Skip to content

Energy tracking

Eneru integrates the power your UPS reports into kWh for the current day and month, and — if you give it a tariff — the matching cost. It is computed on read from the per-UPS stats store, so there is no extra cumulative counter to maintain.

How power is measured

For each sample, Eneru picks the power in watts in this order:

  1. ups.realpower (real_power), when the UPS reports it; otherwise
  2. the fallback ups.load / 100 × ups.power.nominal, flagged estimated; otherwise
  3. that interval counts as unknown (never silently 0).

Energy over an interval is power_W × dt_h / 1000, summed across consecutive samples within a single retention tier (raw, 5-minute, or hourly — never mixing tiers). If the gap between two samples is much larger than the tier's expected spacing (daemon down, data outage), that interval is skipped rather than overcounted, and the window is flagged partial. If no interval in the window has usable power, the result is unknown, not 0.

Configuration

energy:
  enabled: true
  cost_per_kwh: null            # null/unset => cost tracking is OFF entirely
  currency: USD                 # ISO 4217 code (USD, EUR, GBP, ...)
  cost_format: null             # optional override, e.g. "{value} €"
  nominal_power: null           # rated W/VA; estimates watts when the UPS reports
                                # neither ups.realpower nor ups.power.nominal

When the UPS reports no power

Some integrated UPSes expose neither ups.realpower nor ups.power.nominal, so Eneru has nothing to turn load% into watts and energy stays unknown. Set energy.nominal_power to the unit's rated power (e.g. 1000 for a 1000 VA tower) and Eneru estimates watts = (load% / 100) × nominal_power (flagged estimated). The Energy tab's Power (W) line then plots, and kWh/cost populate.

Windows

today is the calendar day (since local midnight) and month is the calendar month (since the 1st) — fixed boundaries that match how an electricity bill is measured, not a rolling 24 h / 30 d.

Cost is gated on cost_per_kwh. While it is unset (null), cost tracking is disabled entirely — no cost field in the status payload, no eneru_ups_energy_cost metric, and no cost widget in the UI — rather than rendering a meaningless zero-currency graph. Set a price to turn it on; then cost = kWh × cost_per_kwh (an unknown kWh yields an unknown cost).

Currency formatting

A small built-in table formats the amount per currency code — USD → $0.20, EUR → 0.20 €, GBP → £0.20 — and an unknown code falls back to amount + code (0.20 XYZ). Set cost_format (e.g. "{value} €") to override placement entirely. The server returns both the numeric value and a preformatted string so the dashboard and reports render it identically.

energy is hot-reloadable — the values are read live on each computation, so changing the tariff or currency takes effect without a restart.

Where it shows up

  • Dashboard → the Energy tab shows today/month kWh, cost (when enabled), and the estimated / partial flags.
  • API → GET /api/v1/ups/{name}/energy, plus the energy block in GET /api/v1/ups.
  • Prometheus → eneru_ups_energy_kwh{period="today|month"} (a gauge, since it is recomputed per window and is not monotonic) and eneru_ups_energy_cost{period=...} (omitted entirely when cost_per_kwh is unset). Unknown values are omitted rather than emitted as 0.

A note on hardware

Not every UPS reports ups.realpower. When it doesn't, Eneru uses the load × nominal estimate and labels the figures estimated — useful for trend-watching, but treat the absolute number as approximate. Reports (Reports) include the same energy summary.