Deye/SunSynk/Sol-Ark - The 2 in 1 BMS port


On newer Deye/SunSynk/Sol-Ark inverter models and firmware, the BMS port is a "2 in 1 port" used for both RS485 and CAN communication. The inverter can read a battery via CAN while SolarAssistant reads the inverter via RS485 in the same port at the same time.

Known models

  • Newer Deye/SunSynk 5 kW models/firmware
  • Newer Deye/SunSynk 16 kW models/firmware
  • Newer Deye/SunSynk 3 phase models/firmware

How does it work?

The BMS port contains pins for both RS485 and CAN. It is possible due to the fact that RS485 only requires 3 pins and CAN only requires 2 pins.

RJ45 splitter

How to test it

The SolarAssistant cable only uses pin 1 - 3. You can temporarily unplug the battery CAN cable from the inverter BMS port and plug the SolarAssistant RS485 cable into the inverter BMS port to see if SolarAssistant can read your inverter. Be sure to click "Disconnect", then "Connect" in SolarAssistant. Once the test is complete, put the battery CAN cable back into the BMS port.

Recommended solution - RJ45 splitter

Use our Deye/SunSunk/Sol-Ark RJ45 splitter or read the product page to source or create your own splitter.

RJ45 splitter

Alternative solution - Crimp RS485 and CAN into one RJ45 plug

Using our RS485 self crimp USB cable you can additionally insert the battery CAN cable into the RJ45 plug when crimping the cable.


When using a RJ45 splitter, it might lead you to connect the RS485 pins into the battery in addition to the CAN pins. The battery might use those pins for a different purpose and disrupt SolarAssistant monitoring communication. The battery CAN cable should only connect the CAN pins to the battery.