Do battery cables go bad?

[Industrial Toys]

I know a company that makes thousand of crimps for fleet equipment. I have no doubt they will last the ten years that the equipment may be in service, but I don't think the crimps are up to OEM standards. OEM will get the perfect die. These guys will use the best they have to fit. Since it is a two piece die, you can see where it is sharp and deformed between the two dies. You don't see that on OEM.

 

[Fuddy1952]

I should have saved the one I changed a couple weeks ago. Carrier transport refrigeration unit that had been looked at multiple times and had two starters thrown at it. Did a volt drop on the positive cable and it was losing 3.8 volts. Cable looked fine visually, no breaks in insulation, no damage at cable ends. Stripped insulation off and the cable inside had corrosion in multiple places throughout. Visual inspection only works on really evident problems. A volt drop test is the most accurate way to determine cable condition. Look for a max of .5 volts on positive and .3 volts on negative. Just because the cable has insulation covering it doesn't mean that it can't get moisture inside of it. There is always a bit of condensation that will form inside.

There you go. Voltage drop measurement is a great test, especially under load. As to why the wire fails internally as I mentioned it could easily be a manufacturing flaw. Domino effect also, a couple strands break, you can't see it from outside, but it's no longer the gauge wire it was.
A chain is only as strong as it's weakest link.

 

[RickB]

I should have saved the one I changed a couple weeks ago. Carrier transport refrigeration unit that had been looked at multiple times and had two starters thrown at it. Did a volt drop on the positive cable and it was losing 3.8 volts. Cable looked fine visually, no breaks in insulation, no damage at cable ends. Stripped insulation off and the cable inside had corrosion in multiple places throughout. Visual inspection only works on really evident problems. A volt drop test is the most accurate way to determine cable condition. Look for a max of .5 volts on positive and .3 volts on negative. Just because the cable has insulation covering it doesn't mean that it can't get moisture inside of it. There is always a bit of condensation that will form inside.

At the rated load. In other words if the cable size was designed to pass 275 amps of starting current with maybe a .5 volt drop or less, then you have to assume the engineer did the math and the cable originally met that spec. When you attempt to apply the rated load that it was designed for and it drops too much voltage at that load, then by definition the cable is defective. I have seen so many that looked so good from the outside, and then you remove the jacket, and then the true nature of the degradation becomes apparent.

I have had similar experiences multiple times.

 

[jaxs]

I'm comfortable in saying with 99.9% certainty OP's problem isn't primarily with a cable. Two schools of thought have come forth,one holding out experience as the answer for electrical trouble,a second say's electrical problems can be solved using principals and theory. Beit headlamps,lack of ignition spark or blown fuses ,the same debate always take's place. One faction claiming to have seen xxxx to cause the exact problem and another saying get out your multimeter. If I were hiring an electrical troubleshooter,a 25 year old that can use a multimeter but only 1 year experience would get the job everytime over one with 30 years experience but can't realize full potential of a multimeter. Shortly after I came to this forum,a member suggested a thread dedicated strictly to basic electrical theory and use of multimeter. There was little response and 75% of it was against the idea. Non of that is suprising,,,,,,,,until,,,,,,,you consider how many weigh in on electrical discussions. If nothing else I say help's a single person,I promise you will never regret taking a semester of entry level dc circuits or brief apprentice with a knowledgeable individual. That will not make you an expert but you will not be asking questions like "voltage drop at what load"and best of all you will chase your tail far less often.

 

[k0ua]

I'm comfortable in saying with 99.9% certainty OP's problem isn't primarily with a cable. Two schools of thought have come forth,one holding out experience as the answer for electrical trouble,a second say's electrical problems can be solved using principals and theory. Beit headlamps,lack of ignition spark or blown fuses ,the same debate always take's place. One faction claiming to have seen xxxx to cause the exact problem and another saying get out your multimeter. If I were hiring an electrical troubleshooter,a 25 year old that can use a multimeter but only 1 year experience would get the job everytime over one with 30 years experience but can't realize full potential of a multimeter. Shortly after I came to this forum,a member suggested a thread dedicated strictly to basic electrical theory and use of multimeter. There was little response and 75% of it was against the idea. Non of that is suprising,,,,,,,,until,,,,,,,you consider how many weigh in on electrical discussions. If nothing else I say help's a single person,I promise you will never regret taking a semester of entry level dc circuits or brief apprentice with a knowledgeable individual. That will not make you an expert but you will not be asking questions like "voltage drop at what load"and best of all you will chase your tail far less often.

yep....and there are the guys with 50 years of experience running service calls, and really really know how to use a multi-meter, or build one for that matter

 

[bcp]

And there are others guys with 1/2 year of experience repeated 100 times.



Bruce

 

[jaxs]

yep....and there are the guys with 50 years of experience running service calls, and really really know how to use a multi-meter, or build one for that matter

Without a doubt but there's an equal number charging $80 an hour to work in shops that think Ohm's Law has something to do with prevention of cruelty to animals. Them boys you speak of can disassemble ECMs and fix them.

 

[RickB]

I should have saved the one I changed a couple weeks ago. Carrier transport refrigeration unit that had been looked at multiple times and had two starters thrown at it. Did a volt drop on the positive cable and it was losing 3.8 volts. Cable looked fine visually, no breaks in insulation, no damage at cable ends. Stripped insulation off and the cable inside had corrosion in multiple places throughout. Visual inspection only works on really evident problems. A volt drop test is the most accurate way to determine cable condition. Look for a max of .5 volts on positive and .3 volts on negative. Just because the cable has insulation covering it doesn't mean that it can't get moisture inside of it. There is always a bit of condensation that will form inside.

At the rated load. In other words if the cable size was designed to pass 275 amps of starting current with maybe a .5 volt drop or less, then you have to assume the engineer did the math and the cable originally met that spec. When you attempt to apply the rated load that it was designed for and it drops too much voltage at that load, then by definition the cable is defective. I have seen so many that looked so good from the outside, and then you remove the jacket, and then the true nature of the degradation becomes apparent.

yep....and there are the guys with 50 years of experience running service calls, and really really know how to use a multi-meter, or build one for that matter

Exactly. Pretty sure us old farts all mentioned voltage drop testing. I guess he thought we spit on our fingers..... I think I’m done here.

 

[4570Man]

How do you load test a cable without the battery drop ruining the test?

 

[Industrial Toys]

You take a reading at each end of the cable. Forget the voltage, you are only interested in the difference. It would be handy to have two meters calibrated the same and connected with clip leads. But again, taking good readings of this miserable 12 volt system in a dirty environment can be challenging.

I don't even like to bring my FLUKE stuff near some dirty old engine! lol