Features → What is a smart charger

What "smart" actually means

Three different things are sold under this word, they sit in layers, and you can own the expensive one while still not being able to do the thing you bought it for.

Layer one: a charger that can be told things

A plain wallbox delivers whatever current it is set to. A smart one has a network connection and will accept instructions — start, stop, change to this many amps — usually over a protocol called OCPP or the manufacturer's own.

This is a capability, not a behaviour. On its own it does nothing except let something else be clever.

Layer two: a schedule

Most wallbox apps, and most cars, will charge between hours you choose so you land in your off-peak window. This is genuinely useful and saves real money, and it is what most people mean by "smart charging".

It is also blind. A schedule does not know whether the sun is out; it knows what time it is.

Layer three: charging on what your roof is making

This needs three things at once — knowing what the panels are making, knowing what the house is using, and being able to change the car's current every few minutes as that difference moves. That is what Sunplug is, and it is a different job from either layer below it.

Which layer do you need?

Depends entirely on what you own, and the answer is often "less hardware than you think".

• A Tesla needs no smart charger at all. The car itself accepts current instructions, so Sunplug talks to the car and your wallbox can be the dumbest box on the market — or the mobile connector on a socket.
• Most other cars cannot be told to change current, so the wallbox has to be the thing that is told — and there you do need layer one.
• A wallbox with its own solar mode may already do a version of layer three, if it can see your grid meter. It will typically handle one car, on its own manufacturer's terms.

The thing worth checking before buying

Not the top speed — that matters less than it looks — but two duller questions:

Will it hold a low current steadily? Solar charging lives at the bottom of the range, and a charger that drops out below 10 A discards good afternoons.

Does it speak something open? A wallbox that only talks to its own cloud can only ever be as clever as that cloud, and only for as long as the manufacturer keeps it running. One speaking OCPP can be pointed at anything — including, if you change your mind about us, something else.

Pointing an OCPP charger at a new service usually silences the maker's own app, because the charger talks to one service at a time. That does not have to happen — Sunplug can pass the conversation through so both keep working.

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