Fatter wiring

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Pentarockstar

Pentarockstar

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Hello Mopar nuts,

I have a 69 dart swinger. I recently installed an electric cooling fan. This is over taxing my factory wiring, since the wire from the alternator appears to be 10 gauge or so. So, I would like to replace the alternator wire and the wire that goes from Alt gauge to the battery. I have a wiring diagram, but I can't find where the wire from the alternator splits off to feed everything else. I know it splits before the Alt guage, but I don't know where. Any ideas would help, thanks.
 
Your fans should get their power directly from the alternator, or as far upstream as possible. If you connect it to the battery the operating load must still travel through the entire charging circuit. Most modern cars have a relay box that is inline between the alternator and battery, if you plan many electrical accessories, this would be a good thing to add.
 
vdoalrvto said:
Hello Mopar nuts,

but I can't find where the wire from the alternator splits off to feed everything else. I know it splits before the Alt guage, but I don't know where. Any ideas would help, thanks.
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I would look on the wiring that is along the firewall for the "splice" where they are all joined together. They mold a big rubber blob around it and cover it in electrical tape.
 
vdoalrvto said:
but I can't find where the wire from the alternator splits off to feed everything else. I know it splits before the Alt guage, but I don't know where. Any ideas would help, thanks.
Click to expand...

That's the limitation of the factory setup, IT DOESN'T!!! The primary wire runs from the alternator through the firewall connector to the amp gauge and then begins to split up to the battery (starter relay), ignition switch and headlight switch. The bulkhead connector was barely adequate for the stock loads when new, and after 40 years of dirt and corrosion, they get problematic (catch fire) if you route heavier loads through them.

As I suggested above, an "axillary distribution/relay box" can be added for fans, lights, stereo, etc... Another good mod is to run a 10 AWG wire from the alternator directly to the battery (use a fuse link to protect). This will divert the main charging load from the bulkhead connector and AMP gauge. The AMP gauge will no longer indicate much, but it and the bulkhead connector will be far less prone to overheating and melting down due to increased load.
 
Thanks for the advice guys. I am currently getting power from the starter relay. The car does have the cooling system it was born with. I decided to add a cooling fan for long waits at lights and for cooling after the car has stopped. I have thought about running the fan directly off the alternator, this would take care of the load while it is running, but when stopped it would have to come all the way from the battery through frail factory wiring. I will look into the relay box.

Thanks again!
 
Where would I go about finding a relay box? So what you are saying C130 chief is to connect alternator and battery then a link that splits off to supply heavy loads and another link to supply the rest of the car. Bypassing the amp gauge.
 
First, if your ALT wire isn't getting hot, it is big enough. A fan load is fairly small (<20 A) compared to max alternator output (>60 A). Even without a fan, the alternator often outputs max to recharge a low battery, so all cars must handle that.

Post #5 is slightly wrong. The ammeter measures current flow in/out of the battery, so a single wire from ammeter to BATT+. The ALT feed splits off between the bulkhead connector and ammeter. It is a "fused junction" wrapped in electrical tape. The schematic shows it as a big "dot". Mine was a bit green from corrosion, and others have had a complete meltdown there. I cleaned and soldered the fused junction.

With corroded firewall connections and a bigger alternator, it is always smart to bypass the ammeter within the engine bay, as recommended. Run a thick wire (~8 awg) from ALT to BATT+. You can tap your fan relay supply from either end or in the middle. If you want to keep your dash ammeter active, you can add a series diode pair that keeps most flow thru the ammeter until it approaches full scale, then shunts around the ammeter. Search for my post for more info.
 
Thanks for the input guys, after doing some reading I see this is not a new thing.

After a drive I on a hot day, I felt the wiring behind the amp gauge and was shocked how hot it was.

I would like to keep the old amp guage and run new wires inbetween Alternator and battery, bypassing firewall connector, mostly for reliablity. Also I am an electrical nut job, that likes to tinker. I would like to look into the Diode fix, but I am not smart enough to find it, so if you could direct me.....

Thanks so much for your input on what appears to be a very common question.
 
vdoalrvto said:
Also a relay box is a good idea for lights and heater fan.
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I installed a relay/fuse box from a 90's Jeep in my two A's, but I will use a separate relay for the radiator fan since that can be a big load (except for wimpy after-market fans). The rad fan is a simple isolated control loop so I want to keep it all separate. I have a Hayden sensor/controller w/ integral relay.

Search for "Modernized Engine Wiring" for my diode bypass mod.
 
And I will start with a thanks for taking the time here. Bill, I liked your idea about putting the voltage regulator next to the Alternator. I will guess that you just brought over a ign. lead to complete the circut. What we are trying to do here is defeat the heat and melting of bulkhead connector. Won't running larger gauge wire and skipping the bulkhead connector accomplish this task? Then couple that with taking the high loads off at the alternator?

I think that maybe my brain is to small, but if you could post a diagram of your shut circuit with part numbers I think we could all benefit from your knowledge. I really like to keep the amp guage I think it is cool and special.
 
Some after-market kits bolt Vreg to the backside of the alternator. In my small block engine, I ran a 12 awg IGN wire to the alternator field+ (across timing cover), so use that for Vreg "sense" as well (neligible voltage drop). It comes from a relay in the box, actuated by IGN1 (& IGN2 jumpered at key) thru the firewall.

My slant engine is similar, but I run IGN across the radiator support to a terminal block on the passenger inner fender, where I also need it for HEI ignition. Still in-work.

The only wires that normally melt the bulkhead are the large ALT and BAT terminals. The others just mess up that circuit when the resistance is too high (dim headlamps, weak spark). 63 & 65 cars are fairly immune to bulkhead melting since Chrysler was smart enough to use big buss bars for ALT & BAT, as are taxis and police with "fleet wiring".

I made no drawing of the shunt bypass. In my small block I used smaller diodes soldered together, that I clamped to my Battery Brain. In my slant, I will use the big diodes I found later that are simpler and more robust. You can put the diodes at either ALT or BAT ends, or even in the middle of the run. But, they must have a good heat sink (P=i*dV, could be 100W w/ 100A alternator) and they can't touch ground. Perhaps right at the BAT+ post would work. BAT+ is also at the big starter relay stud (gone in my cars).
 
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