Master Tangler,

As an alternative to a heavy ATV battery, or fistfulls of AA or AAA batteries, you could try my solution for a power source.  I use 12V rechargeable lithium batteries from a Ryobee 12V drill set.  The drill, batteries (2) and charger kit cost anywhere from $39 on sale to $69 at regular price.  One of the batteries generally will last for a full weeks fishing.
I mounted a small waterproof "Pelican type" box under the seat of my Prism, which will securely hold either one or two of these Ryobee battery packs.
The initial cost may seem high, but I have been using the same set of batteries for three years now.  And have had the cordless drill to use at home...
Crimped on spade elctrical connectors available at any hardware store fit securely into the contacts on the batteries.  A very simple set up.  The batteries probably weigh less, and are easier to mount and pack than a AA or AAA's.
Setting the audible low depth alarm on my detector has helped prevent overnight depth checking in camp... One thing, as others have mentioned about Lithium though, they run until they quit, no getting weak or fading.  They just quit.

Quentin  up

I really like things that you can use for more than one purpose.
Thinking of using drill batteries for a depth finder is really thinking out of the box.

I thought you might like this?
Not practical for traveling, but for home emergency use, maybe base camping or car camping, it might fill a need.

Click on (You need to Login or Register to view media files and links) and the instructions appear as a PDF file.

It's a survivalists sight so don't be put off by it's title. Lot's of good McGyver stuff there.

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You have been holding out on us Quentin  . What other ingenious thoughts are behind that keyboard?

For the sake of discussion I wonder what the pros and cons are vs. what Magic paddler suggested? Is there a clearly superior choice?   

I thank both of you for weighing in......hopefully your advice and expertise will prove beneficial to others as well. It has certainly been helpful to me and has expanded my thinking greatly.

What about this battery pack?
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It is heavy coming in at 27 oz but surprisingly small if the mm dimensions are accurate (my conversion is a length of 5.750 inches)

What is Li-Ion? Different than standard lithium technology? Is the voltage to high? 10,400 mAh.....that sounds good, I wonder how long that would last? Questions, questions.

On my almost Hunter Island trip (I buggered off from Lac la Croix and instead went through Minn, darky river and Argo and then back to Crooked. I had given a walleye earlier in the day to a Canadian family who had not caught any fish and I had just caught a 3lb walleye. They were in 2 canoes...... a man and his wife, 2 kids and a grandpa. The old mans eyes lit up when I asked if they would like a fish.

Well anyways.......I was on a river of sorts and it was kind of hot and lazy and suddenly I came to a place that I didn't recognize on the map. It was my first time in the Q and the realization that I didn't know where I was caused a heightened concern. Not to far away I heard some voices on an island so I paddled in to find out where I was.

Lo and behold it was the Canadian family that I had given the fish to. Turns out I was at least 1 mile further down the river than I thought. They invited me to stay at their campsite and I agreed. Naturally I went out and caught a few more fish for the evenings dinner.

I will never forget the 6 year old boy who wore me out with his questions. Questions about how I caught the fish, how I cleaned the fish, why dragonflies have such big eyes and on and on. Whew!

I hope I'm not wearing you guys out .

 

The elite 4x requires a minim of 10 volts and the battery you are looking at has 4 cells. This mean that each cell must put out at least 2.5 volts or the unit will not work well.   Looking at the top discharge curve for one Li Ion cell you will have 100% of the charge used when the battery is down to 2.5 Volts per cell.
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The battery you suggested has 10.4 Amp Hours divides that by the draw from the elite 4x.   
10.4 Amp Hours/.2Amps = 52 Hours.   
That battery has “Built-in IC chip will prevent battery pack from over charge and over discharge and prolongs battery life”.  I do not know if that requires a smart charger or not. If those batteries are over charged it will destroy them.