Simple, Cheap, Cool, Waterproof and Gummy Diy Battery Holder




About: I'm an Italian freelance structural engineer, graphic designer and photographer, and I'm teaching physics in Waldorf high-schools. I always investigate electronics, robotics and science in general, I'm a pas...

I know how many of you inventors have desired a versatile battery holder to power your projects, I know you can't sleep without that... so this strange accessory has born ;-)
This gadget has a simple function, keep a battery inside, and yes you could buy an ordinary plastic black and impersonal battery holder if you want, but keep in mind that this is coloured (you can choose the Sugru colour that you prefere), rubbery and even water resistant (although you can't dive with it...).

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Step 1: The Actors

I made it for Li-ion 18650 batteries, because they're very powerful and really versatile for electronic projects, but you can build the same gadget for one or more batteries of any type, voltage and shape.
I've used some metal washers to make contacts, maybe copper pieces should have been better because copper is more conductive... I'll let you know after some test.

Step 2: The Roles

To choose the right washers you have to give a look to these two images. As you notice the fat washer can't make contact with the negative side of the battery, so we'll use it for the positive terminal. Same matter for the thin one, theoretically it shouldn't touch the positive tip so we'll keep it for negative flat side. Pay attention to avoid any shortcut when working with powerful rechargeable cells, it could be danger and damage your batteries.

Step 3: The Teams

Let's melt some tin on the washers. Probably you should find it very arduous because tin doesn't stick on the steel of the washers, in that case it's essential spread some flux on them.

Step 4: The Bands

Now you can choose some good quality natural rubber bands (better with flat sides, not as mine), the more they're tense on the batteries, the more they'll keep the contacts connected. You can try with only one band for each battery if it's enough strong.

Step 5: The Bond

To keep the bands in place meanwhile you work on the batteries ends, wrap them with some tape pieces.
I've covered the battery ends with some silicon grease, to avoid the caps attaching to the batteries surface, but I'm not sure it's the best material, it worked not very well... maybe some oil is better? Some Sugru guru certainly has the answer.

Step 6: The Helpers

Now the best material to wrap the washers and keep them over the batteries ends it's the Sugru, because it dry fast and it has all the colours you want, you can indeed mix the basic colours to make the full rainbow! Another solution could be the two elements silicon which I've used to make the remote control plug, but it's ugly pink!
We choose obviously black and red packets from the five colours of the set, we don't need to mix this time.

Step 7: The Wrap and the Split

Now cut in half each packet's content, stir it in your hands and cover the washers on the right sides of the batteries.
Then push it around the cilynders, and over the washers so that it will englobe them. Finish off the external surface of the Sugru (maybe better than I've done), and hung them up to avoid leaving a flat print while they dry. 
After some time (maybe one hour to be sure?) you can pull the two caps away from the batteries and clean them.

Step 8: The Goal!

It's all! You have now two new battery holders which could be useful to power some little electronic project, or maybe your phone or your digital camera too (usually cellphone and cameras li-ion batteries have one cell, so the same voltage of 3.7V 18650 stilo), all with some dedicated plugs to connect at the wires ends.

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    60 Discussions


    3 years ago

    Hi, ! slight problem with the design, and you should put a safety warning with this. Should there be any problem with the batteries over draining, Li-ion batteries need to be able to vent out of the positive terminal. This design could prevent the battery from venting if this should happen. I plan on using it however, after the sugru sets, I'm going to cut a whole in the top of the positive terminal.

    1 reply
    andrea biffiJustinO25

    Reply 3 years ago

    this is really interesting... thanks for the information


    4 years ago on Introduction

    Nice idea, one serious issue. Rubber bands like that dry out and crack. You should use some other stretchy material, perhaps bike inner-tubes? They have same issue as rubber bands but less often. Downside is they do have have as much stretch.


    6 years ago on Introduction

    Nice, so if I make this and use a usb on the wire end, I can charge my cell phone with 1 double A battery?

    3 replies

    Reply 4 years ago on Introduction

    for the record, this is not correct in the slightest. 5.0V is what they put out. The regulation for the battery is inside the phone, the USB charger is USB standard voltage (some exceptions can apply, and there is some logic communication I'm aware of, some of it just through resistors on the data lines setting the current mAh desires.)


    4 years ago on Step 7


    Nice idea but 18650 and the likes have safety vent hole at its positive terminal to prevent explosion due to build up pressure in case of high charging or draining, it is not good to cover those holes shut.



    6 years ago on Introduction

    Great idea! Can see myself using these in future projects, thanks!


    6 years ago on Step 8

    Very well done. I like the colors idea as well. I usually just make some universal battery holders by soldering the leads to two small neos. This way, i can use any size battery...AAA, AA, D, C, etc. They hold well and work great...but do not look as cool as yours.


    6 years ago on Introduction

    Complimenti per il tuo instructable!
    Congratulations for this instructable. The design is excellent, whatever the material one uses (Sugru and rubber band type) for crafting.