Introduction: How to Make AC Powered "Batteries" for Your DC Powered Devices

Picture of How to Make AC Powered "Batteries" for Your DC Powered Devices

I made this copier recently, based on a digital camera and a stand. I dig it. I also made a few modifications, one of which I show in this instructable.

The digital camera I use runs on 2,000 AA batteries, though it uses only 2 at the time. But it eats through these things. It laughed at rechargeables. It cleared 8 batteries in its first day of service. I’ve read that sadly, that’s not abnormal. It’s a good camera, but the cost of batteries was going to render this project prohibitively expensive to operate.

There is no DC input adapter to use an AC power source with it, and my search for how to add one left me frustrated — the few walkthroughs I could find were good, but would require MASSIVE modification to the camera given its size.

So, I had this idea, put it together quickly, and it worked. The goal is simply to run the wire ends from an AC adapter to the contact points in the camera. Almost no modification to the camera [just enough to let the wires through], very inexpensive, and quick to make, simple, and effective.

I didn’t find any instructable or even blog written about this concept. I independently discovered and engineered the solution I will show you. There are likely better ways. Please tell me of your improvements in the comments. If this is your idea, let me know so I can credit you.

*** Obviously this will likely void your warranty.  It is intended for devices WITHOUT an AC adapter socket.  If your device has one, by all means use that.

Step 1: Tools Needed

Picture of Tools Needed

What you’ll need:
AC Adapter (I used the universal kind. This turned out to be REALLY useful for me as I’ll explain later). An old one lying around that’s of the right voltage and amperage would be fine.

Batteries for the device you’re wanting to power. In my case, that’s 2 x AA batteries.

The device you’re wanting to power. In my case, a little digital camera.

A pair of small, short screws. Just about anything you have in your tool box will work.

A screwdriver

A saw (apartment = handsaw, even though I want my circular saw).
Sandpaper/sanding block

Wire cutters / strippers
Dowel of proper diameter (this is on you. Also, it’s ok if it’s a little too small. It’ll work. Too big and you have to shave it or it won’t work).


Vice (or drill/drill press)


***** CAUTION ***** You’re not an idiot. You are dealing with electricity, sharp things, heavy things, and heavy sharp things that use electricity. Be careful. I didn’t hurt myself, and that’s saying something.

Step 2: Cut and Strip the Wires

Picture of Cut and Strip the Wires

My first step, whether it made the most sense or not, was to cut the end off the AC adapter. Then I separated the wires down a few inches, enough to feed each wire through a dowel piece, and stripped the sheathing a little.

Why did I cut the power cord first? Because once I did, I knew I couldn’t return it. Once I did, I’m in until I’m done.

Step 3: Measure & Cut the Dowel

Picture of Measure & Cut the Dowel

Now measure the dowel and mark two lengths, each the same as a AA battery. I just put the AA battery up to the dowel and marked a hair less than that (the screw we’re putting in later will let us adjust the length a little, so better to be a little short than a little long). Go ahead and sand them while you’re at it.

To find the dowel size, I actually googled up an image of a battery showing all its dimensions. I took it to Home Depot, but also took a battery with me. I found a dowel the size of my battery. As I said, I used the battery to measure the dowel lengths. Moral? Don’t make things more complicated than necessary.

Step 4: Test Fit the Dowels

Picture of Test Fit the Dowels

I dropped the batteries into the camera, then the dowels, to see that they behaved like the batteries. That is, did the door close, but I feel a little resistance from the spring? Do they rattle around against each other too much?  This is the time to sand them, cut them shorter, or cut new ones altogether.

Step 5: Drill the Screw Holes & Thread the Wires

Picture of Drill the Screw Holes & Thread the Wires

We’re going to use one screw for each battery to act as the contacts. Place one of the short dowels into the vice and drill a hole all the way through, vertically (see picture). 5/8 in. should be plenty, but you have some wiggle room. The holes need to be big enough to feed your wire through, but not much bigger. You want this to act as a pilot hole for your screw, which you need to lock into the wood tightly later. When you’re done, go ahead and feed one of the wires through one of the dowels, then do the same with the remaining dowel and wire.

Step 6: Mark the Ends

Picture of Mark the Ends

This is important. It can save you a lot of frustration later. Mark the ends of the batteries. Remember, only one end of each will have a contact, so you need mark only one end. But mark them. I did this by using a kitchen timer that takes 1 AA battery. I touched my wires to the leads in the battery compartment. Nothing. I switched them and I got a beep and a working timer. Looking into the compartment for the + and - signs, I now knew which wire was which. For me, the wire with writing on it was the negative. Yours may be different, so test first. You could also use a meter. Feed them through the dowels and mark the dowels.

Step 7: Wire the Screw and Drive It

Picture of Wire the Screw and Drive It

With the wire pushed through the dowel and stripped at the end, you can wrap the wire around the screw body. It is important that you wrap clockwise as viewed from above (or counter clockwise if you have a weird reverse thread). This will make it such that when you drive the screw in, it will actually bring the wire with it, wrapping tighter. If you wrap the other way, the screw will actually unwind the wire as you drive it.

Go ahead and drive the screw into the dowel. I used a manual screw driver for this and recommend the same for you. It doesn’t take long, you have a pilot hole, and you want fine control over how deep the screw sinks.

Step 8:

Picture of

You’re basically done. Drop you’re new batteries into your device, make sure the batteries are plugged in, and power up. It should work. If not, check that you have the proper voltage and current going to the batteries for your device. In fact, check that first. It’ll save you from burning a $50 digital camera by feeding 9 volts to it instead of 3 (accident).

You’ll likely have to hold the batteries in place b/c the door will likely not close b/c of the wires. To solve this, I dremeled a small notch in the battery door to accommodate the wires without rendering the door useless. After all, I don’t want to hold these batteries in the whole time I’m scanning documents. Also, my modification was so slight that it’s barely noticeable and still allows the camera to take batteries. I expanded the camera’s function rather than change it.

Step 9: Final Thoughts

I burned a camera. Check voltage and amps BEFORE turning devices on.

You shouldn’t get shocked, but you could. BE CAREFUL. Also, you shouldn’t get bitten by a snake in your car, but stranger things have happened. BE CAREFUL.

You can make C and D batteries and even AAA too. 9V make take a block of wood given the shape. If you’re making a device specific battery, engineer the most efficient way to get power to both the positive and negative terminals of the device so that the wires and contacts hold themselves while still allowing for the use of DC batteries later.

A table vice clamped to the kitchen counter works wonders. That’s how I did this project. Just be careful not to damage your counters.

Good Luck. Have fun. This project shouldn’t take long once you have all the parts. I expect to make some more of these soon, once I find something else that I need to be AC powered.


EdwardG49 made it! (author)2017-03-01

I was videoing another instructable, but after the 2nd set of batteries died, I knew I had to do something else. So, I put one instructable on hold, found yours and put it together, then got back to my original project. I recorded about 6 hours of video and saved myself a dozen batteries!

KentH8 (author)2015-12-11

I like your idea about using dowels to make the battery connectors. I am making a Raspberry PI 2 laptop and I am using a wireless touchpad that requires 2 AA batteries. Since the batteries only last two weeks at a time I need to get a better power source. I ordered an XT Power 10,000mAh battery pack that puts out 12 volts (for the monitor) and 5 volts (USB Connector for the Raspberry PI) I am going to add an L4931, 3.3 volt Linear Voltage Regulator to bring the voltage from 5 volts to 3.3 volts. Thank you for the idea!

roymc3 (author)2015-07-15

Thanks for sharing your idea and your humble teachable spirit. If there are better ways, this will spark creative discussion.

ktrantham (author)2014-09-20

Or you can just UNSCREW the camera, open it up, find the contacts inside the camera, where it would recive power from battery and solder male and female headers to make your own DC power jack for the camera

sellulose (author)2010-06-25

You can assemble the ciruit on a general purpose board and use and ac adaptor. Circuit is polarity free at the input. use any AC adaptor without worrying abt the polarity at the pin and voltage rating. The output will be 3V always. You may always want the regulator IC LM317T mounted to a small heatsink for protection. Just be sure to insert the batteries correctly. Hope this makes things safer..

ktrantham (author)sellulose2014-09-20


sellulose (author)sellulose2010-06-25

I had uploaded a circuit too. Dont know wher did it go. Help me with uploads.

3366carlos (author)2014-09-01

great idea, always be safe and use a multimeter to make sure you have the proper voltage (ac/dc)

hanlin_y (author)2012-01-27

Hi Ispcrash,
I have a variation of the AC powered "battery." One piece supplies power and the other pieces are conductors. Even though the voltage is underestimated, it's not an issue when my LED lamp is current regulated but the regulator does get very hot dropping 3 or 4 volts at 0.7 A.

aarond80 (author)2010-06-26

Good project, but I should probably point out that you are using a DC adapter, not an AC adapter. If it was AC, you would easily get shocked, and you would blow up the camera. And yes, ALWAYS check the voltage of the DC adapter to make sure it closely matches the batteries you are replacing. (1x AA = 1.5 V).

louis.m (author)aarond802011-08-25

Excuse me , you said that he is using a DC adapter, but the power comes from an AC outlet, so they are AC powered "Batteries", right ?

aarond80 (author)louis.m2011-08-25

The power comes from AC, but the adapter is a DC adapter, as it converts the AC from the wall into a DC signal. Technically it is an AC/DC adapter, most commonly shortened to DC adapter, to clarify which type of power is coming out.

louis.m (author)aarond802011-08-26

So we agree, AC Powered "Batteries", as the article says

aarond80 (author)louis.m2011-08-26

I never suggested the title was wrong, I was merely pointing out that anyone doing the project should ensure they are using an adapter that outputs DC voltage.

louis.m (author)aarond802011-08-26

Sorry, misunderstanding, mea culpa !

paulmcgolrick (author)2010-06-30

Step 5 concerns drilling holes through the ends of the wooden dowels, and specifies 5/8" diameter, which must be a typo. 5/8" would be close to the diameter of a AA battery. The diameter of the holes need only be slightly more than the width of the wires.

lspcrash (author)paulmcgolrick2011-07-14

Yeah that was a typo. I don't remember now what size drill bit I used (5/16" maybe?) But you're right. All you need is a hole slightly wider in diameter than the wires themselves. Good catch.

phanaka (author)2010-07-27

I done this for my wireless phone last year. my phone burnt out after 1 month, caused by unstable power source. So, I think is it posible to use rechargable battery inside gadget and connected to direct charger, the gadget will receive more stable power (voltage).

The Locksmith (author)phanaka2011-05-14

A capacitor would do the job well. I suggest testing with an oscilloscope to find the necessary amount of capacitance.

WurdBendur (author)2010-08-20

My brother did more or less this years ago with an old caller ID box. The connector broke so that the 9-volt battery had no place to attach anymore. He cut the end off of an adjustable AC adapter, set it to 9V, and attached the ends of the wires to the leads in the battery housing. Worked perfectly.

woodvale035 (author)2010-07-25

i had thought of this type of idea but never got round to doing it, glad to see it in operation and it does look a good result with minimal disruption to the unit, i have a power monkey which is a long lasting portable battery power source, it comes with many adopters for many different devices but i wanted to see if it would run my camera as it eats batteries so now im inspired to do the project with this as a part of it as it has no external power socket.. thanks btw just heard of a new high powered rechargable battery called "eneloop" ,reports are that they are great, google them.

diolola (author)2010-07-19

Hi, I am a newbie here. What I saw in the steps up to finish or completion, It was THE same as my idea of making it in reality. That idea is the so called "BATTERY ELIMINATOR". The author's effort is a 5S for me, saving money to use the camera as a standalone unit of document scanning. Me I am using a digital camera, a PRACTICA Model DFIX 740Z, 7 MP, using 2 AA's. Sad to say somebody stole it when I went fishing in one of the beaches in Kuwait (I worked there)..Just a word of caution: be careful in dealing with the dowels and the screws on top, they might be short-circuited by the battery connecting terminal metal strip fastened at the battery cover. This metal strip is used as link on the two batteries when you use batteries and closing the battery cover. More power to you, frankly speaking, I do not know how to post pictures here because I do not know how to make some "clouds" -like making square yellow boxes within a picture, and type comments outside in it. Any help on how I will know it? My very best regards. My e-mail address : I like to have interactions, changing of ideas, I am an electrician, doing small knowledge in electronics, and a mechanical technician.I am also dealing with frequency inverters installations/troubleshootings, and some plumbing works.

Redfrk (author)2010-07-12

I like the commitment to this project by cutting the cords first! LOL.

moneyguy (author)2010-07-05

very good, i don't use many small battery powered devices, but back in 2004 i happened to be recording some lectures for a religious organization and found my self having to miss parts of them, because of battery changing breaks and such frustrations. so i had done a similar mod. but mine was a littler simpler, i had used wire hanger bits taped for insulation and just attached the wires, didn't have to make any holes because wires were thin enough to be pinched by the battery cover. worked just fine, back then i was not a member of instructables. Bravo to you on posting this.

macrumpton (author)2010-07-04

I am so tired of my Sonicare toothbrush eating batteries (Rechargables even need to be recharged every 7-9 days), and this seems like a perfect solution. I am planning a wallwart with a long cord, so any water coming off the brush drips off the bottom of the long loop of wire rather than across to the wall socket.

Cabanaman (author)2010-06-21

I am looking to use this method on a shelf full of AA battery operated fountains. They all take 2 AA's. I know if I wire them in parallel I can power them all using a 3v adapter with the right amount of amps, I'm just not sure how much amps I should have. Any ideas?

wsanriv (author)Cabanaman2010-06-22

That is a good question, I used my tester on a AA 1.5V Alkaline Battery and got 1.15+/- amps, this battery is around half life (First time I use that name and not refer to the game). Then 2 AA I got 2.22+/- I tested my rechargeable Ni-MH 2500 mAh AA 1.5V batteries and got 1.40 amps, they are also kind of used. I hope this helps!

lsocoee (author)wsanriv2010-06-27

You're doing this backwards. Amperage draw is not determined by the battery, it is determined by the device. To test amperage draw, you need to measure the amps at the positive and negative side of the battery circuit when the device is in use. The camera in this instructable will require you to run wire leads to the ends of the battery(inside the camera) to test the amperage. It will be easy to check the amps if the batteries have both of their ends exposed when you take off the battery cover. Connect your multimeter to the positive of one battery and the negative of the other battery. After you get leads to the positive and negative of the battery circuit, you should test your connections. Check the voltage-if you have done this correctly, you will have 1.2 volts * number of batteries. Now, turn on your water fountains, then switch your meter to amps. That's how you determine your amperage. What happens if you use an adapter that has too many amps? You might end up feeding your device too many volts, yes, volts. Most AC/DC adapters provide their technical info with a corresponding amperage. For example, the adapter I used on my baby's swing is rated at 5V and 2A. When I tested the voltage, it was actually 8 V, because there was no load on it. When I added the 2A load, the voltage dropped down to the rated level. What happens if you use an adapter that has too few amps? The device may not work properly, but likelihood of damage to the device is slim. My concern is when your device works, but is drawing too many amps from your adapter. The adapter may overheat and may catch fire.

k4gdw (author)lsocoee2010-06-28

Yuck... A properly regulated power supply shouldn't do that. If it's rated at 5 volts it should put out close to 5 volts even with no load. The voltage shouldn't drop by a significant amount unless you attempt to draw more than it's rated amperage. Of course, if you over load the power supply, it'll also overheat. Just how much overheating it can tolerate and still function is dependent on how well the device is built.

lsocoee (author)k4gdw2010-06-28

True. There are regulated power supplies that will put out 5V regardless of load. There are also unregulated power supplies which is what I was referring to. In a regulated power supply, I don't believe that higher rated amperages will cause any problems, but I'm not sure about that.

RubberRetropack (author)lsocoee2010-06-30

I am considering attempting this instructable, but I'm having a difficult time finding the correct dc adapter to purchase. Do either of you know where one might buy (for example) a 6V *regulated* adapter that is a good amp or two? So far all i've found are some shady Hong Kong operations selling off ebay, and they don't provide much information as to whether the adapters are regulated or not. Thanks.

k4gdw (author)RubberRetropack2010-07-01

1 or 2 amps is probably pushing the limit of the capability of a wall-wart type power supply, regulated or not. A quick google search turned up this: I've never dealt with this company myself so I can't comment on their service. There are several supplies listed within the range you're talking about that are listed as regulated. Note: Even with a regulated supply there will be some variance in voltage as the load is varied. The regulation just keeps that variance to within +/- some percentage. I didn't see where they actually listed that variance in the specs so that's something you'll have to ask them if it's critical to your application.

RubberRetropack (author)k4gdw2010-07-01

I just purchased a 6v 1800mA adapter from a local electronics store, tried it in the device, and it seems to work fine. My multimeter gives a reading of 6V, and surely the multimeter doesn't actually use much amperage, so that should indicate that the adapter is regulated. Is that a safe assumption?

k4gdw (author)RubberRetropack2010-07-01

if that's without a load then I'd say yes. The problem with an unregulated power supply is that it will often produce a significantly higher voltage than the device needs when there is no load. This results in an initial surge in voltage when the device is first turned on. The surge will only last milliseconds so isn't likely to damage your device in the short run but over time these repeated surges can shorten the life of the device. That might be part of the reason why some electronics manufacturers who provide wall warts with their products often provide unregulated supplies. Not only are the unregulated ones cheaper to produce, they can result in the average consumer having to replace the device more often.

RubberRetropack (author)k4gdw2010-07-02

Thanks for the help, here's a photo of my completed project:

I am SO happy with this, I could give you a big smooch!

lsocoee (author)k4gdw2010-07-02

I'm a bit late, but for other folks looking to purchase power supplies...I like to check out a website They sell surplus electronics, so their inventory is always changing.

I found a variable voltage switching regulated supply for $10

A switching supply will draw negligible power when there is no load. Non-switching will always draw power, regardless of whether the device is connected.

k4gdw (author)lsocoee2010-06-28

The regulator circuit, be it an IC or home brewed from discrete components, would only be able to handle so much current passing through it. To build the power supply as cheaply as possible and still meet it's intended purpose the entire system should be capable of handling a small current above the intended load and include a fuse to protect the expensive and/or hard to replace components from an overload such as might happen if the device being powered developed a short circuit or someone attempted to power a device that drew too much current. For example, my 40 amp power supply will run my 100W ham radio by itself all day long and barely be warm to the touch. In fact, I know hams that own cats whose favorite napping spot during the winter is on top of the power supply. However, if I were to try to also power an amplifier at the same time a fuse would blow. If I bypassed the fuse I could expect anything from a fried regulator IC, blown filter caps, or even a melted transformer which would result in directly shorting the AC power coming from the wall plug and all that that could entail.

lspcrash (author)Cabanaman2010-06-26

Good thinking. That's what this project is about. Let me know what you find out will you?

eorionus (author)2010-07-02

This is a very useful article. If you want to make it portable, replace the AC Adapter with a couple of C or D cells in an external holder with a long wire so it can go in your pocket, purse, etc. They last MUCH longer than AAs, are the same voltage 1.5 V and probably cost less.

Albannach (author)2010-07-01

Perhaps you would explain how this is not practical? It seems totally useful to me, and easy to do also. Maybe you are thinking it isn't portable, which is true, but don't forget this was for a copy stand he built as far as I understand it, so it won't be moving around.

Phil B (author)2010-06-18

In order to avoid burning the camera or any other device where someone might follow this approach, two things could easily be done. One would be to limit the power supply's output with an LM371 voltage regulator set for the desired output voltage. See the link to a schematic at this Instructable.  Second, if the current draw is not too much, one could shunt between the output leads with a zener diode rated for the proper voltage, but be careful to use the correct polarity, which is a reverse polarity, so the zener ducts off excess voltage rather than simply create a short circuit.  See this link provided by Lemonie for a question someone submitted.

I was impressed many years ago when a furnace repairman replaced the 24 volt transformer on a household furnace's thermostat control circuit.  He included an in-line fuse that would blow if there were any shorts that might damage the transformer.  I always like to double-check the output of a power supply with a voltmeter before connecting it to a circuit so I do not damage the circuit.

srilyk (author)Phil B2010-06-26

Having used a universal adapter on my camera set on too-high a voltage, rendering my camera useless, this is a darn good idea.

Phil B (author)srilyk2010-07-01

It would be a nice touch if manufacturers would provide a high current zener diode shunt on external power supply jacks, like on a camera. Such a shunt would protect the camera from too much voltage and save the camera.

shad0w88 (author)Phil B2010-06-26

Would a LM317 Power Supply provide enough wattage for this? seeing as it would eliminate the need for a universal power adapter for a normal one or another power source?

Phil B (author)shad0w882010-06-26

An LM317 regulator chip can handle between 1.2 and 32 volts input. Output will be slightly less due to natural loss across a diode junction. Maximum current output is normally 1 ampere, or 1.5 amperes with a good heat sink. I ran a digital camera on a 12 volt power adapter reduced to 9 volts (factory specs on the camera for a power adapter). It was rated at 1 ampere and worked very well. That would vary according to the demands of your camera.

Court_ (author)2010-06-28

I enjoy seeing things like this only because it is interesting. But this is not practical and those are not batteries.

EmmettO (author)2010-06-18

"Don’t make things more complicated than necessary." *sigh* although I chant that every day I still make things more complicated than necessary.

lspcrash (author)EmmettO2010-06-26

'Necessary' is a flexible word.

EmmettO (author)lspcrash2010-06-27

Yeah, sometimes it leads to something that people look at and say "Whoa! That's cool I never thought of doing it that way!" other times they just shake their heads, say "Why do you always have to do things in the most complicated way possible?" and then show me the real way to do it.

depotdevoid (author)2010-06-18

Nice, I like this sort of simple fix to a frustrating problem. I've got a couple of projects lying around that could benefit from this sort of thing, so I my just build something along these lines! 5 stars for sure!

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