Latching Relay or simpler solution

I’m finishing up the wiring on my hot rod project, and have installed a remote master battery disconnect solenoid switch (American Autowire #500834) in the positive battery cable. The solenoid can be actuated by either a negative ground pulse from a remote entry system, or by using a momentary pushbutton switch to ground that latches the solenoid either on or off.

Since I have some accessories that have memory circuits which need to be powered at all times, I’ve decided to install an American Autowire "Lifeline" retained memory jumper across the solenoid terminals. It's a resettable circuit breaker that will only flow 4 amps maximum, but will be enough to keep all of the memory circuits working.

I would like to have a visual confirmation of when the solenoid is latched or unlatched, but with the jumper installed, all of the circuits will always show power. My thought is to have a latching relay that could be triggered with the same pushbutton switch as the solenoid and synchronized with it so that it will power an indicator light when the solenoid is in the “on” latched position. If the light is off, the solenoid is unlatched, and I only have power for memory circuits; if the light is on, then the solenoid is latched and I’m good to start the vehicle. The thought here is that if I go to start the vehicle and the solenoid isn’t latched on, the breaker in the Lifeline will trip, which may wipe out all of the retained memory settings. Maybe not a big deal for the radio presets, but the fuel injection ECU settings may be lost.

I've read a lot of posts on latching relays, and have studied the relay diagrams of this site, but I don't want to install 3, 4, or 5 relays just to light a bulb. I understand that Omron makes plenty of latching relays but I'm unclear if these relays require two switches to make/break the connection or if only one momentary ground signal (from the same switch) will work.

If the latching relay is in sync with the solenoid relay, then I should have a way to monitor the solenoid's status.

If anyone can point me to a part # (and how to wire it up) or have a simpler way of doing what I want to do, I'd appreciate any help.

Thanks...


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I just answered another post with this but you may not need 10 amps!

OMRON ELECTRONIC COMPONENTS G6CU-1117P-US 12DC RELAY, LATCH, SPST-NO, 10A, 12V
£6.00 UK, $9.00 US, 10 amp latch.

If you go to Farnell US, enter latching power relays, 12V coil, it will give you other cheaper samples. BTW cutting POS is IMO dangerous, you should cut NEG.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Howie,
Thanks for the information. I found that relay on Farnell, only $6.03, which is great. I'm looking at the Omron data sheet, and want to make sure I'm wiring this up correctly. In other words, I want to equate the Omron terminals 1, 8, 3,& 4 to the automotive style relay terminals 85, 86, 87, & 30....Looks like terminal 1=86, 8=85, 3=30, and 4=87?
In my case, the momentary ground from the pushbutton that also actuates the solenoid latch would connect to terminal #8, +12v from battery would connect to terminals 1 & 3, and terminal 4 would be connected to one side if indicator light with the other side of the light to ground? I hope I got this right, thanks again for your help.
Steve

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Sorry that's all on the data sheets, I didn't look!

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Yes just looked you're quite correct.
Please note the coil is polarised so 1 = 85, or NEG (-) side to coil.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Hi,
That Omron relay requires the polarity to be reversed to the coil for unlatch/reset. The American Autowire unit is similar to a Cole-Hersee unit that latches and unlatches with the same polarity signal. Without additional circuitry, the Omron piece won't be usable. This piece should work (operates the same per description listed) https://www.goldmine-elec-products.com/prodinfo.asp?number=G20876
Mark

That's correct, the American Autowire solenoid is a Cole-Hersee unit that works off the same ground signal, and I'll need the same type latching relay. I'll take a look at that goldmine website. Thanks for the help....

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Mark, not sure what you're getting at, with the Omron unit you can feed either a pos or a neg or use similar with DPST, I would have thought therefore more versatile.
PS, if you're one of mine, Happy New Year.


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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

The disconnect solenoid requires a single pulse, negative in this case, to latch and unlatch. This pulse is provided by the pushbutton or the remote entry system. To use the Omron relay, the negative pulse would need to supply reversing polarities at the coil to latch and unlatch. One other consideration is the remote entry's output, how much current is available?

OK ta.


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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

If I use the remote entry, it will provide a 500 milliamp momentary ground pulse. I would use it with a diode protected relay, the same as for the door and trunk locks.

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I would test the solenoid for current draw. May need to boost the output of the remote entry system, either by transistor or another relay.

I think I'll go with a relay according to the "Weak Negative Output to Strong Ground Output" diagram....It will provide a degree of separation between the sensitive electronics of the remote entry and the larger current draw of the solenoid relay....

Thanks for your help, much appreciated.

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If you do that diode your relay across the coil, 1N4004, band side to coil +.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.