The EcoFlow Wave 2s XT-150 port should accept third-party expansion batteries --- but it doesnt. EcoFlow locked it down with a communication handshake that blocks direct connection. I found the workaround, https://youtu.be/qfHau5rHlPA and it unlocks 11 kWh of capacity and 24 hours of nonstop heating or cooling. I test the Wave 2 with WattCycle server rack LiFePO4 batteries, discover why direct plug-in fails and why it works on the Wave 3, then build a cable mod using the EcoFlow ...