Victron & Open Energy Monitor (EMON)

Guest post from Alp Tilev, CTO at Great Lakes Energy in Rwanda, about their work integrating the BMV-700 into EMON, an open source software project.

Alp Tilev:

“At Great Lakes Energy we love Victron products. Through 10 years of delivering off-grid solar power systems in Rwanda we have learned that the key to providing reliable energy in off-grid solar sites is remote monitoring. We’ve been using several tools to accomplish this task, including the Victron Color Control. However, sometimes we have to work with sites that have non-Victron equipment installed and for these sites we’ve found that the Open Energy Monitor (EMON) is a great tool.

gle-IMG_0724

Picture shows our test installation, with the EMONpi being the aluminum box on the lower right.

The EMON project is an open source, open hardware project that lets anyone use EMON equipment to monitor electrical equipment. However, the EMON doesn’t come with an off the shelf component to do DC monitoring. Since monitoring battery health is a critical component for off-grid applications, we thought the BMV-700 by Victron would be a perfect component to integrate with EMON.

With help of Victron we added direct read-out of the BMV-700 to EMON – and that has now become standard EMON functionality!

Screenshots

This first screenshot show a graph of the battery voltage, over time:

Second and third screenshot show the configuration:

emon_cms_2

Tech details

The BMV-700, like many other Victron products, uses the VE.Direct protocol to communicate with Victron equipment.

EMON uses a Raspberry Pi minicomputer to take the data from the sensor node, parse it and pass it on to the EMON CMS. The key component that does this is called Emonhub which is a python server that runs on the EmonPi. The Emonhub has many types of interfaces which let it communicate with different type of sensor units.

To get started you need to have an EmonPi, Isolated VE Direct to USB cable and a BMV-700 attached to a battery bank. Settings things up is quite simple and only requires changing the emonhub configuration. See github for further information: https://github.com/openenergymonitor/

Happy monitoring!

Alp Tilev (CTO, Great Lakes Energy)