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From batteries to Wall power supply

Discussion in 'Power Electronics' started by Casper Christensen, Dec 8, 2014.

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  1. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    Hello everyone! I was thinking about getting this:

    http://www.thinkgeek.com/product/ee3d/

    [​IMG]

    I want it as a small light next to my computer but i'm thinking it will drain batteries (and my wallet - due to the batteries) if it has to light up at least 2 - 4 hours a day :eek:

    Therefore i was thinking: is it possible to attach a power supply with a wall plug instead of the batteries? An AC adapter or something? Of course it will require some fiddling. I live In Denmark and we have a stronger wall output than America (if i'm right) if it has an influence on it overall.

    If some of you know about this and how to do it, could you tell me how to and eventually link some items i need to make it?

    The Technical information on the lamp is In the first link :)

    Hope you can help ;)


    -Casper
     
    chopnhack likes this.
  2. chopnhack

    chopnhack

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    Apr 28, 2014
    Hi Casper and welcome to the forum!

    The Minecraft torch is a neat touch for your room :)
    Denmark, home of Volbeat LOL ;)

    To your question, yes, you would need an AC adapter to reduce your mains down to the 4.5V DC that the torch uses. When you get the torch open the battery compartment and make sure that the batteries are in series (most likely). If so, you should be able to modify the compartment to accept your AC adapter.
    Perhaps something like this could help you : Adapter
    You might want to get the mating barrel jack and then wire from the jack to your battery posts inside the torch.
     
    KrisBlueNZ likes this.
  3. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    It wants 3 AAA batteries, so 4.5V nominal but since a fresh alkaline battery can be as high as 1.7V, the device could probably handle an input of 5.1V without harm. Given this, I'd be quite willing to simply wire in a surplus 5V phone charger and call it good but if that scares you a little, throw a rectifier diode in line to drop the voltage down to 4.4V.

    Don't forget to disguise the cord as a redstone wire.
     
    KrisBlueNZ and chopnhack like this.
  4. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    Wow! Thanks for the quick replies! To be honest, i really suck at this stuff and the only tools i have for this is a screwdriver and a hammer (i can buy some tools for it of course however)...

    I thought it would be more simple. Something like just connect the cord from the AC adapter to the lightbulb. It's not that simple i can see o_O but at looking at your posts and you say 'If so, you should be able to modify the compartment to accept your AC adapter' and 'Given this, I'd be quite willing to simply wire in a surplus 5V phone charger and call it good.' Modify the compartment how? Simply wire in a 5V phone charger how?

    Do you know any step by step guides to do something like above mentioned in your replies?

    I LOVE fiddling with stuff like this myself, I just want to make sure I'm not doing anything so wrong i will destroy the torch :(


    Oh! And Volbeat IS amazing ;)
     
    Last edited: Dec 8, 2014
    chopnhack likes this.
  5. chopnhack

    chopnhack

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    Apr 28, 2014
    If you can determine which lead is + and which is -, then it really is simply just a matter of cutting the jack off of the adapter and connecting the wire to the battery posts. If you can get a diode, as KJ6EAD mentions, it will provide a small voltage drop and allow you to recycle some unused phone charger :)
     
  6. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    I bought the torch now, I will post some photos when i get home later, of how it looks inside. Then, if you want of course, you can maybe help me along as i post some progress? I think i got a AC Adapter laying around from an old FM Radio wich can run on batteries too, that should work i think :)
     
  7. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    This going to be a problem...
    http://i.imgur.com/Kf1Iqts.jpg
    I can't seem to get any further from this point :/ Dissempling it further will break it...

    I got two ideas left I'm going to try:

    1) remove the yellow part somehow (image below in link), I'm just afraid to do so if i break it (Feels like it's clued)
    Maybe i could do it from the top towards the bottom o_O
    http://i.imgur.com/hI5ajyj.jpg

    2) Here i will need you guys wisdom... Can i make like 3 dummy batteries, i can put in it. However, those batteries are powered with a cord from the AC adapter wich is plugged in the wall. like my poor paint image here: http://i.imgur.com/CU9TVnG.jpg
     
  8. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    The voltage of that radio power pack will be too high unless modified; you didn't say what it is.

    Yes, you can make dummy batteries for connectors. I've done it before using end caps from old batteries, wood dowel and epoxy. You can use anything conductive that's the right diameter and length that you can wire securely to and for your application, you don't even need to isolate the two ends since the missing third battery will do it for you.
     
  9. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    I talked to a teacher at my school. He says we will have to know how many amphere it is using before we can do anything :eek:

    Now I'm even more confused, is that easy to do?
     
  10. chopnhack

    chopnhack

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    Your teacher raises a good point. Do you have a multimeter? Does your AC adapter have a ratings label giving amperage and voltage?
     
  11. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    We have some equipment at the school, i'll post some further when and if i find a solution :)
     
    chopnhack likes this.
  12. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    Okay now i am even more confused! the teacher says the torch is using different power from each battery so it could not be done... He had to go to class and was in a rush so i didn't get to ask why and if there was a way around it :/

    Do you know what he meant with 'different power from each battery?'

    Is it really that complicated? Inside MY head i'm thinking i "JUST" have to attach a cord to the damn torch on one of the the battery poles... Man... :/
     
  13. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    In your pictures of the battery compartment there's a piece missing that makes electrical connections to the batteries at the open end of the battery compartment.
     
  14. chopnhack

    chopnhack

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    Apr 28, 2014
    I noticed that too, maybe Casper removed it for a better view? @Casper Christensen - how does the center battery make contact with the outer two?
     
  15. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    Yea, i removed it for a better view. The connection thing is on the hatch.
     
  16. chopnhack

    chopnhack

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    Apr 28, 2014
    Does the contact connect all three batteries? If so, then I would assume that the device requires 4.5vdc. I don't quite understand what the teacher is saying, using different power from each battery?? If the contact connects all three, then you only have to worry about providing a clean source of 4.5v, the cell phone adapter as mentioned should fit the bill nicely.
     
  17. BobK

    BobK

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    If there are only two wires coming out of the battery pack, it is only a single voltage, most likely 4.5V if there are 3 cells. If there are more than 2 wires coming out, your teacher might be right, it is might be supplying more than 1 voltage.

    Bob
     
    chopnhack likes this.
  18. chopnhack

    chopnhack

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    Good point Bob. Casper, can you give us a pic of the door contacts?
     
  19. Casper Christensen

    Casper Christensen

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    Dec 8, 2014
    I will post a photo of it later today :) have to get home first
     
  20. Gryd3

    Gryd3

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    Jun 25, 2014
    If you look on the end of the battery compartment, you can see that the polarity is marked from top down : + - +
    Because of the battery layout... there needs to be an additional connection, which could be that small metal post above the screw-hole.
    It would be interesting to see which order the cells are joined, but I highly doubt that the batteries are split to provide power to different portions of the circuit...
     
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