Just because a postcapitalist world should have a battery for every house does not make batteries in and of themselves solarpunk. The story surrounding the battery, in this case, the branding, is actually precisely what matters, because solarpunk is explicitly about speculative futures. It's a genre of science fiction that creates an optimistic and green aesthetic to aid in imagining a postcapitalist world. Posting a link to a currently existing consumer grade technology with consumerist branding is, by definition, not solarpunk.
"A good science fiction story should be able to predict not the automobile but the traffic jam." You're posting the automobile. Science fiction is about the social context of the technology as much if not more than about the technology itself.
Again, I'm not saying that personal batteries are bad, or have no part in a postcapitalist future.
I think that's a very weird interpretation of that, but fair enough :)