Using headphones to save power does help some , the reason is if you look the amount of power it takes to run the headphones and the amount of power it takes to run the speaker , the amount for the headphones is less. It just takes less current to run the headphones .
Now you would have to find out how much power it takes to run the speaker on your detector to be able to calculate the deference between the headphones . That would tell you the amount of time you will gain .
I myself use the headphones as I can hear the lesser sounds that the deep targets make , it is just easier for me to hear them that way. But I have seen some guy's that can hear it with there speaker just as well .
When I use the headphones on my detector the battery does last longer , but I have never timed the amount to see how much more it does help .
I do not use the headphones to save power so it really does not matter to me how much there is in savings . Mostly it is also for when I am around people . The sound coming from the detector will drive some crazy when they are trying to do other things so I use the Headphones so I do not bother anyone else .
