This code is for reading live-, statistical and status-data from an EpEver LandStar B (LS1024B) via a Modbus connection.

The data is then published via mqtt to be fed to gafana and pimatic.

The code is compiled in the Arduino IDE (1.8.6) using the ESP-framework (2.4.2).

I'm using a NodeMCU clone (Arduino IDE Board: Lolin Wemos D1 R2 & mini) and a widespread MAX485 breakout module to connect to the RJ45 port of the solar charge controller.

Both modules are powered using the (in my case) 7.5 Volt supply-voltage that is available at the RJ45 port of the EpEver Charge Controller. If you're using another esp module (e.g. Wemos D1 mini), make sure, the onboard voltage-regulator can handle the 7.5 volts from the EpEver.

To avoid the need of a level-shifter, the max485 module is powered only with 3V3 from the NodeMCU, which works for me, but YMMV.

Power-consumption is roughly 4mA during Deep-Sleep, mostly due to the onboard leds, I guess. When running, the power-demand gets up to about 75mA for 3-4 seconds.

MAX485         NodeMCU 
    DI              TX
    DE              D2
    RE              D1
    RO              RX
    VCC             3V3 !!!
    GND             GND
    


EpEver RJ45                        MAX485      NodeMCU
pin1  +7.5 V       org-wht                       Vin
pin8  GND          brn                           GND
pin6  RS-485-A     grn               A
pin4  RS-485-B     blu               B

connect DE (Max485) with a pull-down resistor (e.g. 6k7) to GND, to hold that line down in Deep-Sleep to lower power consumption

connect D0 (NodeMCU) with reset (NodeMCU) for DeepSleep wake-up to work

connect D6 (NodeMCU)and D7 (NodeMCU) to enable debug-mode. this sets the sleep duration to only 10 seconds

some datasheets list different pinouts for the RJ45 jack! swap A<->B if connection fails. Check voltage-level and -polarity before connecting!

This code started as a small sketch to read the data via modbus and then got additions for mqtt, deep-sleep, debug a.t.l.. It got quite big an should get some restructuring...

If you have another EpEver charge controller (like a Tracer), you may need to adjust the register/data locations according to the datasheet.

I'm excessively using the union-struct trick to map buffer-data to structs here. Most of the defines for the data-locations are for reference only and not actually used in the code.

Some parts are not done yet, or not done properly, like the switching of the load or the evaluation of the charging-equipment status.

I got loads of info for this from:

https://www.eevblog.com/forum/projects/nodemcu-esp8266-rs485-epever-solar-monitor-diy/
http://4-20ma.io/ModbusMaster

For taking the data to grafana, you might want to take a look here:

https://github.com/glitterkitty/mqtt-mysql

Have Phun!!!