Solar Data Logging

The data loggers that I discovered at the end of my installation have been connected to my home wifi by the installer. The default behaviour is that they probe the two inverters and send a burst of data to a cloud service every 5 minutes or so.

The loggers also have a local web interface that provides a way of controlling the device along with some basic data. The default username/password for these devices is admin/admin.

Digging around the menus I found a screen that shows the remote endpoint that is used to update the cloud service.

This screen included a slot for ‘Server B’, so I updated that to point at a local server I created and waited for all the data I needed to be sent to it. Nothing happened, no data was sent. I tried both TCP and UDP listeners, neither worked.

After a series of web searches, it turns out that this value is ignored by certain firmware versions. I could change the first server, but then the cloud-based system wouldn’t get any data. Given that was one of the tools the installers will use for remote diagnostics, I couldn’t replace that. (Although I have considered writing a proxy that takes a copy of the data and forwards it onto the cloud.).

It’s worth noting a quirk when dealing with these data loggers. I have got a setup that includes two inverters. I was working on the smaller and setting the server B options outlined above and suddenly found that I was unable to connect to the web interface. I started backtracking and worrying that I had managed to break something. However, the issue turned out to be significantly simpler than that. The larger inverter is connected to the battery system, but the smaller one is not. Once the panels connected to the smaller inverter stop generating power then the data logger shuts down. So you should make sure you do any research on it during daylight hours!

Searching further on the web interface, I found a couple of Solis support documents that referenced a ‘hidden’ menu under the URL /config_hide.html

The hidden screen includes a reference to a local server TCP server running on port 8899. Searching for information about this port then turned up lots of open source projects that read data from it.