<MpptNum_t> getMppts() const;
+    std::vector<ChannelNum_t> getChannelsDC() const;
+    std::vector<ChannelNum_t> getChannelsDCByMppt(const MpptNum_t mppt) const;
+
 protected:
     HoymilesRadio* _radio;
 

src/PowerLimiterInverter.cpp

@@ -3,7 +3,6 @@
 #include "PowerLimiterInverter.h"
 #include "PowerLimiterBatteryInverter.h"
 #include "PowerLimiterSolarInverter.h"
-#include "inverters/HMS_4CH.h"
 
 std::unique_ptr<PowerLimiterInverter> PowerLimiterInverter::create(
         bool verboseLogging, PowerLimiterInverterConfig const& config)

src/PowerLimiterSolarInverter.cpp

@@ -1,6 +1,5 @@
 #include "MessageOutput.h"
 #include "PowerLimiterSolarInverter.h"
-#include "inverters/HMS_4CH.h"
 
 PowerLimiterSolarInverter::PowerLimiterSolarInverter(bool verboseLogging, PowerLimiterInverterConfig const& config)
     : PowerLimiterInverter(verboseLogging, config) { }
@@ -73,16 +72,13 @@ uint16_t PowerLimiterSolarInverter::scaleLimit(uint16_t expectedOutputWatts)
     if (!isProducing()) { return expectedOutputWatts; }
 
     auto pStats = _spInverter->Statistics();
-    std::list<ChannelNum_t> dcChnls = pStats->getChannelsByType(TYPE_DC);
+    std::vector<ChannelNum_t> dcChnls = _spInverter->getChannelsDC();
+    std::vector<MpptNum_t> dcMppts = _spInverter->getMppts();
     size_t dcTotalChnls = dcChnls.size();
+    size_t dcTotalMppts = dcMppts.size();
 
-    // according to the upstream projects README (table with supported devs),
-    // every 2 channel inverter has 2 MPPTs. then there are the HM*S* 4 channel
-    // models which have 4 MPPTs. all others have a different number of MPPTs
-    // than inputs. those are not supported by the current scaling mechanism.
-    bool supported = dcTotalChnls == 2;
-    supported |= dcTotalChnls == 4 && HMS_4CH::isValidSerial(getSerial());
-    if (!supported) { return expectedOutputWatts; }
+    // if there is only one MPPT available, there is nothing we can do
+    if (dcTotalMppts <= 1) { return expectedOutputWatts; }
 
     // test for a reasonable power limit that allows us to assume that an input
     // channel with little energy is actually not producing, rather than
@@ -101,37 +97,42 @@ uint16_t PowerLimiterSolarInverter::scaleLimit(uint16_t expectedOutputWatts)
         inverterEfficiencyFactor = (inverterEfficiencyFactor > 0) ? inverterEfficiencyFactor/100 : 0.967;
 
         // 98% of the expected power is good enough
-        auto expectedAcPowerPerChannel = (getCurrentLimitWatts() / dcTotalChnls) * 0.98;
+        auto expectedAcPowerPerMppt = (getCurrentLimitWatts() / dcTotalMppts) * 0.98;
 
         if (_verboseLogging) {
-            MessageOutput.printf("%s expected AC power per channel %f W\r\n",
-                    _logPrefix, expectedAcPowerPerChannel);
+            MessageOutput.printf("%s expected AC power per mppt %f W\r\n",
+                    _logPrefix, expectedAcPowerPerMppt);
         }
 
-        size_t dcShadedChnls = 0;
+        size_t dcShadedMppts = 0;
         auto shadedChannelACPowerSum = 0.0;
 
-        for (auto& c : dcChnls) {
-            auto channelPowerAC = pStats->getChannelFieldValue(TYPE_DC, c, FLD_PDC) * inverterEfficiencyFactor;
+        for (auto& m : dcMppts) {
+            float mpptPowerAC = 0.0;
+            std::vector<ChannelNum_t> mpptChnls = _spInverter->getChannelsDCByMppt(m);
 
-            if (channelPowerAC < expectedAcPowerPerChannel) {
-                dcShadedChnls++;
-                shadedChannelACPowerSum += channelPowerAC;
+            for (auto& c : mpptChnls) {
+                mpptPowerAC += pStats->getChannelFieldValue(TYPE_DC, c, FLD_PDC) * inverterEfficiencyFactor;
+            }
+
+            if (mpptPowerAC < expectedAcPowerPerMppt) {
+                dcShadedMppts++;
+                shadedChannelACPowerSum += mpptPowerAC;
             }
 
             if (_verboseLogging) {
-                MessageOutput.printf("%s ch %d AC power %f W\r\n",
-                        _logPrefix, c, channelPowerAC);
+                MessageOutput.printf("%s mppt-%c AC power %f W\r\n",
+                        _logPrefix, m + 'a', mpptPowerAC);
             }
         }
 
         // no shading or the shaded channels provide more power than what
         // we currently need.
-        if (dcShadedChnls == 0 || shadedChannelACPowerSum >= expectedOutputWatts) {
+        if (dcShadedMppts == 0 || shadedChannelACPowerSum >= expectedOutputWatts) {
             return expectedOutputWatts;
         }
 
-        if (dcShadedChnls == dcTotalChnls) {
+        if (dcShadedMppts == dcTotalMppts) {
             // keep the currentLimit when:
             // - all channels are shaded
             // - currentLimit >= expectedOutputWatts
@@ -139,7 +140,7 @@ uint16_t PowerLimiterSolarInverter::scaleLimit(uint16_t expectedOutputWatts)
             if (getCurrentLimitWatts() >= expectedOutputWatts &&
                     inverterOutputAC <= expectedOutputWatts) {
                 if (_verboseLogging) {
-                    MessageOutput.printf("%s all channels are shaded, "
+                    MessageOutput.printf("%s all mppts are shaded, "
                             "keeping the current limit of %d W\r\n",
                             _logPrefix, getCurrentLimitWatts());
                 }
@@ -151,31 +152,38 @@ uint16_t PowerLimiterSolarInverter::scaleLimit(uint16_t expectedOutputWatts)
             }
         }
 
-        size_t dcNonShadedChnls = dcTotalChnls - dcShadedChnls;
-        uint16_t overScaledLimit = (expectedOutputWatts - shadedChannelACPowerSum) / dcNonShadedChnls * dcTotalChnls;
+        size_t dcNonShadedMppts = dcTotalMppts - dcShadedMppts;
+        uint16_t overScaledLimit = (expectedOutputWatts - shadedChannelACPowerSum) / dcNonShadedMppts * dcTotalMppts;
 
         if (overScaledLimit <= expectedOutputWatts) { return expectedOutputWatts; }
 
         if (_verboseLogging) {
-            MessageOutput.printf("%s %d/%d channels are shaded, scaling %d W\r\n",
-                    _logPrefix, dcShadedChnls, dcTotalChnls, overScaledLimit);
+            MessageOutput.printf("%s %d/%d mppts are shaded, scaling %d W\r\n",
+                    _logPrefix, dcShadedMppts, dcTotalMppts, overScaledLimit);
         }
 
         return overScaledLimit;
     }
 
-    size_t dcProdChnls = 0;
-    for (auto& c : dcChnls) {
-        if (pStats->getChannelFieldValue(TYPE_DC, c, FLD_PDC) > 2.0) {
-            dcProdChnls++;
+    size_t dcProdMppts = 0;
+    for (auto& m : dcMppts) {
+        float dcPowerMppt = 0.0;
+        std::vector<ChannelNum_t> mpptChnls = _spInverter->getChannelsDCByMppt(m);
+
+        for (auto& c : mpptChnls) {
+            dcPowerMppt += pStats->getChannelFieldValue(TYPE_DC, c, FLD_PDC);
+        }
+
+        if (dcPowerMppt > 2.0 * mpptChnls.size()) {
+            dcProdMppts++;
         }
     }
 
-    if (dcProdChnls == 0 || dcProdChnls == dcTotalChnls) { return expectedOutputWatts; }
+    if (dcProdMppts == 0 || dcProdMppts == dcTotalMppts) { return expectedOutputWatts; }
 
-    uint16_t scaled = expectedOutputWatts / dcProdChnls * dcTotalChnls;
-    MessageOutput.printf("%s %d/%d channels are producing, scaling from %d to "
-            "%d W\r\n", _logPrefix, dcProdChnls, dcTotalChnls,
+    uint16_t scaled = expectedOutputWatts / dcProdMppts * dcTotalMppts;
+    MessageOutput.printf("%s %d/%d mppts are producing, scaling from %d to "
+            "%d W\r\n", _logPrefix, dcProdMppts, dcTotalMppts,
             expectedOutputWatts, scaled);
 
     return scaled;