Maintaining battery terminals

[nicknorman]

 

Ah so now you know what another poster's intentions and meanings are or is the poster you in another guise

 

No, it was just pretty obvious to nearly everyone.

[matty40s]

Ah so now you know what another poster's intentions and meanings are or is the poster you in another guise

 

Not everyone needs a double identity Grahame. Mmm.. Edited November 30, 2016 by matty40s

[WotEver]

No, it was just pretty obvious to nearly everyone.

Well, everyone who can read and has a sense of humour I guess.

There seem to be some differences of opinion on whether to put grease between posts and terminals on this US mechanics forum.

 

http://mechanics.stackexchange.com/questions/113/how-do-i-apply-dielectric-grease-to-my-battery

 

Personally I think I'd only apply grease to the assembled post and terminal. After all, if you cover the assembly, apart from the tiny bits of air and moisture that are already in the microscopic gaps, no more is going to be able to get in, hence no build up of corrosion. But that means you have to thoroughly clean posts and terminals anytime you take them apart, before putting them back together.

Yep, there's been arguments on both sides for as long as I've been reading about it. I can see both sides but on balance the 'smearing it all over' approach strikes me as the better route for the reasons previously described.

[ditchcrawler]

Lead nails? there's a surprise

We used nails with lead heads for clipping cables

[WotEver]

We used nails with lead heads for clipping cables

Yes we did - and a very neat job they did. We also (well, actually it was before my time) used ceramic wire nuts for twisted connections. I wonder how many fires they were responsible for?

[Murflynn]

 

Ah so now you know what another poster's intentions and meanings are or is the poster you in another guise

why are you so prickly?

[David Mack]

Yes we did - and a very neat job they did. We also (well, actually it was before my time) used ceramic wire nuts for twisted connections. I wonder how many fires they were responsible for?

A couple of weeks ago I bought a new light fitting on eBay,which came with the plastic version of those to connect to the mains cable. I didn't use them!

[WotEver]

A couple of weeks ago I bought a new light fitting on eBay,which came with the plastic version of those to connect to the mains cable. I didn't use them!

I believe they're still in use in the US.

[DHutch]

It was a joke about your last line: "The final nail..."

Ah so now you know what another poster's intentions and meanings are or is the poster you in another guise

No, it was just pretty obvious to nearly everyone.

Not everyone needs a double identity Grahame. Mmm..

Come on, enough already all of you!

 

 

Daniel

[DHutch]

I believe they're still in use in the US.

 

And turkey, if you are lucky, or just cheap sticky tape....

 

 

Daniel

[Col_T]

Many thanks for the replies, chaps.

 

Domestic and engine negatives have to be connected if there is just one alternator and a split charge system, since each battery has to have a negative circuit as well as a positive circuit. You could either connect the negatives at the battery bank, or take a negative from the domestic bank, and a negative from the engine battery, to the alternator negative (and starter negative for the engine battery) - but normally these are all connected at the engine so it doesn't matter. Only if you have a shunt for an AH counter or ammeter do you NOT connect the engine battery negative directly to the domestic battery -ve.

 

 

The set-up on my boat is a Beta 1505 with twin alternators, one connected to the domestic batteries, the other to the engine battery, so I guess the above doesn't apply. I had thought that the domestic and engine -ves were connected was something to do with allowing both sets of batteries to be charged from a single inverter / charger - does this sound sensible?

[nicknorman]

Your alternators have their negatives connected to the engine, so effectively your domestic and engine battery -ves are connected together via the engine. I think engine and domestic battery -ves will always end up connected via something.

[Just Heaven]

The whole population were affected.

No considerably before that when the UK started to ban lead in paints, lead pipes in houses etc, by voluntary agreement at first, probably back in the 60s/70s [snip] Lead in paint, lead pipes in houses had gone or were considerably reduce before then. 50% of some paints was lead in the 50s. Think the final nail was EU stuff through the 90s.

We still have a lead water pipe supplying the house, from the main in the street to the house. (not an inconsiderable distance as our house is set back from the road). A few years ago the water authority came along an did some tests. But they decided that we weren't mad enough to justify the cost of replacing the pipe!

 

Steve

[Geo]

We still have a lead water pipe supplying the house, from the main in the street to the house. (not an inconsiderable distance as our house is set back from the road). A few years ago the water authority came along an did some tests. But they decided that we weren't mad enough to justify the cost of replacing the pipe!

 

Steve

 

I understand that if you are in a reasonably or very hard water area the water lays down a coating of calciums on the pipe's surface lining the pipe and stopping the water from leaching the lead out of the pipe, the inside of the pipe has a white coating. If you live in a very soft water area I understand that does not happen and they have to change the pipes.

[blackrose]

This is the particular post on that forum that makes me think twice about putting any insulating grease (esp Vaseline) between post and terminal.

 

----------------------

 

Dielectric grease does not conduct electricity. Proper application is important! Do NOT get grease between the terminals! This will inhibit good connection and shorten battery life. Vaseline was used for many decades, but with its own downsides. Vaseline is petroleum based, and when it gets hot it likes to run. This can cause the grease to penetrate between connections and cause problems.

 

Silicon based dielectric compound works extremely well because silicon won't run when it gets hot. After the silicon sees high temperatures, it will start to vulcanize. That's a fancy term for saying it will turn more solid, rather than liquid. This attribute makes it better suited for this role than petroleum jelly, and it is safe for rubber too.

 

If you get the grease between the connection, expect to have issues down the road. It might be 2 months, or 2 years. But eventually that grease will turn solid, and you will cause a voltage drop across the terminals. I don't need to go into battery chemistry here, but having too much voltage drop across the battery terminals will shorten the battery's lifespan.

 

Dielectric grease works well to prevent corrosion, but anti-corrosive spray works better in my opinion. It gets in places your fingers can't get the grease to. Dielectric grease can be used in between electrical connections, but only those utilizing low-current. Battery terminals are high current.

 

http://mechanics.stackexchange.com/questions/113/how-do-i-apply-dielectric-grease-to-my-battery

Edited December 2, 2016 by blackrose

[WotEver]

This is the particular post on that forum that makes me think twice about putting any insulating grease (esp Vaseline) between post and terminal.

Did you notice that the users of that forum had voted the post you quote down to a '4' and the post that says "spread it all over" scores a '7' and was accepted by the questioner as the 'correct' answer?

"when it gets hot it likes to run. This can cause the grease to penetrate between connections"

 

How?

 

If I clamp two terminals together there is no space for anything to penetrate between them. If they're loose enough for anything to penetrate then runny vaseline is the last of my problems.

 

Sorry, but I think that guy's talking rubbish and has no practical experience of the matter.

[nicknorman]

I think one issue with petroleum jelly is that it tends to "dry out" over time, so it's fine only if re-applied from time to time.

[Geo]

I think one issue with petroleum jelly is that it tends to "dry out" over time, so it's fine only if re-applied from time to time.

 

Like anything batteries need maintenance and after a couple of years it is time for it, yearly is better. The petroleum jelly on the outside tends to be dryish; if you look that is main dust and muck that have landed on it. Dig inside and it is OK, from my experience.

 

The idea that batteries sit in the corner for years and are ignored is bad. They need cleaning at least once a year, muck on the top leads to tracking and an increase in self discharge, plus encouraging corrosion.

[Geo]

This is the particular post on that forum that makes me think twice about putting any insulating grease (esp Vaseline) between post and terminal.

 

 

 

 

The chap's theory is wrong. A battery terminal surface is rough and malleable. When the petroleum jelly is put on as a smear it builds up in the valleys and leaves very little if any on the peaks. When the termination is screwed/clamped to the terminal the action crushed the surface peaks on both bits and squeezes surplus petroleum jelly away leaving a good electrical connection but leaving vulnerable areas protected from the air. Now do you not think that if the battery companies and the professionals in the industry even thought that PJ had problems they would be telling people not to use it.

[Murflynn]

 

....................................... it is OK, from my experience.

 

 

that's alright then

[Geo]

that's alright then

Well is something over 55 years of looking after batteries acceptable?

[nicknorman]

Like anything batteries need maintenance and after a couple of years it is time for it, yearly is better. The petroleum jelly on the outside tends to be dryish; if you look that is main dust and muck that have landed on it. Dig inside and it is OK, from my experience.

 

The idea that batteries sit in the corner for years and are ignored is bad. They need cleaning at least once a year, muck on the top leads to tracking and an increase in self discharge, plus encouraging corrosion.

 

I installed our Trojans 3 years ago. I use silicone grease on the terminals. I see no need to disconnect the terminals in order to clean the mating faces again or add any more grease to the outside. But I do check and top up the electrolyte level from time to time and that's the time the top surface gets a wipe with kitchen roll even though, with a fairly closely fitting lid, there is never any visible contamination. Despite the "dielectric grease" on the mating surfaces, the batteries still manage to supply just under 200A when we put the electric kettle on. Which is probably enough for most people!

 

So my point is, you can choose Vaseline, which requires replacing every year or two, or silicone grease which never does. I prefer the latter since I see no point in making work.

Edited December 2, 2016 by nicknorman

[blackrose]

 

 

The chap's theory is wrong. A battery terminal surface is rough and malleable. When the petroleum jelly is put on as a smear it builds up in the valleys and leaves very little if any on the peaks. When the termination is screwed/clamped to the terminal the action crushed the surface peaks on both bits and squeezes surplus petroleum jelly away leaving a good electrical connection but leaving vulnerable areas protected from the air. Now do you not think that if the battery companies and the professionals in the industry even thought that PJ had problems they would be telling people not to use it.

You, Nikorman & Wotever may well be right, but what about the other point I raised earlier: If you apply Vaseline only to the assembly rather than the separate parts prior to assembly, how would external air and moisture be able to get to any microscopic gaps between the connections? The answer is that it wouldn't because you've got an effective barrier. Therefore you've got all the advantages of terminal protection without the potential disadvantages of insulating grease between the connections. Anyway, I've only ever put terminal protection onto the assembled terminals and I've never had any corrosion problems so that's what I'll continue to do.

[Murflynn]

Well is something over 55 years of looking after batteries acceptable?

is that all ?

[blackrose]

"when it gets hot it likes to run. This can cause the grease to penetrate between connections"

 

How?

 

If I clamp two terminals together there is no space for anything to penetrate between them. If they're loose enough for anything to penetrate then runny vaseline is the last of my problems.

 

Sorry, but I think that guy's talking rubbish and has no practical experience of the matter.

I'm sorry but I disagree with you. A microscopic gap only becomes finite in terms of how small it can get when you get right down to the molecular level. So even those points of contact between post and terminal will have even smaller gaps between them and depending on how small the molecules of Vaseline become when hot they may well get into those ultra-microscopic gaps and create resistance.