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.
Thanks, this is insightful! Hopefully things can be changed to a fairer system.