Hi all,

I just picked up a new 160 amp alternator to replace my OEM unit. I plan to do the big 3 upgrade by running new parallel (4 ga) lines. The new positive alternator to battery line is simple enough, but I have a question regarding the negative battery to block and block to chassis lines.

Specifically, do you need to use the same connecting points as the stock locations? I found the stock braided wire that runs from the top of the firewall to somewhere near the top back of the motor (it was dark and I couldn't see where it terminated) and I think I found where the stock ground cable runs from the negative battery post to the frame rail and then, I presume, onto somewhere on the block - I think near the front, bottom part of the motor. Both ground locations on the motor seem tough to get to so I was wondering if there are other connecting points that will work.

Any help would be appreciated.

Thanks,

Brian

 

No you don't have to use the same paths. I have been told that grounding nearer to the alt will produce noise, but I used a bolt very close to the alt and no noise. I ran my ground next to my charge wire and up to the fire wall. Then I found a bolt hole close the battery with a bolt in it and used it for the chassis to battery ground.

 

Couple things here, the reason for the main ground strap, to go down to the front passengerside of the motor, IMO is due to it being close to the starter. The starter is by far the highest current draw of anything. The closer the leads are to that, the less voltage drop, and higher cranking speeds. I would ABSOLUTELY NOT, replace that with only 4ga wire. If you notice, the cable between batteries, and down to the starter is 2 ga wire. If you want your truck to go ahead, and most likely not start, or barely crank, on the next cold winter day, then go ahead. Youll need two pieces of 4 ga wire, to equal 2 ga wire. (And actually, two pieces of number 4 is a little better capacity then one 2 ga) The one between the motor, and body on the rear side of the motor is to ground the body, other then through the cab mounting bolts. Be certain not to put smaller gauge wire, then already there. Ground braids are deceiving, because they dont look to be high capacity, but in reality, they are just an extra flexible piece of unsheethed wire. People forget the outer jacket is not good for comparison vs ground braid. It is extremely important, to use a good crimper. And since most dont have the nice $2000 hydraulic crimper, and dies, SOLDER THEM!

Now, that Ive got all that off my chest, can I ask why you think you need to do all that? The only thing I did to the factory system was put a nice piece of 4 ga, between the battery, and alternator, to replace the #6ish fusable link, to help with voltage drop. Now my secondary, rear battery system, I added a second alternator, and have two large batteries (105 AH each IIRC) and some 2 ga wire between the batts, and alternator, and a few shunts for monitoring, to run my inverter and 12v accessories. The only thing on the factory side of things, Id change, (and did) was the wire between the alternator and batteries.

EDIT: Sorry if any of that seems upfront, or mean. Its not intended to be mean, just hate to see good wiring go bad, and cause problems. Also starting a small block gasser motor, with 9:1 compression takes a lot less power to turn over then a 444 cubic inch diesel with 18:1 compression ratio. While I realize you have a gasser, its also a 415 cubic inch V-10

 

Was not planning to alter the stock wiring. I was planning to leave all of the stock wiring in place and add new cable in parallel to what was existing. Based on the output of the new alternator, the manufacturer advised that 4 ga was sufficient when leaving the stock wiring in place.

Brian

 

Thats not too bad an idea then. Im sorry, I was under the impression you were removing/replacing. The extra wire, would not at all be a hurt. The more wire you have, the less voltage drop, in high current applications. (IE starting the car, or if your alternator was making all of its current)

 

What about adding a 2nd battery to a V-10 Excursion,,,pretty much like a diesel setup,,,I am looking at getting an Excursion,, V-10,,,and I need to have a snowplow setup (Fisher)on it,,,I recall with my 04' F-350 V-10,,(1-battery) really noticed a draw on electical system when using the plow,,,not as bad with the 2-battery on a diesel!

 

Thats a really good idea. I always see to forget not all the other super duty trucks come with two batteries, like my diesel. If you add one, be sure not to make the connecting cable between them, smaller then what goes to the starter. It should be atleast the same size. Its also a really good idea to run the same size wire over, and connect the ground side aswell.

 

Just me, but I wouldn't keep the connection live at all times. I would use a fuse on each side plus a 200+ amp solenoid. Wired so that the solenoid connects the batteries with a switch in the cab or when ever the engine is running (not on accy). This will keep one battery on reserve if you leave something on overnight.

 

When we do Big 3 upgrades on trucks with big subs we use 0 Gauge