Cell terminal bolt torque - you might be wrong!

noenegdod

Solar Addict
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Mar 21, 2020
Messages
613
However, to ensure a long service life, a contact aid compound is recommended to fill the voids in the contact area and prevent oxidation or corrosion. Many proprietary compounds are available or, if none are available, petroleum jelly or, for higher temperatures, silicone vacuum grease may be used.
I asked this somewhere on here before but it may be a little better received in this thread.

What opinions do people have on this stuff: https://www.mgchemicals.com/product...tive-grease/carbon-conductive-assembly-paste/

Features & Benefits​

  • Resistivity of 23 Ω·cm
  • Improves electrical connections between irregular, pitted or corroded surfaces
  • Ensures electrical contact between loose or vibrating parts
  • Prevents arching, pitting, hotspots and welds
  • Inhibits corrosion
  • Fills gaps
  • Can be used on vertical surfaces
  • Silicone-free
 

BiduleOhm

Electronics Sorcerer
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Jan 30, 2020
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Location
France
I would avoid putting anything carbon on aluminium. There have been big problems in the aviation world with carbon fiber in direct contact with aluminium.
 

noenegdod

Solar Addict
Joined
Mar 21, 2020
Messages
613
I would avoid putting anything carbon on aluminium. There have been big problems in the aviation world with carbon fiber in direct contact with aluminium.
Thank you! I just looked that up and for sure that is a concern. The question I now have is: Is there any difference with this product as the carbon is suspended in an environment that excludes moisture and O2 or does this not mitigate/eliminate the concern? I just fired off an email to the manufacture.
 

Bobs RV 36'

Something Burning?
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Mar 22, 2021
Messages
26
So after a general consensus I’m thinking 35 foot pounds of torque will be a sufficient enough of downward pressure for 6M and 8M Nuts/bolts Without a problem of stripping. Thank you!

Post torque, Does anybody use the battery terminal spray to seal the terminals from corrosion? My battery build is for an RV that is at the beach quite often, salty air corrosion?

Ps. Those of you that have adjustable torque wrenches problems, if you leave a value of torque on the wrench and put it away without returning it to zero this will De-calibrate Your torque wrench.
 

time2roll

Photon Sorcerer
Joined
Mar 20, 2021
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2,184
Contact resistance falls rapidly with increasing pressure, as shown in Figure 69, but above a pressure of about 30 N/mm² there is little further improvement. In most cases it is not advisable to use contact pressures of less than 7 N/mm², with pressures above 10 N/mm² being preferred. The contact resistance for a joint of a particular overlap area is obtained from Figure 69 by dividing the contact resistance for 1 mm2 by the overlap area in mm2 ."

View attachment 34978
OK so where are we on this graph at say 3 Nm or 4 Nm torque?
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
8,352
OK so where are we on this graph at say 3 Nm or 4 Nm torque?

You'll have to determine clamping force produced by that torque. That depends on thread diameter, material, whether it is lubricated.
Divide by contact area to get pressure, and look up on chart.

In other words, it is not particularly simple to calculate, and the answer will be a range of values. But you can do it using calculators and tables you find online.
 
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