Help from the Electricians...

I have been looking over various threads and links regarding power blocks for acessories. I would realy like to do this. Here is what I would like to do

create a power distribution block to send power to
1 pair of HELLA 550 spot lights
1 single 20 watt tractor spot light
my electric fan
radio
cb

I think that running a single heavy guage power and ground line directly off the battery through the fire wall somewhere and then to a shelf under the passenger side plastic under the glove box. and to build a access hatch for the electrics. switches would be on the center consul just in front of the e brake( where the change slot is)
-will the block be ok where I project (heat?)
-will installing a block like this help remove electrical noise in my cb and radio?
-I suck at math but can someone explain the formula for figureing out wire, fuse and block size for said project?
-one more... I would like to install the "fighter" style switches (to keep them from getting set on accidentaly. I got pulled over last week cause the GF turned on my back up spots and i didnt realize) but would like to have indicator lights for them. how do I wire those up?

thanks for any help
Kyle

you probably wont want all that voltage running into your cab. I would keep the power dist. block, they work quite well, but use relays and keep the high amps out of the passenger area.

for the gauge size, add the amps for all items running at once and add 30% that is more than enough. that is the amperage that you want to figure on gauge size.

for the lights that show the switch on, find a local ground and hook up to the positive side of the switch before the relay, this will give you your light.

for the electronic noise that is coming from some electronic interference of some kind. you would need a electronic noise regulating device, depending on the interference. (someone can tell you alot more than me on this one)

the best thing before making any cuts or buying anything i draw up a wiring diagram. ( glad im an engineer it really helps) that way its much easier to buy parts and not make costly mistakes.

93GRNXJ said:

you probably wont want all that voltage running into your cab. I would keep the power dist. block, they work quite well, but use relays and keep the high amps out of the passenger area.

for the gauge size, add the amps for all items running at once and add 30% that is more than enough. that is the amperage that you want to figure on gauge size.

for the lights that show the switch on, find a local ground and hook up to the positive side of the switch before the relay, this will give you your light.

for the electronic noise that is coming from some electronic interference of some kind. you would need a electronic noise regulating device, depending on the interference. (someone can tell you alot more than me on this one)

the best thing before making any cuts or buying anything i draw up a wiring diagram. ( glad im an engineer it really helps) that way its much easier to buy parts and not make costly mistakes.

Click to expand...

Ya beat me to it - it was just worth quoting in full, being good advice.

I just got done planning an add-on setup for an SAR rig - so I know what it can be like. I've found a few parts I plan to start carrying through WiP...

oh for the calc's on the amperage draw, look on the specs of the equipment. then add that all together, and mulitiply by .30. take the number you got when you multiplied by .30 and add that to your original total. so for example if your max amp draw was 20 amps this is what it would look like.

5+5+5+5=20

20*0.30=6 ( this is your factor of safety, in this case to attain 30% you must have a rating of 26 amps)

ok so you need a wire for 26 amps for all that power..... soo according to this( http://www.powerstream.com/Wire_Size.htm ) site, you need 7 gauge wire from the battery to the power dist. box

5-90 i love that web site. i have run into it a few times. i am home from school and often work in your area. i am an industrial air compressor service tech in south SF and spend much of my time in the south bay area.

sorry didn't mean to hijack.

I have seen a couple of guys set ups where they mount the block and the relays in a box in the rear cubbies. why do I need the relays? (they take down the power how?) could I use the ground to the power block to power the indicator lights? EDIT: I was thinking that the noise I hear in the cb and radio are due to bad ground. in the cb can hear the engine rev... also occasionaly in the aftermarket radio, (but only in radio reception) never in the aux hook up or when listening to cds

well the relays keep the high amps out of the switches witch are probably only rated for 1 or 2 amps cont. at most. relays are rated at 30-50 amps mostly. (someone correct that if its wrong) and this will burn out the switches without relays. relays keep the high amps away from body parts ( it only takes .001 amps across the heart to kill you) , flammable carpets, plastics and other such exciting thigs that are cool to burn/melt destroy in someone elses car. bottom line that much amps in the cab is not really safe, however done correctly and exicuted with extreme caution, and done well this can be an acceptable solution as well.

what you want for the indicator lights (assuming you are using live ground, the jeep is wired that way) is take the wire that comes off the switch that is normally off, (so that when you turn the switch on, there is power there) and run that to your led, or indicator light, or whathaveyou there then from the light go to the appropriate connector on the relay. bingo there ya go!

if you still don't get it i can draw something up to explain it better than words, and ill email it to you.

one more thing if you plan on mounting the power dist. box away from the battery a long ways i would strongly think of upgrading the wire gauge a notch or so.

what Power dist block are you using? i am going to add lights and CB, and trailer brake controller, and i dont want a ton of wires everywhere.

I was planning on putting the block where I put the green and the switches in the red area( i like having them right at my hand).

The relays have me rethinking this. I was originaly thinking it would be nice to have them in the cab for safety but Im thinking now its not so safe. also thought it would cut down on extranious wires.
now Im leaning more towards a waterproof box mounted where my pressure bottle used to be?

perfect. that is sweet i love it. now what dist. box are you going to use?

the switches should stay there i like them in that area, it never gets used anyway

when i install my lights i will be using the area right below the shifter handle on the T case, i figre rocker switches and my small hands will be perfect, plus the area is kinda protected from the t case handle.... now i need a power Dist box now.


where are you thinking for the indicator lights??

I had been looking at West Marine the other day. they have dist blocks rated up to and past 100amp. I fugured that they would work.
do you think if I could put a block that could contain all that I mentioned and seal it in a box? and locate it on the fire wall?
and yes the switches right there... for my short arms when my arm is on the armrest there is less than an inch of reach for my fingers to hit them. but like I said I want the locked out switches to make sure they dont get accidently switched.

yeah that works. the 100 amp ones are ok, a bit excessive probably, but if they are somewhat water resistant that is really great. what is your max amp draw?

I need to sit down with the formula and also look up the ratings on the accessories. I'm needing to rethink my setup and how and where I would run the wires.

good call that will save you alot of money and pain, i would recommend a wiring diagram too. this will help alot. you dont need a huge wire through the whole thing, but if you wire for example your CB, use the safety method with that. so that example of it drew 5 amps, you would only need the postive wire to the CB to be rated for about 6.5 amps, or 13 gauge, that is just an example though, you dont have that many amps for the CB. good luck! i hope it all works out. let me know what you did when you are done, i would also like to do the same.. maybe with on board air too.

quick shot from paint... small squares are relays. I dont think I need a relay for the fan or the cb?

DIN Relays (the regular 1" cubes) are typically rated for 30A max through current, 100% Duty Cycle (that means 30A all day, every day, for years.)

The relay allows you to run a more direct path for power to the consumer, and also allows you to select switches with less of an eye toward load. That's why headlamp upgrade harnesses work - they use relays between the lamps and the battery to switch power to the lights, and the headlamp switch doesn't have to handle full power anymore. Since the headlamp switch is the 'choke point' in the OEM headlamp circuit, you save a lot of strain on the thing. Since you've significantly reduced the length of conductor carrying full power, you have less loss due to the internal resistance of the conductor. Using a relay not only allows you to use a smaller switch (electrically speaking,) but you can also get away with running a smaller wire - since the current-carrying capcity of a wire is not only determined by its cross-section (commonly known as "gage,") but by the overall length of the conductor as well.

Check specs for your CB - if it draws more than about 2A, put it on a relay. Put the fan on a relay - I'm not even going to tell you to check that, since I know it's going to be more than 10A.

If you don't have a current figure on the dataplate (amperes, amps, or A,) look for a power consumption figure (Watts or W.) You can divide Watts by 13.8 (close to system voltage) to get current requirements, or overbuild slightly and divide by 12.0 (nominal voltage.) Using the nominal figure of 12VDC will get you a safety factor built into the thing already - of about 12% (which I've found to be enough for "consumer lines." Use the 30% given for main and secondary distribution.)

One more thing - bear in mind that finding wire gages in odd numbers borders on impossible - select the next even number lower than the gage you calculate. That will be the next larger wire size, which will be fine.

you wont need to run all that wire, the ground is live on the Cherokee, meaning that you can pretty much just attach the ground to any metal surface on the jeep as long as its a good connection. the fan really does need a relay, you probably could get away with no relay for the CB, i think, the good thing about the relay is that it drastically reduces your distance in wiring.

that looks generally like what you want. if you want ill make a really basic one for you. just give me your email address and ill send it to you.


i saw the post on another string about reverse lights, i love the stand idea that is really great.