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.
|pmulogger.zip||Eversolar PMU/Inverter perl data logger||0.1b||20-12-2010|