Hi and building voltage regulator circuit

Discussion in 'The Projects Forum' started by marsrover, Oct 28, 2011.

  1. marsrover

    Thread Starter New Member

    Oct 28, 2011
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    Ok, so I was looking at building a alkaline battery charger. Here's the diagrams I have found on the internet. [​IMG]
    [​IMG]

    So I de-soldered some components from a old UPS I had laying around. But I can't find a LM317, so I'm gona list some parts, you tell me if any of them can be used as a replacement.
    LM2575BT (most center pin is broken off)
    IRFZ34N
    IRFZ46N
    Some smaller transistors with a rounded side and a flat side. (I forget if thats NPN or PNP)
    Various diodes and resistors.

    My power supplies are 12V from a computer PSU, or 5V @350mA from an old cell charger.
    So can I build this circuit with the junk I have?
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    Alkaline cells are NOT designed to be recharged, they are primary cells, and it may be dangerous to attempt to recharge them. As an alkaline battery is discharged, chemicals inside react to create an electric current. But once the chemicals have reached chemical equilibrium. The reaction stops, and the battery is depleted. In rechargeable batteries.The chemical reaction. Can be reversed by driving a current through the battery in the reverse direction. Hence the equilibrium can be shifted backwards towards the original reactants. Different batteries rely on different chemical reactions. Some reactions are readily reversible, some are not. The reactions used in alkaline batteries fall into the non reversible category.
    Attempting to recharge a discharged alkaline battery can cause the production of gas within the canister. As the canister is normally sealed, very high pressures can be created within it. This can rupture the seal, resulting in leakage of the contents , or or even an explosion
     
  3. marsrover

    Thread Starter New Member

    Oct 28, 2011
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  4. Wendy

    Moderator

    Mar 24, 2008
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    Yep, and if you have a fire he'll reimburse you too. Just in case put those puppies where they can't do any harm if he's wrong. The package on the batteries says otherwise.
     
  5. marsrover

    Thread Starter New Member

    Oct 28, 2011
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    I came here to build a circut. Not get advised on safty. I'm very safe, this is my house.
    [​IMG]
    I'm mostly sure that tree is the only thing that can catch on fire.
    IRL, I got tin foil to shield my house from explosions, also, I've already had one battery explode. That's why I'm building this, to keep it from blowing up.
     
  6. t06afre

    AAC Fanatic!

    May 11, 2009
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    Oh well Not everything on the net have the same qualety. And this setup seems to me to be on the more dodgy side. but to answer your question. No I do not think any of the part numbers you have listed can be used in the orginal circuit you posted. How about "Some smaller transistors with a rounded side and a flat side" do you have any part number on them.
    In the link you gave us have you scrolled down to the bottom. Then you may find this
    And I think that is more likely to happend.
     
  7. marsrover

    Thread Starter New Member

    Oct 28, 2011
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    mc340
    mps2 907a
    kn 2222a
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    Afrotech said he did his battery charging test 6 years ago and said that maybe alkaline batteries have changed now. He tested only a few. He did not do a proper test on many.
     
  9. marsrover

    Thread Starter New Member

    Oct 28, 2011
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    Well if I get it built, I'll test every battery in my drawer.
     
  10. wayneh

    Expert

    Sep 9, 2010
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    When you test, put the batteries inside an acid-proof enclosure. Heat and/or fire resistant would be a plus, though I've never seen a fire. But swelling and burping acid is a guarantee if you do this more than a lucky time or two.

    The urban legend that you can recharge an alkaline cell, like many legends, is based on a half truth. You CAN sometimes get a bit more out of an alkaline cell in a pinch by using a brief (meaning far less than full charge time) recharge at low current. It's better than just letting it rest a while, which also works to a degree. Trouble is, in my experience, the probability of popping your battery something near 50%. Win some, lose some. Kinda like the lottery, you feel like a genius when you win and a goofus when you're cleaning up an acid mess.

    IMHO, the poster at that link had better results than most because of the rapid discharge he used prior to his testing. That ensures a premature, apparent discharge that leaves some capacity remaining in the battery. Letting it rest a while, with or without a trickle recharge, will make new power "appear".
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    The trouble with testing only a few batteries is that you can't test all brands and all production dates. The next battery you wrongly charge might blow up.

    It also depends on how much of a discharge the charging battery had. Some people say that if it is discharged too low then re-charging doesn't work since the new charge will not last long. It can re-charge only if it has discharged only a tiny amount. That is what I discovered about 45 years ago.
     
  12. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    I remember my Grandmother buying an alkaline recharger about 45 years ago and I also do NOT remember any batteries exploding. But the bottom line was that it didn't work too well and the recharger ended in the trash (and the batteries, too and the lot was burned up in the backyard. Ahhh, the olden days! :D)...

    From what I know now, this does not sound like a project likely to succeed or one whose risk I personally would be willing to take.
     
  13. herlambang

    New Member

    Apr 30, 2011
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    Basic charger, but it's work fine isn't it?
     
  14. Wendy

    Moderator

    Mar 24, 2008
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    Probably not. If you want to pursue this I would suggest starting your own thread. A thread belongs to the person who starts it, if someone tries to take it over it is called hijacking, which is strongly discouraged.

    Instead of following some half baked unsafe scheme floating around the internet I would suggest this as starting reading...

    The Battery University

    BTW, this site is very safety conscious, it is part of our charm. It is even part of our Terms of Service, which isn't necessarily a good read but highly recommended. Part of my job around here is to enforce it. :)

    Terms of Service

    Both of ya'll are welcome here at AAC. Be safe, and may the farce be with you!
     
  15. marsrover

    Thread Starter New Member

    Oct 28, 2011
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    Well even if I can't charge alkilines I did find a use for it. Recovering bad rechargables. The extra voltage (5V@350mA) kinda jump starts it, then my regular charger can charge them without flashing errors in my face.
     
  16. Audioguru

    New Member

    Dec 20, 2007
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    You must still be using old Ni-Cad cells that had a habit of shorting. The short was blown out usually with a higher voltage charge on a capacitor but soon another short would form due to the way an old Ni-Cad cell works.
    Modern Ni-MH cells have a much higher capacity and do not form a short.
     
  17. marsrover

    Thread Starter New Member

    Oct 28, 2011
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    Nope, it says NIMh.
     
  18. Audioguru

    New Member

    Dec 20, 2007
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    Nearly all of my old Ni-Cad cells developed a short. I have many Ni-MH cells and none has failed.
    You said, "Recovering bad rechargables". What was wrong with your Ni-MH cells?
     
  19. marsrover

    Thread Starter New Member

    Oct 28, 2011
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    Beats me, all I know is the charger would just blink all it's lights at me (means won't charge) and after force charging it for a bit, they charge up and work fine. (in the real charger) Some of them woulden't be fixed by that (some even had reverse voltage... weird) but it fixed my oldest pair, don't know when we got them, but it was with the first charger our family ever had, so i'm sure it's somewhere near 3-4 years.
     
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