node-red-contrib-nordpool-chargecheap 1.0.1

Nordpool price analyzer with smart night/day, rolling 24h and HA override integration for Node-RED

npm install node-red-contrib-nordpool-chargecheap

node-red-contrib-nordpool-chargecheap

A Node-RED node for analyzing Nordpool electricity prices and automatically selecting the cheapest (or most expensive) time periods for charging, discharging, load shifting or other automation purposes.

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✅ Key Features

• Selects the cheapest or most expensive price intervals within a configurable time window.
• Two selection strategies:
  • Discrete selection: pick the N best (cheap) or worst (expensive) intervals.
  • Contiguous block mode: find one continuous block of length N with lowest (cheap) or highest (expensive) average price.
• Supports overnight windows (start > stop) and rolling 24h mode (start == stop).
• Rolling 24h mode provides a dynamic 24h window anchored to the most recent occurrence of the chosen start hour.
• Home Assistant integration via service-style payload (e.g. input_number.set_value).
• Dynamic runtime override via incoming msg.start, msg.stop, msg.count.
• Automatic unit normalization (Öre / SEK / EUR → Öre).
• HA override (msg.ha_enable="off") keeps calculating selection but sends a fixed fallback (force_value) to HA.
• Full context reset using msg.reset.
• Detects interval length (15 / 30 / 60 minutes or other).
• Rich diagnostic attributes (block averages, reference thresholds, data completeness).
• Inverted mode for high-price alerting or battery discharge strategy.
• Additional semantic attributes clarifying override mode, selection purpose and next effective reference.

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🧠 Selection Logic Summary

Mode	What is selected	reference_price meaning	reference_price_role
Cheap (default)	Lowest priced intervals	Highest price among selected cheap intervals (upper cheap boundary)	upper_bound_for_charging
Expensive (invert)	Highest priced intervals	Lowest price among selected expensive intervals (lower expensive boundary)	lower_bound_for_discharging

Why this reference logic?

• In cheap mode, the selected cheap set forms a “price corridor” ≤ reference_price. The reference becomes a ceiling you still accept for charging.
• In expensive mode, the selected expensive set forms a corridor ≥ reference_price. The reference becomes a floor beyond which discharging / shedding may occur.

You also get reference_price_numeric (pure number) and reference_price_effective (null during HA override).
In contiguous block mode the node finds the single block (length = count) with:

• Lowest average (cheap mode)
• Highest average (expensive mode)

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🔄 Rolling 24h vs Normal Periods

• Normal period (start != stop):
  • If start < stop: same-day window (e.g. 07→15).
  • If start > stop: overnight window crossing midnight (e.g. 22→06).
• Rolling 24h (start == stop):
  • A 24h dynamic span beginning at the most recent occurrence of that hour.
  • If current time is earlier than the start hour, the window anchors to yesterday’s occurrence.
  • Example: At 21:30 with start=16 (rolling) → window = today 16:00 → tomorrow 15:59:59.
  • Attribute: rolling_24h = on.

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⚙️ Node Configuration (Editor Fields)

Field	Description
Name	Display name for the node
Start hour	Start of selection window (0–23)
Stop hour	End of selection window (0–23); if same as start → rolling 24h
Count	Number of intervals to select (N price slots)
Invert selection	Choose expensive instead of cheap intervals
Contiguous block mode	Select one continuous block instead of distinct intervals
Payload ON	Output 1 payload when current time is inside a selected slot
Payload OFF	Output 2 payload when outside/idle
Force value outside period	Value pushed to HA when not active or under override
Home Assistant entity	HA entity ID (e.g. input_number.elpris)
Debug	Enables verbose node.debug logs

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🔌 Outputs (4)

Output	Purpose	Example Payload
1	Active slot indicator (ON)	"on" (configurable)
2	Inactive indicator (OFF)	"off" (configurable)
3	State + attributes object	{ "state": 153.22, "attributes": { ... } }
4	Home Assistant service message (optional)	{ "action": "input_number.set_value", "data": { "entity_id": "input_number.elpris", "value": 153.22 } }

If HA override (msg.ha_enable="off") is active, output 4 sends the configured force_value instead of reference_price.

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💬 Runtime Inputs

Property	Type	Description
msg.data	object	Nordpool data wrapper (see format below)
msg.start	number/string	Override start hour (0–23)
msg.stop	number/string	Override stop hour (0–23)
msg.count	number/string	Override count (number of intervals)
msg.ha_enable	string	"on" (normal) or "off" (HA override)
msg.reset	any	Full reset of internal context

Example injection:

{
  "start": 22,
  "stop": 6,
  "count": 8,
  "ha_enable": "on",
  "data": {
    "attributes": {
      "raw_today": [
        { "start": "2025-10-28T00:00:00+01:00", "value": 94.35 },
        { "start": "2025-10-28T00:15:00+01:00", "value": 92.12 }
      ],
      "raw_tomorrow": [
        { "start": "2025-10-29T00:00:00+01:00", "value": 101.44 }
      ],
      "unit_of_measurement": "SEK/kWh"
    }
  }
}

Reset:

{ "reset": true }

Disable HA dynamic updates:

{ "ha_enable": "off" }

Re-enable:

{ "ha_enable": "on" }

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📦 Expected Nordpool Data Structure

Minimal attributes:

• raw_today: Array of objects with start and value (or price).
• Optional raw_tomorrow: Same shape.
• unit_of_measurement: e.g. Öre/kWh, SEK/kWh, EUR/kWh.
• Optional price_in_cents: true (already Öre).
• Deduplication performed on timestamp.

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🧮 Interval Detection

The node infers interval_minutes from the smallest positive gap between consecutive timestamps.
Attributes: interval_minutes, expected_points, actual_points, missing_points, and partial_period (true if incomplete data).
If interval ≥ 55 minutes, count is capped at 23.

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🔐 Reference Price Semantics (Detailed)

Attributes:

• reference_price: Formatted Öre string (e.g. 153.22Öre).
• reference_price_numeric: Pure number (e.g. 153.22).
• reference_price_mode: cheap_selection_max or expensive_selection_min.
• reference_price_role: upper_bound_for_charging or lower_bound_for_discharging.
• reference_price_effective: Equals reference_price unless HA override is active (then null).
• next_reference_when_enabled: Shows future effective reference during override (HA disabled).

Use cases:

• Charging logic: Activate when current spot price ≤ reference_price_numeric (cheap mode).
• Discharging logic: Activate when current spot price ≥ reference_price_numeric (expensive mode).

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📊 Attribute Overview (Output 3 payload.attributes)

Attribute	Meaning
time_01, time_02, ...	Selected intervals (localized time + price)
count	Number of selected intervals
selection_mode	cheap or expensive
selection_strategy	discrete_slots or contiguous_block
reference_price	Threshold string
reference_price_numeric	Numeric threshold
reference_price_mode	Semantics of selection boundary
reference_price_role	Domain-oriented purpose
reference_price_effective	Null when override active
next_reference_when_enabled	Future reference if override off later
max_time, min_time	Extremes within selected set
search_period	Localized start → end label
data_source	Merged sets used (e.g. today + tomorrow)
interval_minutes	Detected slot length
contiguous_mode	on / off
rolling_24h	on if rolling 24h logic used
block_mode_start / block_mode_stop	Bounds of contiguous block
block_mode_average	Average price of block
total_hours_span	Duration of evaluated window
expected_points / actual_points	Diagnostics
missing_points	Count of missing slots
partial_period	True if incomplete data
single_selection	True if only one slot selected
ha_override	on if HA override active
control_mode	override or normal
ha_sent_value	Value pushed to HA entity this cycle
calculated_at	ISO timestamp of calculation

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🏠 Home Assistant Integration

If ha_entity is set (e.g. input_number.elpris), output 4 sends service-style payloads:

Active slot:

{
  "action": "input_number.set_value",
  "data": { "entity_id": "input_number.elpris", "value": 153.42 }
}

Outside slot OR override:

{
  "action": "input_number.set_value",
  "data": { "entity_id": "input_number.elpris", "value": -600 }
}

Disable dynamic updates (override battery logic but still preview future reference):

{ "ha_enable": "off" }

Re-enable:

{ "ha_enable": "on" }

During override:

• ha_override = on
• reference_price_effective = null
• next_reference_when_enabled shows what would be used if re-enabled now.

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🔁 Reset Behavior

Sending any truthy msg.reset:

• Clears stored data (today_data, yesterday_data, tomorrow_data)
• Clears selection parameters (start_time, stop_time, count_hour)
• Clears ha_enabled
• Emits status “Full context reset”

Example:

{ "reset": true }

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🔌 Example Battery Use Case

Cheap mode:

• Select e.g. 12 cheapest 15-min slots (3h total) in evening for charging.
• Use Output 1 to turn charger relay ON only when active slot.
• Use reference_price_numeric in HA automation to decide dynamic pre-charging threshold.

Expensive mode:

• Invert selection to mark high-price windows.
• Use Output 1 to trigger battery discharge or load shedding when inside expensive window.

Override:

• Temporarily force HA entity to a known fallback (e.g. -600) while still previewing future thresholds.

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🧪 Example Flow Outline

1. Nordpool upstream node fetches raw_today/raw_tomorrow.
2. Function/Change nodes send dynamic overrides (msg.count, msg.start, msg.stop).
3. This node calculates selection and outputs:
   • Output 1 → charger control
   • Output 2 → fallback/off
   • Output 3 → attributes for dashboards / DB
   • Output 4 → HA reference value injection
4. Optional UI to toggle ha_enable.

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🚀 Installation

From Node-RED editor:

1. Menu → Manage palette → Install
2. Search: node-red-contrib-nordpool-chargecheap

Or via npm in Node-RED user directory:

npm install node-red-contrib-nordpool-chargecheap

Restart Node-RED if needed.

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⚠️ Notes & Edge Cases

• Missing tomorrow data → partial_period: true.
• Rolling 24h mode may show partial data until future hours arrive.
• count auto-clamped if more than available intervals.
• Large gaps or malformed timestamps are ignored after dedupe.
• Interval detection outside 15/30/60 still supported (custom sources).

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💡 Future Enhancements (Ideas)

• Dual-threshold exposure (min + max reference simultaneously).
• Selection lock to avoid reshuffle when tomorrow data appears.
• Multiple HA entities (charge vs discharge).
• Alternative reference strategies (median, weighted, percentile).
• FX conversion for EUR → SEK with live rates.

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🐞 Troubleshooting

Symptom	Possible Cause	Fix
Waiting for Nordpool data	raw_today empty	Check upstream feed
partial_period true	Incomplete tomorrow data	Wait for publication
Unexpected reference_price_effective = null	HA override active	Send {"ha_enable":"on"}
Charger not turning on	Not in active selected slot	Inspect time_XX + system clock
Price mismatch	Unit conversion discrepancy	Verify unit_of_measurement
Selection seems to shift during day	New tomorrow data appended	Consider lock logic (future enhancement)

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📝 License & Contributions

Open to:

• Performance improvements
• New selection heuristics
• HA-specific enhancements

(Insert license statement here, e.g. MIT.)

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🖼 Screenshots

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🔄 Quick Reference Cheat Sheet

Task	Payload
Override window	{ "start": 7, "stop": 23 }
Change count	{ "count": 12 }
Enable HA	{ "ha_enable": "on" }
Disable HA	{ "ha_enable": "off" }
Full reset	{ "reset": true }
Switch to expensive mode	Toggle invert selection in node config
Rolling 24h mode	Set start == stop (e.g. both 16)

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📘 Suggested HA Automations (Example)

Cheap mode charge trigger:

alias: Charge when cheap slot active
trigger:
  - platform: state
    entity_id: sensor.nordpool_chargecheap_active   # If you map output 1 → on/off helper
condition:
  - condition: template
    value_template: "{{ state_attr('sensor.nordpool_chargecheap','selection_mode') == 'cheap' }}"
action:
  - service: switch.turn_on
    target: { entity_id: switch.charger }

Expensive mode discharge trigger:

alias: Discharge when expensive slot active
trigger:
  - platform: state
    entity_id: sensor.nordpool_chargecheap_active
condition:
  - condition: template
    value_template: "{{ state_attr('sensor.nordpool_chargecheap','selection_mode') == 'expensive' }}"
action:
  - service: switch.turn_on
    target: { entity_id: switch.discharge_relay }

Override awareness:

alias: Notify HA override
trigger:
  - platform: state
    entity_id: sensor.nordpool_chargecheap
condition:
  - condition: template
    value_template: "{{ state_attr('sensor.nordpool_chargecheap','ha_override') == 'on' }}"
action:
  - service: persistent_notification.create
    data:
      title: "Nordpool Override Active"
      message: >
        Dynamic pricing paused. Future reference would be:
        {{ state_attr('sensor.nordpool_chargecheap','next_reference_when_enabled') }} Öre.

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ℹ️ Versioning Notes

If you upgrade from an earlier version:

• New attributes (reference_price_role, reference_price_numeric, override diagnostics) are additive.
• No breaking changes in output ordering or fundamental logic.

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Enjoy smarter price-based automation! Contributions and suggestions are welcome.