RBgrid

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The pool pump's nameplate won't tell you what it actually uses

  • Tested on firmware v1.1.7
  • Intermediate

Every answer online to "what does a pool pump cost to run" is a calculator: horsepower, hours per day, your rate, multiply. For a single-speed pump that is roughly right. For a variable-speed pump it is close to meaningless — the same motor can draw a few hundred watts on its overnight circulation speed and a few thousand when it is pushing a cleaner or a heater. Owners report spreads as wide as a couple of hundred watts against a couple of thousand on one machine. Which number goes into the calculator?

None of them. The pump has a schedule, the schedule has speeds, and the only thing that knows what it actually used is a measurement of the circuit it runs on.

What you need:

  • an RBgrid hub on your home Wi-Fi, with a tariff entered if you want cost as well as energy;
  • the pump's conductor reachable by an rbAmp module — at the board, or at the pump;
  • for a pump house or an equipment pad the hub's I²C cable can't reach, a remote node: a second ESP32 with its own rbAmp modules, reporting by radio. On v1.1.7, up to 6 nodes per hub, 4 inputs each (Remote nodes).

Safety. For any work inside an electrical panel, call a qualified electrician.

1. Measure at the board if you can

Pool equipment usually has its own breaker, often its own sub-panel, and if the hub can reach that panel you don't need a node: one clamp on the pump's circuit is the whole job.

A node is for the case the pool creates more often than most — the equipment pad is outside, at the far end of the garden, behind a wall the hub's cable was never going to cross. Then the node goes at the pad and reports by radio.

Whether the radio makes it is something you find out in ten minutes, before anything is mounted: pair on the bench, carry it to where it will live, and read the link while the pump is running at its highest speed — which is both the noisiest moment electrically and the one you care about. The procedure and the three numbers are in pairing a remote node.

2. What to buy

🔑 A node records energy only if one of its rbAmp modules measures voltage. With current-only modules it reports live current and closes no energy records — which for this job would be the worst of both worlds: you'd watch the speed change and never learn the kilowatt-hours. Buy a single-phase rbAmp set with voltage measurement.

  • An original ESP32 — 4 MB flash, no PSRAM. S2, S3 and C3 are not built or tested.
  • No over-the-air update: a node is flashed over USB, so keep it reachable with a laptop. An outdoor enclosure you can open beats one you have to unmount.
  • On v1.1.7 a node is single-phase only. A three-phase pump at the pad isn't covered by a node today; at the board, the hub handles three phases properly.

3. What the measurement actually shows you

The pump is the clearest possible case for having two timescales, because its whole behaviour is changing speed:

  • Live, every 3 seconds — power right now. Watch it step as the schedule moves between speeds, or as a cleaner starts. This is where "a few hundred watts or a few thousand" stops being a forum anecdote and becomes your pump's actual numbers.
  • Energy, per 15-minute period — kept as history. This is the durable record: how much went into the pump in each period of the day, every day, so the shape of the schedule is visible without you watching it.
  • Cost by tariff zone. Each 15-minute period is priced at the zone in effect for it, and Monitoring → Economics gives the pump's energy and cost for an hour, today, yesterday, the last 7 days, a month or a year.

That combination is what a calculator cannot do. A calculator needs you to supply the hours and one wattage; the measurement reads the hours and every wattage off the machine itself.

⚠️ There is no per-start event and no speed log. RBgrid does not record "the pump switched to high at 14:05" or count how many times it started. You see power every 3 seconds and energy per 15-minute period; the schedule is something you read off those figures, not a list the hub keeps for you.

4. One point, named, and not double-counted

In Management → Points, bind the channel as its own point and name it before Home Assistant or anything else sees it — an entity id is frozen at first discovery.

🔑 If you also meter the pool sub-panel, pick one. Meter either the sub-panel or the loads inside it — not both — or the hub's "unmetered" remainder subtracts the pump twice and reads too low. Your house total is unaffected either way: totals come from the supply point, not from summing the lines. And there is no hierarchy of points in RBgrid — every point is flat and independent, so nothing warns you; the arithmetic is yours.

On v1.1.7, history covers up to 12 measurement points, and a node's points come out of that same pool rather than adding to it (which loads are worth a history slot).

5. When the pad goes quiet

A node holds its clock from the hub and closes its own 15-minute periods, so a dropped link doesn't lose the measurement at once:

  • Up to 8 periods — about two hours — are held in the node's memory, then the oldest is lost for good. They arrive late and land in the hours they belong to: energy is filed by when it was measured.
  • A power cut at the node loses the queue and the period in progress — it is held in RAM, and nothing marks the gap afterwards. Worth a thought at a pad where the supply gets switched.
  • A node that boots while the hub is unreachable closes no periods until it has heard the hub once.

Out of range and switched off look the same to the app: a node that stopped being heard, 15 seconds after its last frame. There is no signal or loss threshold in RBgrid, so the honest check is lost packets at zero and the node online while the pump is actually running.

What this doesn't do

  • It won't tell you how long your pool pump should run. That is turnover and water chemistry, not electricity, and it belongs to you and whoever services the pool. What RBgrid gives you is what the current schedule costs, which is the half of the argument nobody had before.
  • It makes no claim about savings. You get energy and cost at your own rates. Any change you then make, and what it's worth, is yours to judge.
  • RBgrid switches nothing — no relay, no outputs. It will not change the pump's speed or its schedule; that lives in the pump's own controller.
  • No alerts, no per-start log, no speed history — see §3.
  • A shared circuit can't be taken apart afterwards. If one clamp covers the pump and the pool lighting together, no setting separates them later; the separation happens at the clamp.
  • Cost by zone is a running total since the hub last restarted and doesn't follow the period selector. For a month, use the period selector and take the total.

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