mouldy.org

At peak charge a typical cylindrical NiMH cell can be as high as 1.45(n)V or thereabouts. They'll soon enough settle down to a sub-1.40V value if left out of the charger or ran for a moment in any device using more than a tiny mA current. Some prismatic cells might reach slightly over 1.50V but they too tend to peak closer to 1.45V

As for the other end, generally we consider them drained at 0.8V though whether that's the figure to use can have a bit to do with how you're powering your (LED bike light(?), etc, whether there were a regulation stage between the battery pack and device or just a current limiter like a series resistor, at which point you'd consider the device function to be falling below a minimum acceptible threshold.