That article describes exactly what I would not want to do - subject my expensive vehicle to additional discharge/recharge cycles thereby shortening its battery’s useful life prematurely.

Lithium batteries are pretty great (except for when they catch fire and are nearly impossible to extinguish), but their performance degrades slightly with every charging cycle. You may have noticed that after a year or two your phone no longer makes it through the day without extra charging, because its total capacity is reduced.

The same thing happens with EV batteries (translating into shorter driving range) but they’re much larger and more expensive to replace. Moreover, when replaced, the old batteries are still capable of useful work with lower capacity, so it’s excessively wasteful to dump them into the hazardous e-waste stream for whatever passes as recycling.

There are companies that are collecting those used EV batteries and using them for electric grid storage, which sounds like a great way to extend their lifecycle and to acquire useful equipment at bargain basement prices. That’s what I meant about only ever seeing it at grid-scale. It would be nice if somebody sold a controller for those to be repurposed for use as energy storage for a single home, at much lower equipment cost than a brand new home battery.

There will be many more used EV batteries available in the next several years as the first wave of widely adopted electric vehicles ages out, and the oversupply should drive down their costs further.

That said, being able to use a vehicle battery as an emergency backup during a storm event is a wonderful side benefit. It’s just no substitute for a full time home battery (that’s actually connected during the day when the panels are producing, instead of being parked at work away from your house).