CCKen

Crow Horse

If you up the cabling to ridiculous levels, and size the fusible links to match the cable size, you have now created a circuit that is capable of supplying far more current than it was designed for. This is a fire hazard.

What's the solution?

Size the fusing to match the original circuit to maintain the original protection, of course.


This was my concern. If I'm understanding you correctly, if I use 4AWG cable from the alternator (alt. is stock) I should use a 10AWG fusible link (stock).

Crow Horse

I was hoping to start this project by first replacing the negative cables but the battery to fender cable bolt foiled me. Soaked it with PB but it appears that the nut is just spinning. I can probably gain access to it by removing the fender liner but it was getting dark, cold and about to rain, so I called it a night. Any tricks without removing the liner?

Radi

I was referring to AC power wiring. That's the funny part. Heck, you can even buy "audio grade" AC outlets:
http://www.parts-express.com/wattgat...utlet--110-439

Hey, it does come with "lifetime technical support". A fool and his money are soon....well you know.

Radi

For 4AWG you'd normally use a 8AWG fusible link. You could use the stock 10awg (and may want to- see Blue Ridge Mark's comments) but will be limited to stock current capacity.

BlueRidgeMark

Well, let me see if I can help you. Not likely, but I'll have a go at it.

First of all, there is a QUOTE button, and there is a REPLY button. Blindly quoting an entire post just to reply to it is... not the best use of a forum. It's actually pretty rude to other users (especially guys on phones) because it forces them to scroll through a lot of useless noise.




I didn't say it is. In fact, I disagreed with CCKen on this and recommended increasing the size of your battery cabling.


Well, since I've already explained that multiple times, I won't go through it again. I see no reason to believe your reading comprehension will improve through repetition. If you have the stuff laying around for free, and want to put up with the downsides of using ridiculously over-sized cables, go for it. Just don't pretend it's somehow better than a sensible upgrade.

Of course, it would be a good idea to make sure you actually understand the downsides, first, which doesn't seem to be the case.



I did not give my "opinion" of fusible links. (Note the spelling.)

What I gave you is industry standard practices, based on sound science and backed up by many decades of industry experience.

But since you brought it up, here's my opinion of them: I don't like them, and prefer to replace them with functionally equivalent fuses. I understand why manufacturers use them, but since I'm doing one-offs for my own use, and don't have to consider the additional cost millions of times over, and stockholders, and profit margins, it makes sense for me to do what does NOT make sense for car manufacturers to do.


Yes, that's what I said.

Yes, the same reason as I gave and you just re-stated.


Wrong. Short that wire and you'll have either a destroyed battery or a fire, or both. (HINT: Do the math on it. Ohm's Law. Dividing voltage by very close to zero creates currents that approach infinity. It's a bad idea. It tends to let the magic smoke out.)

Building nice cables doesn't make someone an expert on electricity, but assuming you have accurately relayed what he says, you've missed the point.


The reason that starter circuits are not fused has already been explained, and it's NOT because there is no hazard.


I noticed.


The cable to the starter is not fused.



Nobody said it would.



Well, duh. That's the point.



Nope, just trying to communicate basic electrical facts to people who prefer to believe Internet myths, and can't wrap their heads around anything more complicated than, "Bigger is better!".

It's usually a losing battle.

Crow Horse

Would or could using a 8 awg fusible link with a 4 awg alt cable possibly allow for excessive current to potentially damage other components down line ? If so, then it would make sense to retain the 10 awg size.
Electronics not being my forte', I defer to those who are better versed in such matters. I do know that I have the capability of doing something that is potentially damaging and feel more comfortable following the advice from those folks who are experts.
Like most things in life, balance is critical. Exceed the design parameters of one component usually moves the wink link elsewhere. I'm just looking to replace some old cables with some that are a wee bit better yet retain the "harmony" of the electronics.....

CCKen

Hard call to make without knowing the Amp rating of the 10 ga. or the 8 ga. fusible links. I can't find what I was looking for on the web about fusible link Amp ratings.


The fusible link is there to protect the cable from the alternator to the buss bar on the end of the PDC in the event the battery shorts out and draws the maximum current from the alternator, which could be 124 Amps with an OEM alternator.


The rest of the primary circuits in the Jeep are protected by Maxi fuses in the PDC (see pic) so they are not really in the fusible link picture.


As stated, the starter power cable is not protected, just its control circuit.


You could try the 8 ga. fusible link but I have no idea what length it would need to be. The original 10 ga. link was to protect the 6 ga. cable but, again, I don't know its Amp rating. Fusible link Amp ratings are dependent upon the wire length and the wire cross section.


98/99 PDC (97 same - sorta):





99 PDC layout:





Wire (not fusible link) Ampacity chart:

aj2494

First off, I don't want to start a pissing match here, I'm not a big fan of your response and complete lack of respect toward myself. You may disagree with me, but you don't have to be an *** about it. Also, you shouldn't yell at someone for quoting vs replying and then proceed to dissect their post and quote almost every sentence individually. That is very rude, whereas quoting the post you're replying to is definitely an acceptable behavior on forums. It makes it much easier to follow threads IMO.

I might be wrong, and I might be misunderstanding things. Not being an *** to people when they say something inaccurate and actually trying to educate them is generally more effective, and much more productive to the whole helping people thing.

Since most of that post was just you trying to be demeaning, the only technical aspect I want to touch on is the shorting of the starter cable. How would the cable be grounded without someone removing one terminal with the battery still connected and touching it to ground? Anybody who does that deserves to have their vehicle burnt to the ground for forgetting one of the cardinal rules of automotive work. I certainly understand the downside to having a wire be able to carry too much current, and that fusing can resolve this problem. It's just not a necessary step in this case and really isn't done that often.

I never said this would make an XJ's electrical system perform better, or improve any basic electrical functions. No internet myths involved. All I pointed out was that you can get 1/0 welding cable for less than the cost of 4 AWG marine cable, the final product will be significantly beefier, and it gives plenty of headroom for winches, air, lights, etc. I don't know where this was spun to mean I'm saying it's better on a stock system or will somehow be a performance improvement. I'm not quite sure why you made it so personal and began insulting me.

Crow Horse

Guys, I appreciate everyone's advice and opinions but I REALLY need you to put your thinking caps on.. I replaced the negative/ground cables (3) and now I have a crank no start condition. See my other thread and I really could use your help......

rzldzl

umm, link?

Radi

No, it's harmless. The electronic components will only draw what they need, even if the source can supply much more.
The exception is under a fault condition when the larger wiring can allow more current to flow. Of course if you have a fault condition, the device drawing the excess current is already broken.

madmanmarty

I replied in your other post.
You are making this much harder than you have to.
Buy a cable set from someone & install it. Done.
Then diagnose if you still have a issue.

aj2494

I don't really see how buying an off the shelf set at this point makes any sense. Crow's probably work fine. It sounds like something got disturbed during the install.

Crow, I know this sounds simple but I didn't see you mention it anywhere. Did you check all your fuses?

madmanmarty

I agree.
But he mentioned he wanted to change cables.
I replied in his other post regarding his starting problem.
A second thread is part of the problem.