ALTERNATOR recurring failure (22RE). Any help appreciated.

[Dopesick]

Dopesick, must one of the (+) battery cables (the one from battery to fuse block) be a fusible cable or can it be replaced with a normal cable? I know the 80 AMP fuse in the fuse block is connected to a white fusible cable, but I'm not sure if it's the same cable mentioned here.

Battery I just replaced it recently with a 700 Amp capacity one.

Is a fuse-able link needed, No.
Should a fuse-able link be installed, Yes.

I'm pretty sure the alternator isn't the main issue, but rather a symptom or a consequence of _

You are 100% correct. With the photos I can totally see a two fold problem.
1: The ring terminals used.
2: The battery terminals.

First and foremost: I want to stress GET RID of those terrible crimp on ring terminals. Those ARE NOT rated for the capacity (amperage) those cables will see.
The problem there is.... HEAT. Your alternator see those as a load, while it is pushing power towards the battery for charging.
This causes your alternator to work harder than need be, as the connectors are actually just a "resistive load", which the battery also is technically.

Secondly: get rid of those battery terminals completely. Get yourself a set of these: https://www.amazon.com/gp/product/B00JK9FTZI/

If you must use crimp terminals, at the very least use ones like these: https://www.amazon.com/SELTERM-Marine-Terminal-Battery-Eyelets/dp/B073FBS229

When using those, use a proper crimp tool. DO NOT, use a vice like the guy in the video. All he did was flatten the connector to the cable. This does not get as much contact surface as possible of the connector to cable as should be done!.
Do however, use a small propane torch to heat the terminal and back flow it with solder, like this:

 

[BMarino]

how did things work out ?

Sorry for the late response, I was carried away enjoying our truck, which has been working flawlessly since we fixed this issue!


What I did was change the old alternator for an OEM Toyota remanufactured one:







as well as change the fusible link wire, which I'm now pretty sure was the culprit of the electrical problem:







New fusible link wire on the left. As you can probably tell, the old one was definitely NOT an OEM one, as its metal plate was not brass and its crimp connector was pretty flimsy compared to the new one's. That, in addition to the fact that it was already "melted" as observed previously.


It was impossible to get my hands on the kind of battery terminals I would have liked and as Dopesick suggested. Got a pair of Lynx heavy duty battery terminals from the nearest Autozone (3 hour drive), and had to force them a bit open in order to "properly" accomodate on the battery posts. Crimp connectors, same story. However, I DID THOROUGHLY BRUSHED AND CLEANED TO ALMOST SHINING CONDITION every crimp connector which was going to be reused.


This was the final setup:





RESULT: everything's now working perfectly fine ! Voltage readings with a multimeter are adequate as should be.


As I said, I'm now pretty sure the main problem was the old fusible link wire. I'm sure it would be best to upgrade battery cables, wires and crimp connectors as Dopesick and vintageracer have suggested, but for the moment being what's been done has worked, so I'm keeping it that way.


Cheers!