VictronBTLELogger

Recieve Victron Bluetooth LE advertisments. Decrypt and log data by bluetooth address. Create SVG graphs of battery voltage and temperature in the style of https://github.com/wcbonner/GoveeBTTempLogger

Currently graphing SmartLithium Battery and Orion XS DC/DC Charger.

Example SVG Output

Quick Build Instructions

sudo apt install build-essential cmake git libdbus-1-dev libssl-dev
git clone https://github.com/wcbonner/VictronBTLELogger.git
cmake -S VictronBTLELogger -B VictronBTLELogger/build
cmake --build VictronBTLELogger/build
pushd VictronBTLELogger/build && cpack . && popd

Create file /etc/victronbtlelogger/victronencryptionkeys.txt in the following format using encryption keys captured from the VictronConnect App

CE:A5:D7:7B:CD:81  D9AB754E122C1234567890252795729F
F9:48:CF:18:57:62  18C16EB18D3B12345678908B10B9140C

Useful starting links

https://community.victronenergy.com/questions/187303/victron-bluetooth-advertising-protocol.html

https://www.victronenergy.com/live/open_source:start

https://github.com/keshavdv/victron-ble

DBus

I'm using the same dbus connection style to BlueZ I recently learned in my Govee project. This project does not link to bluetooth libraries directly. I've duplicated a couple of functions for handling bluetooth address structures safely.

#include <iomanip>
#include <iostream>
#include <regex>

#ifndef bdaddr_t
  /* BD Address */
  typedef struct {
    uint8_t b[6];
  } __attribute__((packed)) bdaddr_t;
#endif // !bdaddr_t
bool operator <(const bdaddr_t& a, const bdaddr_t& b)
{
  unsigned long long A = a.b[5];
  A = A << 8 | a.b[4];
  A = A << 8 | a.b[3];
  A = A << 8 | a.b[2];
  A = A << 8 | a.b[1];
  A = A << 8 | a.b[0];
  unsigned long long B = b.b[5];
  B = B << 8 | b.b[4];
  B = B << 8 | b.b[3];
  B = B << 8 | b.b[2];
  B = B << 8 | b.b[1];
  B = B << 8 | b.b[0];
  return(A < B);
}
bool operator ==(const bdaddr_t& a, const bdaddr_t& b)
{
  unsigned long long A = a.b[5];
  A = A << 8 | a.b[4];
  A = A << 8 | a.b[3];
  A = A << 8 | a.b[2];
  A = A << 8 | a.b[1];
  A = A << 8 | a.b[0];
  unsigned long long B = b.b[5];
  B = B << 8 | b.b[4];
  B = B << 8 | b.b[3];
  B = B << 8 | b.b[2];
  B = B << 8 | b.b[1];
  B = B << 8 | b.b[0];
  return(A == B);
}
std::string ba2string(const bdaddr_t& TheBlueToothAddress)
{
  std::ostringstream oss;
  for (auto i = 5; i >= 0; i--)
  {
    oss << std::hex << std::uppercase << std::setw(2) << std::setfill('0') << static_cast<int>(TheBlueToothAddress.b[i]);
    if (i > 0)
      oss << ":";
  }
  return (oss.str());
}
const std::regex BluetoothAddressRegex("((([[:xdigit:]]{2}:){5}))[[:xdigit:]]{2}");
bdaddr_t string2ba(const std::string& TheBlueToothAddressString)
{ 
  bdaddr_t TheBlueToothAddress({ 0 });
  if (std::regex_match(TheBlueToothAddressString, BluetoothAddressRegex))
  {
    std::stringstream ss(TheBlueToothAddressString);
    std::string byteString;
    int index(5);
    // Because I've verified the string format with regex I can safely run this loop knowing it'll get 6 bytes
    while (std::getline(ss, byteString, ':'))
      TheBlueToothAddress.b[index--] = std::stoi(byteString, nullptr, 16);
  }
  return(TheBlueToothAddress); 
}

OpenSSL

I had to learn to use OpenSSL to decrypt the AES CTR blocks that are being sent by Victron. This was very quick and dirty, but works.

#include <openssl/evp.h> // sudo apt install libssl-dev

uint8_t DecryptedData[32] { 0 };
if (sizeof(DecryptedData) >= (ManufacturerData.size() - 8)) // simple check to make sure we don't buffer overflow
{
  EVP_CIPHER_CTX* ctx = EVP_CIPHER_CTX_new();
  if (ctx != 0)
  {
    uint8_t InitializationVector[16] { ManufacturerData[5], ManufacturerData[6], 0}; // The first two bytes are assigned, the rest of the 16 are padded with zero

    if (1 == EVP_DecryptInit_ex(ctx, EVP_aes_128_ctr(), NULL, EncryptionKey.data(), InitializationVector))
    {
      int len(0);
      if (1 == EVP_DecryptUpdate(ctx, DecryptedData, &len, ManufacturerData.data() + 8, ManufacturerData.size() - 8))
      {
        if (1 == EVP_DecryptFinal_ex(ctx, DecryptedData + len, &len))
        {
          // We have decrypted data!
          ManufacturerData[5] = ManufacturerData[6] = ManufacturerData[7] = 0; // I'm writing a zero here to remind myself I've decoded the data already
          for (auto index = 0; index < ManufacturerData.size() - 8; index++) // copy the decoded data over the original data
            ManufacturerData[index+8] = DecryptedData[index];
        }
      }
    }
    EVP_CIPHER_CTX_free(ctx);
  }
}

Victron Extra Manufacturer Data

Victron refers to Extra Manufacturer Data. It's all manufacturer data at the bluetooth level. What Victron refers to as "Extra Manufacturer Data" starts at the 8th byte of the manufacturer data, and runs to the end of the Bluetooth Manufacturer Data record. Decoding the extra manufacturer data, Victron bit packs the extra data before encrypting it using the AES CTR method.

Manufacturer Data

Victron Data Structures (Extra Manufacturer Data)

Solar Charger (0x01)

Battery Monitor (0x02)

Inverter (0x03)

DC/DC Converter (0x04)

SmartLithium (0x05)

• VE_REG_BATTERY_CELL_VOLTAGE 0x00 ( 0) when cell voltage < 2.61V 0x01 ( 1) when cell voltage == 2.61V 0x7D (125) when cell voltage == 3.85V 0x7E (126) when cell voltage > 3.85 0x7F (127) when cell voltage is not available / unknown

Inverter RS (0x06)

GX-Device (0x07)

Record layout is still to be determined and might change.

AC Charger (0x08)

Record layout is still to be determined and might change.

Smart Battery Protect (0x09)

(Lynx Smart) BMS (0x0A)

Multi RS (0x0B)

VE.Bus (0x0C)

DC Energy Meter (0x0D)

Orion XS (0x0F)