Newer vehicles will have the inverters too, so taking one apart will have the full infrastructure for a backup power source. Older batteries are already being used for this sort of purpose at least in the Nordics.
Oh. I don't doubt that, I was taking the shadow fleet as a commercial fleet like the Russian one is. I have zero doubt about all non landlocked countries using civilian registered vessels for at least signal intelligence and special operations forces.
Those are vintage memes.