Nice. I hadn't thought about accessing the battery power from anywhere other than the CHAdeMO connector which has the added complication, but also the added safety, of the safety isolation contactors. But it's a very expensive connector, designed for higher current than a 6kW inverter would need. Food for though, thank you.
I have access to a grid tie inverter, a 15kW Electronic Recovery Load like this: https://elektroautomatik.com/en/products/dc-regenerative-electronic-loads/#produktselektor but maybe an off-grid inverter is the way to go for power cut support rather than just V2G (or essentially I would be using it as V2H time shifting and import management for peak loads that a solar system cannot meet).
