switched power source- seperate fuse setup

I would first figure out what power demands each accessory requires. This can often be inferred from either the manufacturer, fuse rating (each item might come with its own fuse) or the wiring each item comes with or the wiring that's recommended in the instructions.

I would run a load-side feed from the battery (or PDC) to a SPDT relay. Use the vert power source (or any other power source you desire) to trigger said relay. This will keep from overloading any circuits, minimize voltage drop, etc. You can then run the output from the relay to each fuse or each accessory (usng an inline fuse for each accessory).

That's just how I'd go about it.
Good luck.

blksn955.o said:

Just want to clearify, run the "main power" wire from the batt. to the relay that will get split off to the diff. loads. Use the vert source to be the "switched" souce only, not getting power from the "switched source" just using it to power the realy.

would it be better to run the 4-5 lines out from the relay directly, with an inline fuse on each line?

or

running the power to a dist. block/fuse block and from there on to each source?

with the n2o and line lock I am worried about too much draw on the vert power source. Plus I wanted to run the bottle warmer from it so that would be 5 things with 3 being higher draw...1 line lock noid, 2 n2o noids, and a bottle warmer. I am afraid of constantly popping that line...and I have yet to see any solid source on exactly what wire it is.

Thanks,

Click to expand...

Here's how I'd do it and I think you will like the cleanliness of this (I really laid this out simply - take no offense if you know all of it. The info might help someone else down the line anyhow):

Tap into battery power where ever you like. The battery, PDC or a remote-mounted distribution block work just fine. Just do what packages the best for you. Normally you can add a few terminals to the PDC bolt (under the cover on the side of the UFB - it's my choice). Use a large enough gauge wire for this wire to handle all your needs (cumulatively, though I doubt you will use all items at once). Fuse it appropriately. This will go to relay terminal 30. 10 AWG should cover you safely for 30 amps, and I'd hope all that crap you're adding doesn't draw that much all at once.

Run a wire from relay terminal 87 to a small fuse box you purchase. I think I have a link to a place with cheap ones saved somewhere..?? I need to buy one of these for my fox vert (I'm going to remove all the fusible links and retrofit fuses under the hood). Anyhow, you will have that wire from 87 to go all of the feed-sides of the fusebox slots. This is acting like your power distribution block (of sorts).

Then tap into the vert top wire or whatever *triggering* power source you desire. You will be drawing about 250 mA to energize the relay, so overloading a given circuit is not a big worry. Run this wire to relay pin 86.

Then run a wire from pin 85 to ground. Just choose a nice ground location near the relay (no need to get exotic here - I've even used the screw that I mount the relay with, if it's a good connection (less than 5 ohms of resistance).

What'll happen is:

When 85 has ground (which is always) and 86 has 12 volts, 30 (fused battery power) and 87 (load-side relay-output) connect. So battery power will go to the feed-side of all of your new fuses.

Then just label each fuse slot with a little label maker (I recommend using an indellible marker underneath each label because I've had labels fade or fall off. Better yet is to make a little diagram and put it in your glovebox). Now run a wire from a given fuse to each switch or solenoid or whatever (treat each new fuse as if it was the vert-top wire [but with lots of available and donatable power] in terms of logistics).

It's just that simple (I'm not very good at explaining it. A diagram would be neat but I dont know how to do them on the computer).

The nice thing with this set-up is that it's very clean and it's modular. If you later want some fuses to be powered by another means, you can simply remove the feed wire to that fuse and source a new one (just like our interior fuse boxes).



Now absent that method, and to answer your questions:
If not doing any of the above.............
You can run multiple output wires from relay terminal 87, but it gets messy. You have one spade connector on 87 to utilize, so you either have many wires jammed into one female terminal or you have lots of soldered-on legs leaving the primary wire that connects to 87. Ugly.

Using a distribution stud is how I'd do it, if not using a fuseblock (you will still need inline fuses on each item, which is why the fuseblock is nice). You can get insulated studs at marine stores or online stores (instead of the fox-style starter solenoid, which is huge and more complicated than you need since it is another relay - but it's not meant for continuous-use so it would not work for your purpose). You can also make one with a bolt, washers, a nut and some thick plastic. It's kinda cheese but it works. One more option is a stereo distribution block. You can get some of them for real cheap. I couldnt even find room on the 94 to mount one the way I wanted it though (I'm kinda anal, and you have different stuff under your hood, so YMMV).

The fusebox idea is cool IMHO. If that made no sense but you like the idea, I can hand-draw a schematic and email it to you.

Good luck.

that would be one hell of a burnout

HISSIN50 said:

...I would run a load-side feed from the battery (or PDC) to a SPDT relay. Use the vert power source (or any other power source you desire) to trigger said relay. This will keep from overloading any circuits, minimize voltage drop, etc. You can then run the output from the relay to each fuse or each accessory (usng an inline fuse for each accessory).

That's just how I'd go about it.
Good luck.

Click to expand...

I used the SPDT to send 12v switch power to my purge, N20, bottler warmer, bottle opener and dual window switch switches, with an inline 30 amp fuse on the constant 12v source. Except I don't have a distribution block. I wired it as follows.

Connection is 1 wire to constant 12v source, 1 wire to ground, 1 wire to a switched 12v source, 1 wire to all the switch source wire (i.e. I splice all the wires together to a 14 gauge wire then ran the 14 gauge wire (1 wire) to the relay so you won't need to run multiple wires from the relay) - Hope I explained that clearly.


The wiring is similar to connecting multiple car amplifiers remote turn using a SPDT.

blksn955.o said:

...with the n2o and line lock I am worried about too much draw on the vert power source. Plus I wanted to run the bottle warmer from it so that would be 5 things with 3 being higher draw...1 line lock noid, 2 n2o noids, and a bottle warmer. I am afraid of constantly popping that line...and I have yet to see any solid source on exactly what wire it is.

Thanks,

Click to expand...

You should have a N20 relay so you won't have much power draw from the switch. I'm not sure about the line lock but if you use a relay then you won't have much power draw from it either - same goes for bottle heater.

blksn955.o said:

I want a fuse block and I really like the detail in the instructions you gave from running off the post (just making sure...that post is were the batt. connects to the underhood fuse box correct?) to a relay to a fuse panel. THANKS that is prob. exactly what I will do.

Click to expand...

You got it.

As an aside, with the relays in your new components' wiring, Al's got some good thoughts there. And his SPST relay will function just like an SPDT in this instance (I find that SPDT's are easier to find, so I mention them by default. Use whichever one you have or can get. The only difference is that the DT has resting-continuity between the common and Normally-closed terminal, and a ST does not have this provision. But you are not using this part of the relay anyhow).

14 AWG should be able to safely handle about 20 amps over 15 feet (or 25 amps over half that distance). I admit to erroring on the side of having the wiring match the relay capability because I do tend to add crap onto circuits as time goes on.

Good luck.