Battery detection depends on the inverter proxying the battery. Some inverters don’t do it, possibly because of an internal setting SolarEdge can control.
You can turn on debug logging and post your startup sequence where it runs battery detection to see what it returns, but almost always this issue is becasue the inverter doesn’t support battery over the modbus/TCP interface. It has been said SolarEdge can enable this internally, but I don’t personally have batteries so I don’t know personally.