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Converting something that runs on batteries...

Discussion in 'Electronic Repair' started by bigbossfan80, Jul 3, 2004.

  1. bigbossfan80

    bigbossfan80 Guest

    I have a friend who recently had a baby. The baby always sleeps in
    this automatic rocking thingy that runs on 4 "D" batteries(6 volts
    DC). Because they use this thing at least 10 hours a day or more,
    they are going through batteries like crazy!

    I want to do him a favor and convert it so that it runs on regular AC
    power from a standard wall socket. I know that basically all I have
    to do is buy a '6 Volt AC-DC Adapter', cut the connector end off,
    strip some wire insulation from each end(+ and -), and wire it into
    where the "D" batteries connect, making sure I match the polarity etc.

    BUT, my only question is with regards to amperage draw. My local
    Radio Shack sells three different '6 Volt AC-DC Adapters', one is
    rated at 1800 mA, one is 800 mA, and the other is 300 mA. Is there
    someway that I can measure how many milli-amps this automatic rocker
    thing draws? I have a Digital Multi-Meter and ASSUME that I can
    somehow use it to measure the amperage draw, but am not 100% sure??

    Does anyone have any help or suggestions?

    THANKS!:)
     
  2. [This followup was posted to sci.electronics.repair and a copy was sent to
    the cited author.]

    Are the batteries side by side, or in a row? You first need to find the
    true + and - connections, and not the contacts that just tie batteries
    together. Once you find that, TAPE one meter lead to the positive of one
    battery. When you place it in the battery tray, keep it insulated from the
    terminal. Place the other meter lead against the contact. This way, the
    current flows through the meter.

    How long do the batteries last? I would think the smaller 300mA would be
    enough. Another option is to use two sets of rechargable batteries.

    Safety could be one reason it runs on batteries. You don't want any risk
    of 120V near the baby. Also, once the baby falls asleep, try turning it
    off. Otherwise, the baby will grow up having to sleep in cheap motels with
    the vibrating beds!!! :)
     
  3. scada

    scada Guest

    I think safety is the key issue here! The wire from the wall wart could
    entangle the baby, or he could chew on it, etc... I never seen anything run
    off of other than battery for a baby!
     
  4. Jerry G.

    Jerry G. Guest

    For these rockers they would be safe to run on a 300 to 500 ma supply. The
    bigger supply would run cooler and be more reliable over the long term. The
    rocker will pull what it needs as long as the supply voltage is correct.

    Personally for safety issues, I would run the rocker on batteries, and use
    chargeable. Get 2 sets of chargeable batteries and the proper charger to go
    with the batteries for this application. You can change each set, and have
    them the discharged ones on charge. If these are not lasting long enough,
    then you can have 3 sets, and rotate these as required.

    Chargeable batteries should have a life span of about 800 to 1000 charge
    cycles, or last about 3 years average. This would be a big cost savings over
    the time that they would want to use the rocker.

    There are some safety issues when using a device that is connected to the AC
    mains. If the baby urinates in a way that the rocker gets soaked, and the
    urine leaks down to the battery compartment, there can be an issue if there
    is any conduction back through to the mains, even though it is on a
    so-called power pack. I would not want to have to deal with this issue.
    Maybe this is the reason why the manufacture didn't go this route.

    --

    I can just see when the baby grows up. He'll like the vibrator and message
    beds in the motels!

    --

    Jerry G. GLG Technologies GLG
    ==========================


    I have a friend who recently had a baby. The baby always sleeps in
    this automatic rocking thingy that runs on 4 "D" batteries(6 volts
    DC). Because they use this thing at least 10 hours a day or more,
    they are going through batteries like crazy!

    I want to do him a favor and convert it so that it runs on regular AC
    power from a standard wall socket. I know that basically all I have
    to do is buy a '6 Volt AC-DC Adapter', cut the connector end off,
    strip some wire insulation from each end(+ and -), and wire it into
    where the "D" batteries connect, making sure I match the polarity etc.

    BUT, my only question is with regards to amperage draw. My local
    Radio Shack sells three different '6 Volt AC-DC Adapters', one is
    rated at 1800 mA, one is 800 mA, and the other is 300 mA. Is there
    someway that I can measure how many milli-amps this automatic rocker
    thing draws? I have a Digital Multi-Meter and ASSUME that I can
    somehow use it to measure the amperage draw, but am not 100% sure??

    Does anyone have any help or suggestions?

    THANKS!:)
     
  5. CWatters

    CWatters Guest

    Poor kid, 10 hours a day in a rocker! Sounds like baby is adicted. I wonder
    what effect that will have on the way his ears develop?

    If the batteries are in series (eg 6V) the conversion is trivial. To measure
    the current put the meter on the Amps range and connect it up in series with
    the battery. Or you could make a guess... D size batteries contain no more
    than about 6000mAH (usually less) so if they last say 10 hours the current
    draw is less than 1A. My guess is that the 800mA supply will be just fine
    but I'd get the 1800mAH unit if the price difference isn't a big deal.

    Note the current draw might be a lot higher when the unit is first switched
    on (eg the first swing?) batteries are very good at supplying high
    currents - the mains adaptor might not be so good or might blow an output
    fuse?
     
  6. jakdedert

    jakdedert Guest

    I was agreeing with the safety issues as I read this thread...to the point
    that I missed the above; which in my mind as well, is the real issue. *TEN
    HOURS a day?* Do that poor kid a favor. Take him out and hold him for a
    couple of hours. Babies are delightful to hold. At my age--with my
    youngest at seven--I WISH I had a baby to hold. I truly miss it. Too soon
    they grow up to the point where you 'wish' you could hold them....

    This is not an electronic issue. It's a parenting problem. NO kid needs to
    spend that much time strapped into an 'electronic mother' substitute.

    In the event that the OP made an exageration, then rechargables are really
    the way to go. But, it sounds like the parents have a bigger problem than
    finding an inexhaustable power source for their swing...and if they think
    it's bad now; imagine what that kid raised with that kind of neglect will be
    like when he grows up.

    jak
     
  7. chuck

    chuck Guest

    Buy rechargable batterys
    be safe
     
  8. chuck

    chuck Guest

    Buy rechargable batterys
    be safe
     
  9. Mike

    Mike Guest

    Goooo smelly, Goooo spotty
     
  10. Asimov

    Asimov Guest

    "scada" bravely wrote to "All" (03 Jul 04 13:40:20)
    --- on the heady topic of "Re: Converting something that runs on batteries..."

    sc> From: "scada" <>


    sc> I think safety is the key issue here! The wire from the wall wart
    sc> could entangle the baby, or he could chew on it, etc... I never seen
    sc> anything run off of other than battery for a baby!

    There is also the small matter of bioeffects of AC magnetic fields on
    developing cells in particular the tiny risk of childhood luekemia.
    The magnetic field intensity from an AC wall adapter is not very easy
    to predict but wall warts are notoriously leaky. I feel, in addition
    to the other electrical shock and fire risks mentioned, the wiser
    decision is indeed two sets of rechargable batteries.

    A*s*i*m*o*v

    .... Inductor designers do it in the gap.
     
  11. Ken Weitzel

    Ken Weitzel Guest


    Hi...

    The motor itself will also be a source of magnetic
    influences...

    If there's absolutely no alternative, I think I'd
    look around for a spring wound one... let it soothe
    the baby to sleep, and then let baby sleep in peace...

    Course as an old guy who's kids (despite having promised
    not to) have all grown beyond much cuddling, and now
    even the grandkids (despite having promised not to AND
    put it in crayon'ing) have grown to the stage where
    hugging is still great, but not too much cuddling,
    I'd vote for the cuddling option.

    Wonderful for both the baby AND the cuddler. :)

    I had a child abducted about 35 years ago. Had a
    massive heart attack. Spent 2 years in hospital.
    One of the "prescribed medications" for me was to put
    in lots of time as a hospital "rocker". Down to the
    infant ward twice a day to hold and rock the babies
    that had no one to visit them. Wonderful therapy.

    So... today's parents are busy; far more than we
    ever dreamed of being... maybe there's not enough
    hours in the day. How about grandparents? Favorite
    absolutely trustworthy older neighbors with time on
    their hands?

    Just thinking... I have a just turned teenager
    grand daughter that I'm raising, and a three year
    old next door to take to the park. And she's promised
    to never grow up on me, AND she's put it in writing,
    AND she promised to never change her mind :)

    Take care.

    Ken
     
  12. Asimov

    Asimov Guest

    "Ken Weitzel" bravely wrote to "All" (04 Jul 04 05:02:12)
    --- on the heady topic of "Re: Converting something that runs on batteries..."

    KW> From: Ken Weitzel <>
    KW> Hi...

    KW> The motor itself will also be a source of magnetic
    KW> influences...
    KW> If there's absolutely no alternative, I think I'd
    KW> look around for a spring wound one... let it soothe
    KW> the baby to sleep, and then let baby sleep in peace...

    Most motors are actually quite good in that respect because the
    engineers of these tend to be efficiency freaks and strive to complete
    most magnetic paths within the motor, not outside.


    KW> Course as an old guy who's kids (despite having promised
    KW> not to) have all grown beyond much cuddling, and now
    KW> even the grandkids (despite having promised not to AND
    KW> put it in crayon'ing) have grown to the stage where
    KW> hugging is still great, but not too much cuddling,
    KW> I'd vote for the cuddling option.
    KW> Wonderful for both the baby AND the cuddler. :)

    Especially in our Anglo-Saxon dominated North American societies where
    physical contact is discouraged and interpersonal distances
    encouraged. Babies seem to be the last group that actually appreciates
    hugs from grandparents.


    KW> I had a child abducted about 35 years ago. Had a
    KW> massive heart attack. Spent 2 years in hospital.
    KW> One of the "prescribed medications" for me was to put
    KW> in lots of time as a hospital "rocker". Down to the
    KW> infant ward twice a day to hold and rock the babies
    KW> that had no one to visit them. Wonderful therapy.

    I empathize, I guess I would either break down mentally or become
    physically ill as you did. There are no words that can help such a
    tragedy. I suppose it took you a long time to care about the world
    again. Really great of you to reply here!


    KW> So... today's parents are busy; far more than we
    KW> ever dreamed of being... maybe there's not enough
    KW> hours in the day. How about grandparents? Favorite
    KW> absolutely trustworthy older neighbors with time on
    KW> their hands?

    In the 50's the future was supposed to be the leisure society but boy
    were they wrong. When we find grandparents working McJobs to make ends
    meet and people tied to their jobs 24/7 via their cell phones and
    internet.


    KW> Just thinking... I have a just turned teenager
    KW> grand daughter that I'm raising, and a three year
    KW> old next door to take to the park. And she's promised
    KW> to never grow up on me, AND she's put it in writing,
    KW> AND she promised to never change her mind :)

    KW> Take care.

    KW> Ken

    Ah, don't do that, kids have to grow strong to create a new world of
    their own from the mess the greedy amongst us left them. If you hold
    them back you will always have to be responsible for them just like a
    bird in a cage.

    A*s*i*m*o*v

    .... Transformer designers take turns doing it.
     
  13. jakdedert

    jakdedert Guest

    I'd say that she's already done some major 'growing' in order to--at
    three--put a contract *in writing!*

    jak
     
  14. Ken Weitzel

    Ken Weitzel Guest


    Actually it's in crayoning, on the front of the fridge :)

    May be unenforcable though - seems that I'm the only one
    able to properly read it. :)

    Her Dad's a Canadian soldier away in Bosnia; her Mom next
    door has a newborn to look after, so I get her company a
    lot. She often goes into the kitchen and "reads" it to me.
    Sometimes it's a story about her and I going to the park;
    often it's a story about her and I going up to the corner
    for ice cream.... and unless it's close to meal time it
    usually works :)

    They learn their "wiles" young :)

    Ken
     
  15. jakdedert

    jakdedert Guest

    My youngest (seven) has been 'writing' books since preschool. She works
    diligently for days--even weeks--on a project and present it to us ready for
    binding. At four or five, she'd dictate to one of her older sisters. After
    she learned the alphabet, she'd have one of us spell out her sentences for
    her as she laboriously wrote down the letters and puntuation. Once she
    learned to read/write, she started doing the projects all on her own. She's
    currently working on an illustrated calender. We have at least ten works
    stashed away to present to the Pulitzer Committee....

    There's nothing like kids. Here I am at 51, wishing I had a baby to
    hold...actually, this morning at church (1st Sunday: all-ages service) I got
    to hold a friend's baby (seven mos.) most of the way through the service.
    When her momma took her out of the sanctuary for feeding, I could swear she
    said 'Bye' to me. A couple of other members heard it too, and commented....

    Babies are cool....

    jak
     
  16. Julie

    Julie Guest

    DO NOT CONVERT TO AC. These things run on batteries for a SAFETY reason.

    Purchase some rechargeable batteries and a charger.

    -end
     
  17. 300 mA is probably much too low a current. My guess is that the device
    draws a lot more than an amp, but for a very short period of time every
    few seconds.
    Very good point. It could be lethal.
    A real rocker!
     
  18. Four Ni-MH 'D' cells would give only 4.8 or so volts. Hopefully that
    will run the rocker, but it's a full volt lowqer than the 6V from 4
    Alkalines.

    Nowadays, the rechargeable 'D' cells are just AA cells in a bigger
    package. Check it out sometome. The ratings on the common 'D'
    rechargeable cells are only about the same as the AA cells, or about
    2200 mAH.

    A fresh D alkaline is capable of delivering several amps no problem. So
    don't kid yourself. Buy an adapter that will not burn itself out trying
    to be a 'D' cell.
     
  19. Ken Weitzel

    Ken Weitzel Guest

    Watson A.Name - "Watt Sun, the Dark Remover" wrote:

    <snip>

    Hi...

    With all due respect, that's not so... you may have
    found some AA's in D size cans like the old Nicad's
    were, but I have D sized NiMh's that are rated at
    8500 mAH. And they perform like they should.

    Check out e-bay, search nimh d and see what you find :)
    Be forewarned, they're expensive! :(

    And just to touch on the original subject, I sure
    wouldn't want *any* nimh near any baby, or even
    a child. They are waaaaaaay too dangerous.

    Take care.

    Ken
     
  20. James Sweet

    James Sweet Guest

    It runs off batteries because an AC adapter big enough it expensive and
    would add a lot to the cost of the unit. As long as the adapter is UL
    approved I wouldn't hesitate to use it.
     
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