Add support for 2mppt

[saschalenz]

This PR adds support for a second MPPT Like the Kodak OG10 has two MPPTs.

• Added config point to give the number of mppts. This can currently be 1 or 2
• Added the new values to the mqtt topic and influx

example output:

{
  "Inverter_mode":3,
  "AC_grid_voltage":233.8,
  "AC_grid_frequency":50.0,
  "AC_out_voltage":233.8,
  "AC_out_frequency":50.0,
  "Load_va":1823,
  "Load_watt":1794,
  "Load_pct":18,
  "Bus_voltage":435,
  "Battery_voltage":55.50,
  "Battery_charge_current":0,
  "Battery_capacity":99,
  "Heatsink_temperature":35,
  "PV_in_current":0.3,
  "PV_in_voltage":90.0,
  "SCC_voltage":0.0000,
  "Battery_discharge_current":0,
  "PV_in_watts":0.0,
  "Load_status_on":1,
  "SCC_charge_on":1,
  "AC_charge_on":0,
  "Battery_voltage_offset_for_fans_on":0,
  "Eeprom_version":0,
  "PV_charging_power":33,
  "Charging_to_floating_mode":1,
  "Switch_On":1,
  "Dustproof_installed":0,
  "Grid_voltage_rating":230.0,
  "Grid_current_rating":43.4,
  "Out_voltage_rating":230.0,
  "Out_freq_rating":50.0,
  "Out_current_rating":43.4,
  "Out_va_rating":43.4,
  "Out_watt_rating":43.4,
  "Battery_rating":48.0,
  "Battery_recharge_voltage":51.0,
  "Battery_under_voltage":44.8,
  "Battery_bulk_voltage":56.0,
  "Battery_float_voltage":56.0,
  "Battery_type":8,
  "Max_grid_charge_current":40,
  "Max_charge_current":100,
  "In_voltage_range":1,
  "Out_source_priority":1,
  "Charger_source_priority":2,
  "Parallel_max_num":57,
  "Machine_type":1,
  "Topology":0,
  "Out_mode":0,
  "Battery_redischarge_voltage":54.0,
  "PV2_in_voltage":89.9,
  "PV2_in_current":0.3,
  "PV2_in_watts":0.0,
  "PV2_charging_power":34,
  "PV_total_charging_power":67,
  "Warnings":"000000000000000000000000000000000000"
}

[Phalanxguard]

This would actually be incredibly helpful if this were integrated into your repo. It would be great to monitor both MPPTs!

[gobotix]

I actually just added QPIGS2 2nd MPPT myself THEN afterwards found your fork in the "pull requests" .... However, I also had to make a change to the send() command because on the /dev/hiddraw interface it not only requires data to be chunked up to 8-bytes but also requires the last byte to be padded up to 8bytes (on my OS anyway) otherwise it simply fails to write the last 1 byte of the QPIGS2 command. This might be useful to others who when testing the QPIGS2 command on the command line it fails when using the hiddraw interface.

while (remaining > 0) {
if (remaining < 8) {
// the commands need to be chunked up to 8 bytes, so if a command is 9 bytes long, it needs to be sent in chunks of 8 bytes but the last chunk must be padded up to 8 bytes when using hiddraw interface
int padcount = 8 - remaining;
for (int pad = 0; pad < padcount; pad++) {
buf[bytes_sent+remaining+pad] = 0;
}
chunk_size = 8; // force it to write a whole byte
}

ssize_t written = write(fd, &buf[bytes_sent], chunk_size);
bytes_sent += written;
if (remaining - written >= 0)
remaining -= written;
else
remaining = 0;

if (written < 0)
  lprintf("DEBUG:  Write command failed, error number %d was returned", errno);
else
  lprintf("DEBUG:  %d bytes written, %d bytes sent, %d bytes remaining", written, bytes_sent, remaining);

chunk_size = remaining;
usleep(50000);   // Sleep 50ms before sending another 8 bytes of info

}