deathrunner

Alright, I did search, but couldn't find quite what I am looking for.

Basically I would like to know when it is appropriate to use a fuse, realy, or fuse and relay.

I want to completely rewire all of my auxilary components to a second fuse block. I want ti to be safe and avoid fires....of course.

I am just confused because some items like air horns and offorad lights use a relay, and some offroad lights and stereo components don't.

Here is a list of what I plan to hook up to my fuse block. If you guys don't mind, I would appreciate suggestions of relay, fuse, or both for each item. Also an explanation of why would be nice so I could figure this out for myself in the future. So here is what I've got:

-Alarm
-CB
-75 watt subwoofer
-two 55 watt pro comp 6" lights
-One Tractor light
-two small interior lights
-Superflow Air compressor (Kragen special)

Also where would be a good place to find a 8-10 fuse block?

Thanks in advance, Spongebob Sethpants

arjan

A fuse for each item, relay for pro comp lights, tractor light, and air compressor.

deathrunner

Cool, now do those items get a relay just beause of teh amperage that they draw?

Cebby

Yes.

Cebby

The subwoofer (if powered) should have it's own power lead from the battery with a fuse.

www.12voltguy.com for the fuse holders. 12voltguy is a wheeler and a member of this board (goes by Seabass)

Bob_98SR5

deathrunner,

whatever accessory you are powering, ALWAYS use a fuse. there are two types of fuses that are common w/ accessories like you mentioned. In-line and ones that are contained within a fuse block. in-line is exactly what it sounds like. they are part of the actual line going from your power source (usually your battery's pos terminal) to your actual device.

relays are good for switched accessories. lights are the most common switched accessory b/c you dont want them on all the time.

where would you use both or all three? in my case, i installed some hella driving lights. the supplied wire came with an in-line fuse which was then routed to the relay. then the switch itself had a powered 12v connection to it. sounds confusing but take a look at the diagram in my writeup.

looking at your list of things you want to wire up, here's what i would recommend:

1) wire up a 6, 8 or 10 port fuse block. there must be an in-line fuse protecting it within 12" of the positive battery terminal.

2) you can wire up your CB, pro comp lights, tractor light, interior light, and depending on the wattage, the air compressor. the air compressor though, sounds like it might carry a big load and might be better to attach directly to the battery

of the above mentioned devices, the lights will definitely need to be relay'd because they are switched devices. the CB i would leave full-time powered as i like to sometimes turn off my 4runner on the trail but still use the cb

now the alarm and the amp are definitely not candidates for hooking up to your fuse box. the alarm is a different beast altogether. we can talk about that in SD on the trip. and for the amp, it would be best to consider this its own "system" and thus, power it directly from the battery using an appropriately sized cable for 75w (whatever that is, not sure w/o consulting a chart) and of course, an inline fuse

references:
www.crutchfield
www.the12volt.com
www.howthingswork.com

places to buy:
www.waytekwire.com for specialty stuff
I like Buss fuses and their fuse box, so i bought mine from Kragen
Radio Shack for wire/cable and connectors
Home Depot has connectors for the wires

my own writeups dealing with some of your planned items:
http://www.4runners.org/articles/cobra/index2.html
http://www.4runners.org/articles/dist/
http://www.4runners.org/articles/12v/ (adding a 2nd full-time cig lighter)
http://www.4runners.org/articles/hella500

I'm 99% sure i'll make it to SD on the Nov 12th weekend, so i can show all of this to you in person, including the alarm install.

Bob

deathrunner

I have most of these items installed already with an inline fuse. I am just getting sick of the cluttered battery terminals. I was hoping to put as much into teh fuse block as possible and basically running one thick wire (4 gauge?) from teh battery to the block.

What size fuse should I put on teh way to the fuse block?

I guess the alarm and sub can still go to the battery, and the Air compressor I guess makes sens going straight to the battery. I would jsut like to keep as much as possible in the fuse block to clear the clutter.

So, what is the difference between the sub straight from the battery with an inline fuse and the sub running through the fuse block? To me, it just seems like it is just in a different physical location.

Bob_98SR5

regarding cable thickness, depends on how much of a load you pla to carry at any one time. meaning, do you ever intend to turn on EVERYTHING at one time? but given the devices you could hook up to a fuse block, i dont think you will draw enough of a load to overload, say, an 10 gauge wire w/ a 30 amp fuse

to determine what wire gauge you need, try googling or ask.com "what wire gauge do i need?"

the alarm will not be powered to the battery's positive perminal. i'll show you in SD.

powering the sub from the fuse block (the same one we are talking about powering your 12v devices) is not a great solutoin, given the load that the amp will draw from it with your other devices attached to it. as ive learned (im still a novice), its best to power your sub directly from the battery and not from fuse blocks, though im sure this will be a source of debate for many.

now in principal though, it is the same in this respect: your amp is being protected by a fuse. two in the case of using a the fuse block. but again, power it straight from the battery and everything will be o'tay!

bob

4Crawler

iTrader: (3)

I run a 6-fuse block off my battery:
- http://www.4crawler.com/4x4/CheapTri...werPoint.shtml

Using about 5 fuses now. I added relays to power my high and low beams, fog and rock lights. Also have a relay on my air compressor:
- http://www.4crawler.com/4x4/CheapTri...r.shtml#Wiring

I pretty much add a relay for anything over a few amps of draw or things I want to have triggered off of other signals. Basically you want the relay up close to the load (keeps the heavy wiring run short for mimimum voltage drop) and then run small gauge wires back from the relay coil to your switch to turn it on or off. On my fog and rock lights, the relay coils get power from the parking light circuit, so if I turn off the main light switch, those lights go off automatically. With the main lights on, I can use the switches to turn the fog/rock lights on and off independently.

I'll be replacing most of my individual relays with a 6-relay RF-controntrolled block from Painless Wiring. It allows the 6 relays to be controlled from a steering wheel-mounted switch module or from a wireless key fob. I'll be hooking my lights to that as well as the winch in and out control.

deathrunner

Hopefully my rig will be ready by the 12th I'm really curious to see what you have toi show me.

Alright so, sub to the battery, compressor to the battery.

Alarm- super secret

CB, interior lights, front and rear lights into the block with exterior lights having relays post block.

I think I'm getting it.

deathrunner

Ok 4crawler got me thinking.

With respect to relayed devices. Say my 55watt lights. From the battery I have a fuse, then the relay. They on the other end of the relay is the switch. Do I need a nother fuse before the switch? That would make sense to me.

Since I plan to have 3 relayed devices and also thier 3 switches (front lights, rear lights, air compressor), coudl I feed all three of the switches from one fuse in my fuse block? Seems like thye would all have very little draw and I could combine them on 1 fuse.

garrett1478

i think thats okay, thats what corey says he does in his tech-write up, bc the switches only need enough power to trigger the relays.

side question - so you're supposed to have an inline fuse from the battery to fuse box even though the 6 ports are fused? eek, i better go do that...

Bob_98SR5

dr,

you really need to read my writeup. the hella500 one. take a look at the two diagrams. depends on how you want to wire it. diagram 2 is probably what is most common amongst people here wanting full time, switched lighting

in between the relay and your actual switch, no, you don't need a fuse. again, see the diagrams in my writeup. i actually re-drew them from the crappy hella supplied directions. my version is crystal clear and legible!

as far as having all three switches wires to a single fuse port, i am 99% sure the answer would be "no" because the state of the circuit must be either closed or open. having three switches and turning them on and off independently would close or open them in a manner that would make it very confusing. for example, if you turned one light on, turned a second light on, but then decide to turn off the first light, the circuit would be "open" and then it would turn off your 2nd light. someone please check my logic on this, but im pretty confident that this is correct.

and about running a fuse between the pos battery terminal and the fuse block or other high load bearing device, it is always a good idea to run a fuse a short distance (w/n 12" of the pos battery terminal). if the load is too great, it can burn that wire all the way to the device. better to let the fuse bust and if the wire burns, its only burning a very short segment inside the engine bay and not your interior.

bob

bob

Gangus2006

For the For the switches used to control my relays, I have all 4 switches tied together, and I used a Mini Add-A-Circuit into the TURN fuse (You use any fuse thats convenient), and for that Circuit, I use a 3A Fuse. Thats right, 3A for 4 LED Switches, and 4 Relays.

Gangus2006

Bob,

I believe he was refering to tieing the +12 prongs of the 3 switches together (have them come fromt he same source.)

deathrunner

Yes, I meant the wire from the source to the switches for the relay. It seems to me that it should be ok to have them all feed from one fuse in the block. The only negative is that if one blows the fuse, they are all inoperative,but I can deal with that.

I think I will be getting one of these:



Where is a good place to find relays? I had 2 that would stay stuck on. Is this because they were cheap or do relays do that sometimes?

Gangus2006

Yes, its ok to use a single fuse for them (as I said in my post).

You can get relays at any auto parts store, or Radio Shack. 90% of the Relays sold out there are the Bosch style relays, with 4 or 5 pins.

I have had a couple relays get stuck on me (drained the battery during a 4 hour work shift), but htey were exactly like the other one's I was using. I think its just a hit/miss thing.

deathrunner

I bought the 6 lug block pictured above from 12voltguy....gotta support our own. What are the two bolts for? I assume I attach the hot lead to one, but what are all the male blades doing by the lower bolt? They wouldn't be fused....wierd

Gangus2006

Im assuming its done that way so you have the choice of inputs styles (ring or fem-slide), and the option to have circuits NOT fused.

Gangus2006

OK, never mind. The top bolt (closer to the fuses) are for power, you hook that side to the battery. The other bolt (the one wiht the spades directly on it) is for grounding. Use a short wire to ground that lug, and ground whatever you need to those spades.