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How to Make AC Powered "Batteries" for your DC Powered Devices

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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.
 
 
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ktrantham2 days ago

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

sellulose4 years ago
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..

sellulose, WHAT???? MAKES NO SENSE AT ALL MAN

I had uploaded a circuit too. Dont know wher did it go. Help me with uploads.
3366carlos20 days ago

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

hanlin_y2 years ago
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.
http://www.instructables.com/id/Using-a-DC-Adapter-as-a-Battery/
aarond804 years ago
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).
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 ?
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.
So we agree, AC Powered "Batteries", as the article says
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.
Sorry, misunderstanding, mea culpa !
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)  paulmcgolrick3 years ago
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.
phanaka4 years ago
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).
A capacitor would do the job well. I suggest testing with an oscilloscope to find the necessary amount of capacitance.
WurdBendur4 years ago
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.
woodvale0354 years ago
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.
diolola4 years ago
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 : edgardodiolola@yahoo.com 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.
Redfrk4 years ago
I like the commitment to this project by cutting the cords first! LOL.
moneyguy4 years ago
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.
macrumpton4 years ago
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.
Cabanaman4 years ago
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?
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 wsanriv4 years ago
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 lsocoee4 years ago
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 k4gdw4 years ago
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.
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.
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: http://www.powerstream.com/power2-3-6.html 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.
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?
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.

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

http://www.flickr.com/photos/exolucere/4756272919/

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

lsocoee k4gdw4 years ago
I'm a bit late, but for other folks looking to purchase power supplies...I like to check out a website www.allelectronics.com They sell surplus electronics, so their inventory is always changing.

I found a variable voltage switching regulated supply for $10 http://www.allelectronics.com/make-a-store/item/PS-10/1-AMP-SWITCHING-POWER-SUPPLY-w/SELECTABLE-OUTPUT//1.html

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 lsocoee4 years ago
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)  Cabanaman4 years ago
Good thinking. That's what this project is about. Let me know what you find out will you?
eorionus4 years ago
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.
Albannach4 years ago
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 B4 years ago
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 Phil B4 years ago
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 srilyk4 years ago
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.
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