I only connected one fusible link (B) to both D and E. This was the same setup as before.

 

Soldered, crimped, interleaved strands? Is the link hot across the whole section or only at the connections?

 

Interweaved and then twisted under a wire nut. The warmth is all along the fusible link. Not hot, just warmer than the surrounding wires.

I may go out and reconnect the battery and see if it warms up all by itself without the truck running. If you will recall, that is exactly when the original burning of the fusible link occurred.

 

Some thoughts:

If the set up was OEM then copying the original fusible link gauge and length is the way to go. If you suspect that the area was hacked then a rule of thumb is a fusible link gauge four wire size numbers smaller than the circuit wire gauge with a maximum length or 9". So a 12 gauge circuit gets a 16 gauge fusible link.

The connection is important on high current connections. Best is to have good clean wire ends, push them together end to end, roll the connection back to tight and then good solder flow with a hot high current iron resulting in a shiny smooth complete solder covering. Then waterproof.

The links can get warm under high current. A double check would be to measure the voltage drop across the whole repair under a full load but battery positive to alternator stud is the same thing. You measure battery positive post to alternator stud voltage drop and add that to alternator case to battery negative post and the total needs to be less than 0.5VDC


George

 

can you sketch out what you are saying here? It sounds like electrical-ese.

 

Here you go:





George

 

they were not equal:

pos to pos = 0.47 V stable
Neg to neg = 0.01V, sometimes 0.02V

so , it looks like 0.48 to 0.49 when I add them

 

That technically meets the limit but the positive to positive readings on the high side. It may have something to do with your temporary connection. Pierce the wires on either side of the fusible link on the permanent wires themselves and see what your voltage drop is. this is all with the truck running of course.

When it comes time to make the permanent connection this is the right way to do it.

you need good clean wires to get a good solder connection. Strip away some insulation and splay the strands out a little bit and then push the strands together and roll them tight. Then you take a small piece of solid wire and wrap a cage around the connection. If the wires are a little corroded then you add some liquid flux first. Then you need a really hot soldering iron, a 15 white pencil iron won’t be hot enough. You make sure that the tip will tin good, nice and shiny with a little solder. If not, clean the tip with a wet rag. If not then you need a new tip. You heat the wire up really good with the iron and then start applying the rosin core solder and keep working the wire till it’s so hot that the solder flows everywhere and makes a real pretty smooth shiny solder joint. Don’t just touch the solder to the hot iron, the wire Has to be hot enough to pull all that solder in and flow it really good. If you can still see raw copper or the joints matte looking or mottled or dirty then you didn’t do it right. Then put a piece of shrink wrap tubing over the joint and heat it with a heat gun and you’re finished. That will give you the lowest resistance connection that’ll last forever:


















George

 

I just went back to let it run awhile and the fusible link got hot. I measured again and got 0.64V and 0.02V

 

I think our messages crossed a few seconds apart. See my last post above about the revised numbers