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I don't need mobility and I think that rechargeable AA batteries are expensive and too much of a hassle.

Is there any way to wall power my device that is normally powered by 2 AA batteries?

I was thinking of buying a 3V power adapter and connecting its wires to some AA shaped plastic casing with metal connectors in the right places. But it would be better if I could purchase such device already assembled.

  • Be warned that power adapters do lose quite a bit of power because of their 24/7 operation. Depending on how much your regular batteries last it may be actually more expensive to run the adapter. Eg if you use 1 set per year or 2 (like in remotes or wall clocks) batteries can be cheaper than mains power. – Agent_L Aug 1 '16 at 11:02
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Battery Eliminators

There are indeed ready made products (called battery eliminators) that perform the function that you envision.

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The "active cell" has the wires that inject the 3VDC from an external source into the battery holder. The "dummy cell" is just a plastic block that has an end to end wire. (Note that when using the pictured type device it is necessary to make sure that your wall mounted device just has two wires from its battery holder off into the internal circuitry).

Installation will require some modification of the device's battery door unless it is possible to operate the device without the battery door in place.

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The whole kit also includes the wall wart type AC mains adapter:

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DIY Eliminator

If you start the search for "AA Battery Eliminator" you will quickly find that these units are moderately expensive. Based upon that you may be encouraged to build your own. The fake cells can be constructed using suitable diameter wooden dowel material cut to length. Sometimes the end caps can be taken from typical dead AA carbon zinc batteries as these end caps are often removable from the cell and can then be glued in place on the ends of the dowel. A hole drilled from end to end of the dowel and one from one side into the center can accommodate the wires.

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In some cases alligator clips can be used instead of dummy cells:

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Rechargeable AA Cells

Keep in mind that it may be another option to invest in a couple of sets of rechargeable AA cells and a separate wall/USB powered charger unit. The cost of such solution may be similar to the battery eliminator.

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Do be aware that many low cost re-chargers are garbage and will do more to destroy your rechargeable cells than the actual use of the cells themselves. There are some decent battery chargers worth considering such as this unit from Lacrosse. I have the the Lacrosse BC-700 model and can report that it is an excellent product.

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Buy AA Cells In Bulk

The overall simplest solution would be to purchase the AA alkaline batteries in bulk. With a little bit of research you can find bulk purchase options that include free shipping and prices of just over a quarter of a dollar per cell.

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  • Be cautious about buying bulk AA batteries. A lot a really poor quality. Eg in a pack of 50, having 10 or 20 not work at all. and generally having them hold very little charge. With that said, it can still be value, paricularly for low power items – Lyndon White Aug 1 '16 at 1:19
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    The low quality has not been my experience when purchasing name brand batteries. For example it really makes little difference if you go the big box store and buy a 40 cell pack of AAs or you buy 10 cards of 4 AAs except for the price difference. On the other had you are looking for trouble if you go to eBay looking for the cheapest batteries you can fine with brand names you never heard of before. One thing that can be a problem is shelf life so make sure not to buy more batteries than you can use in a reasonable amount of time. – Michael Karas Aug 1 '16 at 3:18
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    I've actually never seen bulk packets of name brand batteries. I only ever see ones with brands I've never seen before, at discount stores -- this is was I was talking about. At least in my area, the well-known brands (almost) never come in packets of larger than 16. (Vs the discount store packets of 50, which are often cheaper than the well-known branded packets of 16). I guess we don't really have these "big box stores" you speak of. – Lyndon White Aug 1 '16 at 3:25
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    @Oxinabox - I hear you about availability. One "big box" store here is called Home Depot. They show an Energizer name brand pack of 36 AA cells. See here -> homedepot.com/p/… – Michael Karas Aug 1 '16 at 5:08
  • @Oxinabox: Amazon UK sells 50-count AA Duracell packs at £14.21. With free delivery for Amazon Prime, that's ~29p/cell. If you're not on Amazon prime, delivery adds £4.75 making it ~38p/cell. – T.J. Crowder Aug 1 '16 at 9:45
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There are dozens of plug in the wall 3 volt DC power supplies availible online. Here is a link to an Amazon page that has a lot of them starting at $3.00

www.amazon.com/s/ref=nb_sb_ss_i_8_6?url=search-alias%3Daps&field-keywords=3+volt+power+supply&sprefix=3+volt%2Caps%2C164

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