Trojan short T105 terminals

[ramblinrod]

Originally Posted by daletournier

And this is why I see the half nyloc as a perfect solution. The nut performs one function, keeping the lugs tight on the terminal, nothing more, my shorter post then is irrelevant. They will perform that job well. BTW the nylocs I looked at are rated at 220°C not 120° as Rod has suggested.

Hi Dale,

Again, by all means, make repairs the safest way you can with what you have available at the time.

One more thing about Nyloc nut / Loctite use on battery terminals...

While I have no direct evidence, I suspect that the Nylon insert may tend to hold moisture within the various contact points, and possibly contribute to increased risk of corrosion development. (I think the same may be true for the Loctite solution, and I believe when cured, it is an insulator on its own, but I could not verify the di-electric strength with a quick search of the manufacturer's site.)

[Wotname]

Originally Posted by ramblinrod

Incorrect!

There most certainly can be (and most likely is in all cases) current flowing through the nut near the nylon insert.

Basic electrical circuit theory and analysis indicates otherwise.

For the scenario discussed, there are 3 potential points of lug / battery terminal contact and paths for current flow:

1. Between the battery terminal flat and the bottom of the lug.

2. Between the stud threads and the I.D. of the lug mounting hole.

3. Between the stud, nut, and top of the lug.

Under normal circumstances, one would expect the majority of the current to flow through contact point 1. (Perhaps 90% or even more).

But make no mistake, there most definitely can be current flow through the other two contact points.

And the greater the contact resistance for contact point 1, the greater the current through contact point 3 (and contact point 2) if there actually is contact there.

In a battery application, it is very common for corrosion to be present, resulting in a "bad connection" (aka high contact resistance) at contact point 1.

When this occurs, the higher current flow through contact point 3, (which may also be a high impedance connection due to corrosion and realtively small contact area, could potentially heat the nut to "glowing" hot, and most certainly melt the nylon insert.

I'm not sure what the point is here.

I sort of agree with your general argument in this post and the conclusion that if a fault condition exists (corrosion at the battery terminal), heating will occur. It might even melt the nylon. So what, the melted nylon will be inconsequential to the other fault effects. At the worst, the locking function of the nylock will have been lost however you have argued earlier that the locking function wasn't needed in any case. The metal remainder of the nylock will still be torqued as it was before the fault condition.

In your scenario, the nylock didn't cause the fault and the failure of the nylon insert does't exacerbate the fault.

In fact in some instances, it might even assist in finding the fault - just look for the melted nylon

[Wotname]

Originally Posted by ramblinrod

Hi Dale,

Again, by all means, make repairs the safest way you can with what you have available at the time.

One more thing about Nyloc nut / Loctite use on battery terminals...

While I have no direct evidence, I suspect that the Nylon insert may tend to hold moisture within the various contact points, and possibly contribute to increased risk of corrosion development. (I think the same may be true for the Loctite solution, and I believe when cured, it is an insulator on its own, but I could not verify the di-electric strength with a quick search of the manufacturer's site.)

It is generally accepted that Loctite seals threads and prevents (to a degree) corrosion within the mated thread surfaces by sealing out moisture.

Whether or not it increases the resistance of the mated thread surfaces (without any corrosion) is a worthwhile question to ask. I haven't (yet) found any professional evidence either way but I am still planning to carry some empirical testing of my own to determine an answer. You will be the first to know the results

[hzcruiser]

Originally Posted by Wotname

I'm not sure what the point is here.

I sort of agree with your general argument in this post and the conclusion that if a fault condition exists (corrosion at the battery terminal), heating will occur. [...]

That sums it up nicely, Wotname! No need to argue for arguments sake, especially starting a post with such an agressive statement like: "Incorrect!" and straight away admitting that for more than 90% it would actually be correct...

This pointless "rambling" is a bit off-putting.

[ramblinrod]

Originally Posted by Wotname

I'm not sure what the point is here.

I sort of agree with your general argument in this post and the conclusion that if a fault condition exists (corrosion at the battery terminal), heating will occur. It might even melt the nylon. So what, the melted nylon will be inconsequential to the other fault effects. At the worst, the locking function of the nylock will have been lost however you have argued earlier that the locking function wasn't needed in any case. The metal remainder of the nylock will still be torqued as it was before the fault condition.

In your scenario, the nylock didn't cause the fault and the failure of the nylon insert does't exacerbate the fault.

In fact in some instances, it might even assist in finding the fault - just look for the melted nylon

Many risks, no reward.

[ramblinrod]

Originally Posted by hzcruiser

That sums it up nicely, Wotname! No need to argue for arguments sake, especially starting a post with such an agressive statement like: "Incorrect!" and straight away admitting that for more than 90% it would actually be correct...

This pointless "rambling" is a bit off-putting.

Look, there is no need to get nasty just because you made a mistake.

[ramblinrod]

Originally Posted by Wotname

It is generally accepted that Loctite seals threads and prevents (to a degree) corrosion within the mated thread surfaces by sealing out moisture.

Generally accepted by whom?

The manufacturers marketing department maybe.

[Sailmonkey]

Originally Posted by ramblinrod

Generally accepted by whom?



The manufacturers marketing department maybe.

Do you accept the premise of there being more than one way to skin a cat?

[steamgoat]

That may depend on if it is foam or balsa core!!

[john61ct]

Note there are many other types of stop nuts that are all-metal, it's a rabbit-hole topic unto itself.

If the post thread doesn't extend through the top of a nyloc nut you're not getting the locking effect anyway.

[transmitterdan]

Originally Posted by ramblinrod

Incorrect!

Snip

Originally Posted by ramblinrod

When this occurs, the higher current flow through contact point 3, (which may also be a high impedance connection due to corrosion and realtively small contact area, could potentially heat the nut to "glowing" hot, and most certainly melt the nylon insert.

Rod,

If the nut and battery post carrie enough current that the nut is "red hot" the battery case is going to melt before the nylon. The case is made of plastic too and typically it is polypropylene or some other "poly" plastic. These typically melt at 1/2 the temperature of nylon.

And what does it matter if the nylon melts? The nylon is not creating the contact pressure, the threads are doing that. The nylon resists turning force not pressure due to the threads. If the nylon melts then it merely becomes a regular nut. A Nyloc nut applies the same pressure with or without the nylon.

By your logic a thin nut should not be used either because it has less thread area to carry current. Think about that for a minute before you yell "Incorrect!". When the threads are carrying substantial current the heating battle is already lost.

[ramblinrod]

[QUOTE=transmitterdan;2619685]Snip



Rod,

If the nut and battery post carrie enough current that the nut is "red hot" the battery case is going to melt before the nylon. The case is made of plastic too and typically it is polypropylene or some other "poly" plastic. These typically melt at 1/2 the temperature of nylon.

Missing the point.

The nut can get hot enough to melt the Nylon insert.

It could get "red hot" but it doesn't have to.

I just used that to indicate how incorrect the statement that there is no current through the nut really is.

In some cases, it only has to get to 120C to melt the insert.

How fast will the post sink that heat to the battery case?

Don't know.

How long will it take the battery case to melt, if ever?

Don't know.

None of this matters.

The point is, there are risks associated with Nyloc nuts on battery terrminals.

There are no real benefits.

If the nut is torqued properly and the battery and cables secured properly.

My position is, rather than seek a Band-Aid solution to poor workmanship, which may cause more problems than it helps, just do it right in the first place.

And what does it matter if the nylon melts?

I prefer not to have melting plastic on my boat.

The nylon is not creating the contact pressure, the threads are doing that.

Incorrect!

The nylon insert takes up some of the torque that is applied to the nut that is not contributing to SS thread engagement.

The nylon resists turning force not pressure due to the threads.

Exactly my point above.

If the nylon melts then it merely becomes a regular nut.

Exactly my point. A regular nut is sufficient and preferred (at least by me).

A Nyloc nut applies the same pressure with or without the nylon.

Only after it melts. Less, if the nut is tightened to the specified torque and some of that torque was used to over come the turning resistance of hrte nylon insert.

By your logic a thin nut should not be used either because it has less thread area to carry current.

Correct! One should use the nuts supplied or specified by the manufacturer.

With 3 threads of engagement on a straight thread, the holding force is about 65% as compared to 6 threads.

This is the reason that Mainsail (and I agree completely) on should not use a tapered fitting on a straight thread thru-hull.

Think about that for a minute before you yell "Incorrect!".

I did. Long ago.

When the threads are carrying substantial current the heating battle is already lost.

Nope!

If one is not relying on a Nylon insert to retain the nut, the terminal can heat up and essential equipment will still work, until the fault is found.

If one is relying on the Nylon insert to retain the nut, as the terminal heats up, the Nylon becomes less effective, and could just melt and burn, allowing the nut to back off, and electrical connection lost. Will this happen at an opportune or inopportune time?

[transmitterdan]

Rod,

You realize that one does not torque nylocs to the same torque as regular nuts. They have to be slightly higher torque for same applied pressure. Do you actually have any engineering training? How did you learn that nylocs create any problem? Is there even one well analyzed/documented case where the nylon made any difference?

[Sailmonkey]

Focusing on a Nyloc nut or a short nut as the most heinous offense perpetrated when installing batteries is like not seeing the forest for all of the trees.

If a particular system is so sensitive as to fall apart for lack of a nut (and if we’re going to focus on the nut, why accept stainless nuts and studs at all?) then how can the system be expected to survive in a vibrating salty box at all?

[daletournier]

When does real life experience come into? Ive sailed thousands of nm's with nylocs holding my lugs onto battery terminals without issue, dosent this hold more cred that the theoretical disaster being pitched?
I never heard of it being problem, dosent that count for something? Has anyone seen this nyloc battery terminal disater?

Btw im assuming none of us use a torque wrench on our battery nuts? Im an ex mechanic, changed a few batteries over the years , never used a torque wrench.