What does power-cycle mean in this case?

I've seen this topic come up a lot on a datahoarder forum but there was never any consensus on what it would take to assure the data was refreshed because no one really knew how it worked. People would assume anything from a short power up to simply rewriting all data as possibilities.

The firmware engineer responding up thread is actually the best information I've seen on this. And it kind of confirmed my suspicions. He works on enterprise drives and they run a refresh cycle as background cycle that seems to start on a random timer. I didn't see any response (yet) on how long this process takes but I think we can infer that it takes a while based on it being a background process. Probably hours or more. And this is all for an enterprise drive, I wouldn't be surprised if consumer drives have a less robust or even non-existent refresh function.

I'm of the opinion that that based on the little information about some implementations of this function, the logical conclusion is you should just rewrite all of the data over again on your cold backups for the cycle. Powering it on isn't enough, even powering it on for a day might not do anything. As you said this is a pretty big drawback for uses flash as a cold backup.