proheader

Been a member here for a long time and done some swaps but this one is pretty special.....

69 amx lsx t56 9" ....blah blah blah....

going to run the battery in the trunk but wanting the cleanest way to distribute power to everything in the harness and to the starter as well.

I have a brand new harness for the chassis that I found that is OE!!

My other harness we built here in the shop.....

I have a Ford solenoid mounted on the kick panel but thinking about a main power stud for everything and then branch it off from there....still going to run the original key and ignition switch...

The idea is to keep it clean and simple as possible......maybe someone else who runs the battery in the trunk can shed some light on this subject for ideas....

proheader

rotor vs. piston

iTrader: (3)

I haven't done it yet, parts sitting in the garage, but was just going to run the cable to where the battery originally was and use a lug there, just snugged up to the inner fender or core support. Mainly so I do have to modify the stock harness, just will go where the original leads can already reach.

1989GTA

For the positive side I ran two cables from the battery. One to the starter and on to a distribution block. The other cable went up to the computer and a smaller distribution block. I also tied the distribution blocks together. The alternator went to the larger distribution block. I wanted the computer to have as much voltage as posible when starting the car.

For the ground I ran a cable straight from the battery to the engine block. From there to the chasis and one to the frame. A few others thrown in for good measure using the block as the main distribution point for the battery ground. Using the block for the main ground distribution point hopefully will prevent ground loops and weird electrical problems.

BigEd_72455

iTrader: (7)

I have a single positive going from the battery to the starter post. From there, I have an 8 gauge wire going to the back of the alternator. From there I have a 12 gauge going to the main feed for the fuse block on my 93 S-10. These cars do take some energy to get up and running. But once running it isn't as bad.

GTA is right on the ground. I myself have 2 grounds. Since my battery is in my front passenger floor board, I went to the corner of the block on the passenger side from the battery, then the other cable went from battery to front seat bolt (cable I had at the time fit perfectly). I hit the key and it starts and runs all day long (or til I run out of gas) without issues.

Easiest way, and this would work fine for about 99% of the swaps out there, would be to use 4 gauge from battery to starter. You can branch off the starter if you want to, or run an 8 gauge from the battery on a master fuse (100-150 amp) to protect the car from fire if it rubs or shorts out. Then go from that 8 gauge up front to either a fused distribution block, or to the fuse block that is already there. Then connect what you want to have battery power from that point on.

Easy enough. Just not necessarily cheap.

BigEd_72455

iTrader: (7)

Something I should mention also, I will be moving my battery to the bed of my S-10 hopefully within about a month since it is now sitting for some upgrades/changes. I still plan to run a single 4 gauge wire to the starter and the rest of my wiring will pretty much remain the same. Because my S-10 has the steel bed and it is bolted directly to the steel frame in back, I can ground straight from the battery to the bed, and then add a ground up front from the battery to the frame either by welding in a stud to bolt the cable to, or just finding a spot where I can run a bolt and nut through and be able to tighten them sufficiently.

The LS series of engines have several spots around the block and cylinder heads where you can secure grounding cables/straps to.

Best of luck with your project, and I hope it turns out to be as much fun as my S10 has been so far, and how much more it will be in the near future.

chuckd71

iTrader: (23)

Wouldn't putting the solenoid in the front kick panel mean a constant-hot wire is running almost the full length of the car? Why not put the solenoid by the battery so the wire is dead except when starting

soundengineer

iTrader: (16)

this should help....


use a #0 or a 1awg wire going from the trunk to the front of the car where you can mount a distribution block or a firewall mount terminal
no such thing as too big of a wire when it comes to power...only too small of a wire.

Doug G

Remember, you'll need a cut-off switch that kills motor and all electric to the car if you plan to hit the track....and it's a good idea anyway

Pop N Wood

iTrader: (1)

Do yourself a favor and run a battery cable from the negative battery post to the block like the guys above did. Trying to carry current through the chassis is just a bad idea. The OEMs only did it to try and save a few bucks on ground wires leaving us to chase down electrical gremlins when the connections inevitably corrode.

Also you are better off using a distribution block than running the alternator straight to the battery. This link explains why.

http://www.madelectrical.com/electri...evymain1.shtml

The starter lug works as a distribution point. I used a fused distribution box from a car stereo place.

i r teh noobz

iTrader: (4)

I run a 250A fuse (large blade style for big stereos) right off the battery, then to a 2ga cable to the starter, which branches to a lug on the right inner fender. From there it goes to my alternator (Factory 8ga fusible link wire), LS harness (125A fuse), body harness (factory fusible link), and HID harness (fused).

The battery is grounded to the quarter panel. I have one ground from the block to the body (unibody car). Everything else is grounded to the body. No issues, though my charging voltage is a bit low (12.8v tops) at the battery. I see 14.x at the alternator. Never had an issue with it, fires right up and runs great. Battery is a 3 year old Optima yellow, swap has 15k miles on it.

soundengineer

iTrader: (16)

Your wires are too small for the distance you are going with them...

Main wire needs to be a #1 or a #0
And your alternator wire needs to be a #4 or a #2

#8 is way too small...

Pop N Wood

iTrader: (1)

Man, I have to disagree with you. According to this wire gauge table that 2 gauge wire is probably bigger than it needs to be and for a 140 amp alternator with under 10' to the starter 8 gauge should be fine.

http://www.rbeelectronics.com/wtable.htm

Funny how people run massive power wires then ground things to sheet metal.

Moving the battery to the trunk isn't going to do much good if you add 40 pounds of wire in the process. Might as well just put a smaller battery in the front and get by with shorter and smaller wires.

soundengineer

iTrader: (16)

the thing you have to remember, is your wire length is the total wire... not just the distance from the battery to the front.....
this means all pieces connected, and all hots and grounds...and if you ground thru the chassis....figure the distance back to the battery on that as well

even if you are at a straight line of 10 ft(and you are not)
then its 20 ft total....
20 ft at 150 amps is a #4...minimum.....

and thats if you only have one positive, and one negative cable at 10 feet each


start counting the other pieces its connected to and it goes up...



also...just do a voltage drop test....
"i r teh noobz" see's 14.x at the alternator and only 12.8 back at the battery... thats a pretty big voltage drop....

thats not enough copper.


I see 14.2 at the alternator, and I see 14.1 at the battery...



also, the point of moving the battery isnt necessarily to move weight...
sometimes its just to make room for something else
also, adding wire to the length of the car, doesnt change the fact that you moved some weight to the rear... if you add it in a wire length from back to front, you added it evenly across the whole length of the car, not all of it back at the front
I regularly work with hundreds of feet of 4/0
5 strands of it(3 hot legs a neutral and a ground) at 25 ft long weighs about 100lbs
when we go down to 1/0 the weight drops to about 1/3 of that..

100 ft weighs about 35lbs
the optima yellow top I use weighs 43 lbs


my wire runs are what you see in my diagram above
Battery to front, Hot and ground - 1/0- 12 ish feet each
Junction to Alternator, Hot only, Ground is thru the case to the motor - #2 less than 3 feet
Junction to Starter, Hot only, Ground is thru the case to the motor - #2 less than 3 feet
Motor to Ground lug at Junction, Ground only - 1/0 - 6 inches
power and Ground to my Fuse/relay panel - #2 - 6 inches

realistically I have put 35-40 ft of wire in my car...not all of it is 1/0...only the main run from back to front, and the strap from motor to the ground lug that ties to my battery ground
I would bet that I have less than 15lbs of wire in my car for Battery/Alternator/starter....
so I shifted 30lbs to the rear of the car(behind my rear axle) and spread 15lbs over the rest...
still getting it off of the front most corner(in front of the front axle) of the car where a large majority of automakers put the battery

i r teh noobz

iTrader: (4)

The alternator wire I used is the factory pigtail cut from the GM harness. That's why its 8ga.

I'd always assumed that my voltage drop was from the lack of a dedicated ground wire from the battery to the engine area. Its all chassis grounded.

proheader

WOW!! thanks for the response..... I will post some pics later this evening....

BigEd_72455

iTrader: (7)

Guys, I have been running batteries from the trunk forward and ONLY run 4 gauge wire. There is no reason for a stock starter to have anything bigger. You are only talking a 1700 watt load which takes 150 amps at 12 volts to get spinning.

I will stick with what I am running rather than go and pay $3+ per foot for that big of a wire. These aren't big rig starters we are trying to turn over...

I have never had an issue with low cranking power or weak battery unless it was just an old battery I started with...

soundengineer

iTrader: (16)

it has to do with the whole system...not just the starter...

feel free to run whatever size wire you want...its your car/truck...

my advise is just that...advice...doesnt mean you have to follow it

Old Geezer

iTrader: (3)

^^^^ What Scott said in post #13...
Ohm and volt drop testing is the way to confirm how well the system is performing.

Pop N Wood

iTrader: (1)

long post.

He is running the alternator to the starter lug and from the starter lug back to the battery. Not sure how you get 20' in any of that.

As for his high voltage at the battery first thing I thought of is it a one or 3 wire alternator and where is the sensor wire connected? Grounds are a another issue. 12.8V at the battery actually sounds pretty good to me. Shows it isn't being over charged. The place you need to measure the voltage is at the fuse panel. That is where you want the 14+ volts, not the battery. Read the earlier link I posted.

You do realize the big wire only carries current when the starter is engaged? I have my battery connected to the rest of the electrical with a 30 amp fuse. Batteries simply don't pass or take much juice when the alternator is running. They can if they are wired wrong, like alternator straight to the battery, but that is because they are being overcharged. This is especially true if grounding paths are not properly laid out.

We agree on one thing, his car, his money, do what you want. The table of wire lengths vs. gauge I posted is a great starting point. Just trying to save everyone a few bucks on unnecessarily large wiring.

soundengineer

iTrader: (16)

you obviously dont get it...just because he's only running a few feet to a fuse box, doesnt mean its the only place the voltage is passing...
the entire system creates a load...
even if he's 2 inches from the fuse box, he will still see a drop if the rest of the system isnt up to snuff.

all it takes is one bad spot to screw up the while thing.

most people dont comprehend that the voltage doesnt just flow to one spot
I can explain it this way......
as an example
you have 1000 ft of hot and ground running to a junction box...
the other direction away from it you have 10 feet of hot and ground....
you connect a battery directly at the junction....the pieces on both ends energize...
suddenly the end of the 1000ft length has a short....
the whole circuit will short out....not "just the 1000 ft section"
and it doesnt matter where the short is...you short out the very end of that 1000 ft piece, the little 10 ft peice stops working as well.



voltage always follows the path of least resistance....smaller wire = more resistance

bigger wire (more copper) = less resistance.



also, if you see 14 volts at the alternator, you should see 14 volts everywhere...again...it goes back to what I just said about voltage doesnt just flow to one sopt..it flows to all spots the same