This is an Arduino and Python library for interfacing with the SainSonic Tracer series solar charge regulators.

This was designed to work with a "SainSonic MPPT Tracer 1215RN Solar Charge Controller Regulator 12/24V INPUT 10A"

The protocol is described in Protocol Tracer MT-5 (copy here in docs/) and implemented in Python and Arduino. There's also a copy of the C CRC as stated in the docs by itself with a test.

The Tracer uses an 8P8C connector (the same physical type of connector as RJ-45 Ethernet cables, but very much not an Ethernet connection).

Pin 1 is on the left when looking at the connector with the contacts facing forward and the wire down. See 8P8C for an example of the physical connector and location of pin 1.

1. +12V (seems to be regulated)
2. Gnd (common to both data and power)
3. +12V
4. Gnd
5. TXD (3.3V)
6. RXD (3.3V)
7. Gnd
8. Gnd

It communicates using TTL-232 at 9600 baud. TTL-232 in this context means +3.3V is 1 and 0V is 0 (not to be confused with RS-232 which would be +3.3V is 0 and -3.3V is 1).

The Arduino and C code is mostly incomplete and as such is placed in the public domain.

The Python library is a bit more complete and is licensed under the LGPL v3