My Roof rack lighting issues.

[Dano!]

How you guys doing,
i have a few questions and i will try and explain where i am at in my wiring. i have been taking plenty of pictures and plan on doing a write up on everything i did. i just need to figure some last things out.

My plan started out as putting 6 100w lights on my roof rack, with one relay/switch per 2 lights. i was going to use in line fuses..

Then i found Tbars "how to aux/offroad lights" sticky with Dannyboy's "secondary fuse panel" thread.

I purchased the 12 fuse panel from west marine, unfortunately i purchased the wrong size wire (8g)

I already have..
switch panel
fuse panel
Relays
12g - 16g wire spools
fuses
lights (of course)

My question is, after reading my switch panel wiring diagram it says that each switch can handle a maximum of 15 amp ea.

how much amperage does the switch handle to turn the relay over? will i fry the switch?

My understanding is that i need a 4g - 6.g wire from the positive on the battery,-->

Which has to have a fuse before getting to the fuse panel. -->

From the fuse panel to the relay -->

Relay will also have a ground / switch / and out going wires. (to lights)-->

Ground can go back to fuse panel which goes back to the battery? or to the frame? either.

i am not sure yet as to where and how to get the switch wired to something to make it functional. (where the switches are powered only when the truck is on.) and how many amps the switch will have to handle.

Should i use 14g or 16g for the switch wiring?

Beyond that i think i have everything in order. am i forgetting anything?

Thank you,

-Dano

 

[Dano!]

Found on another forum, posted by a man named Jim

==
I just bench checked a relay and got the following results:

Tyco Relay VF4/45F11 12VDC 40/30A

To energize the coil to make contact 30 connect with 87 it took a minimum of 6.6 volts with 0.08A to make it "click" closed.

At 10.0 volts the current draw went to 0.11A
At 12.0 volts the current draw went to 0.13A
At 13.0 volts the current draw went to 0.14A
and at 14 volts the current needed was 0.15A

Any switch rated at 1A or higher can switch two of these relays on or off with room to spare.

Always size your wire and it's length to the current demands.

Jim
==

It may sound like i am nuking some stuff, and i am. i have never done anything like this before and its kind of scary for me.

 

[FIND]

Here is a good chart to find the size of wire you need for many applications. Amps on a DC circuit are found by dividing watts by volts. Since your car runs between 12.6 and 14.3 volts, it is safe to make your assumptions on a 12 volt system. Therefore, for each 100 watt light, there is an 8 amp draw. Your relays are more than sufficient to run a pair of lights each. Since your stretch from your battery to your distribution block is probably under 8 feet, you will more than likely be safe running 8 gauge wire, but 6 gauge is a safer bet, considering you might not be buying pure copper wire, and you want a little more leeway for heat or fuses that may be slow to blow. You will want a 60 amp fuse protecting this wire at the battery (note, all 6 of your lights together will draw a little under 50 amps, since the 12 volt system in a car is actually running at 12.6-13.6 volts). For each pair of lights, you should be fine using 12-4 gauge wire depending on how far your run of wire is, and protecting the wires with a 20 amp fuse. Remember, fuses are made to protect the wires from burning, not to protect the things on the ends of the wires.

Moving along to your main question. To switch your relays on, VERY little current is necessary. You can switch your relays using small wires and the switches themselves won't be much of a consideration for you either. But, now it appears to me that you have those numbers, and he is right, even on an older worn out relay, it should never take more than a 200 mA current to energize the coil and switch the relay. So, to put that into context for you, pretty much any automotive switch you can buy and 16-18 gauge wire will be MORE than enough to switch your relays.

 

[mr_valingo]

And for the grounds, keep em as short as possible and run em all straight to chassis.

 

[FIND]

And for the grounds, keep em as short as possible and run em all straight to chassis.

This man speaks the truth!

Also, with the additional electric load, you may want to consider upgrading your alternator, and upgrading your battery wires and ground wires, especially your chassis to battery grounds.

 

[Dano!]

Thank you guys.

FIND,
That chart helped a lot and i know i will go back to it when i tackle the audio in the truck later down the road. it will be invaluable. thanks. i will go ahead and get the 4g - 6g wire as you suggested so i can leave room for further upgrades to draw power from. i will have to wait until my next payday for the wire and 60a fuse.
i will do some rough math and figure what amperage i will be drawing after some additional lights ( grill guard ) and pick a fuse up to handle that for later on.

I purchased a high output alternator from another forum member, but i had not thought about upgrading the ground wires from the chassis to the battery. i read some more posts and figured i should upgrade the alternator wires as well. ( seek out the weak link )

Another question. in regards to the high output alternator i have, there are no markings on it and i don't know what it is rated for, can i take it somewhere to have it run up and figure out what its rating might be?

i just want to get this all done and nice the first time. i appreciate all the info.

while i am waiting for payday i am getting everything in its place and wiring most of everything up so i just need put the thicker gauge wire and fuse and splice my switches and i would be good to go.

mr valingo,
Thank you, i will make sure run the ground to the chassis, is there any area in particular you could point me to? or just find an area with a ground already there and add to it?

Thanks again.

-Dano

 

[Dano!]

Another question.
With the Blue sea fuse box, can i run 1 wire from the fuse box to provide power to all my switches instead of splicing them into a hot wire?


Battery ==> Fuse ==> Fuse box ==> 5a Fuse ==> 12g wire with all 5 switches connected to it.

Will this work?

-Dano

 

[FIND]

I'm a little confused. Why aren't you just coming off the battery to your 5 amp fuse into your switches? I'm assuming your switches just switch the relays, so that is fine, but yeah? Are you looking for a switched power wire? FWIW, it is fine, but normally I would say to get your own power from the battery so you don't ever have to worry about putting too much load on the fuse panel. Remember, the panel and existing wiring is designed to operate on the load that is already on it. Granted, you aren't going to be adding much of a load to it by adding some switches and relays, but, just saying. Best practices and all.

On to another issue, since I'm not sure if you are asking this. In a DC circuit, electricity flows only one direction, and comes from only one source. 5 wires leading to 5 switches from one battery to one ground is exactly the same as 1 wire spliced to 5 switches and back to one ground. No matter what, you are starting and ending in one place. It just depends on when you split your circuit. Look at your fuse panel, you notice Ford ran a single wire to provide power for all the devices powered by fuses on it? All the other wires are wires to switches, relays or the end devices.

 

[Dano!]

I understand what you are saying Find.
You answered my question though. I always viewed direct current like water, it will flow in the path with the least resistance, but i haven't had to splice one power wire into five seperate wires before. I guess i could have rephrased the question. My concern was weather or not all 5 switches would get enough power.
My goal is to keep all my wiring in one spot. (Inside an ammo can under the hood.) I will already have a heavy Gage wire going to my secondary fuse block. My idea is to power my switches through that fuse block, along with the auxiliary lights. I am OCD when it comes to messy wires. My goal is to keep as many wires off my battery as possible.

Thanks again Find.

-Dano

 

[Dano!]

Finally got my interior panels off and my headliner off. but i broke my sun roof clips while taking off the sunroof.. minor set back. ill be driving without a sun roof for a few days.

Boo!

 

[Dano!]

My original post was to say i needed to upgrade the wiring i was using, i based this on only one wire gauge chart, but after looking up the one referanced in this thread and blue sea systems wire gauge chart along with Tbars link to wiring FAQS i determined i have more than enough room to work with the 12g wire i am using.

 

[Dano!]

Ohh my good lord,

All day, i have been trying to solder this cannon plug all freaking day. I thought i was on the money when i wired one side rather quickly. But I've been stuck on the same wire for hours, for whatever reason this solder wont stick to the pin.

I can solder, I've done it for a while, i got this plug from keep it clean wiring and its a pain.

End rant.