Pytes battery: Add support for native CAN protocol

The recently added PytesCanReceiver.cpp implements the Victron CAN protocol.

This change additionally adds support for the native Pytes CAN
protocol messages.

Features only supported in Pytes protocol:
- High-resolution state of charge / full and remaining mAh
- Charge cycle counter
- Balancing state

Features only supported in Victron protocol:
- FW version
- Serial number

Note that the only known way to select the native Pytes protocol is
via the serial console (Cisco-compatible cables work):

```
login config
setprt PYTES
logout
```

to return to Victron protocol use:
```
login config
setprt VICTRON
logout
```

to retrun to DIP-switch based protocol setting:
```
login config
setprt DIP
logout
```

The protocol switch should take effect immediately.

Tested on Pytes E-Box 4850

include/BatteryStats.h

@@ -199,6 +199,8 @@ class PytesBatteryStats : public BatteryStats {
         float _dischargeVoltageLimit;
 
         uint16_t _stateOfHealth;
+        int _chargeCycles = -1;
+        int _balance = -1;
 
         float _temperature;
 
@@ -218,8 +220,9 @@ class PytesBatteryStats : public BatteryStats {
         uint8_t _moduleCountBlockingCharge;
         uint8_t _moduleCountBlockingDischarge;
 
-        uint16_t _totalCapacity;
-        uint16_t _availableCapacity;
+        float _totalCapacity;
+        float _availableCapacity;
+        uint8_t _capacityPrecision = 0; // decimal places
 
         float _chargedEnergy = -1;
         float _dischargedEnergy = -1;

src/BatteryStats.cpp

@@ -187,10 +187,13 @@ void PytesBatteryStats::getLiveViewData(JsonVariant& root) const
     addLiveViewValue(root, "chargeCurrentLimitation", _chargeCurrentLimit, "A", 1);
     addLiveViewValue(root, "dischargeVoltageLimitation", _dischargeVoltageLimit, "V", 1);
     addLiveViewValue(root, "stateOfHealth", _stateOfHealth, "%", 0);
+    if (_chargeCycles != -1) {
+        addLiveViewValue(root, "chargeCycles", _chargeCycles, "", 0);
+    }
     addLiveViewValue(root, "temperature", _temperature, "°C", 1);
 
-    addLiveViewValue(root, "capacity", _totalCapacity, "Ah", 0);
-    addLiveViewValue(root, "availableCapacity", _availableCapacity, "Ah", 0);
+    addLiveViewValue(root, "capacity", _totalCapacity, "Ah", _capacityPrecision);
+    addLiveViewValue(root, "availableCapacity", _availableCapacity, "Ah", _capacityPrecision);
 
     if (_chargedEnergy != -1) {
         addLiveViewValue(root, "chargedEnergy", _chargedEnergy, "kWh", 1);
@@ -201,6 +204,10 @@ void PytesBatteryStats::getLiveViewData(JsonVariant& root) const
     }
     addLiveViewTextValue(root, "chargeImmediately", (_chargeImmediately?"yes":"no"));
 
+    if (_balance != -1) {
+        addLiveViewTextValue(root, "balancingActive", (_balance?"yes":"no"));
+    }
+
     addLiveViewInSection(root, "cells", "cellMinVoltage", static_cast<float>(_cellMinMilliVolt)/1000, "V", 3);
     addLiveViewInSection(root, "cells", "cellMaxVoltage", static_cast<float>(_cellMaxMilliVolt)/1000, "V", 3);
     addLiveViewInSection(root, "cells", "cellDiffVoltage", (_cellMaxMilliVolt - _cellMinMilliVolt), "mV", 0);
@@ -430,6 +437,12 @@ void PytesBatteryStats::mqttPublish() const
     MqttSettings.publish("battery/settings/dischargeVoltageLimitation", String(_dischargeVoltageLimit));
 
     MqttSettings.publish("battery/stateOfHealth", String(_stateOfHealth));
+    if (_chargeCycles != -1) {
+        MqttSettings.publish("battery/chargeCycles", String(_chargeCycles));
+    }
+    if (_balance != -1) {
+        MqttSettings.publish("battery/balancingActive", String(_balance ? 1 : 0));
+    }
     MqttSettings.publish("battery/temperature", String(_temperature));
 
     if (_chargedEnergy != -1) {

src/MqttHandleBatteryHass.cpp

@@ -136,6 +136,7 @@ void MqttHandleBatteryHassClass::loop()
             publishSensor("Current", "mdi:current-dc", "current", "current", "measurement", "A");
             publishSensor("State of Health (SOH)", "mdi:heart-plus", "stateOfHealth", NULL, "measurement", "%");
             publishSensor("Temperature", "mdi:thermometer", "temperature", "temperature", "measurement", "°C");
+            publishSensor("Charge Cycles", "mdi:counter", "chargeCycles");
 
             publishSensor("Charged Energy", NULL, "chargedEnergy", "energy", "total_increasing", "kWh");
             publishSensor("Discharged Energy", NULL, "dischargedEnergy", "energy", "total_increasing", "kWh");
@@ -181,6 +182,7 @@ void MqttHandleBatteryHassClass::loop()
             publishBinarySensor("Warning BMS internal", "mdi:alert-outline", "warning/bmsInternal", "1", "0");
             publishBinarySensor("Warning Cell Imbalance", "mdi:alert-outline", "warning/cellImbalance", "1", "0");
 
+            publishBinarySensor("Balancing Active", "mdi:scale-balance", "balancingActive", "1", "0");
             publishBinarySensor("Charge immediately", "mdi:alert", "charging/chargeImmediately", "1", "0");
             break;