Battery Eliminator From a Recycled Wall Wart





Introduction: Battery Eliminator From a Recycled Wall Wart

About: A mechanical engineer, instructor at Thaddeus Stevens College, and lifelong maker. Thanks Dad! A founding member of make717. Check them out at

If you are anything like me you hate to throw anything away...and as devices die, you end up with an endless supply of 110 VAC to DC at some voltage/amp rating "wall warts".

A few weeks ago trout season started and I needed an aerator to keep the minnows alive longer. I ended up with a battery powered one and usually use it at home, so consuming D cell batteries seemed like a bad plan.

The blue tape and grey plastic pipe is my prototype device for providing the DC voltage the aerator required, and yes that is tinfoil on the ends.

So today I decided to iterate on my design and use some great new tools at my disposal. Steps involved:

1) Create a 3D model of a D cell battery shape.

2) 3d print the parts.

3) Assemble the battery eliminator.

4) Give the minnows oxygen :-)

Step 1: My Prototype and 3d Model Creation.

The aerator had a space for 2 batteries, but I just needed to connect the right voltage to the plus and minus terminals.

RIGHT VOLTAGE (and current): This is dependent on your wall wart and the device you are running. If you don't know how to confirm these critical aspects please ask a knowledgeable person.

I first made a crude prototype to just make sure that it was all going to work OK. A piece of PVC pipe, some masking tape, and tinfoil was all I needed (no soldering!).

After running the aerator a few weeks with the prototype I decided to use a great app for iPads called Morphi.

The last picture is a screen shot of the cylinder in edit mode. This software is amazing and doesn't require any CAD skills to quickly master. I am guessing anyone that can use the iPad can use this software.

For the pro user on a budget, you might want to check out

I found the D cell battery dimensions online.

Once the model is completed and exported as an STL file, you are ready for 3d printing!

Step 2: 3d Print the Parts

I have an awesome printer, Robo 3D R1 and printed my parts in less than an hour.

If you don't have a 3d printer then you can use "3d Hub"

With over 16,000 printers around the world, there is sure to be one near you.

Step 3: Assemble the Parts

I found a good positive and negative spring form that I cut in half. Did you know that battery compartments must not make contact when installed backwards? That is cleverly achieved by the shape of the plastic on each end and the shape of the contact.

I bent a loop on the end of the springs and and drilled a hole in the end of the 3d printed battery halves. Then I used some hot glue on the inside and outside of this hole to hold the spring form in place. I filed a slot on each side of the battery halves and hot glued the assembly together.

Then its just like installing a battery, you just need to provide a non pinching path where the wires leave the battery box.



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    20 Discussions

    Just make sure you have the proper voltage for the device, you might want to add that in the instructable.


    1 reply

    I would run wires to a socket with a relay circuit installed to shut off the battery supply when voltage was present at the socket. For portability use Lithium batteries with a charging board & eliiminate batteries completely. I would choose 12v as the input voltage, plug it into the boat or truck also.

    When I get a product that dies, I take the adapter jack out of it. Then when I need a voltage/amperage Adapter to replace the batteries, I hot melt glue the jack into a convenient spot, and solder leads from the jack to where the positive and negative wires to their proper points of contact.

    1 reply

    I'd have gone with simply connecting wires in the battery box, or using a chunk of pvc pipe or wood to accomplish the goal. The 3d printer is overkill. Then again, if you popped a pile of cash for one, it's best to make use of it.

    3 replies

    Especially if the power goes out, you can just replace it with a real battery.

    it's all about options, good point.

    A wall wart is a nick name for a power supply that converts 110v AC to DC.

    What is a "wall wart"?

    I think the title: "3D Printed Dummy Battery" would fit really nice for the Instructable, You choice :)

    1 reply

    true enough...though some may take offense at that :-)

    You need to work this up as a general product with various battery replacements using these universal power sources, easy to use with any product.

    1 reply

    i'm surprised this hasn't been done before, but it just makes so much sense to connect directly to the battery terminals and avoid messing with the internals to connect a power supply. great solution :)

    1 reply

    Rodders, I have to admit that I have done this before, for product testing of a battery powered juvenile product. That device made 4 points of contact and confirmed many different quality aspects, and it could be installed, removed very quickly by the product tester.


    3 years ago

    clever use of 3d printing. Another easy way to create a battery blank would be to buy a battery adapter. a battery adapter is a plastic shell designed to convert a AA battery to a c or d size. they are super cheap on eBay/Amazon.

    1 reply

    tjdux, irony of all ironies, I found a similar adapter in my recycle pile, from an LED flashlight.

    Awesome project. You could as solder (or adjoin a number of other ways) the stripped ends from the wall wart directly to the terminals. It would eliminate the need for the faux battery.

    I wont lie though, sometimes ill take the long way around a project too, just cause its funner haha.