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AC Adaptor in Parallel With Battery?

Discussion in 'Electronic Design' started by Paul, Apr 16, 2008.

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  1. Paul

    Paul Guest

    We plan on placing a +12VDC AC adaptor (110-220AC, which
    will plug into
    an outlet) in parallel with a battery connector using a "Y" connector,
    so that the user can operate our device using either a battery, or the
    wall adaptor. ONLY EITHER the battery or the wall adaptor will
    be hooked up at any time.

    Here is the adaptor we will use:

    http://www.cui.com/pdffiles/DPS120100UPS-P5P-SZ.pdf

    However, will the impedance of the AC adaptor (when it's
    not plugged in) be sufficiently
    high enough to make the current draw on the battery insignificant?

    Because if the adaptor looks anything like the following:

    http://www.coilws.com/images/Switch Mode/1R5W_ckt.gif

    Then I'm not worried about the half-wave rectifying diode, but rather
    the shunt Zener diode which is only 8.2V.

    I'm hoping that the current draw going into the adaptor
    will
    be insignificant, so that i can wire it in parallel to the battery
    connector,
    without having to hassle with putting a relay or switch in there.

    Maybe i can just solder in a series diode in-line with the
    AC adaptor....
     
  2. Guest

    You could have done that in less time than it took to write that post.
    So what do you think the answer is?
     
  3. Phil Allison

    Phil Allison Guest


    ** No !!

    Not only will the output circuit of the adaptor draw current from the 12
    volt battery - but it may in fact place a dead short across it !!!

    This switching PSU is stated to have over-voltage protection that shuts down
    the output ( in case of internal failure) - so very likely it has a SCR
    " crow-bar "

    circuit. This will trigger at some voltage a little above the nominal 12
    volt level and hard short the output PLUS any connected battery supply.

    Use a series diode after the adaptor, for god's sake.


    ....... Phil
     
  4. Paul

    Paul Guest

    Don't ask advice from a numbskull...
     
  5. Paul

    Paul Guest

    How "in fact" do you know this?

    INCORRECT. This is just a wall AC adaptor.
    It's just a linear regulator.

    And the crow-bar would limit the current FROM
    the unit, not limit current INTO the adaptor.


    What the hell are you talking about??

    The over-voltage circuit is separate from
    the over-current protection, and a short-circuit
    protection will do anything BUT short out the output!

    Why would you have a SHORT-circuit protection
    SHORT out the output???!!?

    I probably will, but certainly
    NOT from anything you have typed!
     
  6. Phil Allison

    Phil Allison Guest

    "Paul"
    "Phil Allison"
    How "in fact" do you know this?

    ** Read on - fool.

    INCORRECT. This is just a wall AC adaptor.
    It's just a linear regulator.


    ** Read the damn URL you supplied - asshole !!

    It **IS ** a " switch- mode power supply " !!!!!

    Says so right on the back of the damn unit !!!!!
    ------------------------------------------------------------



    ** If the output is shorted by an SCR - so will anything attached to the
    output, like your battery. Read the damn URL you supplied.

    It says:

    " Over voltage protection 15 -18 V dc max. ( output shut down) "

    Unlike the "Short circuit protection", it is not self restarting and that
    is how an SCR crow-bar circuit behaves.

    What the hell are you talking about??


    ** Listen, pal -

    YOU need to learn some basic power supply stuff.

    Cos YOU fucking don't know ANY yet.


    The over-voltage circuit is separate from
    the over-current protection, and a short-circuit
    protection will do anything BUT short out the output!


    ** I said the " over voltage protection " would short the output - because
    that is what the maker's specs suggest.

    I probably will, but certainly
    NOT from anything you have typed!


    ** Try learning to read - asshole.

    Then get some better manners.

    Cos you have FUCKING TERRIBLE ones now.



    ....... Phil
     
  7. Paul

    Paul Guest

    You don't know SHIT, Aussie-Holiday Faggot!

    Why the hell would an over-voltage protection
    short out the fucking output? If anything, it would
    open a SERIES MOSFET.


    Look in the mirror, Crocodile Dund-Fuckin'-Dee!

    All your "!!" are extremely bad manners, so i
    give them back to you, Shit-wit!
     
  8. Paul

    Paul Guest

    But even if only the battery is hooked up, the
    AC adaptor may still have a not-so-high impedance
    looking into it. In which case, a reverse-biased
    diode will certainly help things.


    Yes, but we'd like to avoid this if possible.

    Yeah, i'm also gonna use an external power
    supply, and measure the current going into the adaptor
    when it's unplugged, and see what the current is.

    That should tell me if I'll need the series
    diode or not.


    Yeah, but a relay would draw current, which i can't
    do if i want the batteries to last. And even just a simple
    manual switch (SPDT) would be a bit bulky, which is what
    i'm trying to avoid.

    Thanks for your input.
     
  9. Phil Allison

    Phil Allison Guest

    "Paul"



    ** This retarded VILE PIG is a FUCKING MORON.

    Killfile the **** now !!




    ....... Phil
     
  10. Phil Allison

    Phil Allison Guest

    "Paul" <>


    ** This retarded VILE PIG is a FUCKING MORON.

    Killfile the **** now !!




    ....... Phil
     
  11. Phil Allison

    Phil Allison Guest

    "Paul" <>



    ** This retarded VILE PIG is

    a FUCKING MORON.

    Killfile the **** now !!




    ....... Phil
     
  12. Phil Allison

    Phil Allison Guest

    "Paul" <>



    ** This retarded VILE PIG is

    a FUCKING MORON.

    Killfile the **** now !!





    ....... Phil
     
  13. Phil Allison

    Phil Allison Guest

    "Paul" <>



    ** This retarded VILE PIG is

    a FUCKING MORON.

    Killfile the **** now !!





    ....... Phil
     
  14. Phil Allison

    Phil Allison Guest

    "Paul" <>



    ** This retarded VILE PIG is

    a FUCKING MORON.


    Killfile the **** now !!





    ....... Phil
     
  15. Phil Allison

    Phil Allison Guest

    "Paul" <>



    ** This retarded VILE PIG is

    a FUCKING MORON.


    Killfile the **** now !!





    ....... Phil
     
  16. John G

    John G Guest

    This discussion has degenerated into a farce.

    If, you, Paul, knew enough about electricity to design something that MIGHT
    work you would know enough to not ask this dumb question about connecting
    the battey and an outside supply.

    A simple ordinary external supply connector as used on many, many devices
    has a mechanical switch to switch from the internal (battery) supply to the
    outside supply whenever it is connected or a properly placed diode would
    allow the battery to do its job whenever there is no external input.

    John G.
     
  17. Whilst I have had the 'pleasure' of encountering this individual
    before posting the same text a dozen or so times to the same thread
    in 24 hours is fairly moronic too.

    Personally, I'm quite enjoying reading his posts now that I'm not
    responding to them. He started out asking fairly advanced questions
    When I see the questions he has posted since, my initial suspicions
    have only been confirmed. It's been quite entertaining to watch
    the level of his question devolve to a level which is now covered
    by compulsory education in most Western countries.

    I wonder who he works for? I dread to think what they'll end up with.
     
  18. Phil Allison

    Phil Allison Guest

    "Andrew Smallshaw"

    ** Not at all

    - as I am posting a much needed public warning.

    It needs to be repeated many times on Usenet to have any effect .

    Both to warn others and to alarm the culprit as much as possible.




    ** How fucking pompous of you.

    When dealing with retarded, hyper-manic sociopaths - direct action is
    best.


    ** How fucking even more pompous.

    When dealing with retarded, hyper-manic sociopaths, direct action is way
    best.


    ** I wonder who YOU work for ?

    Public sector ?

    Academic institution ?

    Railway ticket collector ?



    ....... Phil
     
  19. Guest

    So many times? So frequently? But even so it it just your and
    Andrews opinion. Shouting about it too hard is much worse than any
    harm this guy ever did.
    That looks to me a mature way of doing things. Point out "Hell, this
    is hard" if you really think it is too difficult for somone. Andrew
    did seem smug in his post but he's not the one swearing all over the
    internet.
    I've no idea who he works for but have been lurking on
    alt.comp.hardware.homebuilt for quite a few months. Andrew is one of
    the posters you sense has been there done that. A lot of his posts
    have in depth material you can't simply pull off the internet review
    or technical sites, circuit ideas or full schematics for instance. He
    obviously knows something about the area.
     
  20. Guest

    Or respond to questions from one....
    Your thick, armor-plated skull is resistant to not only the physical
    beatings you must endure every day in real life, but to all forms of
    sense people here are trying to tell you.
    You are an ignorant fuckwit. You are of the dangerous class of people
    who are convinced they know everything and therefore don't need to
    learn anything.
    The only good thing here is that you are playing with mains voltage,
    one can only hope that you die a quick, crispy death.
     
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