What’s the Smallest System You’ve Connected to a Subpanel?

Most of the discussion around subpanels seems to focus on larger backup systems, but I’m curious about the smaller setups. My dad has an EcoFlow DELTA 2 with an extra battery which is a 2 kWh setup. He runs it through a small six-circuit subpanel in his basement for essential loads. What’s the smallest power station setup you’ve connected to a subpanel, and how has it worked out for you?