Can I wire a relay like this?

[Konstantin 10+ year member]

Hello, I am going to add a 3rd amp to my install, plus I wanted to add a few fans to keep all of them cool. After reading and searching I noticed that I will need a relay.



I have a run of 1/0 wire going to a 3 way distro block, from which I want to use 2 outputs to run 4awg wire to 2 amps, and the other output will be 1/0 going into another fused distro block (2 way), which will have 1 output of 4awg going to the 3rd amp, and the second output going to a relay. Then I'd just ground the relay somewhere close where I have the amps grounded. Will this work?

Or how do I wire the relay? I'd like not to run another wire from the battery, but I will if I have to. This options means that I would have to run another wire from the battery to the relay, and back from the relay to the battery? I'd have to add an inline fuse right?

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[IDSkoT 5,000+ posts]

Umm... finding a 1/0 AWG with 2-4AWG and 1-1/0 AWG is gunna be next to impossible... and costly.

Here's a post from headless, it's a really good write-up.

Yes, you can and it'll help. I would not take off the heatsink, though - it is very efficient at removing heat from the internals of the amplifier. Cool the heatsink, it will cool the internals //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
I'm in a similar situation as you, and am in Florida, where trunk temps over 100f are normal all summer long. I have an old RF Punch 100DSM that i'm running a dual 2 ohm (wired to 1 ohm) bridged on....obviously well under the 4ohm bridged they rate the 100 for. It's never actually cut out though //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif But it got hot enough to fry eggs on (too hot to keep a finger on) and my 4150XXK amp pushing my fronts did cut out due to overheating on a couple of occasions...so i put a fan in between the 2 amps, pulling air off of one and over the other. It made a huge difference.

A computer fan is likely going to be pretty low current; but still, don't run it off of your remote wire directly. Your deck remote wire is only rated for extremely low amounts of current - just enough to turn on a few devices. You don't wanna fry your poor remote wire. You need to buy a relay and wire your remote wire to it, then wire your amps and fan to the relay's output - that way your deck's remote wire only needs enough current to turn on that relay.

Also, you can go up to radio shack and buy a 100mm cooling fan that spins considerably faster and pushes much more air than a 120mm computer fan....since your relay will likely be rated at something sick like 40amps at 12v, you won't need to worry about how many fans or of what type you put into your car.

A relay is basically a little box that has 3 inputs and 1 output. input 1 is it's remote/'turn on' input. It pulls a very small amount of current so can be turned on by small devices like your deck's remote wire. The next input is a 12volt power input - you'll wire some 12ga wire directly to it from your battery, or from your rear distribution +12v block. The next input is a standard ground - you'll wire a 12ga wire from the chassis of the car or from your rear distribution block or directly from your battery to that also. The last terminal on the relay is the +12V power output - you will run wire from this terminal to your amplifier's remote +turn on posts, and from this to your +12v power wire on your fan. When the relay gets 12v from your deck's remote wire on it's 'turn on' terminal, the charge from it makes it internally connect the +12v input you hooked up and the '+12v output' post that all your amps remote wires and your +12v power for your fan is wired to. Thus, the relay provides the +12v to those devices rather than your deck.

My solution was to re-wire my remote wire from the deck to the 'turn on' terminal of a relay (which they also sell at radio shack)...run 12ga power from my rear battery to the +12v terminal on the relay, then run a 12ga ground from the rear battery to the ground terminal of the relay. Last of all, i hooked up the remote wires for both amps and my fan to the 12v output of the relay. Now, the deck only needs to provide enough current on the remote wire to turn on the relay - the amps and the fan get a dedicated 12ga 12v power feed from the rear battery. The fans you will get at radio shack are louder than computer fans by a good bit...but you can't hear them in the trunk with the seats up like normal, and just one of them brought the temperatures on my amps WAY down. The 4150XXK hasn't cut out due to overheating since, even with 4 hour road trips at high volumes, and they stay barely warm to the touch UNLESS the trunk is extremely hot during the middle of the day....in which case they do still get hot...but not as hot as before.

Here's the relay you need:

http://www.radioshack.com/product/index.jsp?productId=3020762&cp=&sr=1&kw=12vdc+relay&origkw=12vdc+relay&parentPage=search

here's the fan you need

http://www.radioshack.com/product/index.jsp?productId=2102823&cp=&sr=1&kw=cooling+fan&numProdsPerPage=100&y=0&x=9&pg=1&origkw=cooling+fan&retainProdsInSession=1&parentPage=search

Cliffnotes:

Run the turn-on wire from relay to the remote wire from your amps

Run the 12v+ wire from the relay to your amp's +

Ground it.

Output goes to fan's 12v+ wire

(I assume you have to ground the fan, as well.)

 

[Konstantin 10+ year member]

I currently have a 1/0 -> 2 4awg block, and will be buying one 1/0 - 2 4awg + 1 1/0.

 

[Mike465 10+ year member]

Well you could do it the easy way and wire the wire the fans in with the amp remote turn on, so every time the amps turn on the fan(s) turn on as well. If the fan is a three wire fan (power, switched, and ground) then wire them stiaght to your amp. If it is a two wire fan(power and ground) then wire it to your amp as well. Also stinger makes an amp temp guage that you can wire up to your amps and when it reads a certian temp it will cut the fans on

 

[Konstantin 10+ year member]

So far I am inclined more to run the power wire from the distro block to the relay using 8awg, and ground the relay close to where I have my amps grounded.

I just want to know if this will be ok or not.

 

[Horsemanwill 10+ year member]

you could do it that way since it seems that all your really wanting to do is put the relay on a fuse.

 

[Konstantin 10+ year member]

Actually I just dont want to do another run of wire from the battery all the way back to the trunk to hook up the relay. Since I will have to order the new distro block and I already have this one, I thought I'd just use them all and power the relay using the second distro block.

I just wanted to be sure that it would work.

Edit: do I have to ground the fans also? Or can I just wire the power wire and thats all? I know fans have either 2-3-4 wires, but if I already have the relay grounded, do I just wire the fan's red wire to power it and nothing else?

 

[Atimm693 10+ year member]

The fans will have to be grounded to the car.

It will work.

 

[Konstantin 10+ year member]

Ok thanks. Another dumb question about the grounds: can I wire together all the grounds of all the fans (say, 6), and then just make one big ground for all of them? Or is it a bad idea and I should ground each on their own?

 

[budget76 10+ year member]

Ok thanks. Another dumb question about the grounds: can I wire together all the grounds of all the fans (say, 6), and then just make one big ground for all of them? Or is it a bad idea and I should ground each on their own?

yes you can. Just use a larger guage wire as the "extension" than the fan wires. IE if they are 16ga, use 12 or 10ga as the one that gets grounded to the chassis.

Relay: you can get your power anywhere, just needs to be 12v, and you can ground all in one GOOD grounding location. I did this in my truck. Had 1/0 to the a 1/0-2 4ga distro, then a 4ga to the amp, another to a distro that was 4ga-2 8ga, one 8ga to my speaker amp, a small like 12ga to the relay. Grounds were all the same bolt bolted to the chassis.

oh yeah, relays can typically take like 25 amps max each, so depending on the fans, you may need more than one. They come from the factory typically with I believe 12ga leads, so the 8ga to the relay will be useless. They can't take that much juice anyway.

 

[Konstantin 10+ year member]

Ok then, I'll have to attach a 12awg cable to the 8awg output of the distro block, since it uses fittings I dont think it will be too hard.

Computer fans use like 1amp I believe, so one relay should be enough.

Now to order and wait a few weeks for the stuff to arrive here.

 

[Konstantin 10+ year member]

I got yet another dump question: can I mix 2 different speaker wire gauge sizes? This is because I am wiring everything with 16awg speaker cable, but the rear speakers that I bought have wires soldered directly to the crossover and I dont want to touch that, and I am not sure what gauge they are (LOOKS like 16awg, but could be 18awg as well, or maybe 14).

Can I just connect a 16 -> 18, or 16 -> 14 and similar? Or is it a bad idea? RMS per channel would be max 200, 250 at most.

And another question I have about the fans: I am going to build a fake floor box kinda thing to house the 3 amps and 4 crossovers, plus the distro blocks and the relay, and I was planning on adding 6 fans, 3 ******* in and 3 ******* out (overkill maybe, but the cooler the inside of the box the better), and I will be putting the subwoofer box on top of it. Will it affect the fans? Maybe the magnetic field caused by the sub's magnet will cause harm, or the constant fierce vibrations will screm them up?

 

[edzy 10+ year member]

Yes,

No,

No,

 

[DidUHearThat? 10+ year member]

You can attach the fans positive and ground connections onto small terminal strips or just twist them all together. Or you could add a small gauge fuse/distro for your low power needs (8 ga in, multiple 16 ga outs), that would leave you with more wiring options if you want to add neons or other crap.

Computer fans tend to run very clean and shouldn't create any noise if they are grounded correctly.

 

[Konstantin 10+ year member]

Yes, No,

No,

Excellent. I've searched for an explanation but cant seem to find a decent page to learn about how this works. I just want to know why I can add different size awg wires together. I guess since there wont be that much power going through them and the length of the run would be less then 10ft its ok.