How long will the batteries last? NMP Support Center December 14, 2011 21:39 The average overall life, based on normal use, is between 25 and 30 hours of operation. Related articles Would be possible to use the handheld sonar just for measuring distance/range of fish in front of the diver ? I see a small amount of water leaking from near the activation button and display screen after submerging my Handheld Sonar. Is that normal? Live action use of the DT1H All I get is "---" readings on my depth sounder in certain places. I've noticed that these places have very soft/muddy bottoms and/or very dirty/silty water. DepthTrax 1H Handheld Depth Finder Tech Tutorial Comments 0 comments Please sign in to leave a comment.