Using one relay to trigger multiple relays

[DizzleDizzle]

Is it possible to use a single relay triggered from a 12v ignition source, and have that relay trigger multiple other relays or would it be better to have the 12v wire trigger all the relays separately.

I don't have many ignition switched wires I can use as triggers and don't want to overload a single circuit that will be used as a trigger for relays. Hope this makes sense. 

[Joe X]

It is possible but you don't need a relay for every amp, just need the the turn on signal to control a relay and use your systems 12V to turn on all the amps. There are little modules, very cheap that can make that possible, Not sure if there is a ready made product to do that but I don't think there is.

[DizzleDizzle]

So the other relays will be for air ride compressors shaved door solenoids, electric fans etc. I was also considering using a relay for the head unit since I only have the one switched ignition wire. Then use head units remote wire to trigger another relay which will take care of turning on the 4 amps. 

 

I think what I'll do for now is use the switched power from the AC controls to power head unit and track down additional switched wires for the rest as I go so I don't overload any one circuit.

 

The truck has some funky stuff going on in the wiring it was a show truck and it has been completely rewired in the past. It has a custom dash custom gauge cluster relocated radio and AC controls and alot of the original wiring has been done away with or rewired. It's kind of a nightmare but only because I don't know what's what yet. 

[Joe X]

To answer your question, you definitely can do what you are planning, one relay can turn other relays. No Problem.

 

With that out of the way, relays can't protect a circuit from overload, they are just on/off devices. You could install switches instead to decide what systems you want on or off until you figure out what issues your electrical have.

 

As for amps, it has been proven that the relay itself can take up more current than many amps connected together, you can take a look:

 

I am just sourcing you some extra infos you may be interested in.

 

 

 

[DizzleDizzle]

Thanks I will watch the video in a moment. So the power in this case will be direct from the battery going into a fuses distribution block them into relays so I'm not worried about overloading on that end I'm more worried about overloading a "trigger" circuit. So if my understanding is correct which it may not be, then the the circuit I'm worried about overloading only need to send a small amount of amperage to the relays to trigger them into coming on. 

 

So in my mind if I use a switched 12 volt circuit to trigger a single relay and then that relay triggers multiple other relays it should protect my trigger circuit from overloading. In the same way that a remote wire will trigger a relay that will trigger amplifiers to come on while keeping the remote wire from being overloaded like it would if you just daisy chained it to multiple amplifiers. 

Does this sound correct?

 

Also thanks for answering my question Joe appreciate it. 

 

[Joe X]

Yes, a trigger circuit will require less current to turn on a single relay than what would be needed to turn on multiple relays, no problems there.

 

One would ask if those loads will need an individual relay each if they are to be all turned on and off at the same time and not individually.

 

What you will learn in the video is that most of the times the head unit turn on line will have a harder time turning on a single relay than it would have turning on multiple amps, sure enough it would not be the case if you were turning on something else rather than amps.

 

In any case as I told you before what you are trying to do will work as you plan, I am just asking to myself if you need to do all that in order to get the same result or not but either way it will work and you need not to be concerned that something will go wrong. It will not.

[EricM9104]

You could also just splice the trigger wire at the original relay and have that feed the trigger terminal (jumped from 1st to last) on the rest of the relays, provided their in the same relative location.