General question about dielectric grease

[fredtassin]

Hi,

Dielectric grease is put on battery posts to prevent corrosion, which makes sense. However, dielectric grease does not conduct electricity, so how is the current conducted when both posts are covered with a non-conductor?

Fred

 

[andyd]

You make the connection first , then you grease it.

 

[Cardenio327]

When you tighten the terminal it will squeeze the grease out of the contact area, making a metal to metal connection.

After thoroughly cleaning contact surfaces I apply dielectric grease BEFORE making the connection. This will ensure that moisture can't collect anywhere in the connection. If there is looseness in the connection the dielectric grease may cause the circuit to open, hence the need to make sure all connections are clean and will properly tighten before greasing.

 

[Falken]

^+1

You can use high quality Silicone Grease, Dielectric Grease, Caliper Guide (Slider Pin) Grease, or...

Vaseline!

The clean connection squeezes it out to keep an encapsulated connection don't worry about resistance, conductivity, or opening the circuit.

 

[NHGUY]

I use Fluid Film on battery terminals.

 

[Donald]

Originally Posted By: fredtassin
Hi,

Dielectric grease is put on battery posts to prevent corrosion, which makes sense. However, dielectric grease does not conduct electricity, so how is the current conducted when both posts are covered with a non-conductor?

Fred



On the battery post, Vaseline is very good for battery posts. No need to waste the dielectric grease.

But no grease will help much with a leaker.

 

[Kestas]

One way to look at it is that any loss of conductivity from the grease is more than made up by the fact that it excludes corrosion on the terminals.

I also use it for electrical connections under the hood.

 

[Vikas]

Besides, there is really no such thing as "conducting grease" contrary to what some people might tell you. If anything, it refers to "thermal" conductivity and not "electrical" conductivity.

The job of the grease is to prevent the corrosion and make sure that it itself does not breakdown under high voltage and/or high temperature situation e.g. spark plug boots where silicon grease is called for.

 

[Rylan]

Anybody here (especially the older users) use hairspray to coat the battery terminals to prevent corrosion?
I've heard this also works very well.

 

[Traction]

I would think hair spray would work because I can't find anything other than a razor blade to get off the windows of my wife's car.

 

[friendly_jacek]

The dielectric grease works in a way that I can't understand. I fixed a laptop couple of months ago and I had to replace a motherboard. The new (used) motherboard made a poor connection with LCD and produced garbled video no matter how many times I tried to disconnect and reconnect. I put some dielectric grease in the contacts, and voila! it's fixed right away on the first try.
Magic, can someone explain that?

 

[Kestas]

Hair spray is water-soluble lacquer.

There actually is a conducting grease I just read about. A bearing manufacturer developed it to solve some problem related to hydrogen in greased roller bearings. I believe it contains graphite.

 

[George7941]

Welding stores sell a conductive grease for the magnetic ground clamps with a cable swivel. The grease lubricates the swivel and conducts the welding current.

Here is a conductive grease
http://www.grainger.com/Grainger/CHEMTRONICS-Silver-Conductive-Grease-1UYE2

 

[widman]

There all types of conductive greases. I picked up one from Lowes a couple of years ago. They have high metal contact. Higher priced ones with silver, cheaper with other stuff.

I use it on battery terminals and contact switches for power windows.

 

[Vikas]

Please do this experiment for me, Get a plastic/paper object and put a dab on this conducting grease on it, about a dime in diameter. Then take your digital multi-meter on the ohm scale and measure the resistance of that blob, from one end to the other. You will be in a position to shut down this discussion once and for all.

 

[NateDN10]

Originally Posted By: Vikas
Please do this experiment for me, Get a plastic/paper object and put a dab on this conducting grease on it, about a dime in diameter. Then take your digital multi-meter on the ohm scale and measure the resistance of that blob, from one end to the other. You will be in a position to shut down this discussion once and for all.

To be fair, there's conductive and then there's conductive. For example, spark plug wires are conductive even though they may have resistance of hundreds or thousands of ohms. It all depends on the voltage and current involved.

And while I don't know how this conductive grease works, it may be that there are metal particles in suspension, and when put under pressure they tend to make contact with one another, resulting in a relatively good conductor.

 

[SHOZ]

I put some DOW 111 silicone on top of my terminals once. The stuff is thick type grease but it cold flows.

After a week or two I had to take it off as the car would not crank over.

 

[Vikas]

On the same line, think what resistance would be tolerated at the battery post. Starter needs hundreds of amps out of battery. Think what just few ohms of resistance from the so called conductive grease will do to that! Do the voltage drop calculations and you will see why conductive grease concept is so stupid especially on the battery post.