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Upgraded Battery Cables

fitrider82

NAXJA Forum User
Location
MI
Plan on making my own battery cables for all main power and grounds. Can anyone provide the specific lengths, and hole sizes needed when I make them? Plan on going with 2AWG. Thanks!
 
Plan on making my own battery cables for all main power and grounds. Can anyone provide the specific lengths, and hole sizes needed when I make them? Plan on going with 2AWG. Thanks!


Year?

5-90 used to have a webpage with length and sizes (and you could also buy a set from him) at http://www.geocities.com/JeepI6Power but that page looks to be long gone.



Grab the wife's sewing tape measure, the plastic or paper one, or some string and measure the lengths. Avoid a metal tape measure for obvious reasons. I just grabbed used some ready-made beefy ones from the local tractor supply house. Otherwise, you'll need to borrow a hydraulic crimper since a poor crimp is worse than undersized cable.









 
One caution about that link. He craps on the block to firewall connection as being weak as its braided. But it is that way to reduce EMI interference generated by the engine. The shape of that strap is probably that way due to radio engineering. If it were me and mine looked bad I'd replace it with a like style rather than turning it into a round cable.
 
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One caution about that link. He craps on the block to firewall connection as being weak as its braided. But it is that way to reduce EMI interference generated by the engine. The shape of that strap is probably that way due to radio engineering. If it were me and mine looked bad I'd replace it with a like style rather than turning it into a round cable.


No, nothing so elaborate even if the wire construction could affect EMI. I'm pretty sure it was a flat braid simply to maximize the flexibility so it doesn't fatique and break due to motor movement. The downside of the braided is that the strands are more exposed to dust, dirt, abrasive and corrosion. Just use some reasonable sized wire with a high strand count and a little extra length to improve the flexibility and you'll be fine.
 
I just grabbed used some ready-made beefy ones from the local tractor supply house. Otherwise, you'll need to borrow a hydraulic crimper since a poor crimp is worse than undersized cable


What's wrong with using a hammer lug crimper like this TEMCo TH0007?

https://www.amazon.com/gp/product/B00E1UUVT0



I agree that a really nice hydraulic crimper is ideal, but based on my research it seems like the hammer crimper is a suitable and much cheaper alternative. I made new cables a few weeks back using the above crimper, and every crimp felt solid.



This video convinced me, where the guy cuts apart joints made with just a screwdriver+hammer, hammer crimper, and hydraulic crimper: https://youtu.be/mBSnfHhi5xA. The screwdriver+hammer is predictably weak, the hammer crimper looks solid, and the hydraulic is superior. So if money was no object, I'd have gotten a hydraulic or cables made by someone using a hydraulic, but going homemade, the whole kit (cables, wires, fuse block, heatshrink, lugs, crimper, battery terminals) cost $125 with plenty of leftovers.
 
No, nothing so elaborate even if the wire construction could affect EMI. I'm pretty sure it was a flat braid simply to maximize the flexibility so it doesn't fatique and break due to motor movement. The downside of the braided is that the strands are more exposed to dust, dirt, abrasive and corrosion. Just use some reasonable sized wire with a high strand count and a little extra length to improve the flexibility and you'll be fine.

Seems your right. Its not so much the cable but the place it attaches, which provides a close ground return path for the instrument cluster & radio:


cherokeeforums said:
RADIO NOISE SUPPRESSION

DESCRIPTION

Radio Frequency Interference (RFI) and Electro-Magnetic Interference (EMI) noise suppression is accomplished primarily through circuitry internal to the radio receivers. These internal suppression devices are only serviced as part of the radio receiver. External suppression devices that are used on this vehicle to control RFI or EMI noise include the following:

· Radio antenna base ground

· Radio receiver chassis ground wire or strap

· Engine-to-body ground strap

· Resistor-type spark plugs

· Radio suppression-type secondary ignition wiring.


The above statement is essentially the same in the 1997 FSM but has the following statement concerning the Engine-to-body ground strap:


“Engine-to-body ground strap (if the vehicle is so equipped)”

The radio receiver chassis ground is located at a ground terminal designated G108, which is located on the instrument panel frame structure near the headlamp switch. The engine-to-body ground strap on the firewall provides a close proximity ground path to the radio recever chassis ground point.

Note that the '97 FSM description differs from the '99 FSM description only that it states "if the vehicle is so equipped". Not that it makes any difference here but apparently there is a posibility that the '97 XJ may not have this strap if there is no radio installed.

Earlier XJ's may not use this ground strap strictly for this purpose.

Braided ground straps sold at Advance Auto Parts, and elsewhere, are suitable for replacement if your ground strap is no good. I think a large gauge cable would be an overkill in this application.

 
One caution about that link. He craps on the block to firewall connection as being weak as its braided. But it is that way to reduce EMI interference generated by the engine. The shape of that strap is probably that way due to radio engineering. If it were me and mine looked bad I'd replace it with a like style rather than turning it into a round cable.

You are correct, all "lighting protection cable" is braided for a reason! It's not about the shape, just braiding.
 
You are correct, all "lighting protection cable" is braided for a reason! It's not about the shape, just braiding.


In a lightening protection conductor, braided cable helps reduce the impedance at very high voltages and higher frequencies due to skin effects. It also makes it much more flexible and easier to install. In an area where a few percent difference can be crucial. The benefit starts to diminish at very high frequencies due to the higher capacitance and proximity effects of the strands.



For an engine grounding strap (really a ground return), the added flexibility is the primary reason. In my opinion, the difference in impedance for EMI is neglible, mostly because the bulk of the EMI is from sparking and is airborne.


This is speaking from experience dealing with EMI from high powered motors and some limited training in EMI suppression. Counter intuitively, more ground points can make things worse and grounding the shield of data cables at both end of the wire can make ground loops and induced EMI worse.
 
All you said is true, but it also applies to DC signals, that's way the O2 sensor wiring is "twisted pair". Any signals that a DC conductor picks-up can be "reduced" by "braided" or "twisted pairs"
 
All you said is true, but it also applies to DC signals, that's way the O2 sensor wiring is "twisted pair". Any signals that a DC conductor picks-up can be "reduced" by "braided" or "twisted pairs"


Ah, fun, that gets into my line of expertise. Ethernet (read Network) cables work the same way. They are twisted pair to reduce EMI as well. Googling a bit finds this article:



https://www.eetimes.com/document.asp?doc_id=1279624


Apparently twisting the wires causes them to reject an evenly applied interfering EM wave.
 
Ah, fun, that gets into my line of expertise. Ethernet (read Network) cables work the same way. They are twisted pair to reduce EMI as well. Googling a bit finds this article:



https://www.eetimes.com/document.asp?doc_id=1279624


Apparently twisting the wires causes them to reject an evenly applied interfering EM wave.


EMI and crosstalk. Pushing 350 Mhz and above gets interesting. And the twists in each pair on an Ethernet cable is different in the number of twists per foot. Heck, when you get to Cat 6 stuff, they keep the twists going all the way into the connector. Man, Cat 6 ends are a pain to put on.


David Bricker / SYR
 
EMI and crosstalk. Pushing 350 Mhz and above gets interesting. And the twists in each pair on an Ethernet cable is different in the number of twists per foot. Heck, when you get to Cat 6 stuff, they keep the twists going all the way into the connector. Man, Cat 6 ends are a pain to put on.


David Bricker / SYR


Tell me about it. I wired my parents' house for Cat6 and did half of them wrong before I realized it. It all checked out in the end though.
 
Ah, fun, that gets into my line of expertise. Ethernet (read Network) cables work the same way. They are twisted pair to reduce EMI as well. Googling a bit finds this article:



https://www.eetimes.com/document.asp?doc_id=1279624


Apparently twisting the wires causes them to reject an evenly applied interfering EM wave.


Ethernet is a differential signal, so if the two wires have the same added noise then it cancels out (common mode rejection). Twisting the pairs helps ensure both wires are affected the same, particularly if the source is very close. The 4-pairs are twisted at different rates from each other to reduce the crosstalk between the pairs.
 
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