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Best practice for cleaning and protecting connections?

RVLiFe

Solar Enthusiast
Joined
Jun 14, 2021
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After designing my system and making all connections, I’m concerned that I don’t have proper and safe connections for longevity. All my connections are with new lugs but I didn’t sand them down or clean them in any way. I just crimped them and torqued to specs and called it a day.
What is the best practice for properly cleaning all terminals and connections and what should be applied to connections to ensure the best conductivity and to prevent corrosion over the life of my system?
I believe that the best answer should be put in the Beginners Corner and pinned.
 
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I think it depends to a great degree on whether the connections are located in a dry climate or wet climate (also indoor vs outdoor), which has a moderate effect on how you treat them (like as in determining a risk-factor rating), and how often they will get inspected for continued maintenance, etc...

Generally in a dry climate, and indoors, I would not be as concerned about them, but if in a humid location, I might spend more time and planning on a strategy in keeping them in tip-top shape.

To get the best kind of connection and longevity, I might start by cleaning all the connector-points with wire brush to polish off any oxidation and get a nice bright surface, make sure the actual contact points are flat and have good surface area against each other, use some brake-and-parts cleaner or electrical contact cleaner to do final clean, and put some di-electric (electrically conductive) grease on the connections and tighten them down (some people go so far as to recommend specific torque specs based on bolt size, me I just tend to know for myself how much to torque to based on feel), coating the outside of them to seal them off from oxygen.

On outdoor connections, 'I think like the water', and imagine how water, moisture, or humidity could get to the connection, and build a plan to ensure that these elements cannot get near the connection-point (drip-loops on cables, etc). Also not being ignorant in making sure breakers, relay contacts, etc, are properly rated for outdoor-use if needed, and in outdoor-rated enclosures, is a good idea too.

Generally I see that amperage might play a role in how the connection endures over time. I had generally always seen that something like lower voltage and higher amperage (like 12v battery banks for example), would be more susceptible to oxidizing and corrosion than a higher voltage with lower amps would (like with 48v battery banks).

But using a di-electric conductive grease can help the connection be better quality (fills in the microscopic air-gaps between contact points better), helping current flow, and also providing a sealing barrier to oxygen which is bad for oxidation to build in between connection points.

This answer may be simplistic and general, but it depends to me on exact situation and I just kind of decide what the specific install scenario needs to make it robust and stand the test of time, based on what it will be subjected to, and how long I want it to last (and whether I expect to be around to inspect it periodically, or if I will deliver it to a customer and maybe never see it again).

I used to work on tractors and automobiles a lot in my last career, and often had to deal with wiring things that would be subjected to constant liberal water exposure, and learned to think like the water, moisture, and humidity, do what you need in the specific install to keep those elements away and isolated from the vulnerable points in the circuits.
 
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BTW, another forum member here had recommended this as a good grease to use:

I never tried this particular brand yet, but essentially this is the kind of thing that can help promote a good quality connection and seal it from oxidation and moisture.

I had it in my Wish List on Amazon and was going to buy a tube and try it out. When I used to work in the industry where I needed it a lot, I didn't really care the brand so much, but was looking for something that had attribute of di-electric and electrically conductive (as opposed to the non-electrically conductive type, which I may use for different scenarios).

This grease is also advertised as thermally conductive, which can be a good attribute as well, but not really of as much concern to me here, if it is or isn't, I'm more after the electrically conductive grease.

Thermally conductive grease is more of a thing like on the old Ford engines (or the GM HEI module engines) where you'd put the di-electric thermally conductive grease between the ignition module and the distributer housing, helping it promote heat dissipation to the housing so the ignition module would not overheat. That type is also used on PCs, between CPU and heat-sink for heat dissipation.

But here, for use in promoting a better electrical connection (for use in between two electrical points of contact), we want electrically conductive di-electric grease.
 
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Hmmmm…..dielectric grease and conductive grease are different. Don’t use electrically conductive grease (generally). Dielectric grease is ok (maybe good) for lots of connections to protect and reduce corrosion. Dielectric is not conductive (confusing name). I don’t know anything about thermally conductive grease.

Good practice-lightly sand connecting surfaces (lightly); dielectric grease, firm connection.

My 2 cents.
 
Why would you use non-conductive paste on battery terminals? You want to have something that conducts very well so one does not add unnecessary resistance.

Something I wrote some time ago:


Edit: I'm assuming 'terminals' in this context means battery terminal connections to a bus bar.
 
Hmmmm…..dielectric grease and conductive grease are different. Don’t use electrically conductive grease (generally). Dielectric grease is ok (maybe good) for lots of connections to protect and reduce corrosion. Dielectric is not conductive (confusing name). I don’t know anything about thermally conductive grease.

Good practice-lightly sand connecting surfaces (lightly); dielectric grease, firm connection.

My 2 cents.

Ok nevermind if I'm off on 'correct terminology' (I generally would just improperly call all types as di-electric, as I'm not an engineer and we always used wrong words in the mechanic shop)...

But whatever it is that I put it in between the connection right on the connector contact (for the higher amp connections), then I want electrically conductive grease there. If I use a non-electrically conductive grease, then for sure I want to make sure and put the connector on DRY first and tighten it down, and only use that kind of grease on the OUTSIDE of the connection to seal it from oxidation, but I would never typically put non-electrically conductive grease between the connection on higher amperage application (it is fine for smaller multi-pin connectors).

So I would only use electrically conductive grease in between the connection, and also smear it over the outside to seal it from oxidation. But people can do it however they prefer.

An example of where I would use the normal 'di-electric' (non-electrically conductive) grease would be on vehicle underhood connectors or on the boots of spark plug wires or something. It can safely be used on a multi-pin connector as it will not cause shorting (as the grease is smeared across multiple pins within the same connector).
 
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For connections that were tinned or nickel plated, I scrubbed lightly with a brass brush, cleaned with rubbing alcohol, ne then tightened.

For the aluminum busbars and battery aluminum battery contact area, I put OxGuard.
I believe that the best answer should be put in the Beginners Corner and pinned
I disagree on the pinning. I think the techniques will be all over the place. IMO, its one of the things you need to read through and choose what’s best for you. Afraid something would make it in the sticky that’s not correct or even excessive, and someone would come along and follow it. I would not mind seeing an official guide put out by an organization, if this even exists.
I’m concerned that I don’t have proper and safe connections for longevity.
I would not lose sleep over it.

I did not do the stuff I mentioned when I first installed it, and when I removed the stuff a year later, it was fine. In the meantime, I did shoot with temps with an IR thermometer To confirm no hotspots and watched the batttery monitor for excess loss and had none.

Depending on the quality of a installation, there’s a cost to making it perfect. Things can break when taken apart or something can get dropped where its not supposed to. May just not be worth the risk going in and scrubbing the connections with a brass brush and cleaning with alcohol if they are hard to get to.
 
The thought of people using electrically conductive grease in a diy setting worries me.
I’m not sure you will see and difference in resistance between connections that are properly mated in 3 scenarios:

-sand, connect, tighten.
-sand, dielectric grease on mating surface, tighten.
-sand, electrically conductive grease, tighten.

If there is no meaningful difference, why not make a proper connection? You study did not include a proper (normal) connection.

Using conductive grease when you cannot properly mate and tighten the connection leads me to several thoughts:

-Make sure the method used to make the grease conductive is compatible and will not cause galvanic corrosion.
-Make sure the grease used will not flow, crack, separate, or dry up when exposed to high or low temperatures. This could start a fire.
-Don’t get the grease on anything you previously considered an insulator.

Don’t use electrically conductive grease (generally) seems like sound advice.
 
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I’m not sure you will see and difference in resistance between connections that are properly mated in 3 scenarios:

-sand, connect, tighten.
-sand, dielectric grease on mating surface, tighten.
-sand, electrically conductive grease, tighten.

If there is no meaningful difference, why not make a proper connection? You study did not include a proper (normal) connection.

With some of the EVE LiFePO4 cells, you're limited in the amount of torque you can apply, which means tightening it is an issue.

And with battery connections to bus bars, you definitely see the difference between sand+tighten and sand+conductive grease+tighten which I think I've shown. Never mind that the terminals are aluminium and corrode in no time - the grease helps here too.

Edit: just to make clear: the only place I use it is between battery terminal and bus bar. Crimped connections, and all other ones are to be done without any additional grease.
 
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More reason why a sticky wouldn't work, because different people would prefer to follow their own favorite methodology, for their own environment and installation scenario...
 
I agree it can conduct. I simply would not use a terminal if it could not be properly tightened.

And I don’t want new people using conductive grease with limited understanding. Seems unsafe.
 
I simply would not use a terminal if it could not be properly tightened.

It doesn't help that the terminals on most cells are aluminium originally intended to be welded. They come with studs, or these days welded terminals, but they're still aluminium - and that brings corrosion. The grease can help here too.
 
Do we want the message to be “use this and you will get better connections.” Or ”make good connections and you don’t need this” ?

Edit-I do think the points has been made here so they can read and understand.
 
I agree that everyone’s situation will be different. In my case, my system is located in the front storage bay of my 5th wheel. So it is dry but it is susceptible to outdoor humidity. I oversized my cables, lugs, busbars and everything else from the get go. This gave me the piece of mind that I wouldn’t/shouldn’t have to disassemble anything unless absolutely necessary, and that I could increase my battery storage or the number of PV panels without having to rewire very much. Since all my connections were new when installed, I think my best option would be to just use some grease on the outside to prevent corrosion and call it good. I plan on checking all connections a couple of times a year anyway since everything is susceptible to vibration. My biggest concern was some type of electrically conductive compound between the connections. I think that oversized connections will also help eliminate any fears since I’m talking about not much more then 125 Amps using 1/0 AWG cables.
I still think this is an important topic that should be pinned for us noobs. It certainly warrants something to consider for everyone putting together a system.
I didn’t realize just how expensive some of these grease options could be! Hey, what’s another $50 bill spent, right? I guess I’ll have to consider it cheap insurance.
 
Do we want the message to be “use this and you will get better connections.” Or ”make good connections and you don’t need this” ?

Edit-I do think the points has been made here so they can read and understand.

The message here should be, there are different types of grease typically used for electrical connections, just learn about them and their proper use and how either type could help or hurt your application, and proceed according to what you feel like is best for your situation.
 
I still think this is an important topic that should be pinned for us noobs.

Let me be clear on this: if you're starting out, building a 12V battery fro the first time, or whatever, don't use any grease. Crimp it properly, and tighten things according to spec, and call it a day.
If you want to take it a step further and you notice connection issues in e.g. a large 16 cell 48V pack on individual cells, something like those MG Chemical products can be of help.
 
Let me be clear on this: if you're starting out, building a 12V battery fro the first time, or whatever, don't use any grease. Crimp it properly, and tighten things according to spec, and call it a day.
If you want to take it a step further and you notice connection issues in e.g. a large 16 cell 48V pack on individual cells, something like those MG Chemical products can be of help.
I appreciate your experience and honesty. I agree, I’m probably overthinking all of this with a 12V system. I really just don’t know how much that I don’t know and I’m glad I asked. Thank you!
 
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