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12v auto pump from 110v?

Discussion in 'Electronic Design' started by T-n-T, Dec 7, 2006.

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  1. PeterD

    PeterD Guest

    Yep, that confirms what I said earlier, so I'd say your cheap DMM was
    doing OK! <bg>

    They are *really* inefficient!
  2. Guest

    And they get hot, too. You'd think that the pump designer would at
    least use the pumped liquid to cool down the motor. Naah...

  3. So, which do you want? Super efficient, or something that will work
    when your life depends on it?

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  4. Rich Grise

    Rich Grise Guest

    Your life depends on misting your terrarium???!? =:-O

    [0] ;-)
  5. Guest

    In that case, better get someone with medical experience... oh, Joerg!

    So, which does he want... efficient, reliable, or inEXPENSIVE?

  6. Jim Thompson

    Jim Thompson Guest

    Why is everyone ignoring my yard-mister/valve-body/transformer
    approach? It's cheap-cheap-cheap and safe-safe-safe!

    ...Jim Thompson
  7. Rich Grise

    Rich Grise Guest

    I'm not ignoring it - I just liked mine better. ;-)

    (That would be an aquarium filter pump and hacked Windex nozzle(s), pretty
    much as you suggest, but less clunky. [and more fun to slap together. ;-) ])

  8. Guest

    It likely is, great idea, but it's not clear whether the OP minds
    stringing a garden hose from his backyard into his living room.

    Never mind the heating and cooling costs of leaving his backyard door
    open a crack, at all times...


  9. Jim Thompson

    Jim Thompson Guest

    He's carrying buckets of water to his terrarium?

    Surely he has a water pipe close by?

    Actually I carry water to my aquarium... R/O water, since it's a reef
    tank, and I have no way to get a feed to it... interior wall. But it
    only eats 3 2-gallon-buckets-worth per week (since I added the chiller

    ...Jim Thompson
  10. Guest

    Um, you lose 6 gallons per week even in the fall / winter months?

    Slow leak?
  11. w9gb

    w9gb Guest

    Wall warts ONLY handle currents up to about 1 Amp - MAX.
    That wiper motor is a current hog (more than a Wal Wart can handle!!) --

    burn that up or blow internal fuse (if it has one) first time you try.

  12. Jim Thompson

    Jim Thompson Guest

    Room temperature is ~75°F, humidity is essentially ZERO... this IS
    Arizona after all. Tanks is 250 gallons. Any other questions ?:)

    Tank WAS rising to 84°F, due to the lighting, until I added a
    "chiller" ;-)

    ...Jim Thompson
  13. Mcmaster has nozzels for misting etc.

  14. ehsjr

    ehsjr Guest

    Um, not to give the op hope, but ...
    See cat# dctx 1215 from
    for a 1.5 amp 12 volt wall wart and cat # 16760 from for a 2 amp 12 volt wall wart.

  15. ehsjr

    ehsjr Guest

    If you already have the wiper pump, you can use an interim
    solution to run it until you re-design. Use the wall wart
    to trickle charge some NiCds and run the auto wiper pump
    from that. The NiCds will provide the high current that the
    wiper pump needs, and the charger will replenish them between
    pump cycles.

    Wall Wart +15V ---Vin|LM317|Vout---+
    ----- |
    Adj [R1]
    | |
    +----------+-->|--+------> to
    | pump
    [NiCd's] circuit
    Gnd --------------------------------------+------>

    R1 = 1.25/(C/20) where C is the ampere hour rating of
    your cells. That should be more than enough to charge
    the cells between cycles. For example, say your cells
    are rated at 1000 mAh. At C/20, you would put in a total
    of 480 mAh in a day, and due to losses, the batteries
    would store 80% of that, or ~384 mAh. If you discharge
    for 1 minute 3 times a day at say 7 amps each time, you
    use 21 ampere minutes or 350 mAh hours.

    Have you figured out how to get a mist from that wiper
    pump? To me, that's a harder problem than figuring out
    how to provide power for the pump.

  16. Zak

    Zak Guest

    The designed life is probably an hour or two. But it shouldn't burn out
    when someone mistreats it. Which includes continuous 'pumping' when out
    of fluid.

  17. w9gb

    w9gb Guest

    Yes, these are OLD surplus designs -- new mfg. are generally now avoiding
    (that is why they are on the surplus web sites/resellers).
    They usually do not stay in the duplex outlet without screw attachment to
    cover plate.
    Readily available 1 and 2 foot line cord jumpers --- help with this problem.
    These older designs stretched the definition of WallWart -- due to
    transformer's weight !

    New ones are more "brick like" with short AC cord OR use standardized IEC


  18. ehsjr

    ehsjr Guest

    The new stuff is nice. It seems like most everything new
    is going to switchers. I suspect one of the factors is
    the weight you mentioned. Take a look at the wall wart
    switchers like Mouser part #'s
    418-TR25120-04 2.1Amps
    418-TR30R120 2.5Amps
    831-PW128RA1203B01 2.5Amps
    552-PSA-15R-120-R 1.25Amps
    552-PSA-21R-120-R 1.67Amps

    Allelectronics sells a switcher wall wart at 2.6 amps,
    cat # PS-1226

    For non-switcher new wall warts > 1 amp see Mouser part #'s
    553-WDU12-1200 1.2Amps
    553-WDU12-1900 1.9Amps

    A lot of choices > 1 amp, but not necessarily suitable
    for the OP. I suspect not. I posted a different
    possibility for the OP.

  19. Stephen Rush

    Stephen Rush Guest

    Back to the original problem. If you want to pump mist into a terrarium,
    how about a perfume atomizer driven by an aquarium air pump? Or, for
    real tech overkill, an ultrasonic nebulizer?
  20. Seymour Dupa

    Seymour Dupa Guest

    Get a battery charger and plug it into the wall.
    Connect the pump to the charger.
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