Introduction: 12 Volt Battery Hack! You'll Be Surprised...

Save $40 with this easy to do hack that takes less than a minute! Pay attention to the battery type as that is important.

This can also be done with a 9 volt battery!

Step 1: It's So EZ!!

I picked up a couple of A23 Energizer Batteries at Wal-Mart for $1.88. What a deal!! If you look carefully at an A23, there is a split in the label/housing. I used a small screwdriver and peeled away the housing revealing a piece of paper.

Step 2: What's Inside??

Peeling back the paper, I found 8 (1.5 volt) button cell batteries!! These are perfectly good button cells that will work in any 1.5 volt device they fit in!

Step 3: Save $40!!

I matched the battery at Radio Shack and 1 of those button cells cost $4.99! Do the math! This easy hack gets you 8 button cells for about 1/2 of what one costs! Have Fun, Be Sfae! Hope you enjoyed this EZ, money saving hack!


NerdofSteel made it!(author)2009-12-14

I just attempted this with a Duracell MN 21/23 12v battery and this trick works for it as well. As for the button cells themselves, they have "LR932" written at the top of them. Thanks for the cool tip Kipkay! :)

frenzy made it!(author)2010-06-28

This posting has won today's "I Made It" Challenge. For winning you will receive a 3 month pro membership!

Thanks for using instructables!

faultythink made it!(author)2017-05-05

dont do there mite be acide in it

Daniel434 made it!(author)2017-02-04

We can recondition batteries like this - very good way

Thank you Kipkay !

holymoses made it!(author)2015-07-15

Here you get a 12V Nonspecialbrand-Battery for about 50 Cent, so you get 8 ButtonCells for that price.

LR932 (ca. 9,3 x 3,2mm) can easily replace LR1130 (11,6 x 3,1mm)!

I just use them to feed my LED powered Pocket- 30x Magnifier.

A23 are sometimes also named "8LR932" sic!

Cool Stuff!


holymoses made it!(author)2015-07-15

Just took a Pic!

For fixing the smaller cells I just placed some wrapped paper around them, but actually it´s not necessary here, the loupe just makes less noise being shaken now.

fotoboy made it!(author)2015-01-08

just a heads up, the batteries he is comparing at $4.99 are silver oxide, a different and superior (and more expensive) chemistry to the alkalines in the 23a just so we are comparing apples to apples.

Master+Wasi+47 made it!(author)2014-11-01

I would never ever thought of that. WOW

mrvolts made it!(author)2014-09-21

You can reverse the above and repair an A23 battery!
A23 batteries are still available, though they began as photoflash
batteries for cameras nobody uses anymore. The reason A23s are still in
use is that they are just right for simple remotes that aren't really
used much, such as your garage door opener remote (2 1-second presses
per day? 4, maybe?). The A23's 12 volts allows easy design of a door
opener which puts out an infrequent but powerful burst of
radio-frequency signal that is strong enough to work reliably from a
fair distance under poor conditions.

Now back to the battery.
Of course your door opener will fail at the worst time. It has only
been two or three years since you replaced the battery, and that one was
the second one in your A23 pack. Amazon will get you another pack, but
it will take a week. Maybe you can find the battery locally, but don't
bet on it these days.

But you can repair it !! Think
about it. Why should an alkaline battery fail in two or three years of
minimal use? The rating of the A23, 40 mAH (milliampere hours), is
144000 milliampere seconds. If each press is 1 second long and draws 10
milliamperes from the battery, you should get 14400 presses from an
A23. At four presses per day, that's 3600 days of opening your garage,
or about ten years from that little battery! And most of us will
agree that an unused alkaline battery will still have most of its life
after ten years on the shelf, so it shouldn't be dead of old age in only
two or three years. So why is my garage door opener battery dead in
two years?

I took the battery apart to find out why my
digital voltmeter read the battery as having only 7 volts output. Each
cell measured over 1.54 volts. They were like new. All right, then,
why doesn't the battery give me 1.54 x 8 = 12.32 volts? It's that black stuff on the LR932 cell terminals from the cheap plating
that the manufacturer used. There are 8 LR932 cells, so there are 16
metal surfaces that can corrode, and corrode they had. The cells had
not leaked; it is the kind of corrosion that happens with low-voltage contacts made by inappropriate metals,
which is what the Chinese who made the cells used. Those of us who
have designed or repaired electronics for a living have seen the same
problem of contact corrosion resulting from the wrong plating in the
wrong place many times.

So now let's fix the battery and
get that garage door to open again. Take the battery apart, being
careful to save the additional metal terminal parts and washers at each
end. There's a spring under the + contact (red), so be ready for that
and protect against it flying away. If you have a voltmeter, check each
cell, making contact on the side of the cell for + and on the small end
for -. You will not have to press very hard. I think you will see
what I saw--the "dead" battery just has corroded contacts on the cells
that are inside; otherwise the cells are fine.

Get some sandpaper,
100 to 200 grit (medium fine), and rub each end of each cell until the
black stuff is gone. Don't overdo it--just make most of the black stuff
go away. After that, wash each cell using a little rubbing alcohol or
distilled water and a Kleenex or Q-tip to get the sandpaper dust off the

Get a two-inch strip of blue painters' masking tape,
the kind that isn't super sticky but sticky enough, fold the ends about
a quarter inch, and attach it to your work surface so it is flat with
the sticky side up. Assemble the battery horizontally with the cells
touching in series just as it was when you took it apart. Now take
another piece of the blue masking tape and gently attach it to the sides
of the cells that the first piece of tape does not touch. Push the
cells together and smooth the second piece of tape around the battery.
The goal is to neatly cover the battery with one layer of tape.

When you are done
you'll have a blue cylinder of tape around the battery. Don't close
the ends; instead, open them with a pencil or small tool. Collect the
small terminal parts you saved and put them back in place by pushing
them into the cylinder and tweaking their position. (Hint: The end of
each terminal that sticks out has a washer on it. And don't skip the
spring.) Now push on each end where the terminal is, and make sure it
is square, and lastly push on both ends at once. Now close the ends of
the tape cylinder by folding over the tape. Trim the tape with an Xacto
or other sharp knife so that the tape does not build any higher than
the terminals, and clear away the tape where the terminals are. Test
the battery for 12 volts if you have a meter, and then go open the
garage door again.

How long will this last? Probably at least long enough to get another battery,
but if your door opener remote has strong spring pressure on its ends,
it could be two or three years till the cells have to be cleaned again.
If the cells had been plated properly for a few more cents, the A23 battery would never have had to be taken apart.

HymanT made it!(author)2014-10-19

I use an A23 battery in a wireless bike computer. It started skipping, and I saw that it was down to 9 volts from 12. I could only find and buy MN21/23. The battery is the same shape, 2mm shorter, but it does not work. It goes into a housing with a spring, so the 2 mm length seem not to matter. It tests as having 12+ volts. So why does not work? Your help would be appreciated.

eyesee made it!(author)2012-12-21


jschap1 made it!(author)2012-07-11

What's the difference between an A23 battery and a AA battery?

tridecagon made it!(author)2012-12-20

Replying to old posts, FTW.
A23 is small and 12V for certain cameras.
AA is for general purposes and are 1V5 (1.5V)

toezar00 made it!(author)2012-08-29

Can u give tips on more little batteries in batteries?
I would like to know.

pipsqueakboy made it!(author)2012-07-13

Okay, so now im confused. before i open a battery and possibly scar myself with battery acid, Is this real?

minimoto made it!(author)2009-07-13

LISTEN UP THIS ONLY WORCKS WHITH ENERGISER. I opened up a 1.5v battery up and got 8 button battery's. Than I opened up a 9v battery and found 6 AAA batters inside. Last I opened up a 6v heavy duty battery up and found 32 AA or AAA I forgot !!!!!!!!

cjmproduction made it!(author)2009-08-14

wrong 1.5 battery is actually a cell not battery 9 volt has 6 AAAA cells in it...(1.5v each) 6 volt has 4 large cells...(1.5v each) if a 6 volt had 32 AA or AAA batteries it would be 48 volts

mikerice126 made it!(author)2009-11-01

minimoto right
cjmproductoin partial credit. :)

32 AA or AAA *in series* would be 48 V. (32 * 1.5 = 48). However, 8 *parallel* banks of 4 AA or AAA in series would be 6 V at 8 times the current (amps).
(4 * 1.5) = 6, 8 times. Series connection adds the voltages; parallel connection adds the currents.

*                    * is 6 v, i amps

*    *   *     *   *
*    *   *     *   *
*    *   *     *   *
*    *   *     *   *
*    *   *     *   *
*    *   *     *   *
*    *   *     *   *
*                    * is 6 v, 8i amps

brocknessmonster27 made it!(author)2012-04-15

what do you mean

minimoto made it!(author)2009-12-08

shosh up alright thats just what i found and the 6v heavy duty has so got that many batteries otherwise it would last 5min in a torch

account3r2 made it!(author)2010-10-16

do you have a camera for pictures?

Colonel88 made it!(author)2009-11-03

If it is wired in parallel then it is more current not voltage so it will be like 6 volts and a lot more mAh. But it does have 4 D cells...

sbeltz made it!(author)2011-10-31

HD 6V batteries have 4 F cell batteries. THERE ARE NO AA BATTERIES in 6V batteries.

account3r2 made it!(author)2010-10-16

9v=6AAAA not AAA

account3r2 made it!(author)2010-10-16

32AA or 32 AA batteries as in there are thirty-two batteries

sharlston made it!(author)2009-11-02

no a lantern battery has around 4 d cells

ktalex made it!(author)2009-09-22

lol u can get like 8 of those batteries at the 99cent store. good hack though?

doo+da+do made it!(author)2012-02-18

Be weary of the dollar store usually they are out dated or very bad performance. Doodado

nepheron made it!(author)2009-11-21

The trouble with dollar store batteries is that they work awfully. The voltage on those is not standard 1.5v...and they only hold a charge for a matter of minutes.

KingOfCatfish made it!(author)2010-10-04

The ones that I bought from 99 Cent Only Store are holding up fantastically!!

KingOfCatfish made it!(author)2010-10-04

This is so true! I saw those at the 99 Cent Only Store a couple of days ago and bought a pack, I'm so going back for more!!!

grharder made it!(author)2012-02-16

Just tried this the other day (2-16-12) and it was still as described here. It was a generic brand though, so that may make a difference.

dacker made it!(author)2011-10-09

While it is cool there are button batteries stacked inside the A23 casing, your cost comparison is off. it is like comparing tangerines and oranges.

The Eveready Energizer A23 is clearly marked "Alkaline" whereas you compared it to a single silver-oxide button battery. Two different chemistries with big performance differences and big price differences.

busterbuster18724 made it!(author)2011-09-23

i tryed a Duracell MN 21/23 12v but acid came out :(

jumpingcat made it!(author)2011-08-11

yay it works

aweaver4 made it!(author)2011-07-03

Apparently Energizer saw this instructable and now have "tamper proof" metal tubes to encase the little batts. It has a solid bottom on the positive side and is rolled over the negative end, which is obviously a "watch" battery.

baven made it!(author)2011-05-23

I´ve just opened a Sony 12v 23A battery and found this. Sorry for blurry picture I´ve taken it with my phone camera.

WendyLD3 made it!(author)2010-12-30

does it work on chinese energizers?

account3r2 made it!(author)2010-10-16

why are there A23 12v batteries when there are 23A 12v batteries? 23A are smaller.

account3r2 made it!(author)2010-10-16

it would be bad if stores found out... ...probably

Cheezpaper made it!(author)2010-08-26

Does this only work for this specific kind of battery, or can it be found in other more common batteries like AA or AAA batteries?

camiller made it!(author)2010-09-30

No, AA and AAA cells are a single cell unto themselves and are each 1.5 volts. For cylindrical alkaline batteries with a voltage that is a multiple of 1.5 volts it is likely (but not absolutely) true that it is a stack of 1.5 volt cells inside.

warmario made it!(author)2009-07-19

Are the batteries inside the A23 LR41's?

chi+chi+chippy made it!(author)2009-09-12

i think there lr44

mikerice126 made it!(author)2009-11-02

Not LR44.

clibanarius made it!(author)2009-12-13

 Just opened my first A23 (Energizer, from Target, $4.14 for 2-pack); it had eight button cells, just as advertised. Cool! The batteries Kipkay matched them with are LR45s; elsewhere I've seen them referred to as LR932s, about which I can find no data. I was kinda hoping they were LR41, so I could use them in some finger flashlights, but they seem to be a mm or so too wide.

Paulkartking25 made it!(author)2009-11-21

this is awsome

BucketBasher made it!(author)2009-09-09

I have a question: Does anybody know if the info from this instructable is still usable? You know, if you can still find some A23 Energizer batteries a a relatively low price? Cause I noticed the date this was published is August 18, 2007, which was 2 years ago and the batteries could have changed since then.

BucketBasher made it!(author)2009-09-09

"at" a relatively low price. P.S. Since seeing this Instructable, I have only looked at 1 WalMart for those A23s and couldn't find any. I don't mean any criticism by my previous ?, I just would like to find out where I can get some A23s, That's all.

nepheron made it!(author)2009-11-21

Go to meijers and poke around the camera area. Look next to the Li batteries. I bought some for only $3.45.

About This Instructable



Bio: Tinkerer, hackster and prankster. Hit me up on Facebook: Thanks for checking out my Instructables!
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