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Author Topic:   Operating SONAR on AC-Power and On Land
rashbrook posted 04-27-2010 09:39 AM ET (US)   Profile for rashbrook  
I have a Humminbird 365i. I have come to the point where I would like to be able to add waypoints and practice and familiarize myself with [the Humminbird 365i] in the evening, while not always sitting in my boat. I looked at the requirements in the manual, and can see only that [the Humminbird 365i] requires 10 to 20-VDC. It also notes a current draw of 350mA, but I don't know how this figures in.

That said, I have an AC adapter that outputs 12-VDC and 1.5A. If I could use an in-line 1A fuse on the positive wire, and just connect positive and negative wires from the adapter to the positive and negative of the (extra) Humminbird power cable I have, would that work? Or would the amps blow my unit? I don't entirely understand what "current draw" means.

I called Humminbird, who said that they do not make an AC adapter, but suggested bringing a marine battery into my livingroom for this purpose and connecting it directly. Not really.

The people at [Bass Pro Shops] surely don't have 12-V Marine batteries powering all of those in-store units behind the counter, do they? Advice anyone? There must be some way. If a 12-V marine battery can power it directly, wouldn't the AC with 12-VDC output work, too? Thanks for your advice - RA

fishgutz posted 04-27-2010 11:37 AM ET (US)     Profile for fishgutz  Send Email to fishgutz     
I don't see a problem using that AC adapter. I do that sort of thing all the time. From testing trailer lights to trickle charging/balancing rechargeable batteries. I save all old AC adapters from cellphones, answering machines, games, printers, etc. just for that purpose. I bet I have over 20 AC adapters in a bucket in the garage. Very useful.
rashbrook posted 04-27-2010 02:12 PM ET (US)     Profile for rashbrook    
What about the amps coming from the AC adapter - or does the Humminbird care?
number9 posted 04-27-2010 02:25 PM ET (US)     Profile for number9  Send Email to number9     
When it's labeled 12VDC, 1.5A, that indicates the maximum it's designed to put out. Same as your battery is rated to put out more than electronics. You should fuse as the manufacturer recommends for normal operation.
jimh posted 04-27-2010 03:00 PM ET (US)     Profile for jimh  Send Email to jimh     
If you plan to operate a SONAR device without a transducer attached to it, you should consult with the manufacturer to see if there will be any damage.

If you plan to operate a SONAR device with a transducer attached but with the transducer not immersed in water, you should consult with the manufacturer to see if there will be any damage.

If you do not understand what "current draw" means, as a general inference I would say you should avoid trying to configure new means to power your expensive marine electronics.

A good understanding of the units used to express the flow of electrical current can be gained from reading

The unit of milliamperes is normally abbreviated as "mA." In one ampere there are 1,000 milliamperes.

rashbrook posted 04-27-2010 03:08 PM ET (US)     Profile for rashbrook    
Given your post, I hope I haven't caused any damage to my humminbird sitting in my garage learning how to configure it - with the transducer not immersed. ;-)


fishgutz posted 04-27-2010 04:19 PM ET (US)     Profile for fishgutz  Send Email to fishgutz     
Don't worry about using your sonar out of the water. That would be a very weak design if you could damage your transducer by using it out of the water. Most would be ruined prematurely from pulling the boat out of the water at the ramp with the sonar still on. Few people turn off ALL their electronics while still in the water. Heck with my Humminbird on my old Alumacraft, I left it on overnight in the garage. I have never heard of such a thing happening.


jimh posted 04-28-2010 08:31 PM ET (US)     Profile for jimh  Send Email to jimh     
fishguts is apparently expert on how all marine SONAR devices are designed and can assure you that there is no possibility of damage by operating the SONAR without a transducer attached or with the transducer out of the water. Ignore that loud clicking sound you hear. Why bother checking with the manufacturer!
fishgutz posted 04-28-2010 10:10 PM ET (US)     Profile for fishgutz  Send Email to fishgutz     
[Apparently replied to my prior comment only to point out that I misspelled his handle.]
Chuck Tribolet posted 04-29-2010 12:16 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
I'm with fishgutz. I've left the depthfinder on and driven
all the way home. No problems, and never heard of anyone
having any. I don't have a combined GPS/depthfinder, so
never had a need to run the depthfinder without a transducer,
but I've got lots of buddies who have that sort of unit, and
have run them without the transducer to load maps and

If it were a problem, the manufacturers would be shouting from
the rooftops: "DON'T DO THAT", and there would be contrite
posters here (like those who have hooked their battery up
backwards) asking how much damage they did.


jimh posted 04-29-2010 09:03 AM ET (US)     Profile for jimh  Send Email to jimh     
Again, now that fishgutz has assured us no damage can occur to your expensive SONAR or any other SONAR if you operate it with the transducer not attached or with the transducer out of the water, we can turn to your other question.

"...would the amps blow my unit?"

"What about the amps coming from the AC adapter - or does the Humminbird care?"

To make an analogy to engines, your question is akin to asking what about the 250-HP from an outboard motor when it is idling. The rating of the power supply in amperes refers to its maximum capacity to supply electrical current. If the power supply is asked to supply less current, that is what it does. It is analogous to asking a 250-HP motor to only supply 3-HP at idle.

However, the Humminbird does "care" a great deal about the voltage of the power supply you connect to.

jimh posted 04-29-2010 09:44 AM ET (US)     Profile for jimh  Send Email to jimh     
Notwithstanding the expert advice offered here, I am a prudent fellow, and, if someone proposes operating an electronic device in an unusual manner, particularly a device that costs a lot of money and is impossible for the average owner to repair, I think it is prudent to recommend checking with the manufacturer of the device to see if the proposed mode of operation is permitted. The fact that a proposed mode of operation is not explicitly forbidden in the manufacturer's documentation does not mean it is endorsed. In the owner's manual for my car it does not explicitly say the car cannot be driven underwater, but it is not reasonable to conclude that driving the car underwater can be done with no damage.

It may very well be that a Humminbird 365i can be continually operated with its transducer unattached or with the transducer attached and out of the water and no harm will occur, but inasmuch as I do not know that to be a fact myself, the notion that one ought to seek the advice of the manufacturer seems entirely reasonable to me.

My experience includes seeing many SONAR devices being used on store shelves and apparently without an attached transducer, but in almost all cases the devices are running in a special mode of operation, demo-mode. It may very well be that in demo-mode the operation of the SONAR transmitter is disabled. This seems somewhat reasonable when you consider that on store shelves there are often dozens of SONAR devices on display and operating simultaneously, and if they were all transmitting SONAR pulses there could be interference among them.

fishgutz posted 04-29-2010 10:20 AM ET (US)     Profile for fishgutz  Send Email to fishgutz     
I said I see nothing wrong with using your sonar out of the water. I would NOT use it without the transducer connected. Often electronics, especially transmitting devices (sonar transducers, two way radios, etc.) must have a load on them or damage can occur.
rashbrook posted 04-29-2010 11:09 AM ET (US)     Profile for rashbrook    
I called Humminbird.

According to them, if you want to run your Humminbird (of any kind) out of water, you should use the simulation mode, accessed during startup. In that mode, you can run it as much as you like, as it does not use the transducer.

The person on the phone also said that it is not recommended to run it in normal mode out of the water. Distressed by that a bit - I asked her what would be signs of damage in that case - and she said that you would typically get an error saying "transducer not found" or a white screen, or another transducer related error on the screen. I've seen none of those, but am still a little concerned. Hope it's ok still.

To a large degree, this is what I have done with the new unit to configure (the bulk of the time so far), however, there was probably about a 20m period here or there when I first bought it and mounted it on the boat when I did not know how (or that you even could) go into simulation mode - and I ran it out of water in "normal mode" and played with the menus, made sure it worked, etc. Now, I've done that in the past with my old boat's Humminbird here and there and like the other posters here noted - I was not aware of any problems as a result. I just wish the weather would clear up around here on the weekends so I could put it to the test.

Another note. Humminbird also emailed me the following link - for people who wish to run their Humminbird's out of water, using simulation mode:

Not too shabby. ;-)

jimh posted 04-29-2010 01:07 PM ET (US)     Profile for jimh  Send Email to jimh     
Wow--Good thing you called the manufacturer to check if your expensive marine electronic device could be operated in a way not intended in the normal use of the product.
rashbrook posted 04-29-2010 01:52 PM ET (US)     Profile for rashbrook    
So the answer is yes, it can, just in simulation mode, using a battery (the one above could be used) connected just like you would in a boat, direct.
jimh posted 04-29-2010 10:56 PM ET (US)     Profile for jimh  Send Email to jimh     
There is no need to use a 12-volt lead-acid storage battery to power a SONAR device. You can use any source of 12-volt DC power you like.
jimh posted 04-30-2010 12:11 AM ET (US)     Profile for jimh  Send Email to jimh     
A SONAR transducer is typically a piezo-electric device. It responds to an electrical current flow by producing movement. In the case of a marine SONAR, the application of voltage tends to put the transducer into oscillating movement at a frequency of 50 to 200 kHz, depending on the resonance of the piezo-electric material. The movement of the element produces ultrasonic sound waves. The amount of movement is proportional to the applied voltage. In this way you can think of a SONAR transducer as akin to a drum. If you strike the head of a drum with a stick or mallet, the drum head vibrates and produces a sound.

If you strike a drum in the air, you get a certain movement and a resulting sound. If you were to place the drum so that the underside of the drum head was in complete contact with a very deep column of waterr, and strike the drum head with the same speed and force as you did before, you would get a different movement and a different sound. The difference is due to the density of the medium below the drum head. With the drum head coupled to the water, the movement of the drum head that results from a strike will be less than when in the air. So it would be with a SONAR transducer. When the SONAR transducer is in the water, it is coupled to the water, which tends to dampen the movement. When the SONAR transducer is in the air, there is no dampening of the movement, and I suspect the amplitude of the movement will increase and perhaps the frequency of resonance of the transducer will change.

I cannot predict if a particular SONAR transducer will be damaged if it is operated in air for a long period of time, but I do strongly suspect that during that time of operation the transducer will be driven to greater amplitude of movement than when it is immersed in water. If the transducer piezo-electric element is not built with enough material strength to tolerate the greater movement, it may fail.

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