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Emergency Battery Hack – Make an AAA Battery Work as an AA Battery

Guy McDowell 10-09-2013

Did your TV remote control suddenly go dead? Wireless mouse died near the end of your term paper? Need AA batteries and all you have are AAA? I’ve got a quick hack for you to get you through those last minutes until you can get to the shops for some proper batteries. Time needed is about 5 minutes, supplies needed cost about 50 cents – not including your AAA batteries. You may very well have all these items on hand.


I did this today when my mouse died and I realized all I had were AAA batteries. I popped out the AA batteries and looked at them compared to the AAA batteries. Both put out 1.5 Volts per battery and the same Amps. That’s important since it means we won’t damage the electronics inside the mouse. The AA battery does have greater capacity, meaning it will run the same device longer than a AAA would – but this is a stop-gap hack, not a permanent solution. The only real difference between the two sizes is, well, size. The diameter of the AA is greater than that of the AAA. If you’re curious about differences in batteries and types such as Li-Ion or Ni-Cad, check out my article, Not All Are Made Equal: Using The Right Batteries For The Job Use the Right Battery Type for the Job Batteries are batteries right? Sure, and computers are computers, and tires are tires. Oh, what's that? You say there's a big difference between a Mac and PC, and tractor tires and car tires? Well, so... Read More .


How would I deal with the issue of diameter? I didn’t bother searching the web for a solution, because I wanted to see what I’d come up with on my own. Duct tape came to mind first, but that is a bit of overkill. How about plain old transparent tape? You can find that in almost any office or junk drawer. I took the AAA battery and began spooling the tape on to it, just like in the picture below.


It wasn’t long before the diameter of the AAA battery was about the same as that of the AA. You don’t have to be exact here. You just want to make sure that the ends of the battery are relatively centered with the contact tabs inside the battery compartment.



When I went to put the AAA batteries in, I realized that they were significantly shorter than a AA battery. I don’t know how I didn’t notice this before, but that’s the way life goes sometimes. How could I fix this? My first thought was to ball up a bit of tinfoil, but I didn’t have any at the office. Also, tinfoil could cause problems if two pieces of it happened to touch each other, or touch a part of the mouse’s circuit board. Tinfoil just didn’t seem like the ideal solution.


Wouldn’t a spring be just perfect? I thought to myself. It would give enough pressure that the batteries wouldn’t jiggle loose, like tinfoil might. What could I salvage a spring from? I opened my drawer and saw a bunch of paperclips. “Hmmm,” I thought, “How can I make a spring without any tools?” Fortuitously, I recalled that most ball point pens have a small hole perpendicular to their main shaft.



I stuck the end of a straightened paperclip into the pen housing, and wound the clip around until I had a spring. Using the cap of the pen, I managed to get the bent bit out of the hole. Maybe you shouldn’t stick it all the way in.


Again, good fortune smiled on me as I realized that this straight piece would help the battery make contact much more surely. That’s when I put a similar bend on the other end of the paperclip.



After making two of these, I easily got the batteries into the battery compartment, and then slipped the springs into the gaps. As you can see in the photos, the LED illuminated. After some testing by using the mouse as I normally would, I found that the batteries were, indeed, securely in place. If they weren’t, I wouldn’t have been able to write this article.


Although this is maybe more of a little trick than a real hack, it shows you a few things. You’re not helpless even when you think you are helpless. Also, it shows you that when you start to try to solve a problem in earnest, little things tend to happen along the way that help you even more. And lastly, and most least, it shows you that sometimes I have too much time on my hands. Have you got a little time on your hands? Nancy Messieh has a nice piece on little hacks you can do at home, 10 Great Geek Hacks: Repurpose Everyday Objects & Get The Most Out Of Your Electronics 10 Great Geek Hacks: Repurpose Everyday Objects & Get The Most Out Of Your Electronics If you're looking for a way to get the most out of old everyday objects that have become obsolete, like cassette tapes and CD's, or want to put everyday objects like binder clips, bread clips... Read More . If you’re thinking of something a little more advanced, try Saikat Basu’s, The 7 Best DIY Tech Hacks For Your Car The 7 Best DIY Tech Hacks For Your Car I am no grease monkey, but I am just as interested as a car lover to know the kind of DIY tech hacks for cars that are out there. Regular MacGyver’s would need something more... Read More . A lot more advanced than my little office hack, but it gets the mind thinking about what might really be possible!


Have you ever solved a little office problem in a similar manner? Can you think of any other ways to solve nagging problems at least temporarily? We’d all be glad to hear your office hack stories, and we all might learn a thing or tow in the process. After all, we’re here to help.

Image credit: tomblois/flickr

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  1. Cory
    June 16, 2016 at 3:50 pm

    Ok so my kid did the 9volt battery "hack" on my iPad and now it cuts out and doesn't hold a charge, seriously! Options and suggestions

    • Guy McDowell
      June 21, 2016 at 7:39 pm

      I have no idea why anyone would connect a 9 volt battery to an iPad.

      I suspect that maybe it damaged the internal battery. Best bet is to take it to someone local who does iPad repairs.

  2. Nathaniel
    January 20, 2016 at 2:00 am

    Quit using the word Hack where it is not needed.

    • Guy McDowell
      January 20, 2016 at 4:42 pm

      What can I say? When it comes to being a writer, I guess I'm just a hack. ;)

  3. Anonymous
    January 13, 2015 at 1:35 am

    You can also just take out the old battery, drop it on the floor, and put it back in. Works alot on the same battery-if the mouse dies frequently, then it's obviously time for a new one.

  4. Matthew H
    January 3, 2014 at 6:19 pm

    Holy crap, this is awesome. Awesome stuff Guy.

  5. Able Screen Printing
    September 27, 2013 at 1:27 am

    I used a rechargeable AAA to power a AA wall clock once. Made a spring from a paper clip as well. Didn't need any tape, though. In your situation, I probably would have used a scap of cardboard or paper to build up the bulk around the battery, then used a piece of tape to seal it. But if your employer is paying for the tape, then you had no motivation to conserve tape. Still clever. Ironically enough, I use tons of tape in my T-shirt printing activities, but it didn't occur to me that I'd need it to improvise a battery adaptor.

    • Guy M
      September 27, 2013 at 1:02 pm

      I actually bought the tape. Didn't think of cardboard at the time, but that's an excellent suggestion.

  6. Roger
    September 13, 2013 at 10:21 pm

    Hard to get "one up" on this crew but I betcha didn't know that a 9-volt battery is made up from a stack of small "coin" batteries. Some of those little LED flashlights from the Dollar Store use the coin type batteries so when you're looking for that small screw that rolled under your motherboard while working on your computer (AND you better find it!) and your flashlight dies you can take the 9-volt battery out of your little Emergency FM Radio, tear the battery apart, and let there be light.
    Stray screws under a motherboard can run upwards of a couple hundreds bucks at times???

  7. Ed Rule III
    September 12, 2013 at 6:35 pm

    Pinch off a piece of foam from a water noodle or pipe insulation (I always have some of these types of stuff around) and wrap it in aluminum foil. Put at the spring end of the battery compartment and then force the battery in, squeezing the foil-wrapped foam much as an extension spring would be used. Maybe even a foil-wrapped eraser tip from a pencil?

    • Guy M
      September 13, 2013 at 7:38 pm

      Either of those could work, if you happen to have those materials on hand. Good lateral thinking, Ed!

  8. Leah
    September 12, 2013 at 5:40 pm

    Now figure out how to battery hack an AA battery to work as an AAA battery. :p (I know, I know, too big, but come on, I always seem to run out of AAA batteries before I do AA or maybe it's because I buy more AA batteries).

    • Guy M
      September 13, 2013 at 7:37 pm

      I gave instructions 3 comments above yours. It can be done, but what a bother it would be.

      You probably run out of AAAs because they don't have the capacity of AAs. AAAs are mainly used where the designer wants to keep the over all size of the device as small, or thin, as they can.

      Seldom is the capacity of the battery considered in the design process, since that can just be the consumer's problem.

  9. Roger
    September 11, 2013 at 4:00 pm

    Since you brought it up..........
    Here's the rest of the course"

    Quiz on Friday................ much to read!

    • Guy M
      September 13, 2013 at 7:34 pm

      Roger, very cool resource! Thank you.

  10. Guy M
    September 11, 2013 at 2:23 pm

    Take the AA, slice it from end to end. (Wearing acid resistant gloves, goggles and face shield of course. Have some Sodium Bicarbonate handy to neutralize the acid as well.)
    Slice the top and bottom around the diameter of the caps.
    Peel it open. Now you have a jacket you can put back on later.
    Shave down the anode and cathode to equal diameters but with a total diameter not exceeding that of a AAA minus the jacket.
    Trim the positive and negative pole caps to the diameter of that found on a AAA, using side cutters, tin snips, or strong scissors.
    Put the jacket back on the core, trim it lengthwise to remove any excess, use tape or whatever to seal it up so the core doesn't leak inside your electronics.
    Voila. AA into a AAA, some minor acid burns and damaged electronics.
    This hack makes no sense whatsoever. Might as well solder leads to the ends of the battery and then solder those to the contacts inside your electronic device.

    • Able Screen Printing
      September 27, 2013 at 2:04 am

      Or... instead of soldering the wires to the battery, you could use... oh, I don't know... clear tape?

      My first thought regarding Jake's question was to either install a jack to plug in a "wall wart", or to wire up an external battery holder. You can wrap the wires from the external battery pack around the springs that hold the normal batteries in the device if you don't want to solder it to the device. Installing alligator clips on the battery holder wires would be even more rugged, but requires way too much effort and forethought. I know it's a waste, but now I really want to go make a battery holder with alligator clips attached. Unless such a thing already exists. I which case, I want one for my junk drawer.

      Makes me think of the time I made battery packs to power a pair of mini light up Christmas trees at a craft fair that charged a ridiculous fee for electrical hookups. Dressed up the battery packs to look like presents under the tree.

      So, yeah... sarcasm... uhm, I mean 'hacking up batteries, burning yourself with acid and destroying your electronics" is not the answer. Reminds me of the time I destroyed my new cell phone trying to power it with an improvised battery pack/booster. *blush*

      Now, if you'll excuse me... I feel the sudden urge to make a McGuyver mask outta some Sugru and duct tape. And maybe a gum wrapper and a paper clip for the sake of authenticity...

    • Guy M
      September 27, 2013 at 1:01 pm

      Oh I agree there are simpler ways to do it. The trick is being able to put the battery inside the device. With the wireless mouse example that I used, having leads dragging around wasn't really an option.

      I did see a neat hack once where a person took the battery pack of their cordless drill and used it as an inverter of sorts so he could plug the drill into the wall.

  11. jake1212
    September 11, 2013 at 1:14 pm

    Very cool... now, if you can come up with a way to use a AA when you need (but can't find) a AAA... ; )

  12. sai
    September 11, 2013 at 10:55 am

    CR@ZY ...Keep up

  13. Anandu
    September 11, 2013 at 8:57 am

    This IS The Best.Very Cool!!!!!!!!

  14. anonymous
    September 11, 2013 at 7:24 am

    well, the world-known Mc Guyver's tricks are just kidd's jokes now :) good job Guy !

    • Guy M
      September 11, 2013 at 12:35 pm

      I like to try to challenge myself to solve problems with whatever is on hand. Something I picked up in the military.

  15. Ray
    September 11, 2013 at 3:38 am

    Duct Tape will conduct electricity bad idea...

    • Guy M
      September 11, 2013 at 12:34 pm

      I didn't know that. I'll have to check that out.

      If I did use duct tape, I would have used it just around the center-most portion of the battery - far away from the terminals and electronics. So it could have worked. But I wasn't going to waste my zebra-print duct tape on that.

  16. Sandy
    September 11, 2013 at 3:18 am

    I have done this with button batteries. Some have the same diameter but are half as thick. I just double up on them and it works fine.

    • Duno
      September 11, 2013 at 10:03 pm

      Bad idea. You would be connecting the batteries in series which will double the voltage. This can damage your electronic device.

  17. hartvix
    September 11, 2013 at 1:29 am

    Maybe I'm ruining the fun here, but i actually have proper adapters to "convert" different types of batteries into a bigger size. So far I've mostly used them to produce UM1 or UM2 size from UM3 (=AA). Handy in a "crisis", but the smaller batteries won't last very long, of course.

    • Guy M
      September 11, 2013 at 12:33 pm

      That's the second-most ideal situation. But if I had the forethought to have battery adapters, I would also have spare batteries.

  18. Royce
    September 10, 2013 at 11:11 pm

    i use crumpled aluminum foil (flat ball) instead of paper clips. It's much faster to make!

    • Guy M
      September 10, 2013 at 11:24 pm

      Tinfoil works, however I was trying to make something that would maintain pressure on the batteries. Also, I didn't have any tinfoil at work.

  19. ksfkay@gmail.com
    September 10, 2013 at 8:14 pm

    This is more like how to build a DIY battery adapter. A real hack would be how to make a AA fit into a AAA compartment vs the other way around.

    • Guy M
      September 10, 2013 at 11:13 pm

      I can see adjusting the length, but the diameter would get tricky. It could be done, but I don't see the point in it. If you had a pen knife, paraffin wax, and some sort of side cutters you could wax some paper, trim the metal ends to the right diameter, disassemble to AA and wrap the components back up in the wax paper. I don't find wax in the office very often though.

      Time is also an issue. By then I could have walked the 3 miles to town, bought batteries and walked back.

  20. Christopher
    September 10, 2013 at 8:04 pm

    Love it, shows me there are still some folks out there with 'more than two brain cells'!
    For me, with the prices for both sizes being what they are (at the Dollar Store) - I just buy a 24 pack and be happy. :0

    • Guy M
      September 10, 2013 at 11:06 pm

      That's what I normally do too. Except I usually end up giving most of them away to other people in the office.

    • dragonmouth
      September 11, 2013 at 12:30 pm

      " I just buy a 24 pack and be happy"

      Not very green of you. Why not use rechargeables?

    • Guy M
      September 11, 2013 at 12:43 pm

      It's my contribution to keeping the economy moving. Plus, all those batteries will become a mining resource in the future. ;)

      You are absolutely right though, we should probably be using rechargeables.

    • Rob H
      September 11, 2013 at 2:40 pm

      An AA cell will power your devices about twice as long as an AAA so regard this as a quick fix 'till you can get som AA cells. If AA and AAA are costing the same then your running costs if you use AAA are double that of using AA.

      I was rather annoyed when I found that some rechargeable D cells I bought were assembled using a similar approach to that described here. Most of the casing was empty with just an AA cell in the middle providing the power.

      BTW, dragonmouth mentioned rechargeables. There are some issues with those:
      Shelf life between charges can be just a few weeks so in seldom used kit they can get annoying - whenever you want to use it the batteries are flat.
      The voltage from rechargeable is around 1.2v compared with 1.5v for disposables. That's sometimes inadequate.
      Alkaline cells effectively "give more warning" that they are going flat over a longer period, a torch bulb becomes dimmer or a radio needs the volume turned up more whereas rechargeables tend to "fall off a cliff" - go from OK to dead much more rapidly.
      On the other hand rechargeables are better in applications that need a lot of power.

  21. Igor R
    September 10, 2013 at 8:00 pm

    I didnt know i could do such a hack...great

  22. Mihir Patkar
    September 10, 2013 at 7:33 pm

    Brilliant, Guy! Ingenious hack.

    Apart from scotch tape, I'm sure some Sugru would work pretty well too.

    • Guy M
      September 10, 2013 at 11:05 pm

      Thank you Mihir. Sugru's pretty expensive isn't it? The tape was dirt cheap and easy to remove if I need just a AAA.

    • Justin
      October 8, 2013 at 7:31 pm

      Even some cardboard rolled up (cereal box top?) with just a little tape should work fine. Trash->Treasure

  23. Spencer Carriveau
    September 10, 2013 at 7:32 pm

    You don't need a mouse to navigate around on a computer. You can go solely on your keyboard, it just may take you more time.

    • Guy M
      September 10, 2013 at 11:03 pm

      Sometimes you do. Some OSs don't always have keyboard shortcuts or buttons that can be tabbed onto, or mouse keys even. It can also be very difficult to use some programs without a mouse, especially graphic design packages.

  24. mRINAL
    September 10, 2013 at 6:53 pm

    oe that was awesome. Duct tape part was cool but I liked how you make DIY spring ..

  25. SplashWire
    September 10, 2013 at 6:49 pm

    Simple but Impressive! Loved this post.

  26. Jay I
    September 10, 2013 at 5:59 pm

    This is one of the best hack's i've ever come across. I really appreciate the author for his tenacity to get AAA batteries to be substituted for AA ones. Way to go.

    I want to add that, there are springs to be found inside many pens also. The ones which you click the top to slide the pointed nib down and back up always work with springs. But, I find your technique of rolling paper-clips into pins more fun and meticulous.

    Thanks for writing and sharing this piece.

    ~ Jay

    • Guy M
      September 10, 2013 at 6:08 pm

      That's a lot of praise, Jay. Thank you. Now I have to figure out how to get my oversized head out the door. ;)