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Topic: Conductive paste for 12V high current terminal connections (Read 596 times) previous topic - next topic

Conductive paste for 12V high current terminal connections

I have been looking for a conductive paste or grease to use when attaching high current cable lugs to help reduce connection resistance. Has anyone ever used this for electrical connections? Not just an anti-oxidizing grease, but something with suspended silver or gold.  Surprisingly, this seems to be somewhat of an obscure item. There are a lot of thermal conductive pastes which are electrically non-conductive and a lot of anti-oxidizing grease products. So far I have found 2 products on Amazon from Chemtronics and MG Chemicals, not sure how good they are for the price or which one is better.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Conductive paste for 12V high current terminal connections

Reply #1 –
I've used one that is carbon based but no long term results known.  Big fan of Deoxit D5 for enhancing conductivity, along with a coating after assembly of the silicon gel stuff.
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Conductive paste for 12V high current terminal connections

Reply #2 –
It probably isn't needed or used much, which is why it's hard to find. I've never seen paste/grease used on huge bus-bars in power plants. And they carry a lot more current and voltage than our RV systems.

I've looked for conductive grease in the past, and just gave up. Instead, I just make sure they are clean when I put it together. If you worry about oxidation, cover it in grease.
1998 U270 34'

Re: Conductive paste for 12V high current terminal connections

Reply #3 –
Caig Laboratories in CA. makes a number of electrical/electronic connection/contact cleaners, deoxidizers, lubricants used in both low power instrumentation and control (I&C) applications and in high voltage, high current applications found in electric power plants as well as in grid switching applications/switchyards.

http://store.caig.com/s.nl/it.A/id.2943/.f
http://system.netsuite.com/core/media/media.nl?id=68235&c=ACCT113328&h=4f88d67c69ac16dc3333&_xt=.pdf&ck=SRwMWwslAjd0WJPr&vid=SRwMWwslAjl0WBEj&cktime=140555

We used both the lithium and mineral DeoxIT greases and sprays in nuclear power plants.  The L260 and M260 greases and sprays (lithium and mineral base) are available in spray cans, jars, grease sticks, even 5 gal. grease pails.  Inexpensive, routinely used in the nuclear power industry.

Personally, I find Corrosion-X to work and last just as well in the Foretravel AC and DC I&C and power applications.  So there is one less thing to carry and store.  In a motorhome application, we require neither the ultra high precision instrumentation nor the voltages and currents in the (many) 1000's of volts and amps (that create the need for the specialized DeoxIT products).
Neal
The selected media item is not currently available.
Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
'04 Gold Wing
'07 Featherlite 24'
'14 Jeep Grand Cherokee Summit
MC #14494
Exeter, NH & LaBelle FL
Quality makes the Heart Soar long after Price is Forgotten

Re: Conductive paste for 12V high current terminal connections

Reply #4 –
Have used plenty of conductive grease on ASCO switch gear, very expensive. Approx. $400.00 per table spoon worth. Used on movable high current contact assy in the 4,000 amp area. If you need a part #, let me know.

Re: Conductive paste for 12V high current terminal connections

Reply #5 –
Deoxit D5 is a cleaner and deoxidizer.  Use it on the many multi pin 12 volt system connectors and eliminate pesky voltage drop thru connections.  It is one of  the few products that can clean the tiny male and female components of multi pin connections.

Corrosion X is a lubricant.  Use it to lubricate and to protect with a very thin film of oil, primarily in freshwater moisture applications. For a truly effective corrosion protection in harsher environments, use LPS3, far superior. 
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Conductive paste for 12V high current terminal connections

Reply #6 –
Even when terminal lug and power posts seem perfectly smooth, on a microscopic level the contact is made on the ridges and bumps. My specific area of interest is where my 4/0 cable lugs attach to the inverter power posts. At full inverter power of 4000 watts (approx 330 amps) the terminals and lugs get noticeably hot to the touch.

Another idea I have is to put a Fine silver washer (99.9% silver not Sterling silver) between the terminal lug and power post. In addition to higher conductivity than copper, Fine silver is very soft and will conform to any surface irregularities. A source for Fine silver washers is also not easy to find, I am finding these can be sourced as a jewelry item. I plan to try these and measure contact resistance (voltage drop) with and without and see if there is any benefit.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Conductive paste for 12V high current terminal connections

Reply #7 –
Peter,
One area of concern could be the lug on the cable, why we 1st crimp then Solder to eliminate/reduce the heating within the terminal.
Of course proper terminal setup copper & silver hardware are good too. Any heating is lost energy.
Good luck
Dave

Re: Conductive paste for 12V high current terminal connections

Reply #8 –
Dave, yes, good point on considering the complete wire connection. Will post results as I try some things. I need to take some voltage drop measurements as a baseline.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B
 

Re: Conductive paste for 12V high current terminal connections

Reply #9 –
Quote from: prfleming –
Even when terminal lug and power posts seem perfectly smooth, on a microscopic level the contact is made on the ridges and bumps. My specific area of interest is where my 4/0 cable lugs attach to the inverter power posts. At full inverter power of 4000 watts (approx 330 amps) the terminals and lugs get noticeably hot to the touch................

Peter,

DeoxIT has Lithium and Mineral based formulations with Aluminum and Copper particles to enhance the electrical conductivity of imperfectly mated surfaces.
    • L260Np Lithuim formulation with no particles
    • L260Ap Lithuim formulation with aluminum particles
    • L260Gp Lithuim formulation with graphite particles
    • L260Qp Lithuim formulation with quartz particles
    • L260GQp Lithuim formulation with graphite and quartz particles
    • M260Np Mineral based with no particles
    • M260Cp Mineral based with copper particles
    [/list]

    Don't forget that a large fraction of the inverter terminal/cable connection heating may originate from the component/terminal connection within the inverter itself.  Are the internal (terminal) connections soldered or mechanical?  Even though soldered connections, that fraction of the terminal heating may well be from high-current, skin-effect-heating as opposed to some finite resistance through a mechanical connection.

    Quote from: Chuck Pearson –
    Deoxit D5 is a cleaner and deoxidizer.  Use it on the many multi pin 12 volt system connectors and eliminate pesky voltage drop thru connections.  It is one of  the few products that can clean the tiny male and female components of multi pin connections.

    Corrosion X is a lubricant.  Use it to lubricate and to protect with a very thin film of oil, primarily in freshwater moisture applications. For a truly effective corrosion protection in harsher environments, use LPS3, far superior. 



    Chuck,
    Agree.....DeoxIT D5 is a great product for cleaning, improving and providing light preservation of electronics connections.  I carry it and use it.
     
    But, I was trying to be of help in answering Peter's question regarding "a conductive paste or grease to use when attaching high current cable lugs to help reduce connection resistance".

    Just so that others are not mislead by your characterization of Corrosion X, it is much more than "a lubricant, used to lubricate and to protect with a very thin film of oil, primarily in freshwater moisture applications."  Corrosion X is a general purpose lubricant, protectant and penetrant, as penetrating as linseed oil BTW, used in protecting metals of all types.  It provides a polarized protected surface, thereby helping to preserve the surface from oxidation/reduction reactions and it has dielectric properties that enhance conductivity thereby promoting its use on any normal AC and DC voltage connections found in households and vehicles.  I agree that it is not as (rust and corrosion) protective as LPS3......in salt water environments.  However, that was not Peter's question, and in fact, due to its self-healing, wax base, LPS3 would be the worst thing to use in "attaching high current cable lugs to help reduce connection resistance".


    Neal
    The selected media item is not currently available.
    Neal (& Brenda) Pillsbury
    '02 U320 SPEC, 4200, DGFE, Build #5984
    '04 Gold Wing
    '07 Featherlite 24'
    '14 Jeep Grand Cherokee Summit
    MC #14494
    Exeter, NH & LaBelle FL
    Quality makes the Heart Soar long after Price is Forgotten