RBgrid

RBgrid Use Cases

Overview

RBgrid turns an ESP32-WROVER hub and one or more rbAmp measurement modules into a self-hosted energy monitor. It measures and records — live power per circuit, statistics and history, time-of-use cost, and import/export — and serves it all from the device. RBgrid does not switch or actuate loads; it is a measurement and accounting system.

A hub drives up to 8 rbAmp modules and keeps flash history for up to 12 measurement points (a point is one circuit).

Scenario 1 — Whole-home consumption monitoring

For: an apartment or house that wants to see total and per-circuit usage and what it costs.

Main supply the grid connection, measured at the main feed
Circuits individual loads (kitchen, water heater, rooms…), one measurement point each
Hardware ESP32-WROVER hub + rbAmp module(s); voltage from the module's voltage input

You get: live power per circuit (W), accumulated energy (kWh), voltage and frequency, and historical consumption — hourly for 60 days for every circuit; your supply also keeps daily, monthly and yearly totals.

Scenario 2 — Time-of-use cost tracking

For: a site on a multi-zone tariff that wants cost broken down by period and circuit.

Define your tariff zones (day/night, peak/off-peak, weekend) with their rates and fees. RBgrid applies your own rates to measured consumption and reports cost per zone, per circuit and per period, and projects monthly and annual cost from your history. It shows you when the cheaper periods are — you decide whether to shift usage; RBgrid does not move loads for you.

Scenario 3 — Selling surplus back at your own per-zone rates

For: a site with a second supply feeding back to the grid, that wants the two-way flow measured and valued.

Enable bidirectional metering on the main supply. RBgrid measures import and export separately and, per zone, applies the buy rate to import and your feed-in rate to export (net metering), netting them over the period:

Net Cost = (Imported × Buy Rate) − (Exported × Feed-in Rate)

RBgrid measures and accounts for the flow at the meter. It does not control the second supply or any loads.

Measurement hardware

All measurement is by the rbAmp I²C modules — current per channel, and voltage from the module's voltage input. The ESP32 hub does no measurement of its own; it reads the modules, computes and stores. See the hardware and module documentation for the supported modules and CT options.

Open three-phase fuse box with the main switch off: an rbAmp STD-U3I3 with clamps on the three input phases, and an rbAmp Basic 7 with one clamp per phase on the EV charger and heat pump plus one on the kitchen circuit — 8 measured points on one I²C bus to an ESP32-WROVER hub; laundry and lights are left unmetered.Open full-size image
  1. One STD-U3I3 on the input: all three phases, one point
  2. Three-phase loads take one clamp per phase
  3. Two modules on one I²C bus, one hub
  4. 8 measurement points, all with history
  5. Neutral required for the STD voltage inputs.
Open three-phase workshop panel with the main switch off: an rbAmp STD-U3I3 on the input and an rbAmp Basic 5 with one clamp per phase on the compressor plus clamps on the lighting and sockets circuits — 6 measured points on one I²C bus to an ESP32-WROVER hub; lathe and welder unmetered.Open full-size image
  1. One STD-U3I3 on the input: all three phases, one point
  2. Machines on three phases: one clamp per phase
  3. Two modules on one I²C bus, one hub
  4. 6 measurement points.

Statistics and history

Period Kept (per point)
Hourly 60 days
Daily ~13 months
Monthly 3 years
Yearly 10 years

Stored on the device's own flash — no account, no cloud — for up to 12 measurement points per hub.

Tariffs

  • Two-zone (day/night) and multi-zone (peak / semi-peak / off-peak, weekend) time-of-use plans.
  • Per-kWh energy tax, grid fee and renewable levy.
  • Import and export priced separately — import at the buy rate, export valued at your feed-in rate (net metering).

Integrations

  • Home Assistant via MQTT discovery — energy entities for your Energy dashboard and your own automations on the HA side.
  • REST + WebSocket API and MQTT for any platform.
  • CSV export of measurements and statistics.

RBgrid publishes its measurements; any control logic lives in your own system (for example, Home Assistant), not in RBgrid.

Sensors

Sensor Use
SCT-013 clamp non-invasive current measurement, clips around an existing conductor

The clamp connects through an rbAmp module; the module measures and digitises — sensor configuration is per channel, in the app.

Safety

  • Install with the power off; have mains work done by a qualified electrician.
  • The rbAmp CTs clip around existing conductors (non-invasive).
  • Never work on live circuits.

Data security

  • A password-protected web interface, an admin token for changes, and data stored locally on the device — local network, no cloud.

Ready to start? Pick the scenario closest to yours, then follow Get Started to flash the firmware and take your first measurement.