The Sol-Ark-12L-P model does have additional ports, one specifically mentioned "Modbus". However, the manual does mention it being not active or cannot be used for battery. I guess it is worth a try, which I will consider some time.If your inverter is reading your battery via the RS485 then yes a splitter won't work for you. Even if the inverter is just set to read from RS485 and you connect SolarAssistant to the port it can't read from it. That leaves you with only one monitoring port, the WiFi/RS232 port. Some of the other Sol-Ark models has multiple RS485 ports.