I currently have this fuse box installed in my truck.



Its a nice box and all but because I did the headlight relay conversion on my truck and I also have two Apollo KC driving lights I currently have 3 relays bolted under my hood and want to clean it up when I redo my wiring while my engine is out.

https://www.ebay.com/itm/12-Way-Rela...f1d02bf95061fa

I found this 12 way relay box which has 6 fuses, 5 bosh style 5 pin relays and 1 4 pin relay. I don't need the 4 pin relay so that will be left empty. The 5 bosh style relays I could use, I am at 3 relays currently and I might be adding a fourth one for my electric choke. The 6 fuses are a bit on the close side as I have currently one 30A fuse for my headlight circuit, one 30A fuse for my driving lights, one 5A fuse for my CB, and one 15A fuse for my CB amplifier. That just leaves me two fuses for future expansion which I don't know if I could get four more auxiliary lights protected by just two more fuses.

In any case I am still looking at boxes but I wanted to ask how can someone take a box like this and buss it so there will be one main power wire coming in for all battery power circuits? I really don't want to have an exterior mounted buss for battery power as my goal is to clean up all the bolt ons I currently have for my setup as it is now.

I already picked up a factory style power box already and that was not able to be used, something like this is more to my requirements size wise as it can easily be bolted on the inside of the fender.

 

Nevermind I was not thinking straight on this. I just need to source some 6 pin ATC bussed pins to have the fuses bussed then run the power from the fuse to the power side of the relay. Don't know what I was thinking with wanting to buss the relays together for battery power when that's what the fuses are for.

 

perhaps you could install a Buss Bar similar to this inside the bottom cover ??

 

I might be able to. I been reading reviews lots of people have talked about wire routing is critical due to how compact the unit is. I found one on amazon that shows a bussed fuse pin but its only four pins which would force me to install a four pin bussed unit then install a two pin bussed unit and use a jumper wire to connect. Ive been looking online for the fuse box pins you can buy them but just cant find bussed variants surely they make them that you cut down to number of pins you need. Ive seen the GM weather lock style socket/pin terminals done this way.

But I will need a buss bar of some kind still for ground. I will be replacing my negative battery cable for one with a pigtail that I will run to a ground buss bar or maybe a ground stud like I have now. I just never been happy with how I have wiring going all over its not all the same length and just looks trashy looking.

This is the one on amazon I am looking at same as on ebay but comes with relays and bussed fuse terminals. Relays how ever are 4 pin relays not 5 pin.


But for me I could just wire up four circuits but I rather wire up all circuits for power and then leave a pigtail for future expansion if I decide to do it. I already know I might need to do a choke relay to send battery voltage to my choke off a stator trigger if the aftermarket carb choke wont operate properly on the reduced voltage.

I also am still playing around with adding four more KC Auxiliary lights, possibly two spot lights and two flood lights which would require two relays themselves which would have me out of relays unless I decide to have my choke circuit ran by the single oddball RTT7121 4pin relay port included on this box.

Might need to spend tomorrow at work drawing up some kind of diagram on how I would do all this. I already got everything wired up but the choke its circuits that were added over the years and now is the time in my eyes to make a stand alone auxiliary harness for these added on circuits.

 

ya the ATC bussed connectors are a bit hard to find I've seen the 5 pin but not 6, you might search Digikey

now I have seen those boxes on FleaBay just like yours that actually come with the bussed terminals

EDIT: here is an example that comes with several of the bussed terminal strips ... https://www.ebay.com/itm/Vehicle-6-Way-12-24V-Fuse-Holder-Box-Block-Panel-Board-ATO-ATC-6-Relay-Socket/303172902909

 

It's very rare to need the 5 pin relays. They are mainly used for control wiring, when you want something to work the opposite way (turn off when the relay is turned on). That is, if they are the 5 pin I am familiar with, with a extra normally closed pin.

 

yeah, most time ya only need to use the C and NO pins, depending on the relay Pin 87b is internally connected to pin 87, often times pin 87a/87b are not installed but it still has the 5 pin foot print. these are the most common style automotive relays.

 

Yep I been looking but haven't been finding many 5 pin bussed terminals. Would save me a lot of space that would otherwise be taken up by wires being looped. I been working on a diagram on and off the computer for this harness I will be making. Looks like I will be using up to five of the fuses and four of the six relays.

Yep but it seems like 5 pin relays are the easiest to find 40A relays in. 4 pin relays I can find but seems like they are 30A always. I got some 5 pin relays at work that are actually rated at 60A as well. I just need to figure out what my circuits will be. I already figured out I currently have fuses that are overkill for the circuits I have considering the load they have when active. I just wish I could find a 6 pin bussed fuse connector so I can buss all the fuses with one wire.

I don't think I ever used the center pin outside of it being used for aftermarket cruise control units that need battery voltage till you apply brakes for deactivation. In my application, it wouldn't be needed to switch on lights or even to activate my electric choke.




I also found a place that has SXL Cross Linked wire which is preferable for under hood applications. They also have lengths of wire where I should be able to get all I need in 10ga, 12ga, 14ga, 16ga and 18ga for under $150.

I know my main power from solenoid to the bussed fuses will have to be 10ga to provide a 40A capacity of the wire. The rest will be 12ga, 14ga, 16ga and possibly 18ga for my circuits. Going to be fun to try and link two 12ga wires to one relay terminal in the box so I can jumper my two driving lights to one relay terminal.

 

Aliexpress has em 10 up strips... but hey slow boat from China

 

lol I don't mind slow boat from china, where I got all my LED bulbs from.

 

here is the connector number I searched .... BX2091C


EDIT: IF you go the Aliexpress Route I would advise contact the seller and make sure they understand you want the terminals all on 1 strip... I saw pictures in one of the Feedback showing they came in 10 terminals per strip from one satisfied Russian... but better safe to make sure

 

Of course, What I did is I did ebay searches for the same title and was able to find the same listing on ebay.

https://www.ebay.com/itm/4-Way-BX204...sAAOSwhxBZshKn

This here is supposed to have 8 terminals on one strip but I see 6 terminals for sure in the photo which is all I need. I just am not sure what kind of strip I need cause I saw some photos showing terminals all on a straight flat strip and others on this wavy style strip. I settled on getting the wavy strip as the photo of the kit I am buying from Amazon shows what appears to be wavy strips as well.


I know the amazon one is more than else where but it does come with five four pin relays which I may or may not use. I probably wont use them but keep them as spares for emergency cases. I know cheap fuses and cheap relays don't tend to last. The relay kit I got for my headlights on my truck I used the cheap Chinese fuse that they supplied damn thing popped one morning after just a month of use. Put a quality busman ATC fuse and it never popped again.

Another reason for me to do this is the Chinese harness I had to extend it to route it somewhat nicely and that's when I found out the so called thick gauge wire was actually 18 or 20 gauge silver stranded wire with a super thick insulator giving the appearance of a 12 or 14 gauge wire.

The math I did for my H3 Silverstar Ultra`s at 55/60 watts at 12.7v and 13.8v indicates a 8.57A and 9.75A requirement so I will be downgrading my oversized 30A fuse to a more appropriate 15A fuse. I also did the math to figure out wire size on an estimated 7ft length, Where my box will be mounted at straight to my solenoid terminal is like 6ft 3in so if I use sizing for 7ft lengths I should be sized on the safe side. In this case my headlight circuit with a 15A fuse shows I really need a 14ga wire and I will be safe for up to 7.29ft length. I am kind of wondering if that's why my headlights don't seem as bright as I think they should be. But then again I also am only running the stock 1G alternator but once I upgrade to a 3G 95A alternator I rather have this stand alone circuit sized properly.

I just don't know how I am going to squeeze two 14ga wires into one relay terminal as I will need to double up low beam and high beam outputs for supply to left and right headlights. Like wise my driving lights are 100w a piece so the 200w load is showing 14.28A and 15.74A which will require a 12ga wire which will be safe for up to 6.95ft length. But this is where I run into a problem. I can run a 12ga wire from the fuse to the relay for power supply but since I am doing two lights I wonder if I truly need to double up 12 ga wires. Each wire only has to handle a 100w load a piece which is 7.87A @ 12.7v which means I could use a 16ga wire and double it up for each light but I am not sure how well a single 16ga wire could handle a short to blow a 25A fuse for instance. That is one thing I am still unsure of when it comes to wiring.

I know all the other stuff from years of doing this but never fully figured out how to size a wire to a fuse that is sized to have the nominal load to be as close to 75% as possible to prevent failure due to age which I learned first hand happens easier for a fuse that is sized close to what the load actually is.

I know from the calculators I have saved to help me along with this states if I run two 16ga wires the effective gauge would be 13ga. which is close to 12ga feed wire I will be using in the box itself for the relay. But and I might be over thinking this, if just my left driving light for instance chafes through and shorts to ground on my bumper that means that one single 16ga wire would have to bring the total load over 25A to blow the fuse. Considering each light is pulling 7.14A @ 14V that comes out to a combined nominal load of 14.28A @ 14V. That is quite a large jump that one wire will have to see to bring 14.28A to 25A or more to pop the fuse.

That is just one problem I am dealing with in my head on planning this out. The other problem is my CB and CB Amp. With a huge 10ga wire supplying main power to the bussed fuses means lots of current flowing through it which increases the chance of interference to my CB power and CB Amp power wires. I know they make a insulator for wires to stop interference from wires like this but just don't know what its called or where to find it. Probably wont make a difference but I still would like to run the two wires in it as a precaution. That way if there is any kind of noise I know it is coming from the alternator itself and will have to look as a noise filter then.

~Update~
I think I need to change the wire size for the feed from the fuse to the relay. I don't think I need to run for instance 16ga from the choke fuse to the choke relay when 10A at 16ga is good for up to almost 7feet. I think I should size it for 2 feet as there is no way the wire from fuse to relay will be 2 feet. Doubtful it would be 1 feet but I rather oversize the wire by one size since it will be encased in the box and wont have air cooling.

 

Yes it would be the "Wavy" style... the ones with the thin straight strip are meant to be used individual, they are designed to run on automatic crimping machines.

that wire with real thick insulation may be High temp silicone insulation, I use that stuff pretty often.... while not so much in Vehicles but I do a lot of work on other Electronic Projects, and CNC Electronics Design.

sounds like you have it all pretty much under control... Ohm's Law is your Buddy

 

Yep I been making harnesses at work for a few years now so I got it down pat. Just didn't have time to do the circuits for my truck so like the headlight relay kit I just bought a $20 kit from china which is where it came with that undersized wire. Probably not bad but I rather go on the slightly large size to reduce voltage drop as well as to have the fuse as the weak link not the wire.

Only thing I am taking my time on is the wiring. I want to make sure I get just the right amount to do the job. Going to get the wire from Wiring Depot, they got small cuts so I don't have to buy 100 ft of wire I might never use. Plus its considerably cheaper, im looking at about $100 for 15 different cuts of wire in different gauges and colors from 10ga to 20ga.

 

I got some stuff coming in. What I have on order so far is as below.

1) IWISS open barrel terminal crimper plier 24-14Ga (I got regular crimpers but nothing to crimp the open barrel terminals properly)
2) x2 Deutsch dual pin connectors (wont try to salvage the two on my truck now plugged into my KC Apollo driving lights)
3) Audak 2 piece H4 ceramic adapter H4/9003 Male plug in plastic with H4/9003 Female plug in ceramic (was cheaper than buying a 6 pack of the ceramic plugs in kit form to assemble, just need to locate female and male brass pins for this connector so I can make my own wires vs splicing in.)
4) 12 slot fuse/relay box as shown above, I cheaped out and got the $12 one that has no relays I can reuse my relays or pick up some from work if need be.

Only thing that is posing a problem is trying to locate the brass terminals that are exactly like the ones used on this heavy duty headlight adapter so I can simply crimp new wires and maintain one color vs soldier joints.


I did find a pack of 100 of theses but it doesn't state what gauge wire they will accept. I would hope I could get some up to 12 gauge but for my driving lights I have to run 16 gauge as the deutsch connector I have to use to fit the factory connector on my driving lights only come in a size up to 16 gauge. So I might down grade my headlight wires from 12 gauge down to 16 gauge. I could really drop it down to 18 gauge as each light with nominal battery voltage with just under 5 amp draw, I could run 7 feet of wire on 18 gauge, and 16 gauge would be good for nearly 12 feet.

But none the less I need to probably wait till I get what I ordered and try and figure out what terminals I need to get that will work. The male end needs to plug into my OEM truck harness that is how my relays will receive their ground and low/high beam triggers for the low and high beam relay. Then the other ceramic terminals will be the feed at the light as I am running silverstar ultra H4`s and rather use high temp ceramic to eliminate any kind of burning like I see all the time on new trucks at work.

Wire I havent ordered yet and I am kind of glad as I do have to change the 12ga green wire to 16ga green wire for my driving lights due to limitation for the connector. But with what I have on list already I am looking at about $100 for 338 feet of wire in various gauges from 10ga to 20ga and in 9 or 10 colors. Not a bad price though, buy 10ga wire at the local store you would pay more than $5 for 8ft.