Smart Solar Plus: surplus solar power becomes hot water

Anyone with solar panels knows this: at midday the battery is full, the solar charge controller throttles back, and the best power of the day sits unused on the roof. Smart Solar Plus spots exactly this moment and sends the surplus where it is useful to you: as heat into the boiler, as cold into the cool box or as charge into your batteries. Fully automatic, without you having to stand next to it at midday.

Solar Plus heats your boiler, switches on your inverter for the 230V sockets and runs devices connected to Switchy or Ampy. The function runs directly in the SmartKnob, so you do not need a module of its own for it. Setting it up takes just a few minutes: a wizard asks you five simple questions, one per page.

The battery is full and the sun keeps delivering: Solar Plus is storing heat in the boiler.

How the SmartKnob recognises a real surplus

It does not just look at a single value, but at four things at the same time:

• how full the battery is,
• how much power is coming from the solar panels,
• whether the solar charge controller is already throttling back because the battery cannot take any more. Then there is a proven surplus.
• and, if a battery monitor is installed, whether power is currently flowing into or out of the battery. This way Solar Plus notices whether the battery would have to help pay for the boiler and devices.

So that not every short ray of sunshine switches everything on, the conditions have to be met for half a minute. Only then does Solar Plus get going. If you have several solar charge controllers, the SmartKnob adds up their power, and a controller without sun, such as an unplugged extra panel, does not slow down the automation. Without a battery monitor, Solar Plus sees "full" at the solar charge controller. With a battery monitor it is more precise.

What you do with the surplus

• Store heat: with the surplus, the boiler heats beyond its normal temperature and stores the energy as hot water. Think of the boiler as a second battery, except that it stores heat instead of electricity. A warm shower in the evening with the sun from midday. If your boiler has a 12V or 24V heating element, Solar Plus always uses that one: the solar charge controller feeds it directly, without a detour through the inverter. The weekly hygiene programme and the hot water timer also prefer to use the surplus. Everything about the boiler is in Smart boiler control: the boiler widget.
• Charge batteries when the sun pays: e-bike, power station, tool, camera or laptop batteries charge exactly when the sun delivers more than your leisure battery needs. Just plug in the charger: power comes as soon as there is enough sun to spare. Whatever can wait, waits for the sun instead of nibbling away at your reserve.
• Store cold: a cool box, freezer box or second fridge on Switchy or Ampy cools down properly at midday with the surplus and lives off it in the evening. The compressor stays quiet for longer at night.
• Run what can wait: dehumidifiers, roof fans or a fan that cools down the interior run along as long as there is a surplus, and then switch off again. Anything you switched on yourself stays on, of course.

Setting up Solar Plus: step by step

Before you start: in the dashboard, first set up your solar charge controller as a solar widget in Power Hub, ideally together with your battery widget, your boiler and the devices that should run along. Solar Plus only shows you what already exists. Anything you are still missing, you can also add later and select in the Solar Plus settings.

Then off you go: open the dashboard (how to do that is in How to open the dashboard), switch to the Features section and tap Add Widget. How creating widgets works in general is explained in Adding a function: creating a widget.

Choose the widget type

Under "All widget types" you will find the Solar Plus tile with the subtitle "Put surplus to work". Tap it. There is exactly one Solar Plus per vehicle, because it looks after the whole system.

In the Features section, choose the "Solar Plus" tile.

Step 1 of 5: What Solar Plus needs

The first page explains in two sentences what it is all about: sun, battery full, energy put to use. Below that, Solar Plus checks straight away whether everything is there:

• Solar charger found: without a solar charge controller, Solar Plus cannot tell when the sun delivers. If it is still missing, you see a yellow note. Then add it in Power Hub. You can still continue.
• Battery found: if you have no battery widget, that is fine. Solar Plus then sees "full" at the solar charge controller.

Tap Let’s go.

Two green ticks: the solar charge controller and the battery are already set up.

Step 2 of 5: Where should the spare sunshine go?

Now you decide what should happen with the spare sunshine. You can pick more than one. Tap a card and it opens up, showing your matching devices, each with a switch:

• Heat water (recommended): your boilers appear here. A boiler needs a temperature sensor for this, otherwise it is greyed out. Once you have switched a boiler on, you set below how hot the water may get: between 50 and 70°C, 65°C is recommended. That is hotter than usual, so more sunshine fits into the boiler. Solar Plus never goes above 70°C, so the boiler’s overheat protection at 75°C never trips.
• Power the 230V sockets: your inverters appear here, meaning those Volty can switch remotely, and combined inverter/chargers. You can pick at most two. Ideal for e-bike, laptop or tool chargers.
• Run devices: the switchable outputs of Ampy and Switchy appear here, for example a cool box, fan or dehumidifier. Up to eight devices are possible.

Cards marked "Coming soon" cannot be selected yet. Good to know: once the surplus is over, Solar Plus switches off everything it switched on itself. Anything you had already switched on yourself stays on. If you pick nothing at all, Continue stays locked.

"Heat water" is selected: the boiler may heat up to 65°C with solar power.

Step 3 of 5: When should Solar Plus start?

Your battery always comes first. Here you set the battery level at which Solar Plus starts and the level below which it stops at the latest. There are three options:

Option	Starts at	Stops below at the latest	Good for
When the battery is full (recommended)	95%	90%	Keeps the battery full for evening and night.
A little earlier	85%	75%	Uses more sunshine, the battery fills up a bit more slowly.
My own values	50 to 100%	10 to 99%	You set start and stop yourself.

With your own values, the stop value automatically stays at least 1% below the start value. Tap "How Solar Plus decides" at any time to have it explained again when it starts and when it stops.

Also while driving: if you switch this on, Solar Plus also uses the energy from the alternator as soon as it has charged the battery up to the start value. So you arrive at your pitch with hot water. Solar Plus recognises driving from the charging booster, if you have set one up as a widget. If you have none, it also works through voltage input 2 on the Volty: above 13.3V there (26.6V in 24V systems) counts as "engine running". Suitable is a signal that only carries voltage while the engine runs, for example D+. What you connect to input 2 is your responsibility. Please follow the Volty installation guide. For driving, Solar Plus also needs a real battery level, meaning a battery monitor.

Advanced: here you choose how Solar Plus recognises spare sunshine.

• The solar charger slows down (recommended): when the battery is full, the charge controller holds back. That is the safe proof that energy is left over.
• The sun delivers enough power: Solar Plus starts as soon as the sun delivers at least the number of watts you enter. The default is 200W. Tip: enter as many watts as your heating element needs, then the sun covers it on its own. This starts earlier, but may take a little power the battery would still have liked.

Either way, the battery must first reach the start value. Some solar sources cannot report whether they are slowing down at all. For them, the watt rule applies automatically, and the setup shows you this.

The recommended "When the battery is full" starts at 95% and stops below 90% at the latest.

Step 4 of 5: May Solar Plus use the battery?

Sometimes a cloud drifts past, sometimes the heating element needs more than the sun delivers. Here you decide what happens then:

• Sun only (recommended): Solar Plus waits out a short cloud, the battery bridges it. But if the battery has to help pay for 5 minutes in a row, Solar Plus stops and takes a 15-minute break. So nothing keeps clicking on and off, and your battery stays almost untouched.
• Yes, down to 90%: Solar Plus keeps going even when some power comes from the battery, for example until the water is hot. Below your stop value it stops at once. The number in this option is your stop value from step 3.

If you have switched on "Also while driving", the setup gives you a tip: a charging booster usually delivers less than a heating element needs. With "Sun only", Solar Plus would therefore soon pause while driving. One tap on "Use battery while driving" sets it up to suit.

"Sun only" spares the battery, "Yes, down to 90%" finishes heating the boiler even behind a cloud.

Step 5 of 5: Done, this is what Solar Plus will do

Finally, Solar Plus sums up your answers in one simple sentence, for example: "As soon as the battery reaches 95% and sunshine is to spare, Solar Plus heats the boiler to 65°C. If the sun isn’t enough, it takes a break. Below 90% everything goes back to how it was." So you can see at a glance whether everything is right. If something is not, go back with the arrow at the top left.

• Switch on right away: if this switch is on, Solar Plus starts working as soon as it has been created. You can switch it on and off on its card at any time.
• Name: the default is "Solar Plus", you can use up to 14 characters.
• Add to Home favorites: the card then also appears on the Home tab.

Tap Create Solar Plus. Done.

The summary shows in one sentence what Solar Plus will do.

The Solar Plus card in everyday use

At the top, the card shows in large numbers how much your solar panels are delivering right now. To the right you see the path of the energy: sun, battery and whatever is using the surplus. When the lower line flows, surplus is being used. Below that are the Automation switch, the Battery row with the start and stop values and the Target row, for example "1 boiler to 65°C".

A small label tells you in words what is going on and why. For example:

• "Active · storing heat" or "Active · consumers running": the surplus is being used right now.
• "Active · while driving": the alternator is supplying the energy.
• "Waiting · battery 93% (starts at 95%)": the battery is not full enough yet.
• "Waiting · not enough sun": there is too little sun to start.
• "Waiting · charger still bulk-charging": the solar charge controller is not slowing down yet because the battery is still taking power. If you want to start earlier, you will find the watt rule in the settings under "Advanced".
• "Conditions met · starting…": it is about to start.
• "Paused · the sun wasn’t enough": Solar Plus is taking its 15-minute break and shows you how long is left.

With only 48W, Solar Plus waits until there is enough sun again.

If you want to change something later, tap the three dots at the top right of the card and then Settings. There you will find the same questions as a clear list: "Spare sunshine goes to", "Starts" and "Use battery". Each row opens the matching page. The summary appears below again, and Save applies your changes.

In the settings you change each answer on its own.

Safe, and you have the last word

Safety stays in place: for the boiler, all protection functions apply, such as dry-run, overtemperature and fresh water protection. And you always have the last word. If you switch something yourself during surplus operation, your decision applies immediately, and the automation holds back until the surplus has ended once. Every start and every end is recorded in the boiler’s event log.

12V, 24V or 230V

Devices connected directly to the leisure battery at 12V or 24V run with the surplus straight away. This is the most efficient, because nothing needs to be converted. Devices with 230V, for example many e-bike chargers or power stations, need a running inverter.

That is what the option "Power the 230V sockets" is for: the SmartKnob switches your inverter on by itself as soon as there is a surplus, and off again afterwards. If it was already running because you had switched it on, Solar Plus leaves it alone. Which inverters and inverter/chargers can be connected is shown in the energy compatibility list.

What you need

• The SmartKnob and Volty with a solar charge controller that you have set up as a solar widget. Which solar charge controllers and battery monitors Volty can read is in the energy compatibility list.
• A battery monitor, for example a SmartShunt. It is recommended for the exact battery level and for protection against discharging. For "Also while driving" it is required.
• For heat storage, a set-up boiler widget with a temperature sensor.
• For the 230V sockets, a set-up inverter or inverter/charger.
• Switchy or Ampy for the devices that should use the surplus.

Smart Solar Plus is a smart add-on feature. At the moment all add-on features are included, so you do not need to unlock anything.