Where the extra energy-conversion step actually happens — and why the architecture with fewer conversions isn't automatically the right choice.
Every battery in a solar-plus-storage system stores DC energy. But solar panels also produce DC, and homes run on AC — so somewhere in every system, power crosses between DC and AC at least once. The question "AC-coupled or DC-coupled?" is really just asking where the battery sits relative to that DC/AC boundary, and that single placement decision determines how many times energy gets converted on its way from panel to battery to load — and, just as importantly, whether the battery can be bolted onto a solar system that already exists.