This project intially started by reverse engineering the communication protocol of the Tracer solar charge controller.

Fortunately EP Solar hinted to look at the Tracer-MT-5 protocol (111213).doc file and searching for that I found a Python and Arduino library for the Communication Interface for Tracer MT-5. Great to see there is more people hacking these controllers! And even got something not entirely unlike a datasheet

I initially made two tools written in C, meant to probe/fuzz and experiment with captured communication logs. Now that became a single tool which is useful to output the status information of the Tracer and switch the load power on/off.

tracerstat allows sending MT-5 (pseudo-ModBus) requests via a serial port to the device and translates the result into various useful output formats.

• -o one-line output (no newline, useful for syslog)
• -c comma seperated output
• -j JSON output

tracerstat automatically outputs in collectd's expected format if called from collectd's Exec plugin.

LoadPlugin exec
<Plugin exec>
	Exec "daemon:uucp" "/usr/bin/tracerstat" "/dev/ttyUSB1"
</Plugin>

When called with parameter -I or -O, the load output is switched according to the parameter.

To query the status of your controller on the command line, call tracerstat without any parameters assuming that the controller is connected to your host via /dev/ttyUSB0.

If using a serial port device other than /dev/ttyUSB0, simply put the device node filename as a paramter.

Thanks and have fun!