“Dumb” inverters integrated with ablesio
Summary. Many balcony solar plants have an inverter without its own monitoring – or only a manufacturer cloud you have to hand your data over to. A Shelly smart plug between the socket and the inverter measures what your balcony plant generates instead: every 15 minutes, locally, without the manufacturer's app. ablesio attaches these values to your feed-in meter – and you see the yield, peak power and value of your electricity. Only one thing matters: The plug has to be plugged in the right way round.
1Why bother?
A balcony plant pays off over the years – but only if you know what it actually delivers. Many cheap micro-inverters don't show anything at all. Others send their values exclusively to the manufacturer's cloud, with their own app and sometimes a subscription. And anyone who already has an electricity meter with bidirectional counting only sees there what flows backinto the grid – not what the balcony plant generates in total and what was used in the house.
A smart plug solves this in one go: it sits between the socket and the inverter and measures every kilowatt-hour the balcony plant sends into the house wiring – whether it is used in the house or goes into the grid.
2What you need
- a balcony solar plant with a plug, connected to a permanently installed socket
- a Shelly smart plug Gen2 or newer, e.g. Shelly Plug S MTR Gen3 or Plug PM Gen3 – it handles 16 A, which is plenty for balcony plants up to 800 W
- ablesio with a meter of the type “🔌 Electricity feed-in meter” (a balcony plant or inverter meter works just the same; these meter types need the paid add-on “PV system & feed-in” or “balcony power plant”, or Ultimate)
3How to connect it
- Unplug the balcony plant from the socket.
- Plug the Shelly into the socket.
- Plug the inverter into the Shelly. Done – the power now flows through the Shelly, and it measures along.
🔄 Plug it in the right way round! Not every plug measures power flowing “backwards” in both plug orientations. If during the day in sunshine no values arrive or the yield stays at 0, pull the Shelly out and put it back in turned by 180° . If necessary, just try it – ablesio shows you immediately in the device file whether values are arriving.
Safety. Follow the instructions of the Shelly and inverter manufacturers, use a permanently installed socket (no multi-socket adapters and no extension cables in between) and if in doubt check with a qualified electrician. The usual rules for balcony plants still apply, e.g. registration in Germany's market master data register (Marktstammdatenregister).
4Setting it up in ablesio
- Create the meter: Meters → “+” → “🔌 Electricity feed-in meter”, e.g. “Balcony plant”.
- Switch on the smart plug: Meters → Edit → tick “🔌 Smart plug”.
- Connect: Under Devices → 🔗 Connect choose the way: set the Shelly up yourself directly (click by click: Shelly app, web interface, paste the script, start), have the ablesio.de team set it up (small fee; you just plug it in) or via your smart home (ioBroker/Home Assistant: there you can switch on “enter balcony power plant readings automatically” – off by default). At the end ablesio checks live whether values are arriving – test during the day; at night the inverter generates nothing.
The script recognises the generation context itself: if your Shelly counts feed-back separately, it uses that counter. If the counter restarts at 0 after a power cut, ablesio accounts for it – your total yield stays correct.
5What you'll see
The generation file of your feed-in meter shows you: yield today, over the last 7 and 30 days, the peak power, the average yield per day and a rough estimate for the year (rough, because winter is much weaker). On top of that, what this electricity is worth at your electricity price , and a curve of the last 7 days with the previous week for comparison. Because the values are attached to your feed-in meter, they also flow into your reports and your energy year.
6Bonus: checking smart inverters
Even if you have an inverter with its own monitoring, you benefit: add the inverter as a separate meter (e.g. “☀️ Inverter”) and the Shelly as the feed-in meter. The generation file then shows a comparison: what the inverter reports, what the Shelly measured, and the difference in percent. Tick “🔗 measures the same system” there – then ablesio counts the Shelly only as a check and not twice in the overview and energy year. If you have two separate systems (e.g. roof and balcony), leave it unticked.
| Difference | What it means |
|---|---|
| up to ± 5 % | normal – inverter and plug measure at different points and with different accuracy |
| 5–12 % | take a closer look: does the inverter perhaps measure before its own losses? Are values missing (Wi-Fi gone, plug offline)? |
| more than 12 % | something's wrong – check the inverter data, plug orientation or gaps |
7Checklist
- Shelly Gen2 or newer plugged in between socket and inverter
- checked during the day: values are arriving – otherwise Shelly turned by 180°
- Feed-in meter created in ablesio and “🔌 Smart plug” switched on
- Script pasted and started with the wizard
- optional: smart inverter added as a second meter and the comparison checked
Conclusion. A “dumb” inverter becomes smart with one plug for little money: you see every kilowatt-hour your balcony plant delivers – measured locally, analysed in ablesio. And anyone with a smart inverter finally knows whether its numbers are right.