Where did you see the copy time quoted as 13 hours? If it was at the start of the copying process, in the copy window, then don't rely on that.
Start the copy process, and just keep an eye on the copy window for a few minutes. The predicted time will probably start at something ridiculous, dance around all over the place for a while, then gradually settle down to a realistic figure, which will decrease at a steady, accurate rate.
Either that or you've got a *hell* of a lot of data!!