TriStar MPPT Driver for Venus OS

Modern Python driver for Morningstar TriStar MPPT solar charge controllers

✅ Production-ready - Tested on Venus OS v3.67 ✅ Zero compilation - Pure Python, just copy and run ✅ No QML required - Configure via D-Bus command line ✅ 100% compatible - Same data as original C++ driver ✅ WAN-ready - Works over internet with optimized timeouts ✅ Advanced features - Voltage override, tail current detection, 31-day history

In my off-grid system the Morningstar Tristar MPPT 60 is used to charge a 7.7kWh Lithium battery with top charge voltage of 28.7V. As lithium batteries doe not like to stand top-charged over time, I normally charge to 28.36V and only top charge, using this driver, every month to ballance the cells or if I need more capacity for my next visit to the cottage

My Venus OS is connected to Home Assistant where I expose all the extra features in this driver.

📚 Complete Documentation - All D-Bus paths, logic, and advanced features

Recent Updates (v2.26)

✅ Charge Profile Management - Switch between summer/winter/custom profiles with safe EEPROM programming ✅ Automatic Voltage Scaling - Auto-detect 12V/24V/48V systems for precise EEPROM writes ✅ Voltage Override System - Battery top-charging with automatic tail current detection ✅ 31-Day History - Daily max/min tracking with state persistence ✅ EEPROM Counters - Lifetime kWh from TriStar's internal registers

Quick Start

# 1. Copy files to Venus OS
scp dbus_tristar.py install.sh root@<venus-ip>:/tmp/

# 2. SSH to Venus OS
ssh root@<venus-ip>

# 3. Install (creates service and starts driver)
cd /tmp
chmod +x install.sh
./install.sh

That's it! The driver is now running as a service.

Configuration

Settings are configured via D-Bus command line (no GUI menu in Venus OS v3.67):

# Set IP address (REQUIRED)
dbus -y com.victronenergy.settings /Settings/TristarMPPT/IPAddress SetValue "192.168.1.100"

# Optional settings (with defaults shown)
dbus -y com.victronenergy.settings /Settings/TristarMPPT/PortNumber SetValue 502
dbus -y com.victronenergy.settings /Settings/TristarMPPT/Interval SetValue 5000
dbus -y com.victronenergy.settings /Settings/TristarMPPT/SlaveID SetValue 1
dbus -y com.victronenergy.settings /Settings/TristarMPPT/DeviceInstance SetValue 0

# Restart driver to apply changes
svc -t /service/dbus-tristar

Battery Top-Charging (Quick Example)

The driver supports advanced battery top-charging with automatic tail current detection:

# Enable voltage override to 28.7V for top-charging
dbus -y com.victronenergy.solarcharger.tristar_0 /Control/VoltageOverride SetValue 28.7

# Monitor progress
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/VoltageOverride/TimeAtTargetVoltage GetValue
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/VoltageOverride/TailCurrentTimer GetValue

# Check status
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/VoltageOverride/Active GetValue
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/VoltageOverride/StopReason GetValue

# Disable when done (or let automatic tail current detection stop it)
dbus -y com.victronenergy.solarcharger.tristar_0 /Control/VoltageOverride SetValue 0

Automatic stopping conditions:

Battery full (tail current < 2.0A for 5 minutes)
Time limit reached (max 2 hours/day)
Nightly reset (03:00 local time)

Configure thresholds:

# Set tail current threshold to 1.5A
dbus -y com.victronenergy.settings /Settings/TristarMPPT/BatteryFullCurrent SetValue 1.5

# Set max voltage to 28.95V
dbus -y com.victronenergy.settings /Settings/TristarMPPT/MaxVoltageOverrideVoltage SetValue 28.95

📚 Full documentation: DRIVER_DOCUMENTATION.md - Complete guide with all settings, D-Bus paths, and logic

Charge Profile Management (Quick Example)

Switch between seasonal charging profiles with safe EEPROM programming:

# Apply summer profile (lower voltage, shorter absorption)
dbus -y com.victronenergy.solarcharger.tristar_0 /Control/ApplyChargeProfile SetValue "summer"

# Apply winter profile (higher voltage, longer absorption)
dbus -y com.victronenergy.solarcharger.tristar_0 /Control/ApplyChargeProfile SetValue "winter"

# Monitor progress
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/ChargeProfile/ApplyStatus GetValue
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/ChargeProfile/ProgressPercent GetValue

# Check active EEPROM values
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/EEPROM/AbsorptionVoltage GetValue
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/EEPROM/FloatVoltage GetValue

Default profiles:

Summer: 28.4V absorption, 27.2V float, 7200s (2h) absorption time
Winter: 28.8V absorption, 27.6V float, 9000s (2.5h) absorption time
Custom: 28.6V absorption, 27.4V float, 8400s (2.3h) absorption time (user-configurable)

Customize profiles via D-Bus Settings:

# Configure custom profile for your specific battery
dbus -y com.victronenergy.settings /Settings/TristarMPPT/ChargeProfiles/Custom/AbsorptionVoltage SetValue 28.8
dbus -y com.victronenergy.settings /Settings/TristarMPPT/ChargeProfiles/Custom/FloatVoltage SetValue 27.6
dbus -y com.victronenergy.settings /Settings/TristarMPPT/ChargeProfiles/Custom/AbsorptionTime SetValue 9000
dbus -y com.victronenergy.settings /Settings/TristarMPPT/ChargeProfiles/Custom/FloatCancelVoltage SetValue 26.4

# Apply the customized profile
dbus -y com.victronenergy.solarcharger.tristar_0 /Control/ApplyChargeProfile SetValue "custom"

Safety features:

Automatic DISCONNECT before EEPROM writes
Backup creation before changes (saved to /data/dbus-tristar/eeprom_backups/)
Verification after every write (0.1V tolerance)
Automatic controller reset
Thread-safe operation (main loop paused during writes)
Automatic voltage scaling for 12V/24V/48V systems

📚 Full documentation: DRIVER_DOCUMENTATION.md - Complete charge profile reference

Verification

# Check service is running
svstat /service/dbus-tristar

# Check logs
tail -f /var/log/dbus-tristar/current

# Check D-Bus registration
dbus -y com.victronenergy.solarcharger.tristar_0 /ProductName GetValue

# Check current values
dbus -y com.victronenergy.solarcharger.tristar_0 /Dc/0/Voltage GetValue
dbus -y com.victronenergy.solarcharger.tristar_0 /Yield/Power GetValue

Your TriStar MPPT will appear as a Solar Charger in:

Venus OS main screen
VRM Portal dashboard
Remote Console

Features

Monitoring

✅ Full Modbus TCP communication (connect-read-close pattern)
✅ All TriStar registers: voltage, current, power, yield, temperature
✅ Target regulation voltage (charge setpoint)
✅ Daily history: kWh, max values, time in absorption/bulk/float
✅ Total yield tracking
✅ Full VRM Portal integration

Control

✅ Charge profile management - Switch between summer/winter/custom profiles with safe EEPROM programming
✅ Voltage override - Top-charge to configurable voltage (e.g., 28.7V)
✅ Automatic battery full detection - Tail current monitoring with configurable thresholds
✅ Mode control - Enable/disable charging via D-Bus
✅ Equalize trigger (read/write coil with verification)
✅ Charger disconnect (read/write coil with verification)
✅ Controller reset (momentary button)
✅ Comm server reset (momentary button)
✅ Automatic nightly reset at configurable hour (default: 03:00)

Diagnostics & Health Monitoring

✅ Connection statistics (/Custom/Stats/SuccessfulReads)
✅ Failure tracking (/Custom/Stats/FailedReads)
✅ Consecutive failure counter (/Custom/Stats/ConsecutiveFailures)
✅ Last success timestamp (/Custom/Stats/LastSuccessTime)
✅ Backoff factor (/Custom/Stats/BackoffFactor)
✅ Remote debugging via VRM Portal or dbus-spy

Reliability

✅ Automatic reconnection on network loss
✅ Settings change callback (auto-reconnect when IP/port changes)
✅ WAN-optimized: 1-second timeout with 5 retries
✅ Connection watchdog (3-minute timeout detection)
✅ Exponential backoff on persistent failures (1x → 2x → 4x interval)
✅ Graceful shutdown handlers (SIGTERM/SIGINT)
✅ Data validation (sanity checks on voltage/current/power)
✅ Critical coil verification (read-after-write for EQUALIZE/DISCONNECT)
✅ Statistics paths for remote diagnostics (/Custom/Stats/*)
✅ MQTT integration via Venus OS broker

Supported Hardware

Morningstar TriStar MPPT 30
Morningstar TriStar MPPT 45
Morningstar TriStar MPPT 60

Requirements:

TriStar with Modbus TCP enabled
Network connectivity between Venus OS and TriStar
Venus OS v3.4+ (tested on v3.67)

Files

dbus-tsmppt/
├── dbus_tristar.py              # Main driver (v2.26)
├── install.sh                   # Installation script
├── README.md                    # This file (overview)
├── DRIVER_DOCUMENTATION.md      # Complete technical reference (📚 READ THIS!)
├── QUICKSTART.md                # Quick start guide
├── test_connection.py           # Connection testing tool
├── dbus_tristar_mock.py         # Mock driver for testing
├── docs/                        # Technical docs and PDFs
└── Reference Cplusplus code for dbus_tsmppt/   # Legacy C++/QML code

Documentation

DRIVER_DOCUMENTATION.md - 📚 COMPLETE REFERENCE - All D-Bus paths, voltage override system, tail current detection, settings, troubleshooting
QUICKSTART.md - 3-minute installation guide
test_connection.py - Test Modbus connection to your TriStar
docs/TECHNICAL-DETAILS.md - C++ compatibility analysis and technical details

Troubleshooting

Can't connect to TriStar?

# Test connection
python3 test_connection.py <tristar-ip> 502 1

# Check network
ping <tristar-ip>

# Review logs
tail -f /var/log/dbus-tristar/current

# Check connection statistics
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/Stats/ConsecutiveFailures GetValue
dbus -y com.victronenergy.solarcharger.tristar_0 /Custom/Stats/LastSuccessTime GetValue

Connection drops frequently?

Check /Custom/Stats/FailedReads and /Custom/Stats/SuccessfulReads
High failure rate indicates network instability
Check if backoff is active: /Custom/Stats/BackoffFactor (should be 1 normally)
Exponential backoff will activate after 10 consecutive failures

Unrealistic values showing?

Driver has built-in sanity checks for voltage/current/power
Check logs for warnings: "Unrealistic battery voltage" or similar
Indicates possible Modbus packet corruption over WAN
Corrupted values are automatically rejected and old values retained

No data showing?

Verify IP address is correct in settings
Check TriStar has Modbus TCP enabled (usually port 502)
Check slave ID matches your device (usually 1)
Review logs for connection errors
Check /Connected path: dbus -y com.victronenergy.solarcharger.tristar_0 /Connected GetValue

Settings menu doesn't appear in GUI?

Expected behavior in Venus OS v3.67
Use D-Bus command line instead (see Configuration section)
Settings are fully functional via D-Bus

MQTT write not working?

CRITICAL: Venus OS MQTT requires JSON format: {"value": 1} not just 1
MQTT topics use device instance (e.g., solarcharger/0), not service name (e.g., tristar_0)

Test D-Bus write first to verify driver is working:

dbus -y com.victronenergy.solarcharger.tristar_0 /Control/EqualizeTriggered SetValue 1

Example MQTT write command:

mosquitto_pub -h <venus-ip> -t "W/<portal-id>/solarcharger/0/Control/EqualizeTriggered" -m '{"value": 1}'

Check logs after MQTT write to see if driver received the command:
```
tail -f /var/log/dbus-tristar/current | grep "Coil write"
```

Technical Details

Architecture:

Pure Python using Venus OS SettingsDevice API
Connect-read-close Modbus pattern (matches TriStar hardware)
pymodbus v2.x/v3.x compatible with auto-detection
GLib main loop with exponential backoff on failures
WAN-optimized: 1-second timeout, data validation, smart retry logging

D-Bus Service:

Service name: com.victronenergy.solarcharger.tristar_{instance} (configurable)
50+ D-Bus paths: Standard Victron + Custom monitoring/control
Full settings integration: /Settings/TristarMPPT/*
State persistence: 31-day history in /data/dbus-tristar/state.json

For complete technical details, D-Bus path reference, Modbus registers, and troubleshooting: 📚 See DRIVER_DOCUMENTATION.md

Home Assistant Integration

Venus OS has a built-in MQTT broker that automatically publishes all D-Bus paths. This makes integration with Home Assistant simple and native.

Control via MQTT

Read coil status:

N/<portal-id>/solarcharger/tristar_0/Control/EqualizeTriggered
N/<portal-id>/solarcharger/tristar_0/Control/ChargerDisconnect

Write to coils:

W/<portal-id>/solarcharger/tristar_0/Control/EqualizeTriggered {"value": 1}
W/<portal-id>/solarcharger/tristar_0/Control/ResetController {"value": 1}

IMPORTANT: Venus OS MQTT write requires JSON format. Use {"value": 1} not just 1.

Note:

Replace <portal-id> with your Venus OS VRM Portal ID (found in Settings → VRM Portal)
Replace tristar_0 with 0 if using default device instance (MQTT uses device instance, not service name)
Example: W/b827ebe38b8c/solarcharger/0/Control/EqualizeTriggered {"value": 1}

Example HA Configuration

mqtt:
  switch:
    - unique_id: tristar_equalize
      name: "TriStar Equalize Charge"
      state_topic: "N/<portal-id>/solarcharger/tristar_0/Control/EqualizeTriggered"
      command_topic: "W/<portal-id>/solarcharger/tristar_0/Control/EqualizeTriggered"
      payload_on: '{"value": 1}'
      payload_off: '{"value": 0}'

    - unique_id: tristar_disconnect
      name: "TriStar Charger Disconnect"
      state_topic: "N/<portal-id>/solarcharger/tristar_0/Control/ChargerDisconnect"
      command_topic: "W/<portal-id>/solarcharger/tristar_0/Control/ChargerDisconnect"
      payload_on: '{"value": 1}'
      payload_off: '{"value": 0}'

  button:
    - unique_id: tristar_reset_controller
      name: "TriStar Reset Controller"
      command_topic: "W/<portal-id>/solarcharger/tristar_0/Control/ResetController"
      payload_press: '{"value": 1}'

Note: Replace <portal-id> with your Venus OS VRM Portal ID (found in Settings → VRM Portal).

Legacy Code

The original C++ driver and legacy Python versions are preserved in:

Reference Cplusplus code for dbus_tsmppt/

Contents:

software/ - Original Qt/C++ driver (Venus OS v2.30 and older)
qml/ - QML files for Venus OS v2.80-v3.3
dbus-tsmppt.py - Legacy Python driver
Old installation scripts and documentation

These are kept for reference only. Use dbus_tristar.py for all new installations.

License

MIT License - See LICENSE

Credits

Original C++ driver: Ole André Sæther (2018-2019)
Python rewrite: 2024 - Modern Venus OS v3.4+ compatible
Architecture: Based on Victron Energy Venus OS and velib_python
https://github.com/mr-manuel/venus-os_dbus-mqtt-solar-charger

Enjoy your TriStar MPPT on Venus OS! ☀️🔋

Questions? Check the logs: tail -f /var/log/dbus-tristar/current

TO DO LIST:

Check modbus parameters to be used for I and V. Now it is a mix of fast and slow.
Remove/change excess power estimation as this is not working properly
Add monthly top charging in driver with indircation for discharging afterwards

Navigation Menu

Repository files navigation

TriStar MPPT Driver for Venus OS

Recent Updates (v2.26)

Quick Start

Configuration

Battery Top-Charging (Quick Example)

Charge Profile Management (Quick Example)

Verification

Features

Monitoring

Control

Diagnostics & Health Monitoring

Reliability

Supported Hardware

Files

Documentation

Troubleshooting

Technical Details

Home Assistant Integration

Control via MQTT

Example HA Configuration

Legacy Code

License

Credits

About

Releases

Packages

Contributors

Languages

Name		Name	Last commit message	Last commit date
.claude		.claude
Reference Cplusplus code for dbus_tsmppt		Reference Cplusplus code for dbus_tsmppt
docs		docs
.gitignore		.gitignore
.gitmodules		.gitmodules
CHANGELOG.md		CHANGELOG.md
DRIVER_DOCUMENTATION.md		DRIVER_DOCUMENTATION.md
LICENSE		LICENSE
QUICKSTART.md		QUICKSTART.md
README.md		README.md
dbus_tristar.py		dbus_tristar.py
dbus_tristar_mock.py		dbus_tristar_mock.py
install.sh		install.sh
morningstar_questions.txt		morningstar_questions.txt
test_connection.py		test_connection.py

Latest commit

History

Folders and files

Repository files navigation

TriStar MPPT Driver for Venus OS

Recent Updates (v2.26)

Quick Start

Configuration

Battery Top-Charging (Quick Example)

Charge Profile Management (Quick Example)

Verification

Features

Monitoring

Control

Diagnostics & Health Monitoring

Reliability

Supported Hardware

Files

Documentation

Troubleshooting

Technical Details

Home Assistant Integration

Control via MQTT

Example HA Configuration

Legacy Code

License

Credits

About

Resources

Stars

Watchers

Forks

Releases

Packages

Contributors

Languages