Sunplug

Setup guides → Fronius

Fronius

Fronius inverters answer questions directly on your own network, with no account, no API key and no subscription. It is the friendliest solar hardware Sunplug supports, and the local route is better than their cloud in every way that matters.

Tested against a simulator

Exercised against a simulator of the inverter's own API, including the split between production and grid. No physical Fronius yet.

How freshAbout a second, locally
Sees house loadWith a Fronius Smart Meter
Sees the batteryYes, on hybrid systems
Setup timeFive minutes

Local, or Solar.web?

Local, if you possibly can. The inverter's own API needs no credentials at all and answers in about a second. Solar.web — Fronius' cloud — requires a Premium subscription for API access and lags the inverter by minutes.

The only reason to choose the cloud is if you cannot run anything on your network. Everything else favours local.

Local setup

Install the agent on something that stays switched on and sits on the same network as the inverter. It finds the inverter itself — you do not need to know its address. 

docker run -d --name sunplug-agent --network host \
  -v sunplug-agent:/data --restart unless-stopped \
  sunplugapp/sunplug-agent:latest

docker exec -it sunplug-agent sunplug-agent setup

You need a Smart Meter

Without a Fronius Smart Meter fitted at your supply point, the inverter can report what your panels are making but not what your house is using — and surplus is the difference between the two. The agent tells you which you have when it finds the inverter.

No meter? Two options: have one fitted, or add a Shelly meter instead and let Sunplug work out the rest.

Solar.web instead

  1. Solar.web → Settings → API keys → create a key
  2. Copy the access key ID and value — the value is shown once
  3. Copy your PV system ID from the dashboard URL
  4. In Sunplug: Settings → Equipment → Fronius Solar.web, paste all three

API access needs an active Solar.web Premium subscription. If Sunplug reports that Solar.web rejected the key, that is almost always why rather than a typo.

When it does not work

The agent finds nothing

The machine is probably on a different network segment from the inverter. Skip the search with sunplug-agent setup --host 192.168.1.50.

House consumption reads zero

No Smart Meter, or it is not commissioned. Check Solar.web or the inverter's own display shows house consumption — if it does not, Sunplug cannot see it either.

Import and export look reversed

A Smart Meter fitted the wrong way round. Fronius' own display will show it too, which is the quicker place to confirm.

Stuck? Email me.