Dielectric grease on cable lugs? Lets test!

[AntronX]

I measured across a set of 1/4in 2awg lugs bolted together hand tight.

Great! How many amps did you test with? Can you test again but tighten the bolt with tools as tight as you can? Makes sense that copper particles would enhance conductivity but I wonder if they make a difference with properly tightened lugs.

 

[glandpuck]

Whether or not this is useful was solved many years ago when auto makers said to use dielectric grease when installing spark plugs in your car.

 

[zcskywire2]

Great! How many amps did you test with? Can you test again but tighten the bolt with tools as tight as you can? Makes sense that copper particles would enhance conductivity but I wonder if they make a difference with properly tightened lugs.

Yea I can do that.

First off though, Power supply was set to 30v 30A, with a read back current of ~29.15A

Went back and torqued the bolt to torqued AF. No grease resistance dropped significantly to 0.835mV. Greased resistance also dropped to 0.826mV. Not much difference in the short term here, but over the long term I am sure it makes a huge difference. Especially with fast rusting metals like 1000 or 1100 series aluminum (Battery Terminals).

 

[AntronX]

Went back and torqued the bolt to torqued AF

LOL I like your torque spec.
0.826mV / 29.15A = 28.3 uOhm. That's 2x better than my result.