Thread Locker on Alt POS Batt Post?

S

Solstice

.
May 10, 2008
392
Catalina 355 Boston
Mainsail,
I helped a friend move his AO from starter to his House Bank yesterday. He asked me whether it was a good idea to add a Thread locker to the post along with the locknut--specifically Vibra-Tite--because he is concerned about the lug vibrating loose. He has no good place to really secure the positive wire as his engine covers are his bulkheads and the new wire is much bigger than the original.
As I thought about it I didn't have a good answer. Since the post itself is a poor conductor (SS) I don't see that as an issue and we did add a copper washer (thanks to your advice when I installed mine).
Any reason not to do this?
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Solstice said:
Mainsail,
I helped a friend move his AO from starter to his House Bank yesterday. He asked me whether it was a good idea to add a Thread locker to the post along with the locknut--specifically Vibra-Tite--because he is concerned about the lug vibrating loose. He has no good place to really secure the positive wire as his engine covers are his bulkheads and the new wire is much bigger than the original.
As I thought about it I didn't have a good answer. Since the post itself is a poor conductor (SS) I don't see that as an issue and we did add a copper washer (thanks to your advice when I installed mine).
Any reason not to do this?
Click to expand
The alt post is usually zinc or nickle coated copper or brass, never seen one that is SS. No need to use a thread locker. If the stud is long enough just use a lock washer and then back it up with a nyloc. If your alt gets hot enough to melt the nyloc, YOU HAVE OTHER MAJOR ISSUES......;) Most nylocs are rated for a safe working range of up to 284F but the melting point of the nylon is in the 425F range.... If your alt is regularly getting over 220F then it will have a very short life.... So, split washer then nyloc, done...

Your friend will still want to find a way to secure the cable. Metal insulated clamps can be bolted to engine parts etc....
 
S

Solstice

.
May 10, 2008
392
Catalina 355 Boston
Maine Sail said:
The alt post is usually zinc or nickle coated copper or brass, never seen one that is SS. No need to use a thread locker. If the stud is long enough just use a lock washer and then back it up with a nyloc. If your alt gets hot enough to melt the nyloc, YOU HAVE OTHER MAJOR ISSUES......;) Most nylocs are rated for a safe working range of up to 284F but the melting point of the nylon is in the 425F range.... If your alt is regularly getting over 220F then it will have a very short life.... So, split washer then nyloc, done... Your friend will still want to find a way to secure the cable. Metal insulated clamps can be bolted to engine parts etc....
Click to expand
Thanks MS,
His Alt is at least 10 years old and working fine so I don't suspect he has a heat problem. I did find a flex nut alternative at McMaster for him, but they are pricey so I'll suggest that a Nylock will do the trick.

http://www.mcmaster.com/#hex-locknuts/=rw37dg
 
S

Solstice

.
May 10, 2008
392
Catalina 355 Boston
Solstice said:
Thanks MS, His Alt is at least 10 years old and working fine so I don't suspect he has a heat problem. I did find a flex nut alternative at McMaster for him, but they are pricey so I'll suggest that a Nylock will do the trick. http://www.mcmaster.com/#hex-locknuts/=rw37dg
Click to expand
update--

So we went back today to install the connection to my friends boat with using a Nylock. Problem is we did not have enough threads as the lug is too thick :( we are using a battery lug from GD. So we are now trying to find a 1/4" thin walled ring terminal to fit on a 2AWG wire. Not sure if they exist, but it looks like Genuinedealz may have them. We were considering going down a wire size in order to use a #10 terminal, but the problem with that is a #10 is .016" smaller than the 6mm post, so that won't work and defeats the purpose of going down a wire size. any other suggestions would be welcome!

As an aside, I was asked what would happen if he didn't rewire the Alt with regard to the EC, and simply topped up the Reserve while on Shore Power. And short of responding 'because Maine Sail said', I realize I don't know the technical answer. I went back and reread all of your posts, including the infamous rant thread and could not find the reason.
If we cannot find a terminal to do the job, can he use the EC exclusively while on Shore Power, or should he write the EC off and go with an ACR or Combiner? Will he do any damage by leaving it in place until we find a solution?
 
S

Solstice

.
May 10, 2008
392
Catalina 355 Boston
Maine Sail said:
Just use a regular lock washer & nut...
Click to expand
The problem is the regular lock washer and nut won't even allow enough threads to secure. The problem is the end of the post does not have threads, so even though the post should be long enough, the actual length that is useable for threading is not.
We would go down (reluctantly) to a #4, but I am not sure if we will have the same problem in finding a thin walled 1/4" terminal ring. The boat has almost a 30" round trip to the batteries, hence the initial selection of #2...
 
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