Eversolar Inverter Monitoring with Linux

In November 2010 I have a 1.5kw solar power system installed by Nu Energy. It came with an Eversolar TL2000AS inverter and since it came with an RS-232 & RS-485 interface I figured it wouldn’t be too hard to monitor & graph it on my web server.

I fired off an email to Nu Energy asking for software to do this but they referred me to Eversolar so I contacted them directly. Unfortunately it seems that the RS-232 interface is only used for uploading firmware, despite what the manual says. They gave me two options – purchase their Power Management Unit (PMU) or one from a German company Solar Log. I went with the former (US$300 vs US$1000).

The Eversolar PMU connects to the inverter via RS-485 using a straight-through RJ-45 cable and is connected to my LAN via ethernet. It can also be connected directly to a PC via USB and comes with some Windows software called AS Control. Since I wanted to monitor it from Linux I was hoping that it would support SNMP, but alas, that wasn’t the case.

The AS Control software communicates with the PMU via HTTP on port 8080. I used WireShark to look at the communication and implemented enough to be able to pull what I needed from the PMU with a Perl script and graph it with MRTG & RRDtool. You can see the graphed results in my Power Stats page.

One thing I discovered about the PMU is that it will actually run on power from the Inverter via the RS-485 connection so you don’t actually need the external power pack. The downside of this is that it it only works when the Inverter is providing power but I can live with this.

I’d be interested in hearing from anyone who’s doing something similar with Linux or has any information on the communication protocol for the Eversolar PMU.


DownloadDescriptionVersionUploaded
pmulogger.zipEversolar PMU/Inverter perl data logger0.1b20-12-2010

52 Comments

  • Steve says:

    Sorry, I never really looked at doing anything with RS485 after I got the PMU with ethernet connectivity so I’m afraid I can’t help. Hopefully someone else may be able to assist.

  • solmoller says:

    Hi Steve,

    This is just to let people know that your code lives on – it has been migrated from google code to github today. I see that people are posting support questions here, there may be help yo get in the new location
    https://github.com/solmoller/eversolar-monitor/

    (there is a wiki under the branch wiki with frequensly asked questions)

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