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!

find yourself a DEI 611T latching relay...amazon/eBay

Intellitec water pump controller- single wire to switch (which just grounds). Why reinvent the wheel.

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.

digikeyI 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.

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.

Remote water pump switch - latching relay? | Good Sam Community

27 Replies

DryCamper11
Explorer
Nov 04, 2013
DryCamper11 wrote:
The Intellitec came in, and this weekend I had time to begin the installation. The Intellitec wouldn't function. It was in an original sealed bag when received - it looked to be an original factory label and seal, but who knows. I took it to a friend's RV who had the Intellitec water pump control and swapped my new one for his old one - and yep - mine was bad.

It turned out that the MOSFET was bad. I was able to replace it with a similar MOSFET from an old computer UPS in my junk box. One comment for anyone else adding remote switches. My water pump was powered from the main control panel through a switched wire carrying +12 volts. I didn't think about it until I received the Intellitec and the installation instructions, but the Intellitec doesn't switch the positive lead.

It's designed to switch the negative lead, not the +12v lead. I wanted the Intellitec mounted at my control panel, as that's where the control wires all go, but my water pump was grounded to the frame near the water pump. I couldn't just switch +12 volt line or replace the previous on/off pump switch with the Intellitec. I had to run a separate ground wire from the control panel to the water pump and switch that wire, plus find a good solid ground connection near the control panel to feed the pump.

If I'd purchased a latching relay as I'd originally planned, I could have just installed it to switch the +12v wire that was already installed between the control panel and the WP. It wasn't a big deal, but given I've already had one MOSFET failure and needed to do the extra work to run the ground wire, I probably would go for a latching relay if I did this again.
DryCamper11
Explorer
Oct 28, 2013
DryCamper11 wrote:
I bought the Intellitec for $30 shipped. All the relays I could find were more than that.

The Intellitec came in, and this weekend I had time to begin the installation. The Intellitec wouldn't function. It was in an original sealed bag when received - it looked to be an original factory label and seal, but who knows. I took it to a friend's RV who had the Intellitec water pump control and swapped my new one for his old one - and yep - mine was bad.
DryCamper11
Explorer
Oct 14, 2013
I bought the Intellitec for $30 shipped. All the relays I could find were more than that.
DryCamper11
Explorer
Oct 03, 2013
Chris Bryant wrote:
Not exaclty what you were looking for, but should work (rated at 100 amps, 220 volts, with a 7 volt coil, but works on reversed polarity, not impulse).
http://www.skycraftsurplus.com/7vdclatchingrelay100amp.aspx
$10

But.. Intellitec stuff is very well designed, as a lot of it is used on emergency vehicles.

Thank you. That will do it - I can wire for reversed polarity. OTOH, I'm now leaning towards the Intellitec. I did some searches and only found two documented electronics failure of the Intellitec, and one was just a diode failure that the owner easily replaced. I have one more box of relays in my junk box area to check. I vaguely recall seeing something similar to the flip flop solenoid relay I posted, but if I don't already have what I need stuck away in a corner, I'll probably go with the Intellitec.

Many thanks to all for the comments and links.
Chris_Bryant
Explorer II
Oct 01, 2013
Not exaclty what you were looking for, but should work (rated at 100 amps, 220 volts, with a 7 volt coil, but works on reversed polarity, not impulse).
http://www.skycraftsurplus.com/7vdclatchingrelay100amp.aspx
$10

But.. Intellitec stuff is very well designed, as a lot of it is used on emergency vehicles.
DryCamper11
Explorer
Oct 01, 2013
MEXICOWANDERER wrote:
It ain't just the cost.

Crap doesn't fail until you are 88 miles north of Eastjesus. All expanded and set up. Comfortable. Your one and only vacation...

THEN your truly cerebral doo-dad decides to stick it's middle finger in the air.

And guess what? That doo-dad whether you know it or not controls the most vital object in your better-half's RV lifestyle.

"Welcome to heaven here's your harp. Welcome to hell here's your accordion" time...

Gotta great sofa? You're gonna need it.

Simplicity. How to manage breakdowns. I happened to choose the PhD level of learning location. Ask for a "latching relay" and they're going to look at you like you're asking to buy a Geiger Counter, or directions to the local satellite launch pad.

Sorry, I don't have 150 dollars to spend on a unique article that is less reliable than 3 five dollar Bosch-type relays, 12 or so .250" faston connectors and maybe a foot or so of 16 gauge wire. Now if the load was serious, say above 30 amperes, that's a horse or a different color.

Most of the electrical issues I read in this Tech forum involve items that are far and away too complicated and unique for the job they do. Read susceptible, vulnerable, and expensive. Throw in a bucket load of "A Pain In The Ass To Replace" and you have a loaded 12-gauge with a quarter ounce pull trigger aimed right at your vacation, your piece of mind and possibly a good chunk of your sanity.

Just Sayin'

I like your posts Mexico, but I can't quite figure this one out. Are you saying that a simple latching relay is a "cerebral doo-dad" that's likely to fail in the boonies, or are you saying that the Intellitec circuit with it's solid state FET and transistorized switching circuit is the "cerebral doo-dad"?

Personally, I consider the Intellitec to be the complicated device that's likely to fail from transients and spikes. I've fixed enough solid state devices to know that good old 1960's tech relays are incredibly reliable as compared to the save-a-buck circuit designs I'm likely to find in most modern fancy devices that don't spend the extra buck to use decent components.

The link I posted above to that latching relay is as simple as you can imagine. The solenoid pulls in and the microswitch changes state. You can even manually press down on the solenoid rod to change state on to off. I'll probably also wire the main water pump switch so it bypasses the relay switch for emergency use. When the pump is on using the solenoid or main switch, it will light the "pump on" light on my main panel. If the main power switch is turned on, the pump is on regardless of the latching relay. If it's off, the pump can be switched with the remotes, or turned off by pulling the fuse. I'll never be in a situation where a failure of this system interferes with the water pump.
DryCamper11
Explorer
Oct 01, 2013
wnjj wrote:
Are there any in that list at Digikey I posted that will work? Many are only $7 - $8.

Thanks for posting again. I would eventually have gotten around to digikey. It's where I buy many active components (I bought a $6 IGBT that fixed a $200 voltage regulator in my Onan a few months ago). The little digikey link on your post somehow escaped my notice. it helps to pay attention. The best unit I saw was by filtering to "impulse" type relay. This one looked good: Click here. At $48, it's a bit more than I want to spend, but it's exactly what I'm looking for. You can see it's a solenoid with a toggle/ratchet on a microswitch:

I'll keep looking, but at least that's the best option so far. Thanks again.
MEXICOWANDERER
Explorer
Oct 01, 2013
Better keep in mind that a water pump manufactures more spikes than a blackberry bush. It's the nature of the beast. Inductive reaction. It won't hurt the contacts in a power control circuit, but it can ("can" is not strong enough) play havoc with control circuits. When that pump shuts off under a 15 amp load, WOW!

I'll short circuit the inevitable "Oh, there's a switch!"

It's the NEGATIVE oriented transients I worry about. Where's *that* switch? Ain't one.
wnjj
Explorer II
Oct 01, 2013
DryCamper11 wrote:
Tom_M wrote:
Another type of latching relay uses a single coil and magnet. The first pulse pulls the contacts in and the magnet holds them in place. To release the contacts you pulse the coil with a reversed polarity pulse.

Yes, I've seen that type also. There are also some latching designs that have a small circuit inside to simulate ratchet type. They pulse on, pulse off, but need power all the time to hold on. One relay I found also has a mechanical button on top to mechanically operate the ratchet inside and switch it on/off. I looked up the Potter Brumfield relay I have in my scrap box just to see if there was a similar 12V version. (The one I considered rewinding). The replacement cost for that double relay was $150!

Are there any in that list at Digikey I posted that will work? Many are only $7 - $8.
MEXICOWANDERER
Explorer
Oct 01, 2013
It ain't just the cost.

Crap doesn't fail until you are 88 miles north of Eastjesus. All expanded and set up. Comfortable. Your one and only vacation...

THEN your truly cerebral doo-dad decides to stick it's middle finger in the air.

And guess what? That doo-dad whether you know it or not controls the most vital object in your better-half's RV lifestyle.

"Welcome to heaven here's your harp. Welcome to hell here's your accordion" time...

Gotta great sofa? You're gonna need it.

Simplicity. How to manage breakdowns. I happened to choose the PhD level of learning location. Ask for a "latching relay" and they're going to look at you like you're asking to buy a Geiger Counter, or directions to the local satellite launch pad.

Sorry, I don't have 150 dollars to spend on a unique article that is less reliable than 3 five dollar Bosch-type relays, 12 or so .250" faston connectors and maybe a foot or so of 16 gauge wire. Now if the load was serious, say above 30 amperes, that's a horse or a different color.

Most of the electrical issues I read in this Tech forum involve items that are far and away too complicated and unique for the job they do. Read susceptible, vulnerable, and expensive. Throw in a bucket load of "A Pain In The Ass To Replace" and you have a loaded 12-gauge with a quarter ounce pull trigger aimed right at your vacation, your piece of mind and possibly a good chunk of your sanity.

Just Sayin'

Forum Discussion

Remote water pump switch - latching relay?

27 Replies

About Technical Issues

Related Content

The batteries killed my Happijac remote

Autimatic Transfer Switch?

Automatic Transfer Switch (ATS)

Remote Fridge Cutoff Switch

Suburban SW12DEL Water Heater On/OFF switch melts???