Fusing Alternator Output?

shawn

shawn

running dog lackey of the oppressor class
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Mar 13, 2005
Location
Raleigh, NC
I upgraded the alternator in the Jeep, now looking at replacing the feed wire back to the battery. It's a bit undersized for the new alternator.

What I'm wondering... is the factory puts a fusible link on that line. What are they worried about that I'm not considering? I'd just run a decent wire from the alternator back to the PCM. I've got bigger unfused wires (starter lead, winch lead, etc) running all over the chassis. Why's the alternator special?
 
only thing i can thank of is so if you get a short you will not fry your PCM
just my .02 i would not worry about puting one
 
What if the voltage regulator fawks up? I had a vatozone alt that the VR went out on. It was charging 14v at idle (measured at the battery with a multimeter), and 18v at 2500 RPM. I usually shift gears at 3k RPM.
 
I had an alternator go nuts and overcharge in my fj40. The wire insulation melted and caused it do ground out frying alot of crap. Run a fusible link.
 
sgtbriangreen said:
What if the voltage regulator fawks up? I had a vatozone alt that the VR went out on. It was charging 14v at idle (measured at the battery with a multimeter), and 18v at 2500 RPM. I usually shift gears at 3k RPM.
Click to expand...


The voltage regulation is done in the PCM on TJs

But it looks like there are a couple of failure modes that will create a short to ground. So that's the reason for the fuse protection.
 
Yep. Diodes can short out among other things. Napa sells fusible link wire or a mega fuse holder with two big 5/16" lugs that you drop a mega fuse over. Mega fuses come in 100-200 amps at least in various increments. Ford uses a 175 mega fuse to protect most of their 130 amp alternators so you can also grab the fuses and sometimes ford fuse holders when you're pulling Taurus fans.

Sent from my XT907 using Tapatalk 2
 
Yeah, I bought another ANL holder and 150A fuse. I've got a couple of those on the trailer already, so there are plenty of spares around should I need them for whatever reason.

4ga alternator lead, here I come....
 
I have 00 battery and starter cables and a 4ga (I think) on the alternator with a 200 amp mega fuse. 2000 cranking amps flow very well through it and spins my old diesel over real quick!

Before I did the Cummins swap and was still running the 12/24 volt system on the old 6.2 in my CUCV, I managed to ground the alternator lead while tightening the belt. It melted all sorts of fusible links, but I'm glad they were there!
 
Is it definitely a fusible link or a diode to prevent back feed motoring the alternator and drain issues?
 
Ron said:
Is it definitely a fusible link or a diode to prevent back feed motoring the alternator and drain issues?
Click to expand...

Wiring diagrams say "Fusible Link".

I'm guessing that means it's a fusible link.
 
When did you learn to read diagrams?
Do you need to post symbols for us to be sure?

:flipoff2:
 
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