OpenSprinkler Forums Hardware Questions Relays to run more solinoids

  • This topic has 3 replies, 2 voices, and was last updated 6 years ago by Ray.
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  • #42283

    Stano
    Participant

    So I have the Open sprinkler 24vac unit and have realised that with the solenoids we use on the farm I can really only open 3 at a time (they draw just over 300mA each and are also 24vac).

    Since the pump is capable of more than this I figure that I need a relay board in between…will the one below do the job :

    http://pages.ebay.com/link/?nav=item.view&id=221930595470&alt=web

    Or do I need a 24v one???

    Thanks for any help…

    #42302

    Ray
    Keymaster

    How much current does the pump require? I assume you mean a pump start relay? It’s rather rare to connect a pump directly to a sprinkler zone as a pump typically needs powerline voltage (110V or 220V). In this situation, you typically use a pump start relay, which has similar electric spec as a standard sprinkler valve (and draws somewhere between 100mA to 200mA current).

    In any case, it sounds like what you need to do is not to use a relay board, but rather to increase the current output of your 24VAC transformer. Say, get one that can output 1amp, or even 1.5amp.

    #42304

    Stano
    Participant

    No, the pin does not matter at is is huge and has its on pressure sensing variable speed drive.

    I have a 24vac power pack running the Open sprinkler unit with 1 expansion module on it.

    Currently there is 13 solenoids attached.

    Now, let’s turn on 4 solenoids at once…I’m already over the max draw of the power pack as they draw just over 300ma each (they are 2.9w ea).
    So if I put a 2amp power pack on it I could then run 6-7 by the power pack but is 2 amps too much to pull through the unit???

    With all this in mind if I turn on all 13 bays at once (not likely unless it is like 42 degrees and we just need to keep everything wet) I would be drawing over 4amps, which I probably shouldn’t pull through the unit should I!?!?!? That’s why I though a relay between the unit and the solenoids that would supply them from a larger power pack.

    Ambiguous on the right track or should I just put a bigger power pack on the main unit?

    #42416

    Ray
    Keymaster

    Are you sure you want to turn on 13 valves at the same time? That’s going to draw at least 13 * 0.2 = 2.6 amp. In practice the current draw may be less because the transformer’s output voltage typically drops as you draw more current from it, resulting in less current drawn per station.

    In any case, if you plan to turn on no more than 4-5 valves at the same time, I think the controller can totally handle that. If you want to turn on more than 6 to 7 valves, using relay is probably a better idea.

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OpenSprinkler Forums Hardware Questions Relays to run more solinoids