Battery ground cable

[Guest]

Ok, so in tinkering this past weekend I noticed that the battery negative cable which appears to be connected to the block had some of the insulation melted. When I ran the engine a bit the cable got fairly hot. I have new cables and ground straps for the battery, what would you guys recommend as far as routing for ground, or why it would be heating up? does this sound like a placement issue? Any input would be welcomed.

[jopizz]

I don't think it's a placement issue as the normal spot is attached to the generator bracket. Is it the original ground wire. The originals were way too thin in my opinion. Use a good heavy duty replacement and that should fix the problem.

John

[Guest]

Not the original

Not sure why it was so hot, as the cable appears fairly heavy duty. I will see when I get it off if there is any issues lurking. I am wondering if the battery that was in the vehicle previously was incorrect or something. I just swapped batteries with one my cousin got for me (works for a battery distributor) and he also got the new cables. It may resolve with the switch, I just want to make sure I am installing it correctly (seems like it should be a straight forward swap though).

[simplyconnected]

Ford spent the least amount of money possible on heavy cables. They work, but just barely.

The National Electrical Code would never allow these wire sizes in a house or garage. The first rule is, the supply must meet the damand. The second rule is, the wires must be protected by an overcurrent device (like a breaker or fuse). Well,.. it kinda works if you consider duty cycle but there is no wire protection. If you ever found a wire in your house that gets hot, it needs to be upgraded and fused properly.

So Ford ran a short #8 stranded copper wire to the nearest point on the engine to the battery. The real load is at the Starter Motor, another three feet away! So count up three feet of heavy copper wire times millions of cars. The cost savings is huge.

For proper (but not concours) and most efficient Starter Motor operation, BOTH wires should be connected at the Starter Motor because current flows much easier through copper than it does through iron. In fact, iron (by definition) is 2% carbon. Carbon is a resistor.

Pop for the few extra feet of stranded #6AWG copper wire (for 12 volts) and bolt it to the bell housing close to the Starter Motor. You will notice a healthier cranking speed, your engine will start sooner and your battery won't need to work as long. Oh, and... your wires won't get hot.

Keep your connections clean and tight, and don't let the end connector take all the strain from vibration. I use one of those empty bolt holes on side of the block to strap both wires before they terminate. That way the middle of the wires are the only places that vibrates, so leave some slack between the engine and the body.

#6 American Wire Gauge? Yep. For my 55's six volt system I use #1 welding wire. The 6 volt battery is 85amp/hour (not 55a/hr).

One last thought: Make sure your car body is grounded. Ford used a strap coming off the LH head to the firewall. New cars use a #10 from the battery (-) to the radiatior support. If you think about it, grounding at the battery is better because that wire never sees engine vibration. Hope this helps. - Dave

[Guest]

Can I revive a dead thread? I have a dead short, when I hook up the negative battery cable to the terminal, it smokes and there is a big spark. A test light hooked from the negative battery terminal to the negative battery cable lights up. When I disconnect the yellow wire from the solenoid to the generator, the test light goes off. The ground wire is connected to the generator bracket. Why the short?

[jopizz]

If the short goes away when you remove the cable from the solenoid then I suspect you either have a bad generator or the wire is shorting on the generator case. There's an insulator on the generator lug. It's possible the insulation is gone and the lug or the ring terminal is touching the case.

John

[simplyconnected]

...When I disconnect the yellow wire from the solenoid to the generator, the test light goes off. The ground wire is connected to the generator bracket. Why the short?

All battery power starts at the starter solenoid if you have the original setup. Start there, disconnecting each power lead and see which one makes your 'test lamp' shine. Don't forget that the starter solenoid can also be shorted to ground. The yellow BATT wire for your charging circuit goes through your voltage regulator FIRST, before connecting to the generator.

There are three relays inside the voltage regulator. The far RH contact, right above the BATT terminal is the cutout relay. It disconnects the battery from your generator every time you turn the key off. The Cutout Relay only energizes when the generator starts producing power. So, a shorted generator is possible but it is disconnected from the battery and it will never turn on the cutout relay.

If you suspect the charging system, troubleshoot from the voltage regulator's three terminals (Batt, Armature & Field).

If you suspect components in the car body, troubleshoot from the yellow wire, starting at the starter solenoid and leading to the headlight switch (as shown in the electrical diagram). - Dave

[Guest]

I'm sitting here having breakfast, but I think you guys have resolved the problem. I have a wire that goes from the solenoid to the generator. That doesn't seem right, as Simplyconnected says, it should go to the voltage regulator first. That must be the problem. I will check tonight, the car is on my friends lift, he is at work. Thanks.

[jopizz]

The way the wires are run it can make it appear that it goes directly from the solenoid to the generator. They are also the same color and thickness so it can be confusing. The yellow wire that goes from the solenoid to the voltage regulator splits and goes to your horn relay so that could also be causing your short.

John

[Guest]

Resolved! Yes, you are right, it looks like that wire goes to the generator, it doesn't, there is another similar wire that is right there. Anyway, it was the two wires on the solenoid, they were touching the body, and, shorting.

[simplyconnected]

...When I disconnect the yellow wire from the solenoid to the generator, the test light goes off. ...Why the short?

All battery power starts at the starter solenoid if you have the original setup. Start there,..

Resolved!... Anyway, it was the two wires on the solenoid, they were touching the body, and, shorting.

I wonder why you didn't know that when you took the yellow wires OFF of the solenoid. Am I missing something here? - Dave

[Guest]

Yeah, I don't know, I thought everyone would buy that. I had someone crank it, I attached the wires to the solenoid. Big spark. I did it again! Big spark. Then, I put it back together. No spark on attaching negative cable to post, no test light on between negative cable to post. Everything seems OK. ??? Please, you tell me. I'll bet the generator doesn't work... I've got to run it, and, check the voltage at the battery.

[simplyconnected]

Yeah, I don't know, I thought everyone would buy that. I had someone crank it, I attached the wires to the solenoid. Big spark. I did it again! Big spark. Then, I put it back together. No spark on attaching negative cable to post, no test light on between negative cable to post. Everything seems OK. ??? Please, you tell me. I'll bet the generator doesn't work... I've got to run it, and, check the voltage at the battery.

All we know is what you tell us even if it is false information, we know these cars and we see through your words. We don't need to 'buy that' at all. We HAVE told you with in-depth and accurate advice even though you grounded your battery cable twice, then cried 'short'.

If you're the type of mechanic that sets his car on fire doing an oil change, you might consider hiring a garage to do your work. It will be faster and cheaper for you.

I spelled-out how your voltage regulator isolates the generator. Now, you are asking us if the generator is still good. My friend, you will need sound troubleshooting techniques to answer your question and put your mind at ease. I am an Apprenticed Electrician, not a magician and Detroit is ten hours from you.

BTW, both my folks come from just east of you in Wilkes-Barre and Kingston. I know the area to be full of honest, hard-working people who are eager to help their neighbors with car problems. - Dave

[Guest]

Just trying to fix it.

[jopizz]

If the yellow wire to the voltage regulator was touching the body the worst you probably did was smoke the regulator. I would be more concerned about the main yellow power wire that goes from the solenoid to the headlight switch. That would've also been grounded. That powers the entire car. If you have power windows or power seat it has a circuit breaker for protection so you should be ok. If not you may have smoked the headlight switch or burnt the wire. If you start the car and the GEN light goes out then your generator is probably ok. Putting a voltmeter on the battery when it's running will tell you for sure. I would keep an eye out to make sure everything else is working and you don't smell anything burning.

John