Bejing EPsolar EPEver EPIPDB-Com 10A 20A Dual Battery Solar RVS/Vessels Controller EPIPDB-COM-10 EPIPDB-COM-20 https://www.epsolarpv.com/product/64.html
Display used for data verification https://www.epsolarpv.de/produkte/item/mt-1-display.html?category_id=3
The device is running an ATmega8 as seen on the top view of the PCB.
The above picture shows this library running on a TTGO along with a SSD1306 OLED display. The source code is provided in arduinoHardwareSerialAndSSD1306.ino.
The relevant components are:
- LILYGO®TTGO LORA32 V2.0 ESP32 from aliexpress
- 3A DC-DC 7-28V to 5V converter from aliexpress
- Quad Channel Bi-Directional Logic-Level-Shifter from aliexpress.
I have been running the another instance of this without any level shifter (only a ~100Ω resitor in series to RX of the ESP) for ~6 months in my car now and the TTGO/ESP32 still works but I would recommend using a level shifter.
Client side:
Client Board (top view!):
The most relevant pins would be :
- Supply from both batteries via diodes with ~1V drop
- EPCOM TX (connect to Arduino RX), caution: 5V level
- EPCOM RX (connect to Arduino TX)
- GND
- GND
The RX and TX pins are protected via diodes inside of the EPIPDB-Com as seen here:
.