Smart Grid Controller for Signal K

Intelligent AC grid management plugin for Victron MultiPlus II systems. Automatically controls when grid power is connected based on battery state, power demand, scheduled charging windows, and comprehensive safety protections.

📦 Install: npm install smart-grid-controller or via Signal K App Store

⚠️ CRITICAL CONFIGURATION WARNING

This plugin MUST be configured for your specific battery type before use!

Default settings are for Li-NCM 15S (55.5V nominal) batteries. Using wrong voltage thresholds for your battery chemistry could result in:

• Battery damage from over/under voltage
• Fire or explosion risk
• System failure during critical moments

Always configure your battery type in the Signal K admin panel before enabling the plugin.

Features

Four Enable Conditions (grid connects if ANY condition is met)

• High Load: AC load >2500W for 3+ seconds (configurable)
• Low Voltage: Battery voltage drops below threshold for 3+ seconds (auto-set by battery type)
• Low Battery: State of charge <10% for 3+ seconds (configurable)
• Scheduled Charging: Configurable time window (default 00:00-06:00 UK time)

Multi-Layer Battery Protection

• Standard Protection: Disconnects at high voltage/SoC (auto-set by battery type, can be overridden by high loads)
• Emergency Protection: Immediately disconnects at critical voltage (auto-set by battery type, cannot be overridden)

Smart Timing

• 3-second delays prevent false triggers from momentary spikes
• 30-second grace period before disconnecting when conditions clear
• Hysteresis thresholds prevent rapid cycling

Installation & Configuration

1. Install Plugin:
   • Via Signal K App Store: Admin UI → AppStore → Electrical → Smart Grid Controller → Install
   • Via npm: npm install smart-grid-controller
   • Package Info: View on npm
2. BEFORE ENABLING: Configure your battery type in Signal K admin panel
3. CRITICAL: Verify all voltage thresholds match your battery specifications
4. Test in safe conditions with monitoring
5. Wire hardware according to your setup (see Hardware Configuration below)

Supported Battery Types

• Li-NCM 15S (55.5V nominal) - High energy density systems
• LiFePO4 16S (51.2V nominal) - High voltage LiFePO4 systems

Configuration Parameters

Access through Signal K admin panel → Plugin Config → Smart Grid Controller:

• Battery Chemistry: Select your battery type for automatic safe defaults
• Load Thresholds: Customize high-load switching points
• SoC Limits: Adjust state-of-charge behavior
• Schedule Settings: Modify charging window and timezone

Requirements

• Option A: MultiPlus II GX (built-in GX device) - No external hardware needed
• Option B: Cerbo GX with VenusOS "Large" firmware + external contactor
• Signal K server with Victron plugin
• Properly configured battery settings

Hardware Configuration

Option A: MultiPlus II GX (Recommended)

Grid AC ──► MultiPlus II GX ──► AC Loads
                │
                └─ Built-in GX controls AC input directly

• ✅ No external contactor needed
• ✅ Direct AC input enable/disable control
• ✅ Cleaner, more reliable control
• ✅ AC input current limits configured in Victron settings

Option B: External Cerbo GX + Contactor

Grid AC ──► [Contactor] ──► MultiPlus II AC Input
              │
              └─ Cerbo GX Relay 1 Output

• Requires external contactor wired to Cerbo GX Relay 1
• For systems with separate Cerbo GX units

Configuration

Control Method Settings

1. Auto-detect (Recommended): Plugin tries both control methods
2. MultiPlus II GX: For systems with built-in GX (your setup!)
3. Cerbo GX: For external Cerbo GX with relay control

For MultiPlus II GX Users:

• Set Control Method: "MultiPlus II GX (built-in GX)"
• No external wiring needed - plugin controls AC input directly
• AC input current limits: Configure in Victron system settings (not in this plugin)

Safety Notes

• Verify configuration before first use
• Plugin includes emergency protection but proper configuration is essential
• Test thoroughly in safe conditions with monitoring
• Ensure proper contactor ratings for your system
• Monitor system logs during initial operation
• Have qualified electrical support available

Troubleshooting

Plugin Not Working

1. Check Signal K logs for error messages from "Smart Grid Controller"
2. Verify data paths - ensure Victron plugin is running and data is available:
   • electrical.chargers.275.voltage (battery voltage)
   • electrical.inverters.275.acout.power (AC load)
   • MultiPlus II GX: electrical.inverters.275.acState.ignoreAcIn1.state (AC input control)
   • Cerbo GX: electrical.switches.relay1.state (relay control)
3. Test control manually in Signal K admin: Server → Data Browser → navigate to control path

Common Issues

• No relay control: Check Cerbo GX relay configuration and wiring
• Invalid data warnings: Verify Victron system is connected and providing data
• Timezone errors: Ensure timezone string is valid (e.g., "Europe/London", "America/New_York")
• Rapid switching: Adjust hysteresis gaps in configuration

Getting Help

• Check Signal K server logs for detailed error messages
• Verify all configuration parameters are within valid ranges
• Test individual components (relay, voltage readings, load measurements)
• Join Signal K community forums for support

Version History

• v1.0.0: Initial release with Li-NCM 15S and LiFePO4 16S support

Contributing

Issues and pull requests welcome at the GitHub repository.