If all internal systems on the Navis float are functioning within normal parameters, the end of the floats functional life should be caused by the depletion of the main batteries. The only warning of eventual failure is that prior to full battery depletion, the float will typically see a voltage drop with 5-15% of the float life remaining. The internal battery voltage measured at various points in the float’s mission cycle can be viewed in the float .LOG file which is transmitted with the sensor telemetry.
