Features

What Sunplug actually does

One page, in plain terms, for deciding whether this is for you. Short answers here, with the fuller argument a click away wherever there is more to it — the wiring itself is in Setup guides.

Cars at onceUp to three, ranked by what's actually urgent

Local readsEvery 30 seconds, off your own hardware

Works with11 solar brands directly, anything else via a meter

CostFree while in beta

The engine

How it decides

Sunplug watches what your panels are making and what your house is using, and gives the difference to the cars — adjusting through the afternoon rather than switching on and off. With two cars it also decides who goes first; with a battery, who goes first between the car and the house.

Two cars, one supply A supply that cannot give two cars what they both want. Why "half each" is the answer that sounds fair and charges least, and when one car is given nothing on purpose. Why it waits Six minutes before stopping, nine before restarting. Every delay is a measurement, and shorter ones put less energy in your car rather than more. What "surplus" means Charge on what is left after the house, or on everything the roof makes? Two settings answering different questions — and one of them buys grid power on purpose. The battery decides first With a home battery, every spare kilowatt has two possible homes. Why the battery usually wins, what the reserve protects, and when to turn it round. When it cannot see your solar The agent goes quiet, the inverter reboots. Every one of those ends with the cars failing safe to zero — and the quiet failure that makes it necessary. One cable, two cars Swap the lead and nothing tells the wallbox. The cars' own apps mostly know, so it can usually be worked out — and when it cannot, it asks rather than guesses.

Worth knowing: ten amps into one car often puts more charge in its battery than five plus five split across two — the overhead of simply being switched on gets paid twice. Sunplug knows the floor below which splitting stops making sense, and gives everything to one car rather than trickling both.

Schedules, floors and blockouts

Sun is not always enough, and some mornings you simply need the car full.

Charge windows top the cars up from the grid regardless of sun — your off-peak hours, typically.
Blockout windows forbid charging entirely, whatever else is configured.
A floor per car, so a car never starts the day below a level you are comfortable with.
Per household or per car schedules, because two people leaving at different times might want different windows — a single household schedule is an assumption inherited from products that only ever handled one car.

Tariffs, and what each hour costs

Sunplug knows what your electricity costs at any given hour: a flat rate, an off-peak split with its own hours, or a market tariff where the price changes every hour of the day.

A market tariff is read from the day-ahead prices for your own bidding zone — anywhere in the EU or EEA, Switzerland, and Great Britain through Octopus Agile's published rates. Tomorrow's prices arrive the day before in quarter-hour steps; you choose whether Sunplug works in quarter hours or whole ones, to match how your contract bills. Setting yours up takes about five minutes, and covers the country-specific contracts too.

Market prices: ENTSO-E Transparency Platform and ESIOS (Red Eléctrica).

Charging in the cheapest hours

While a car is plugged in, it fills to its grid level in the cheapest hours there are — at full rate, in blocks of at least an hour, and never above a price you would rather not buy at all. Cheap is not a time of day: a windy afternoon can undercut the small hours, and Sunplug takes whichever is actually cheaper. The sun carries the car further from there, as far as its solar target.

A trip wins over all of it. Set a departure time and a target and the car is ready, even if the only way there is to buy above your ceiling — in which case Sunplug buys, and tells you it did. Boost still charges now. A Tesla is given the plan as charge schedules while it is awake at plug-in, so no wake-ups are spent on it; every other car is driven at the socket by its smart charger. How it picks the hours →

What a dynamic tariff is The off-peak hours you already know, and then a price for every hour of tomorrow. Why the cheap ones move, how the blocks are picked, and what negative prices really cost.

What it tracked, and shows you

Every decision is recorded with its reasoning in the same words a person would use — which car it chose, how much it gave each, and what it was looking at. Alongside it: self-sufficiency, what each car really got for free, and what that saved, kept honest by tracking energy taken away from home — a motorway rapid, a workplace charger — separately.

Reading your own hardware Every thirty seconds off the box on your wall, or five minutes through most manufacturers' clouds — enough to follow the sun across an afternoon. Fifteen minutes and slower is where the agent starts to matter. Where the sun in your car came from How the free-versus-bought split is worked out with two cars on one roof, why motorway charging is kept separate, and why the savings figure understates. Export limits and curtailed solar Why an inverter held to an export limit can erase a whole afternoon's solar surplus, with or without a battery, and what Sunplug does to recover it.

It runs on your equipment

Solar is read either from your manufacturer's cloud or, more often and better, from the hardware itself by the Sunplug agent — with a ready-made Raspberry Pi image if you would rather not think about it. Directly:

Enphase→ Fronius→ SolarEdge→ SolaX→ Sungrow→ GoodWe→ LuxPower→ SMA→ KOSTAL→ APsystems→ Hoymiles→ Victron→

Anything else through a JSON endpoint you send your own readings to.

Cars: Tesla needs nothing but its app login. Volvo is read by Volvo, Ford by Ford. Chargers, any of:

OCPP→ Easee→ go-e→

And your manufacturer's own app can keep working alongside, which is not usually true when a service takes over a charger.

On your phone

Native apps for iPhone and Android, from the App Store and Google Play, and the same app in any browser at app.sunplug.app — one account across all three. In English and French, with a dark and a light theme, it works offline for what it can, and tells you plainly when a number is older than it should be, rather than showing a stale figure as though it were live.

Before you buy

Choosing your kit

Not sure yet what you actually need? Three common questions, answered honestly rather than sold to.

Do you need a home battery? No — and the difference one makes is smaller and stranger than it looks. What changes with, what changes without, and the case where it matters a great deal. How fast a charger do you need? A 22 kW wallbox on a solar roof spends most of its life at 1.4. On solar the specification that matters is the floor, not the ceiling — and nobody prints it. What "smart" actually means Three different things sold under one word, in layers. Which one you need depends on your car — and with a Tesla the answer is none of them.

What it will not do

Worth saying, because a features list that only lists strengths is not much use for deciding.

It will not command a car it cannot place at home, and location is off by default.
It will not charge on guesswork. When the solar reading goes stale it fails the cars safe rather than acting on an old number.
It will not pretend hardware is proven when it is not. Every setup guide says at the top exactly how far that device has been tested, generated from the code rather than written by hand.

Switching over

Coming from ChargeHQ

ChargeHQ closed on 7 September 2026. Sunplug takes the same push API fields, imports ChargeHQ's daily export, and charges up to three cars where ChargeHQ managed one — what moving over involves.

Questions? Email me.