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I have terminals attached to a battery, which will conduct high-current (40A to 200A), and these are copper plates. As the plates, and battery terminals are not perfectly even (even if they appear to), just squeezing the contact with a screw won't make the most contact surface as I can get.

Is there some sort of semi-liquid paste, grease, spray or something of similar consistence that I can put between the plates before I squeeze them together to improve the contact area and so improve high-current flow through the contact?

There are thermo-conductive pastes that you put under the fan of the CPU to improve heat flow, as there similar pastes for improving electricity conductivity?

I have been searching to find some, but was unsuccessful, maybe I don't know the right keywords. What kind of pastes I should look for? With copper, silver or graphite? What would be the best?

There are some copper pastes, but they are sold as a lubricant for high temperature applications, for breaks, etc. I am not looking for a lubricant, these plates won't move, I am looking just to improve battery electrical contact. There is also graphite spray, which is said to give electrical conductivity to any surface, meant to be used for applying electrical conductivity to the outside of devices to prevent electrostatic damage, but is that the best thing I could use for my application, considering that none of them listed improving high-current battery contact as a possible application?

I just find it strange that I couldn't find any product which has listed improving a high-current battery contact electrical connection, and it'd seem that'd be a pretty common and useful application, i.e. car batteries?

There is also silver glue, which is meant to be used for repairing circuit boards, but I don't want to glue this thing together, I just want some paste/grease.

ria
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3 Answers3

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Two common products used in the power industry include NO-OX-ID and Noalox. These products primarily improve conduction by preventing oxidation. The NO-OX-ID page specifically mentions its use in battery terminal applications.

You can also try DeoxIT which I found using the search term "electrical grease".

madrivereric
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  • Nice, but this NO-OX-ID thing seems really hard to get, I am now in Germany and no online shops seem to have it, and in US only 1 eBay seller, and it'd take days to ship, and I'd like to have something tomorrow to do this. But will order some for the future, in the meanwhile what type of generic paste (that can be commonly found in many countries) can I use the best? – ria Aug 28 '12 at 17:22
  • I would expect that there should be similar products available locally in Germany from local electrical/industrial supply companies if you are unable to wait for shipment from the US. I'm in the US and am not familiar with European/German companies so I can't offer any suggestions... – madrivereric Aug 28 '12 at 18:47
  • Try: http://www.fixtest.de/ (got it by poking around on Caig's site for international distributors). Don't speak German, but it looked promising (and had a picture of DeoxIT in their products / Kontaktpflegemittel page)... Good luck! – madrivereric Aug 28 '12 at 18:49
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    Is this about the same thing as "Liqui Moly 3140 Battery terminal grease" or a similar thing by Nigrin? These seem to be here in the local shop, but I don't know how good it is at improving contact, or is it only against corrosion? – ria Aug 28 '12 at 18:53
  • Not familiar with this and the data sheet I located from the mfg (http://www.liqui-moly.de/liquimoly/mediendb.nsf/gfx2/3139%20Batterie-Pol-Fett_EN.pdf/$file/3139%20Batterie-Pol-Fett_EN.pdf) didn't give a lot of details other than its for battery terminal connections which seems to be your application. If you're in a hurry, you might give it a try. I'd also suggest making sure you do not oversize your bolt holes for your bolt hardware and use appropriate conical washers to maximize the contact surface area. – madrivereric Aug 28 '12 at 19:04
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There is a product sold by Chemtronics -Kennesaw, ga see CircuitWorks Conductive Pen.It is called Circuitworks conductive pen. It puts out pure silver that does conduct electricity but it is not cheap. They also no offer a Nickle conductive Pen.

Mahendra Gunawardena
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Tom Castleberry
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I think metal based thermal compound are electrically conductive and should work. The compound only needs to be more conductive than the air gap it is filling. And it cannot prevent the much better metal-metal contact from occurring (apply sparingly). You could test different compounds using the the four point method to measure the contact resistance with and without an applied compound.

When different metals touch, be careful not to set up a corrosion reaction!