DIY AA Batteries!

Today we're going to learn how to easily make our own batteries from very inexpensive household materials.

An AA battery is a standard size cylindrical battery commonly used in portable electronic devices. The exact terminal voltage and capacity of an AA size battery depends on the cell chemistry but are usually rated at or near 1.5 volts.

An AA cell measures 49.2–50.5 mm in length, including the terminal and 13.5–14.5 mm in diameter.

AA batteries account for over 50% of general battery sales and the average price of a quality AA battery can range from $0.59 to as much as $1.42 or more.

Think this would be helpful in an emergency? Is this a viable and renewable source of energy? Would this be a good way to teach kids about science?

Step 1: What You'll Need

To get started, the materials you'll need include:

- (1) Strip of Corrugated Paper (Cardboard Box)

- (12) Copper Flat Washers [Size #10]

- (14-16) Zinc Flat Washers [Size #10]

- (1) Shrink Wrap Tubing [2.5"x1"]

- (4oz.) Distilled Water

- (1oz.) Vinegar

- (4 Tblspns) Table Salt (NaCl)

You will also need the following tools:

- Soldering Iron

- Solder

- Mixing Bowl

- Digital Multimeter

- Scissors

- Sand Paper

- Needle Nose Pliers

- Lighter (or Heat Gun)

- An Old AA Battery (for reference)

Step 2: Prepare Copper & Zinc

The Copper and Zinc Flat Washers are going to serve as your anodes and cathodes for your battery separated by an electrolyte. This battery will be constructed of 11 cells in series to create a robust 1.5 volts.

The Copper and Zinc washers should be clean, free of debris and roughened with 100 grit sandpaper and wiped until brilliant and shiny.

Step 3: Cut Cardboard

Next, we'll be cutting our corrugated paper into 11 squares. These will serve as a tiny sponge to absorb and suspend the electrolyte between our copper and zinc anodes and cathodes.

When cutting the cardboard squares be sure they are precisely the size of the washers. If they are too large they will create a short; if they are too small they will not hold sufficient electrolyte.

When finished put them to the side.

Step 4: Prepare the Electrolyte

Voltage is a potential difference which we find with copper and zinc. The electrolyte is the medium through which this charge can pass.

To prepare the electrolyte, first stir the 4 Tablespoons of Table Salt into the 4oz. of Distilled Water until the water has reached it maximum salinity and the salt no longer dissolves. The water should have a milky white appearance. Be sure to mix thoroughly before adding vinegar.

Once settled, add 1 oz. of Vinegar, mix and allow to sit.

Step 5: Soak Paper

Once your electrolyte mix has been left to stand for approximately 5 minutes, you can insert your cardboard squares to let soak. Be sure to submerse all squares, stir and allow them to float until they are ready to use.

Step 6: Stretch Shrink Wrap

To ensure a tight fit we have selected a shrink wrap that is slightly smaller in diameter than our washers. We will need to stretch it temporarily in order to insert our washers and paper squares.

Insert the closed Needle Nose Pliers and open them slowly while working them around until stretched to 110% in diameter. Repeat on other side.

A washer should now fit snugly when placed in the tube horizontally.

Step 7: Test Components

As discussed, we will be building 11 cells consisting of Copper, Electrolyte and Zinc.

Before constructing our battery we will make one cell to test our components.

Simply stack one Copper Washer, one soaked Cardboard square and top it with one Zinc washer.

Next we will test it with our Digital Multimeter. The red wire should be in the Voltage slot, the black wire in the COM slot and the Multimeter should be set to at or near 20vDC. Then, contact the black lead to the Copper washer and the red lead to the Zinc making sure they are isolated and not touching each other or anything else.

You should now see a display of somewhere between 0.05 and 0.15 volts!

If your reading is higher than this, don't worry, the voltage may climb but will then reduce. If you're reading is lower than this check your components and try again. If your reading is zero, check your contacts and make sure your Multimeter is set correctly.

Step 8: Plan the Core Build

Before getting started, take a look at the image showing how the construction of the cells will make your battery.

Notice the order: Copper, Zinc, Electrolyte, Repeat.

Step 9: Build the Core

To build the core, we will be stacking the components making sure they are flat, without spaces and without compressing the electrolyte mixture out.

First insert a Copper Washer pushing it 1/4" from the end and making sure it is horizontally straight. Next, drop a Zinc Washer on top and then add one of your soaked electrolyte squares. It is helpful to have a pen or nail to push the cardboard down evenly, just be sure not to press too hard.

Then repeat, Copper, Zinc, Electrolyte, tap down, Copper, Zinc, Electrolyte, tap down... until the last zinc washer tops the stack.

Before sealing your battery, compare to a standard AA Battery to ensure the correct length. If necessary, add additional Zinc Washers until the correct length is reached. Note that the protruding nub on the positive side will be added later with solder.

Once the correct length is reached, begin heating the end that you started with, making sure to make a tight seal. Next heat the sides of your battery until the Heat Shrink Tube tightly contours to the ripples of the washers. Then, trim the excess leaving only 1/4" and heat until a tight seal is formed on the other end.

Step 10: Add Terminals

Now we're going to add our terminals. Plug in your Soldering Iron and wait until hot.

Secure your battery copper side up (the side you started with). You will then apply heat to the solder while holding it above the hole formed on the end of your battery. As it melts, press solder into the hole until full and finish with a small bead of solder on top.

Once cool, flip your battery over so the Zinc side is up. If you added additional washers this side will require quite a bit more solder. Repeat the process until full and top with a large bead of solder to signify the positive side. More or less solder can be added at this point to exactly match the correct length.

Step 11: You're Done! Time to Test It!

Your battery is now complete!

If you've done everything correctly you should be able to attach your Multimeter (same settings as before) and get a reading at or around 1.5 volts!

Compare it to a standard AA battery to see how you did!

*Troubleshooting: It is normal for your voltage to be high at first and then level out. If your voltage is slightly low, try pulling the battery from the ends to stretch it slightly. If your voltage is very low you may have a short (electrolyte square misaligned) or you may have stacked components in the wrong order.

Step 12: Use Your New Battery!

Your battery will fit into any standard AA slot and will provide the voltage you need to power all your favorite gadgets!

This homemade battery can power LED Flashlights, Portable Recording Devices, your Computer Mouse or any other device that requires AA batteries.

Now that you can make your own batteries at home you'll never need to buy expensive store-bought batteries again!!!

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Comments

[Drew Paul Designs]

I just want to give a special thanks to the Instructables community for your votes and support and to the Instructables staff and sponsors for awarding this project the Grand Prize for the Make Energy contest!
This is truly the most innovative site on the net and I am proud to play a part in helping people all over the world to make their own energy! Stay tuned for more projects! I am honored and inspired!
Thanks again!!!

[daby64]

WELL DONE SIR. It has been said that in the US. alone they use approx 40 Billion batteries every year. Gosh, what toxic waste they must make on this fragile earth. That's apart from the nuclear waste.

[Drew Paul Designs]

It's the little things we do every day that make the biggest impact. This is my little contribution. Thanks! More to come soon so be sure to follow!

[Cerd71]

If you think that's bad, have you seen how nasty the insides of a hybrid car battery can be? Using lithium cells is far more hazardous than lead acid batteries.

[Tecwyn Twmffat]

Well done!

[Jonathanrjpereira]

Congrats

[Ganesh Selvaraj]

Congratulations! You deserved it! :)

[Drew Paul Designs]

Thank you, sir. Yours was fantastic as well!

[Ganesh Selvaraj]

Thank you :)

[chriss965]

how long do they last compared to store bought

[Drew Paul Designs]

Pretty well!

[JeremyA2]

Where did you get the notion that rechargeables actually drain out faster? This is simply not true anymore. This hasn't been the case in years since most rechargeable batteries switched from NiCD to NiMH. You can easily do some research and find people that have run tests on this:

http://www.powerstream.com/AA-tests.htm

Alkaline batteries typically hold around 2,000 to 2,500 mAh. Here are some rechargeable Eneloops that are also 2,500 mAh:

http://www.amazon.com/Panasonic-BK-3HCCA4BA-Pre-Ch...

These EBL's hold 2,800 mAH:

http://www.amazon.com/dp/B00DNPT1AO

Also the 1.2V vs 1.6V is also misleading. Alkaline's voltage curve drops off very quickly. Only a fully charged Alkaline will show 1.5V or more. As soon as you start draining it the voltage falls rather quickly to levels at or below 1.2V. The NiMH (Rechargeable) battery on the other hand maintains very close to 1.2V throughout it's discharge cycle. It provides a much more constant voltage which is much better than a fluctuating voltage for most applications.

This is partially due to the much lower internal resistance in the NiMH which also gives it the advantage of not having a much lower capacity (or voltage) at higher discharge rates. If you pull a lot of current from an Alkaline battery, you may only get 500 mAh from it instead of the 2,500 it's rated for. The NiMH on the other hand will provide 2,500 mAH regardless of how much current you draw from it because very little energy is wasted as heat from the batteries internal resistance.

In real world use, about the only application that Alkaline lasts longer than NiMH in is storage. If the battery is not being used at all Alkaline has a self discharge rate of almost nothing. So they can sit on the shelf for years with no loss of capacity. NiMH has gotten better, but still need to be recharged about once a year or two to keep them topped off.

But any application where you are actually using the battery and drawing anything more than 100mAh from it, NiMH will last significantly longer than Alkaline plus you can recharge it instead of throwing it away which saves both money and the environment. (Especially if you're not "properly" disposing of them.)

[EMU2]

It also helps to store NiMH cells in the refrigerator to slow down the self discharge rate.

[gene328]

I agree with Stoobers, when I use
rechargeable
batteries they louse power pretty
quick where Alkaline
batteries last much longer. I bought an alkaline battery charger that
works pretty good.

This is the one I have.

At Amazon

Maximal
Power FC999 Universal Rapid Charger for Alkaline, RAM, Ni-MH, Ni-CD,
AA, AAA, C, D, 9V Batteries

[MartinG40]

@gene328 - That's what you get for using cheap rechargeables. Bite the bullet and buy some Eneloops. I usually buy the Sanyo ones since they are a bit cheaper than Panasonic, but here in Canada Costco currently has a starter pack with a charger, ten AA, and four AAA Panasonic Eneloops for just $55 CDN, which is a great deal even if it didn't include the charger.

Unlike regular NiMH batteries, Eneloops have an advanced dielectric that reduces self-discharge so much that they are sold already charged, like Akalines, which is something just not possible with regular rechargeable batteries.

[PhilKE3FL]

I concur, these batts are great! I use them in my 2m HT, my scanners, other radios and portable batt operated TV, also flashlights & mp3 players (mostly the AAAs for those). I have enough that it may take me a year or more to cycle through all my batteries. The flashlights last forever since I hardly use them and the batteries do not self discharge at all quickly, they claim a 10 year shelf life meaning they will still have 70% of the initial charge after 10 years.

[SteveA35]

Just a couple notes to your otherwise good write-up: Some
devices (such as one Olympus camera we own) detect 1.2 volts as a cut-off and
will go on strike after 2-3 photos. This in addition to several test
instruments I own that want to see more than the 1.2-1.25V from NiCds or NiMh
cells. For those I have tried several different brands of rechargeable
alkalines and their performance is all over the map, some (Chinese) have
vomited chemicals after a few cycles or faded while stored despite being
appropriately charged.

The last of Kirkland (Costco brand) AA alkalines cells
finally died in a wall clock with a ‘stale date’ of 2002!

I salvaged some Burgess NiCad ‘D’ cells from an Air
Force junkyard in France in the mid-60s which I used into the early 90s before
their capacity degraded too far to be useful.

[stoobers]

Sadly, some devices require a minimum voltage to operate.

Consider a device with 4 AA's in it. The Alkaline should be around 6 volts. But 4 NiMH cells will produce 4.8V.

So when using NiMH batteries, they dip from 1.2v to 1.1v, you get 4.4v, which is quite a ways below 6v. The chip inside the device turns off the device, or it goes into "almost dead battery" mode and doesn't work well.

The is plenty of energy in the NiMH cells, but you can't get to the energy, since the device is designed for 4 batteries at 1.5v per battery.

I have this problem with some walkie talkies and also a camera. If they just didn't go into low power mode, there wouldn't be an issue.

[JeremyA2]

As has already been explained, this is simply not true. Any device that is meant to use Alkaline will be designed to accept much lower voltages because Alkaline batteries suffer massive voltage drops under load.

An Alkaline battery, with 50% of it's capacity left, will be below 1.0 volts. A NiMH with 50% of it's capacity left will still be at nearly 1.2V. So for most of their discharge cycle a NiMH will actually have a *higher* voltage than Alkaline, not lower.

Brand new out of the package Alkaline will read 1.5 volts, but as soon as you start drawing power out of it it drops *very* quickly. Read the links I posted, look at the graphs. Watch how quickly the Alkalines fall below 1.0V while the NiMH stay right at 1.2 until almost completely depleted. Even at only 100ma the Alkaline falls to below 1.2 volts before it's even down to 70% remaining of it's overall capacity.

So any device that was designed to be used with Alkaline batteries that "shuts off" once the battery gets below 1.1V would never be able to use more than 30% of the total energy available in an Alkaline. That same device would manage to capture 70% of the energy in a NiMH. So this would still be a case where NiMH comes out ahead. In fact devices that are designed for Alkaline batteries are generally much more tolerable of lower voltages because an Alkaline battery still has considerable capacity left even at 0.8 volts. if devices stopped working at lower voltages you'd be wasting a massive number of batteries by tossing batteries with plenty of charge remaining.

I do have devices that exhibit this symptom but it's not really a problem. One example that comes to mind are my outdoor wireless sprinkler timer/controllers. I will put freshly charged NiMH batteries in around Feb/March and by May the "low battery" warning light will come on. But since the voltage of a NiMH takes so long to drop, the device continues working fine until I put the sprinklers away for winter time in November every year. I've never had a set of Eneloop AA batteries that didn't last me all year on a charge. The Duracells I used previously would have to be replaced about half way through the summer every year.

[RobertG100]

Not true. I have several devices that require more voltage than NiMH batteries provide. They work fine with Alkaline batteries an NiZn rechargeables. One is a laser that requires 2 cells, and the other 2 are signal processors. Newer versions probably work with lower voltage, but the laser is pretty recent. Low dropout regulators, lower voltage digital circuitry and v to v converters aren't always used.