Soldering Directly Onto a Battery




Introduction: Soldering Directly Onto a Battery

In my first instructable I needed to use an AA Battery to plate some copper onto a quarter, and I ran into an issue. I didn't have a battery holder, and I was too cheap to go out and buy one. So I scoured the internet looking for ways to solder a wire directly onto a battery and found nothing except that a tin strip could be welded onto a battery.

Like most people I don't have a welder so I started experimenting with using flux and other various agents until i finally found that filing the end of the battery would allow solder to pool. then I could solder a wire onto it easily.

This technique can be used for both normal and rechargeable batteries, so if you need to replace some rechargeable batteries in battery packs like the one from the Xbox 360 you can now do it. I also used it when making this instructable

 Comments are welcome and appreciated

Step 1: Materials

What ya need der:

-A Soldering iron

-Some rosin core solder

-A file

-Two pieces of wire preferably red and black to avoid confusion

-The battery

-Wire Strippers(not shown, but still needed)

-Some Skill with Soldering

Step 2: Filing the Terminals

Take a file to the positive and negative ends of the battery and rough them up. make sure the whole surface of the battery terminal is evenly rough. its OK if you mess up the covering a little bit.

Step 3: Applying the Solder

Make sure your soldering iron is clean and then tin the tip of it. Secure the battery in a vice or clamp or something and make sure your iron is hot and ready. Using the iron heat up the terminal of the battery and apply solder, you don't have to heat the battery terminal all the way up to solder melting temperature, you can just use the iron to melt the solder. The solder should pool on the terminal, if it doesnt you need to rough it  up more, and try again.

Step 4: Attaching the Wires

Strip both ends of each wire and then tin one end of each wire. Use the iron to heat up the solder on the terminal and insert the tinned end of the wire into the solder pool. FYI red wire is positive, black wire is for negative, common, or ground. and thats it. It may not be the simplest way of utilizing a battery, but you cant get much cheaper.



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    31 Discussions

    I have a tool I made with a copper nail ( I bent and flattened the end... Cause I like it that way) in a wooden handle. It's basically like a soldering iron without an element. For hard to solder metals I heat it up red hot with a micro torch instead of my soldering iron. (The soldering iron takes too long to bring the battery surface up to temperature.) Then you only have to leave it on the battery for a second. It is tinned like the iron as well. So I heat it up then put the solder on the tool and RUB it on the surface of the battery. It sticks and I don't have to do it twice because it's rarely a cold solder joint. Done. Save that metal tape when you rip up battery packs too. It's cheaper...

    1 reply

    It's also good for fast solder jobs because you can just use the torch and tool instead of waiting for your iron to heat up.


    1 year ago

    what happens if i solder it to a 9v battery

    Interesting. This has piqued my interest in this stuff. I am getting a new soldering iron, and may get to solder some 26650 cells.

    Was making up my mind between a Bakon 950D and a CXG DS110T, guess I'm going to lean towards the DS110T 110W unit; ought to help.

    sorry in my comment I said "resin" I meant "rosin". Anyway use flux-free solder and do not use the separate flux.

    Very helpful. I would suggest a small follow up to make this process even easier: 1. File the battery ends a bit with a metal file or sandpaper. This helps the solder adhere. Just a little filing/sanding is enough, just take off a little bit of the shine. Batteries have very smooth/shiny ends for good contact and solder has a tendency to slide off without filing/sanding. If you are using shiny leads then file/sand them as well. 2. Use resin-free solder aka flux-free solder (the kind where the resin/flux comes in a separate bottle in the solder package). Sometimes called "silver solder". The resin/flux causes the solder to slide off the battery and also can blacken the battery reducing conductivity.

    Is it safe to do this with 9V PP3 batteries? It's for a simple door alarm and obviously I will need to desolder and replace eventualy.

    2 replies

    I would just use a 9v snap on connector. Find an old smoke detector or other outdated radio and rip it out. Or, just go buy one.

    Pull apart a dead 9v...pull off the terminals and reuse them as a snap connector...there are ibles about how to do this.

    Any reason that copper/conductive tape would also work?

    I'm no good at soldering is why I ask.

    1 reply

    Not as sturdy, but still should work

    how hot does the solder need to be?

    Too hot, it would boil the battery, too cold, it won't work..

    I was curious if this could even be done, and you did not disappoint! Great ible!

    How cool! What a truly helpful instructable! you did a awesome job! Nice copper plating bit on the quarter too!

    careful about coin batteryies . i have exploded one unfortunately.

    but works with a123,nimh (dont heat so much) and 18650 cells. but dont try on flat li ion cells. i have puffed one when soldering. but lipo has external terminals and they safe

    Any reason not to use some copper/conductive tape?

    I like this ,will try...Thanks..

    And..I like .. Phil B says: too :)
    " The people who make the most unkind comments are those who have published no Instructables and think they are experts on everything. It all looks a lot different when you have published something of yourself for others to comment upon it. Do not be discouraged."

    Great instructable. I've been soldering on to batteries for years, mostly on power tool batteries. Never thought to make an instructable on the soldering on to the batteries it self, but i have transplanted cells from one battery to another without any problems.

    1 reply