Blue Lantern is a modular renewable energy monitoring system, or at least, with enough time and effort it will be. It is named after the Blue Lantern Corps organisation that appears in DC comics, not because I'm a fan of DC comics, but because the the emotion of hope for the future on which it is based seems apt when it comes to renewable energy. Hope for the future.

One of design criteria was that it should be easy for a developer to interface with a new piece of equipment by writing only the code necessary for communicating with the relevant piece of equipment. Ideally it should be possible for the developer to use the language of his choice.

For a communications bus, MQTT is utilised. Instructions for building Mosquitto are included below.

In order to link your equipment, all you need to do is write the interfacing code for communicating voltage, current and power (if available) onto the mqtt bus, where other components will subscribe to the information they require to operate.

For a start, it will support Victron Multiplus inverters, and the Victron MPPT charge controllers, for no other reason than because that is what I have available.

The other components of the system are:

• A web server, written in python and pyramid, that collects the related charge and discharge values, and aggregates it into a json stream for display use in a web application.
• A web application, using angularjs, for displaying gauges and providing other functions (currently still very crude and not at all useable yet).
• A logging component that will log power values to a local or remote database (not yet implemented).

For development you will need:

• Python, and preferably virtualenv.
• If you intend in-depth development on the web interface, you need nodejs to get the angular part working. This pulls in heaps of javascript libraries. This part is optional.
• An MQTT broker. Instructions are included below for Mosquitto.

Some equipment requires specialised hardware.

• For Victron Multiplus and Quatro inverters you will need an MK2-USB module.
• For the Victron BlueSolar MPPT charge controllers equipped with a VE.Direct port, you will need the VE.Direct USB cable, or a similar USB to Serial (TTL level) converter. I strongly advise the use of the Victron cable for galvanic isolation.
• For the Victron BlueSolar 150/70 and 150/85, you will need a canbus interface. I own a 150/70, therefore I created an arduino solution that converts the relevant info into VE.Direct.
• I hope that in due time this will also work with the popular Voltronic inverters.

First install python and virtualenv. Then, to develop, change into the source directory and:

virtualenv venv
venv/bin/pip install -e .

This will pull in all dependencies and install the in the virtual environment, leaving your original python installation unchanged.

Start it with venv/bin/pserve development.ini

This step is optional, although a working MQTT server is required. You can use iot.eclipse.org for development or testing purposes, or you can use an alternative broker available for your platform. Mosquitto is free, has few dependencies, and works well for development.

sudo apt-get install libwrap0-dev libssl-dev uuid-dev

git clone \
  http://git.eclipse.org/gitroot/mosquitto/org.eclipse.mosquitto.git \
  mosquitto

OR

wget http://www.eclipse.org/downloads/download.php?file=/mosquitto/source/mosquitto-1.4.7.tar.gz
tar zxf mosquitto-1.4.7.tar.gz

Change into source directory, edit config.mk:

1. set WITH_SRV:=no (or alternatively install libc-ares-dev)

2. set WITH_DOCS:=no (or alternatively install docbook-xsl)

   make

Edit mosquitto.conf and set:

bind_address 127.0.0.1

You can start mosquitto without installing it, if you just want to use it for development.

src/mosquitto -c mosquitto.conf

Likewise, you can use the utilities that comes with it, but for that to work the library must be loadable. You can work around this by setting LD_LIBRARY_PATH.

LD_LIBRARY_PATH=lib client/mosquitto_pub -t battery01/inverter/power -m 555.42

You don't need to do this unless you intend to do heavy development involving the upstream dependencies. Everyone else can skip this as the code comes prepackaged with a version of angular and all support libraries.

To develop this part, you need nodejs. After installing nodejs, running npm install is sufficient to set up all the required components.

Add lines similar to the below to your development.ini file. The port setting relies on udev symlinking your usb-serial ports by their ids. This is the default setup on most Linux distributions and should work straight out of the box.

pyramid.includes =
    ib.bluelantern.victron.mk2

mk2.instance = battery01
mk2.name = inverter
mk2.port = /dev/serial/by-id/usb-VICTRONENERGY_MK2USB_COM_Interface_FTABCDEF-if00-port0

Add lines similar to below to your development.ini file.

pyramid.includes =
    ib.bluelantern.victron.vedirect

vedirect.instance = battery01
vedirect.name = mppt
vedirect.port = /dev/serial/by-id/usb-Silicon_Labs_CP2103_USB_to_UART_Bridge_Controller_0001-if00-port0

Add to your development.ini, and point the logger to a file location.

pyramid.includes =
    ib.bluelantern.stats.csvlog

csvlog.directory = /tmp
csvlog.statistic.Victron_MPPT_150_70 = mppt@120 voltage:avg,current:avg

This will create a file Victron_MPPT_150_70.csv with average current and voltage readings for each 120-second window. You can add more than one statistic line, each will go to a different file.