If you look at the help page for FindPeaks and click on the "Details and Options" it shows that the data must be in the form of {y1,y2,y3...} or some more complicated forms and not in the form {{x1,y1},{x2,y2},{x3,y3}...}
If you tried FindPeaks[Map[Last, OvT]] then that would discard the x, give you the y and FindPeaks might then work for you.
