Hot alt batt+ cable - new build
 

Guys, was hoping someone can give me some insight on an issue I'm having with my new build.

81 C10
383 Stroker

I'm using 90% of the original harness minus a few things not being used at all + some soldering I've done at my charging side. Attached is a lot of information about how my charging system is hooked up. My cable at the Alternator to a new splice I made is getting hot enough to melt the loom it was in, it's at about 170-190F after the truck runs for 15-20 min. Tricky thing was that it's only from the alternator to the splice, the other two cables that go to the battery and cab are fine.

A few points:
-Alt charges at 13-14V according to OEM voltmeter
-cut off the factory butt connector like the one in the pic below (is there a resistor in there?)
-recrimped with yellow butt connector using OEM cable (10Gauge)
-noticed the melted loom after cam break in
-replaced butt connector and oem cable with new 10Gauge cable purchased from OriellyAuto and solder'd at splice.
-temp lowered BUT still gets hot
-with laser temp gauge it's hottest at Alternator batt+ port but not much difference.

Please chime in and let me know what else to check, grounds are good, connections clean, voltage drop is 0.1volts at random connections i checked.

My charging system
Attachment 1315176
Splice before the solder and new 10Gauge cable to Alternator Batt+
Attachment 1315178
OEM Connector that used to exist but I removed it and soldered new cable
Attachment 1315177

Re: Hot alt batt+ cable - new build
 

You should start by moving the ground to the block and then ground the frame and body.

Re: Hot alt batt+ cable - new build
 

Grounds are there. 8 gauge ground straps.
Attachment 1315208

Re: Hot alt batt+ cable - new build
 

I can only offer some information here....for one, I prefer to keep all the hot 12V leads away from the starter and just use the firewall junction instead-heat builds resistance and having it all @ the starter IMO is a mistake-why it took GM so long to change that idk. Second, parts store wiring is NOT j1128 rated which means its not suitable for under hood operating temps-and, neither is the parts store plastic conduit-the Delphi conduit I use is heat resistance and flame retardant and you can see the difference because the high temp stuff will have a blue or red stripe along the spine.

There are differences in the quality of wire which is the main reason why I wouldn't suggest Chinese Dorman wire rolls-you probably noticed just the act of soldering the butt splice that the replacement wire jacketing started to melt a little from the heat. A cam break in will generate a lot of under hood heat and the thicker gauge wire can handle it a bit better since they transfer heat a little slower than thin stuff.

Re: Hot alt batt+ cable - new build
 

....and chrome holds heat really well-I'd suggest a natural aluminum cased alternator too. Heat is an electrical killer.

Re: Hot alt batt+ cable - new build
 

Good info!!! I agree the starter area generates tons of heat and I know it's bad for electricity. I'll prob end up installing a separate lug for those electronics & purchase the J1128 rated cable...I'd hate to have an electrical fire within my first few months of trying to enjoy my truck...

Re: Hot alt batt+ cable - new build
 

I'm still puzzled as to why only that piece of cable is getting very hot and the others that are solder'd to it are fine...

Re: Hot alt batt+ cable - new build
 

You'll quickly see the difference in quality with the wiring. Are you missing the factory firewall 12V junction then?

Re: Hot alt batt+ cable - new build
 

Are you talking about the fusible link that was on the top of the firewall near the driver side? I removed it cause it wasn't really being used. A plug at the heater core was the only thing hooked up to it I think. The PO did some riggin' of his own so the truck wasn't factory when i purchased it.

If I put one I want to install it in the frame, the firewall has been smoothed down and looks clean.

Re: Hot alt batt+ cable - new build
 

Ahh...OK, that makes sense-yeah, PO must have had a better idea than GM ;)

Re: Hot alt batt+ cable - new build
 

Ain't that the truth. My PO really had some garbaged up stuff on his wiring.

I would measure the resistance on the alternator feed wire between the alternator and the starter for excessive resistance in the splice and maybe do a voltage drop on the wire.

Running a temporary feed wire from the alternator to the battery positive cable around the splice might be a way to
tell if there's excessive resistance in the splice as well.

Re: Hot alt batt+ cable - new build
 

So the + cable to the starter in #8 as well?
The big battery cables (+ and -) are there to run the starter--that's all.
If the big - cable isn't connected to the block you're guaranteeing yourself trouble sooner or later.

Re: Hot alt batt+ cable - new build
 

I have a voltmeter; I'll measure the resistance at the cable from the alternator to the starter. I know that heat causes an increase in resistance so I'll measure it cold and hot...(give me 2 weeks for results, currently working offshore)

I'm more than likely going to replace the new cable that I bought from Oriellyauto and get something rated for high temps.

Re: Hot alt batt+ cable - new build
 

No the cables that go from the alt to the starter are 10 Gauge. (Just like OEM I believe)

I went with a 2 Gauge + cable from the battery to starter because I relocated the battery to the rear of the frame, about 12-15ft with routing. The 2 Gauge ground (2FT) is bolted to the frame all contacts cleaned with wire wheel before-wards.

I may have to disagree with you that I need to run the NEG cable to the block because I have 0.1 Ohms resistance between the negative post and block plus zero issues with starting cold or hot. And no issues at all other accessories or components from the cab to the radiator mount where my headlights and parking lights are grounded. I might be wrong please correct me if so...I take criticism well. ;-)

Re: Hot alt batt+ cable - new build
 

CORRECTION: Ground straps are 4 gauge; 5 total with ground washers.

-1 on each side of cab to frame
-1 on each side of engine block to frame
-1 from frame to radiator support

Re: Hot alt batt+ cable - new build
 

Sounds like you are well grounded to me

Re: Hot alt batt+ cable - new build
 

I'm going to install a separate busbar in the forward frame like this one and move all cables away from the starter to keep them away from the high temps.
http://www.texasindustrialelectric.c...-375-RC_sm.gif

I was also thinking of upgrading the 10 Gauge charging cable from the Alternator (Batt+) to this new busbar (that will connect all the way back to the battery via 2 gauge cable) but I'm not sure what gauge, 8, 6, 4? Definitely J1128 like gmachinz mentioned.

After the build I will have:
-Vintage A/C
-Two amplifiers for sound system (highs and lows)
-Dual BeCool Fans
-Electric Fuel pump
+OEM headlights, parking lights, etc...

Re: Hot alt batt+ cable - new build
 

You have a pretty large amp draw on the system with all that. In my opinion a 10 SI alternator rigged up to put to 120 amps is going to overheat and not last very long. I would upgrade to a CS 144 or an AD 244 and be done with it.

Run a 4 gauge alternator from the alternator to the buss bar and then use an 8 gauge from the buss bar to the starter where the battery cable connects.

Use fusible links on all the wires that come off the buss bar including the battery charge wire to the starter. You'll have a relay for the fuel pump so a 30 amp AGC fuse can be used in the feed line from the relay. If you had TBI with the same pump you can use whatever was there.

There is an adapter harness plug that will plug into the sI alternator plug and the other end will plug into the CS alternator. They're available at most of the auto parts stores.

Re: Hot alt batt+ cable - new build
 

Sounds like a thermal overload at that splice. Cause may be the battery in the back and an over worked alternator. I'd go wit a CS style alt and recheck the splice. crimp it then solder it. use a fluoropolymer heat shrink (PTFE) for high temps.

Re: Hot alt batt+ cable - new build
 

I am going to buy a DC amp clamp meter and get an idea of every accessory load on my system. Would everything powered on and the clamp on the main battery cable be the best way to measure the amperage load? If it's over 100amps after everything is running then I'll look into the CS or AD upgrade.

Here's an updated drawing of how the charging system will look after bus bar and fusible links are installed. http://www.imageupload.co.uk/images/...23/Wiring2.jpg
Let me know if there is something I can change before buying all the pieces I'll need.
Attachment 1315712

Thanks to all who's been responding!!

Re: Hot alt batt+ cable - new build
 

DWCSR, I'm getting rid of that splice all together and upgrade the charging cable and add a bus bar and fusible links...see the pic. Thanks for your input though.

Re: Hot alt batt+ cable - new build
 

Your diagram shows an 8 gauge wire going to the starter from the buss bar and the large battery cable going to the buss bar. I have modified it in the diagram below to show the large 2 gauge battery cable going directly to the starter. I don't think the 8 gauge wire will handle the amp draw for the starter.

With your permission I'd like to use this diagram for future posts.

Attachment 1315800

I think the buss bar is a great alternative to the stock system.

Re: Hot alt batt+ cable - new build
 

Now would be the ideal time for a serpentine swap! Then a 140A CS144 alternator upgrade would be a snap!

Re: Hot alt batt+ cable - new build
 

Vette I agree with you about the 8 gauge cable. I'll go with a 2 Gauge. I like your drawing BUT I wanted the battery cable to go directly to the bus bar and then feed everything including the starter cable off of there because the high temp near the starter would cause some resistance at that battery cable at long drives not allowing it to be used at its full potential. Less resistance =more efficient flow of electricity. Agree?

Re: Hot alt batt+ cable - new build
 

I like your enthusiasm...I've been turning wrenches, sweating, cursing, bleeding, and starring at this project since Dec2013. I'd like to get it on the road and enjoy it for a little bit. I'll prob do the serpentine upgrade when my a/c belt breaks and I have to remove a perfectly intact belt just to replace it. It's a luxury I'm living to live without for a little while.

You definitely motivate me though...