dielectric grease in battery lug?

Capt. Bill -- yes, that was my question....whether to apply the grease onto the tip of the wire before inserting into the lug and crimping.

Now looks like that's not such a good idea.

V/R
 
Let me add this point I just found in a BoatUS article ( http://www.boatus.com/boattech/articles/choosing-cables-and-terminals.asp )

"The reason for [lower ampacity of wire in an ER] is that engine rooms are usually hot. Even before a circuit is turned on, a cable is warm. In these conditions it takes less current flow to bring the cable to a dangerous temperature than it does in a colder environment; hence, the de- rating in high ambient temperatures. If any part of a circuit runs through engine room spaces, the lower ampacity rating is used to determine the proper overcurrent protection for that circuit."

So the WM ampacity link in my first post didn't tell the whole story, it appears. And so Pascal's 2/0 recommendation for a 1500w inverter makes eminent sense.

Got it.

V/R
 
Penetrox E might be used in this application, and has suspended copper particles in it. I've not used it though.
 
William's post is getting old and I assume he now knows that to do.

Here's the info on working with 2/0 cable or even heavier, for others.

The connectors you are using must be sized the same as the cable size.

You'll need a crimper with a die sized for 2/0. You can't make a good high amperage connection by squeezing the fitting in a vise or hitting it with a hammer.

Cutting the 2/0 cable isn't easy. If you don't have a big hydraulic cutter like the manufacturers do, your best bet may be a hacksaw with a new, very fine blade. Once you have the 2/0 cut to length, slip on a length of shrink tubing to the cable. You'll need that later.

Next dress the cut end of the 2/0 cable (the end will be ragged) until you can slip the 2/0 connector onto the cable. It will be a very tight fit.

Once you have the connector on, crimp it. No dielectric grease needed or wanted. Then slide the heat shrink tubing up to the end of the cable and apply heat.

Now you'll have a real battery cable.

Bill
 
CC67,
I did exactly that, finely cut the cable with a hacksaw, dressed the end, inserted cleanly into Ancor lug (no grease) and used a crimping tool (the type where you whack the piston with a hammer; I used a heavy one), and then heat shrink tubing. Seems to have worked well.

Thanks for the note.

V/R
 
quote:
Originally posted by pdecat

dielectric is an insulator.

For connections that scrape together to make the connection such as multipin I don't see any problem. Battery lugs are compressing and scraping however.

Click to expand...


That's the correct answer and the one I'm going with. Properly crimped,, there is no space for moisture to enter the connection but putting a moisture repellent on after making the crimp is a good idea.
 
I haven't mentioned anything about using dielectric silicone grease as I've been advocating it's use for electrical connections for almost a decade. The main thing is it seals out air and water so prevent corrosion from even happening. A propane torch got the grease to char white but not melt. Left in the freezer, it did not even harden or thicken.

Most of you have seen connectors that already have silicone grease heat shrink adhesive in it. Many critical marine electronics advise using the plastic silicone filled squeeze button for their connections, even though they use light gauge tinned wiring.

http://www.vpi.us/butt-splice-connector.html...might have to close out and re click on the link.
 
Charlie - Even the linked ad for those button splice connectors similar to Scotch-loks does mention they are meant for use with small gauge solid conductors as found in landline telephone wiring, not multistrand which could be harmed by the inner guillotine-type splice blade .

That said , I have definitely used them to join those tiny marine electronics interface conductors, with shrink wrap or self-amalgamating tape over the whole grouping, and with no problem over time. Darn handy, as long as the correct size is used for the application with correct # of wires inserted.
 
A "dielectric" material does not conduct electricity. Dielectric grease is ideal for uses such as plug and socket connections because the grease is wiped away as the contacts slide together but remains as a barrier to moisture. The dielectric (insulating) properties prevent shorting from one set of contacts to another in the same plug/socket. A typical use for dielectric grease is the plug and socket for a boat trailer's wiring harness where it connects to the tow vehicle.

Putting dielectric grease into a lug or onto a cable before crimping would mean at least a partial insulation of the connection and that would be a bad idea. There are conductive pastes that could be applied but they are not necessary.

Make the crimp without any grease or other products and then seal it from moisture if you wish.
 
Maybe it's the name (di-electric) that has y'all discombobulated. Not just 'di-electric', but virtually any cream, grease or ointment is 'di-electric' in the sense that they will not conduct an electrical current. About the only 'grease' that I'm aware of that has the potential of conducting an electrical current would be Copper, Aluminum or Stainless Steel infused 'Neversieze' (There are a number of similar brands out there)

As I've mentioned before, the advantage of a true Di-electric silicone grease is that it will not burn or even melt under a propane torch, freeze or even thicken in a freezer, will not readily wash away or even dissolve in most solvents other than MEK or mineral spirits. Will not harm most materials other than silicone based parts...like silicone O-rings or gaskets.

It's biggest advantage is that it prevents moisture and air from passing thru it so prevents corrosion as long as the components are clean and dry.
 
I have used a copper based conductive corrosion inhibiting grease for years. I forgot who makes it but it is a small 6oz bottle with a blue label.
It is made for inside crimp connections as we are speaking about. I can get the product name tonight.

As Pascal said, welding cable is a no-no. Frequently it is chosen by the novice (self included 25 yrs ago) because of its flexibility with the smaller strands. It is very easy to handle and move around a tight bilge. The cable jacket may not be rated for fuel, etc....
 
http://ecat.burndy.com/Comergent/en/US/adirect/fci?cmd=catProductDetail&showAddButton=true&productID=PENE4&_bcs_=-1%08%23%23%08%23%23%08http%3A%2F%2Fecat.burndy.com%3A80%2FComergent%2Fen%2FUS%2Fadirect%2Ffci%3Fcmd%3DcatLanding%08%23%23%08true%08%07100%08penetrox*%08Search%3Dpenetrox*%08%23%23%08%23%23%08false%08
 
quote:
Originally posted by TJM

I have used a copper based conductive corrosion inhibiting grease for years. I forgot who makes it but it is a small 6oz bottle with a blue label.
It is made for inside crimp connections as we are speaking about. I can get the product name tonight.

As Pascal said, welding cable is a no-no. Frequently it is chosen by the novice (self included 25 yrs ago) because of its flexibility with the smaller strands. It is very easy to handle and move around a tight bilge. The cable jacket may not be rated for fuel, etc....

Click to expand...


But then again it was used for decades by many boat builders, including Grand Banks as I recall, with no real I'll effects.
 
I inherited welding cable on my '68 Bertram, from the genset battery to the genset. Diesel kinda wore out the jacket, though.

V/R
 
I used copper welding cable on my previous boat. 5'-6' of cable to jump from a pair of 6 Volt batteries to the opposite side. Worked flawlessly, was easy to guide into place and after 8-9 years there was no corrosion anywhere on the lugs. Sealed lugs with liquid electrical tape.
Freshwater. Dunno if there is an issue in salt.
 
I'm a commercial electrician with 30 years experience. All of our AL/CU crimp on lugs have an anti oxidation compound inside. It looks like grease, but is designed to keep aluminum from oxidizing. The CU only lugs do not have anything inside. On my boat I used the CU only lugs, didn't use any compound, but used adhesive lined heat shrink tubing. When you heat it, it melts the adhesive as the tube shrinks, thus making a totally waterproof seal.
 
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