2/0 wiring upgrade
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
I would have just run my 2nd wire straight from the alternator to battery without going through the splice.
The sense wire can get a perfectly accurate signal from the existing wire.
In other words, my new wire will run parallel (without the splice).
Right now, there is a break point in the splice, and if you were to do a bit of looking with the heat gun, bet you that is where the "hot spot" is.
The wire is only as good as the thinnest point.
Thread Starter
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Fleet Owner
Joined: Nov 2003
Posts: 27,901
Likes: 3,617
I would have just run my 2nd wire straight from the alternator to battery without going through the splice.
The sense wire can get a perfectly accurate signal from the existing wire.
In other words, my new wire will run parallel (without the splice).
Right now, there is a break point in the splice, and if you were to do a bit of looking with the heat gun, bet you that is where the "hot spot" is.
The wire is only as good as the thinnest point.
The sense wire can get a perfectly accurate signal from the existing wire.
In other words, my new wire will run parallel (without the splice).
Right now, there is a break point in the splice, and if you were to do a bit of looking with the heat gun, bet you that is where the "hot spot" is.
The wire is only as good as the thinnest point.
As far as the fusble link goes, I agree it is a good thing. We just did not have one as part of the original equipment, so I assume it can wait a reasonable amount of time.
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Mark:
Here are the common 3G 4G and 6G wiring harnesses to the alternator.
Can you pick out which one looks like yours?
RJM Injection Tech Alternator Accessories & Parts
Here are the common 3G 4G and 6G wiring harnesses to the alternator.
Can you pick out which one looks like yours?
RJM Injection Tech Alternator Accessories & Parts
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Use the top diagram 6G schematic. Not the 2nd one.
Out of the 3 connectors from the alternator, only 2 are used.
They are as follows:
You have a Light Green / Red stripe wire that is from the instrument panel.
That is the alternator warning light wire, or the I wire.
The other wire is the Yellow / White stripe wire that is the "Sense" or A wire.
If you want to be real cute ---- you can hook up a simple (fused) wire directly from the 2 batteries to the Yellow / White stripe wire.
What you have done right now (by not bypassing the harness) is you left the existing "megafuse" intact.
So technically, you do not need a new fuse. However, you are now being "fused" at the factory capacity ---- very safe, very conservative ---- just the way I like it.. but a tad too conservative if you are pulling real output.
If you start pulling big amps that exceed the fuse / old wiring capacity, that is where the blown fuse can be found.
Think the "megafuse" and wire really need to be upgraded when you go 3rd battery.
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
There is a small chance that your vehicle (if you are not the first owner) was a 6.0 with dual alternators that have been converted back to single alternator.
If that is the case....
Read this tsb:
https://www.fleet.ford.com/truckbbas/non-html/Q91.pdf
Don't waste your time on it if you think yours is a stock single alternator.
If that is the case....
Read this tsb:
https://www.fleet.ford.com/truckbbas/non-html/Q91.pdf
Don't waste your time on it if you think yours is a stock single alternator.
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Oh btw.... what caused mine a lot of grief is my pigtail is suspected to be a problem...
So I replaced it when I got my new 140a tow truck alternator.
So I replaced it when I got my new 140a tow truck alternator.
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Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Here is the "official" guide to cabling requirements:
6.0 L Diesel Cable Requirements
Desired length of
battery cable
extension (beyond
OEM length)
138" Wheelbase
Desired length of battery
cable extension (beyond
OEM length)
158" & 176" Wheelbase
Cable Required
(Gauge)
Up to 27" Up to 12" "00" (Same as
OEM)
Up to 39" Up to 24" "00" + "2" in parallel
Up to 51" Up to 36" "00" + "1" in parallel
Up to 63" Up to 48" "00" + "0" in parallel
Note: Cables in parallel must have appropriate terminals on each end to
assure full current carrying capacity of the pair.
https://www.fleet.ford.com/truckbbas/non-html/Q102.pdf
6.0 L Diesel Cable Requirements
Desired length of
battery cable
extension (beyond
OEM length)
138" Wheelbase
Desired length of battery
cable extension (beyond
OEM length)
158" & 176" Wheelbase
Cable Required
(Gauge)
Up to 27" Up to 12" "00" (Same as
OEM)
Up to 39" Up to 24" "00" + "2" in parallel
Up to 51" Up to 36" "00" + "1" in parallel
Up to 63" Up to 48" "00" + "0" in parallel
Note: Cables in parallel must have appropriate terminals on each end to
assure full current carrying capacity of the pair.
For example, the 6.0 L diesel engine starter draws up to 850-900 amperes and the
glow plugs draw approximately 270 amperes peak. A small increase in voltage drop due to
increased battery cable length or splice may result in no-start complaints, especially at low
ambient temperatures.
glow plugs draw approximately 270 amperes peak. A small increase in voltage drop due to
increased battery cable length or splice may result in no-start complaints, especially at low
ambient temperatures.
In order to reduce the possibility of environmental conditions resulting in increased starting
voltage drop, all battery cable connection should be coated with a corrosion protectant after all
connections are torqued.
voltage drop, all battery cable connection should be coated with a corrosion protectant after all
connections are torqued.
https://www.fleet.ford.com/truckbbas/non-html/Q102.pdf
Senior User
Joined: Dec 2007
Posts: 115
Likes: 1
From: miami beach
might seem like a stupid question, but I need to replace the wiring coming off the passenger battery that goes I think to the engine or alternator body. On the passenger battery in my 6.0L there is the main positive battery cable that comes to the positive battery post, but then there is a smaller secondary red, positive wire running off that back to the engine or alternator. I found this wire to be burned the other day. In fact the red rubber cover that slips over the positive terminal had a hole burned through it. Now the battery seems to have died..the driver battery has been doing the work, but it was slow starting the other morning then yesterday the truck needed jump starting. I've had problems with the batteries not lasting more than 15 months in this truck for the last three battery changes. I started to figure it could be the alternator, but maybe it was this wire all along? Where can I get a replacement wire for that smaller secondary positve cable off the passenger battery?
Hotshot
Joined: Dec 2003
Posts: 15,368
Likes: 121
From: Stuttgart, Ar
might seem like a stupid question, but I need to replace the wiring coming off the passenger battery that goes I think to the engine or alternator body. On the passenger battery in my 6.0L there is the main positive battery cable that comes to the positive battery post, but then there is a smaller secondary red, positive wire running off that back to the engine or alternator. I found this wire to be burned the other day. In fact the red rubber cover that slips over the positive terminal had a hole burned through it. Now the battery seems to have died..the driver battery has been doing the work, but it was slow starting the other morning then yesterday the truck needed jump starting. I've had problems with the batteries not lasting more than 15 months in this truck for the last three battery changes. I started to figure it could be the alternator, but maybe it was this wire all along? Where can I get a replacement wire for that smaller secondary positve cable off the passenger battery?
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