"Sound travels faster underwater, so perhaps it pings or listens harder out of water, I'm not sure. "

Hence my question.

Mine is an X-4 portable.
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Judging from memories of my old green box with the two knobs, muddy bottoms in deep water required a higher setting than hard bottoms in shallow water. Does that also equate to more current draw?

The last three I've used had a manual and an auto setting for depth. Auto was fine by me. My theory is when the ducer is attached to the hull of an overturned canoe all night, it was striving to ping the moon at full blast. The same ducer in a bucket would be minimal current draw as my theory goes. This was probably the fullest feature one I've used and it was also siliconed to the hull. Batteries were totally dead the next day.
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I've never heard the ducer out of water worry before. You guys all shoot through the hull right?

I was curious is all. Glad I don't have to worry that I knowingly damaged anyone's transducer.
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No worries. That mapping feature you figured out is pretty cool.

What would be really cool in my book is a bluetooth transducer and an app or two for my phone that uses Tesla's wireless power grid, and WiFi! No wait, maybe just depth maps of all the Q lakes...

Nice setup db, I wouldn't have thought to use velcro.  Simple but effective.

I had picked up an x-4 unit locally off FB marketplace earlier this year for $35, thinking it might be a good idea to grab one of these low power B&W units while they can still be found.  Here is my take on making it portable with a Ryobi battery for power.  I have a 9Ah in the picture, but I'm thinking a 4Ah size would last more than a week of fishing given the low power draw of the unit.  I haven't tested run time with it yet.
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I have looked at power draw with the transducer out of water vs in water and the current draw doesn't noticeably change.  I know Magicpaddler was the one that initially told me about not running the transducer out of water, but I have since seen the same advice given in other online forums and groups.  Transducers seem pretty robust, but they are the moving part of the unit, even if you can't see it moving, you can hear the clicks.  Like brake pads on a car, they eventually wear out.  Hours and how you drive makes a difference in how long they last.  I do run my transducer in a through hull configuration consisting of a foam block with a transducer shaped hole cutout siliconed to my canoe floor which I then fill with water and seat the transducer.  I don't know if this is considered sufficient to prevent damage, but I haven't had an issue so far. 

Magicpaddler,

For the down converter, I considered three different units: ZK-J5X, LM2596 & the Mini360.  They are all advertised as highly efficient, but I decided to test them out to see which would be the best fit.  For testing I dialed each one in to 14.5V and I used a 1.3 Ah Ryobi battery and recorded run time of my Fishfinder(no transducer). I used the same battery for each test.

ZK-J5X: ($8-$10)This is the fanciest of the three, with a LCD screen which can show input/output voltage and current draw.  It features 4 buttons and is quite easy to adjust and use.  It is rated at a maximum 5 amps, which works since my unit draws under 1 amp.  I really like this downconverter overall, as it gives you a lot of information.  It's downfall for this application is that the screen cannot be turned off without also turning off the downconverter itself.  My 1.3 Ah battery lasted 3:58 using this converter.

LM2596: ($1) Less frills with this unit, with just a screw adjustment potentiometer and a blue LED status light.  This unit is rated at a max of 3 amps, again adequate for this application.  My 1.3Ah battery lasted 4:09 using this converter.
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Mini360: (<$1) Also rated at a max 3 amps.  This thing is tiny(fingernail size).  It's almost hard to work with, it's so small.  The pot adjustment is sensitive and a bit futzy.  But once wired and setup, this unit seems to be the best fit.  My 1.3 Ah battery lasted 4:39.  Winner, winner, chicken dinner. 

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