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I laugh and think - Solenoid Valves

Discussion in 'Hobby Electronics' started by [email protected], Nov 21, 2007.

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  1. Guest

    Hi all,

    Well, thought I'd get into a bit of water conservation, and as I have
    quite a few micros around, my thoughts turned to turning water on and
    off.

    As a lot of power supplies are 12v DC I initially thought that there
    were heaps of cheap
    solenoids out there ready to buy. Unfortunately I must have been
    somewhat deluded as there are not many 12v DC solenoids in existence -
    maybe more 24v AC.

    Checking on Ebay showed some in the USA at about (from memory) $AU10,
    but being the ever great Australian product consumer, thought I'd find
    the same here.

    Well, as it turns out, after submitting a request to (apparently) the
    largest supplier of solenoids in Oz that the equivalent cheap plastic
    solenoid here is around $AU75.00
    FMD! What justifies this great markup?
     
  2. Poxy

    Poxy Guest

    A 1" Richdel/Irritrol solenoid with an AC coil should cost about $20-$25.
    The 12v DC coils for these are usually the latching type - a pulse with one
    polarity opens the valve, a pulse with the reverse polarity closes the
    valve, requiring an H- bridge or dual-pole relays to control each valve. The
    catch, as you've found is that the DC latching coil costs $30-$40, which is
    bloody expensive compared to a 1" valve, however the same coil is used on
    much more expensive valves, such as 2" units.

    If you are not running high flow rates, why not hack one of the
    previously-mentioned Holman tap-timers - they sell a $20 2-knob version
    which has a neato motorised ball valve. The catch is the fluid path, while
    straight, is only about 8mm diameter - fine for drip irrigation but probably
    not for sprinklers or pop-ups.
     
  3. Robbo

    Robbo Guest


    What do 1/2" garden retic solenoids cost? They are AC - perhaps drop the
    voltage down & run off DC??
     
  4. Guest


    Hmm, Peter Costello.. known associates. Now what was I going to do
    this Saturday?...
     
  5. Guest

    Hi Poxy, and thanks,

    I would hack a tap-timer, but common sense suggests that a 12vDC
    solenoid should be available, but not at $AU75.00 (unless you wish to
    rip-of people)...

    Thanks again Poxy for the great ideas though.
     
  6. Guest

    BTW, Please excuse the rather strange topic. I was thinking of the
    lyrics of a long-gone Australian group - Anyone know what the song/
    group is?
     
  7. Terryc

    Terryc Guest

    Could be economies of scale.

    At one stage, Twainese bicyles were shipped to USA, then reshipped to
    Australia,
     
  8. Guest

  9. rodney

    rodney Guest

  10. rodney

    rodney Guest

  11. tuppy

    tuppy Guest

    I have had many years life with these 24v ac solenoids (daily
    watering). I deliberately ran one off a 12vdc solar irrigation
    project knowing that eventually the core would polarise and solenoid
    wont pull in properly. Those $18 24 ac solenoids lasted 2 years
    before failing on DC. I replaced the solenoid with another but this
    time I reverse the leads every couple of months or so. Been about two
    years on DC no failure yet. I did plan to buy a cheap mini car
    inverter and run a 240/24v xformer to feed solenoids AC in future
    anyway.
     
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