joining multiple small compressors for mobile use.

  1. normspanners Member

    Messages:
    8,119
    northwales
    Hi just wondering if anybody has done this, I do have a couple of decent size 12v compressors but physically mounting them is a problem.
    now lidle have had some small 40 ltr/ minute compressors 12v, for silly money they have decent sized motors and seem to run ok, i bought 5 of them they can be easily hidden /mounted around the underbonnet of disco and was going to combine the outputs and switching and put them on a relayed pressure switch, and airside into a stainless air tank, my thoughts are 1 check valve or 5 ? as I dont want the head pipes remaining pressured, size of cv is a problem, also cost as some are dearer than the compressors were! After all each comp will have its 'in head' reed valve and starting isnt a problem coz of the size of piston
    Just wondering if anybody had tried this, and their findings .
     
    Last edited: Oct 12, 2017 at 10:07 AM
  2. pdg

    pdg Member

    Messages:
    9,227
    Location:
    Wiltshire
    If you do receiver>nrv>manifold to all pumps - and switch them all together - it'll be fine.

    Put an unloader on the manifold and it'll depressurise all the primaries together.

    A 'normal' compressor pressure switch will work fine and provide decompression - it doesn't matter what voltage is stamped on it because it's an electrically passive component - but a relay will be good to reduce the current at the contacts.
     
    normspanners likes this.
  3. WorkshopChris Forum Supporter

    Messages:
    2,858
    Location:
    South East Essex
    Whenever i have joined compressors i have always fitted a NRV to each unit and adjusted the pressure switches so that all start at separate pressure to avoid a high start load.
     
    normspanners likes this.
  4. normspanners Member

    Messages:
    8,119
    northwales
    Thanks Chris but the pressure switches are bigger than the compressors! so am only planning on one PS and with DC I dont think startup loads a problem it will be only be 50 ish amps anyway and as a starter takes 500ish ...
    By my calcs it will be approx 700W or Ihp of compressor not huge but will get there,---eventually, if I use 25/30 ltr tank ---- ample enough to have a ready supply of air when needed for tyre pressure, blowing off, quick little die grinder job etc.
     
    Last edited: Oct 12, 2017 at 10:47 AM
    WorkshopChris likes this.
  5. Robotstar5

    Robotstar5 Casanunda Staff Member

    Messages:
    15,692
    Location:
    Birmingham
    When they all fire up you can tell folks you have a compressed air powered Disco? :laughing:
     
    normspanners likes this.
  6. slim_boy_fat

    slim_boy_fat Forum Supporter

  7. normspanners Member

    Messages:
    8,119
    northwales
    ERH NO------ it does that enough whilst I am driving it, my tools go everywhere as it is !!
     
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  8. dannyp Member

    if you dont have air con on your disco retrofit an aircon pump, they make very good compressors
     
    normspanners likes this.
  9. normspanners Member

    Messages:
    8,119
    northwales
    Thanks Danny, yeah I know, we used to use them on the tranny service barges using the same idea, worked ok but if I set this up as an easy fit and remove, I can swap it from vehicle to vehicle easily and quickly plus if I am working at a place with mains, I could just run it off the batteries and have a charger to keep the battery topped up that would save having to drag my portable 240 suitcase compressor around. Not sure how much air it will give, at the moment they say 40 ltrs per minute so in the real world say it is 25 average and I have 25ltr tank I am guessing it will take one comp 10mins to fill to 10 bar, so with 5 it might take two mins ??? that is not too bad I dont use much air now with the milwaukee gear but it is very handy for little jobs to have a 10bar tank at your disposal.
    I tried one on the disco tyre the other day and it was at about 25psi and it fairly quickly got it up to 60.
     
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