Battery terminal grease

[Sailing Paul]

I am aware that vaseline is no longer recommended for battery terminals, but what to use instead?

Silicone grease seems to be OK and unless there is a good reason not to I would like to use 100% silicone grease as it is non-toxic. Other, supposedly dedicated dielectric greases all seem to come with warnings. Wash off immediately with soap and water, etc.

What are the views on this? Is normal, cheap, non-toxic silicone grease good enough?

What about with other contacts such as bus bars and powerpole connectors? Basic silicone grease on those as well?

[Jammer]

Any kind of grease will work. Some will work better than others. The main goal is to allow the terminal to tighten evenly so that there's good metal-to-metal contact. A secondary goal is to fill the gaps where there is no metal-to-metal contact with something that will repel water, salt, acid, etc. that could lead to corrosion.

I use the corrosion-inhibiting grease sold for use on aluminum electrical cable, when it's readily at hand. Otherwise ordinary chassis grease. Or vaseline. The stuff that's sold as dielectric grease is OK too but I don't like to use siloxanes indiscriminately because they can end up contaminating surfaces that I want to paint and varnish and are impossible to remove completely. They also form nonconductive sand when exposed to an electrical arc, instead of the carbon formed by petroleum-based grease.

[Bowdrie]

Originally Posted by Jammer

I don't like to use siloxanes indiscriminately because they can end up contaminating surfaces that I want to paint and varnish and are impossible to remove completely.

Yes.
Generally speaking, the fewer uses of siloxanes/silicone on a boat the better.

[diverd]

I was shown a really interesting battery issue this weekend. A friend has had a number of battery issues, and has done all the usual checks. In total darkness today he was able to see a tiny line of blue tracking between the terminals. Its obviously caused by salt contamination on the battery top. It stopped instantly when he cleaned the battery top and wiped it down with vaseline. I have just replaced my batteries as well, so wiped the top of them with scuba grade silicon grease, to minimise the risk.

I wonder if the energy tracking could have also been causing some of the galvanic corrosion issues he has been suffering

[wrwakefield]

I have always used Corrosion-X spray. It doesn’t take much as that stuff crawls after being applied.

Below is a photo I took this summer of batteries [and cables] installed and sprayed with Corrosion-X in Jun-2014 [9 years prior.]

Zero corrosion on any wire terminals.

FWIW

Cheers, Bill

PS: Before photos can be seen in this 2014 blog post.

[shimari]

+1 for Corrosion-X

[Sailing Paul]

Originally Posted by wrwakefield

I have always used Corrosion-X spray. It doesn’t take much as that stuff crawls after being applied.

Below is a photo I took this summer of batteries [and cables] installed and sprayed with Corrosion-X in Jun-2014 [9 years prior.]

Zero corrosion on any wire terminals.

FWIW

Cheers, Bill

Thanks for that. CorrosionX is an example of the sort of thing I was questioning. I don't doubt that it is good stuff, but I can see from the label some warning signs about getting it into your eyes and other warnings. Is it damaging to aquatic organisms? I am trying to cut down as much as possible on anything that is damaging.

Basic silicone grease may not be as good a corrosion inhibitor as CorrosionX and other proprietory products, but is silicone grease good enough?

Is CorrosionX good for frequently plugged connections, or do you need to re-apply when regularly connecting/disconnecting? I am thinking about things such as portable solar generators, trolling motor to battery connections. That kind of thing.



ps, the wiring on my boat is 20 years old and shows no sign of corrosion worth doing anything about. The previous owner used nothing except vaseline. The boat doesn't even have tinned wire.

[Sailing Paul]

Originally Posted by Bowdrie

Yes.
Generally speaking, the fewer uses of siloxanes/silicone on a boat the better.

Yes, minimal is my aim. Would you put nothing on electrical contacts? Or just very small amounts -wipe it on, wipe it off?

[Scubaseas]

Permatex 80370 Battery Protector and Sealer.

[KeepInTune]

Wouldn't basic dielectric grease suffice for this or would offer unintended issues?

[Jammer]

Originally Posted by Sailing Paul

Thanks for that. CorrosionX is an example of the sort of thing I was questioning. I don't doubt that it is good stuff, but I can see from the label some warning signs about getting it into your eyes and other warnings. Is it damaging to aquatic organisms? I am trying to cut down as much as possible on anything that is damaging.

MSDS here, decide for yourself - https://www.corrosionx.at/uploads/co...cx-aerosol.pdf

Basic silicone grease may not be as good a corrosion inhibitor as CorrosionX and other proprietory products, but is silicone grease good enough?

Good enough for what?

Best practices are to keep the connections clean, dry, and tight; check them with an IR thermometer under load periodically, and retorque them periodically. Best practices are to use tinned conductors and crimped-on terminals applied with manufacturer-specified tooling and techniques. Keep battery tops clean and dry -- free of dust, salt, moisture. Every six months or a year is a good interval for all this. When the terminals or cables show signs of deterioration, replace them.

I don't have a crimper and have achieved good results with solder slugs and a torch. YAMMV.


Corrosion-X, dielectric grease, Vaseline, and other compounds and elixirs may help a little. They are not a substitute for frequent inspection and will not make anything last forever.

ps, the wiring on my boat is 20 years old and shows no sign of corrosion worth doing anything about. The previous owner used nothing except vaseline. The boat doesn't even have tinned wire.

I am not surprised.

[Bowdrie]

Originally Posted by Jammer

Best practices are to keep the connections clean, dry, and tight; check them with an IR thermometer under load periodically, and retorque them periodically. Best practices are to use tinned conductors and crimped-on terminals applied with manufacturer-specified tooling and techniques. Keep battery tops clean and dry -- free of dust, salt, moisture.

Excellent practice, and another reason to have some kind of covers/lids, or some arrangement where the tops of the batteries are not exposed.
A note on crimpers, the ones that you hit with a hammer or use in a vise are quite inferior to real crimpers.
The best ones will make a "hex" crimp, all stress to wire and connector shell are well distributed, and this shape allows the tape/heat shrink to make a good seal.
The ones that produce a divit/U-bend make a shape that is not easily sealed.
IIRC, (maybe it's changed,) many authorities, CG and ABYC come to mind, do not recommend solder for the starter motor connection, (I think the CG will flat-out not allow it on a vessel that carries passengers).
A jammed/failed Bendix can quickly heat that connection above the melting point of the solder.
I'm sure most of us can imagine the scenario if the starter cable falls out of its connector and than touches the engine block.
Something, anything that you can create to keep the starter cable from touching anything, (even if the stud on the starter solenoid breaks off,) is time/effort well spent and peace-of-mind is yours.

[Jammer]

Originally Posted by Bowdrie

A note on crimpers, the ones that you hit with a hammer or use in a vise are quite inferior to real crimpers.
The best ones will make a "hex" crimp, all stress to wire and connector shell are well distributed, and this shape allows the tape/heat shrink to make a good seal.
The ones that produce a divit/U-bend make a shape that is not easily sealed.

The idea is that the crimp is supposed to form a gas-tight metal-to-metal connection. You're right, you won't achieve that with one of those hammer-to-crimp jigs.

IIRC, (maybe it's changed,) many authorities, CG and ABYC come to mind, do not recommend solder for the starter motor connection, (I think the CG will flat-out not allow it on a vessel that carries passengers).
A jammed/failed Bendix can quickly heat that connection above the melting point of the solder.
I'm sure most of us can imagine the scenario if the starter cable falls out of its connector and than touches the engine block.

No imagination required, I've seen shorted starter cables.



The thing with crimp is that, as you point out, you have to use the proper tooling or the connection won't perform as expected. Due to space and cost constraints, I don't have crimpers aboard for battery cable. The solder slugs melt at 350 F. By the time the terminal is that hot, the insulation on the wire and the insulating bushing on the stud will both be drippy, odoriferous goo. I think a good solder connection is better than a sloppy crimp connection. I agree that a properly made crimp connection is the best way to go, though, and would recommend that whenever the tools are available.

[MicHughV]

Never thought there was so much science behind greasing a battery terminal.

I had been using some off-the-rack tire hub grease for the best part of 40 years without a hiccup.
Of late, I have a silicon grease product that comes in a spray can. Really good to grease the mainsail track with, but equally good sprayed on battery terminals.

Have seen no skin ailments in all that time on my hands either.

[Bowdrie]

Originally Posted by Jammer

No imagination required, I've seen shorted starter cables.
I think a good solder connection is better than a sloppy crimp connection.

You're right on both counts.
I had a shorted cable on an old work truck, the battery exploded.
On the OPs job.
I've never used it, but can terminals etc. be sprayed/coated with "Glyptal"?
I remember it from decades ago for use in electric motors.

Glytpal-Products