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DryCamper11's avatar
DryCamper11
Explorer
Sep 30, 2013

Remote water pump switch - latching relay?

I want to install remote water pump switches that operate a latching relay to turn the pump on/off with a single press of a momentary contact switch. I'm tired of being out in the boonies and getting a piece of dirt in the pump or a leaky faucet and having the pump BRRRP every couple of hours at night while trying to sleep. I don't want to turn off the master pump switch while sleeping (which I could do now) since I don't want to walk to that switch each time I want to use water, so I need remote controls at 1) the kitchen, 2) in the bathroom and 3) in the outdoor water compartment.

I've got the momentary switches, 4 conductor wire and LEDs for pump ON/OFF display, but I need to buy a latching relay. The relay has to be zero power in both on and off states. A ratchet type relay is preferred. I have a double relay - two DPDT relays that mechanically interlock so when one fires, the other changes state, too, and vice-a-versa. Unfortunately, the relays are 120AC, so I'll have to rewind the coils. I'd prefer to buy one that's 12VDC and is a single ratchet type.

The pump is 5.5 amps, so I need about 10A DC capacity for the contacts. Does anyone know of an RV system like this sold commercially where I can just buy the relay part? I can probably find one at Grainger's, etc. but perhaps someone else has built this before and has a relay number. I've found some latching relays online, but can't seem to verify that they use zero power in both states (they may latch with power - it's hard to tell).

Any suggestions?
Thanks!
  • DryCamper11's avatar
    DryCamper11
    Explorer
    Sep 30, 2013
    Chris Bryant wrote:
    Intellitec water pump controller- single wire to switch (which just grounds). Why reinvent the wheel.

    Thanks for the suggestion. To avoid reinventing is why I asked. That claims "Negligible standby current", which means it's not what I'm looking for. There's no reason to have any standby current.

    Also, the DEI 611T Relay Timer is an option, but again, it's solid state, and I'd rather just have the mechanical ratchet type. The solid state devices are more sensitive to spikes and other misc. issues found on an RV 12V electrical system.
  • wnjj's avatar
    wnjj
    Explorer II
    Sep 30, 2013
    digikey


    I changed the range hood switch to SPDT and added a 2nd switch in the bathroom. That isn't real practical for 3 switches or if you can't run the wires but it's low tech and zero power.

    I too wanted to turn the pump on from the bathroom for night visits or just stopping along the roadside.
  • OnaQuest's avatar
    OnaQuest
    Explorer
    Sep 30, 2013
    DryCamper11 wrote:
    Chris Bryant wrote:
    Intellitec water pump controller- single wire to switch (which just grounds). Why reinvent the wheel.

    Thanks for the suggestion. To avoid reinventing is why I asked. That claims "Negligible standby current", which means it's not what I'm looking for. There's no reason to have any standby current.

    Also, the DEI 611T Relay Timer is an option, but again, it's solid state, and I'd rather just have the mechanical ratchet type. The solid state devices are more sensitive to spikes and other misc. issues found on an RV 12V electrical system.


    Get real!
    The Intellitec Monoplex Controller has less than 2 milliamps standby current. Your batteries loose more charge, just sitting totally disconnected, than that. I doubt very seriously that the average RVer caries a meter that will detect, much less measure, a current that small.
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Sep 30, 2013
    OnaQuest wrote:

    The Intellitec Monoplex Controller has less than
     2 milliamps standby current. Your batteries loose more charge, just sitting totally disconnected, than that. I doubt very seriously that the average RVer caries a meter that will detect, much less measure, that.


    I thought that as well, but then realized that while the standby current is negligible, they don't give a working current- while the pump is on (but not running). I suspect that it is holding a relay closed, which would draw more current. I could be wrong though- they do use latching relays in other applications.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Sep 30, 2013
    Use genuine TYCO relays, not junk alternatives and this puppy will last you 30-years. And you don't need to return to Mickey Mouser if it doesn't. Any Bosch type relay will do in a pinch. Means any part store has them. But I've not seen a TYCO blow up.





  • OnaQuest's avatar
    OnaQuest
    Explorer
    Sep 30, 2013
    Chris Bryant wrote:
    OnaQuest wrote:

    The Intellitec Monoplex Controller has less than
     2 milliamps standby current. Your batteries loose more charge, just sitting totally disconnected, than that. I doubt very seriously that the average RVer caries a meter that will detect, much less measure, that.


    I thought that as well, but then realized that while the standby current is negligible, they don't give a working current- while the pump is on (but not running). I suspect that it is holding a relay closed, which would draw more current. I could be wrong though- they do use latching relays in other applications.


    They don't use a relay, it's a field effect transistor. When the controller is OFF, there is NO standby current at all. When ON, once the pump comes up to pressure, and opens the internal contacts to stop the pump, the controller is in STANDBY and that's when the 2 milliamp current would apply.

    These controllers are used in radio circuitry as well as motor circuits. Actually, anywhere low voltage control wiring is required or applicable.
  • OnaQuest's avatar
    OnaQuest
    Explorer
    Sep 30, 2013
    MEXICOWANDERER wrote:
    Use genuine TYCO relays, not junk alternatives and this puppy will last you 30-years. And you don't need to return to Mickey Mouser if it doesn't. Any Bosch type relay will do in a pinch. Means any part store has them. But I've not seen a TYCO blow up.






    Since those are not mechanically latching relays, they certainly won't meet the OPs requirements for no stand-by current draw. Once turned ON, it has to be pulsed again, to turn it off to drop the two relays out. Certainly more current draw than 2 milliamps.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Sep 30, 2013
    Anyone who sweats how many watts the relay coil of a Bosch Tyco relay pulls really needs to go back to lantern and bucket level living. When the load is switched OFF the relay coils, yeah all three of them are off. If you want to, go STANDBY your battery monitor and verify this. The OTHER way is to get a pair of T rated 3-way switches, then run a traveler between the two. C'mon people, this ain't rocket science.

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