diy solar

diy solar

Use solder paste on terminals-busbar to improve conductivity?

I presumed that the zinc was chosen as sacrificial anode to try to protect the aluminum.
That is my supposition as well, since when you look at galvanic charts, it is almost exactly between aluminum and copper. Aluminum and copper just happen to be at almost identical extreme opposite ends, and thus any aluminum/copper interface (doesn't have to be carrying current) will have a problem.
Living in Florida, this is a constant battle we fight. We watch as people fail to protect their metal and the consequences are significant. From cars and boats, to power lines and electronics, corrosion is on display everywhere, so it's easy to discover what works and what doesn't.
I don't currently live in Florida, however I have lived in two different houses with aluminum wiring. I speak from real firsthand experience with the problem. Both those houses did happen to be in Florida. One in the early 1980's, and one just this past decade. I can tell you that after 40 years of use, you need to do maintenance, like tighten or replace the connections to the switches and outlets. This is a fact.
Sure, your dry desert makes this a non-issue. I'm happy for you. That is a very small portion of the planet, and you'll never get me to stay there for any length of time.
I do currently live in the desert. I know that any connection between aluminum and copper will have a corrosion problem, and in particular anything that will carry high current will exhibit the problem all too well. The problem is that the aluminum will corrode at twice the normal rate, and that aluminum oxide is an extremely poor conductor. That means in a few years time, you need to be checking your connections. It's not this month, or even next year, but down the road there will be corrosion. Resistance and heat are the symptoms, most likely any BMS will pick it up as strange cells readings.
Please, do what you want with your system. Me, from real life experience, I understand the problem exists, and there is a product designed specifically to help prevent the problem (and required by many building codes and inspectors). I'm not going to preach anymore, but I have no intention of cleaning my connections every few years, and that's why I'll use the product.
 
I agree that there will be problems.
I have magnesium "ribbon" that I will try to wrap around the contact areas to act as sacrifice metal.

The copper bus-bars are tinned.
Looking back probably zinc coating would have been better / easier.
For sure more shiny :)

It's stupid product like noalox isn't available here.
If it was, I for sure would use it.

Lack of..
Best I can come up with is silver conductive paint.

While it's even further in the chart for galvanic corrosion, as it's a paint it will totally seal the aluminium surface so no oxigen.

No oxigen should be also no corosion, any type of corosion, including galvanic corrosion.

IMG_20201215_155653_copy_750x1000.jpgIMG_20201215_155713_copy_750x1000.jpg

The silver syringe is cheap.
Electric paint more expensive.
(
Amazon link, I purchased local Webshop to avoid the absurd costs)
Screenshot_20201215_161106.jpg
The last one seems to be cold solder.
I hope it's good and strong enough to get strong contact with my cell that have lost its thread..
(I've used 2 components epoxy to try to get headless bolt inserted strong enough)
All additional improvements for contact is welcome :)

Just don't know how it will act under higher loads.
Time will tell.

I have enough silver paint to "seal" both terminal and bus-bar.
The oxidation of the paint (silver oxide) won't have negative influence.
As (so I read) silver oxide is just as conductive as silver.
Where aluminium and copper have great reduction in conductivity with oxidation, silver doesn't have this problem.

Alternatives as the "real accepted" solution is not available.

If it's as good as?
Time will tell.
 
That is my supposition as well, since when you look at galvanic charts, it is almost exactly between aluminum and copper. Aluminum and copper just happen to be at almost identical extreme opposite ends, and thus any aluminum/copper interface (doesn't have to be carrying current) will have a problem.
Zinc is not between copper and aluminum. It is at the lowest end of the noble metal chart. Only magnesium is lower. That's why it is sacrificial. It will always be the first to corrode.
 
Absolutely correct.
Despite its location in the scale, main purpose stayed the same..
Sacrifice... :)
 
My brother (dual trade electrician and electrical linesman) recommended Alminox to me. Looks to be similar to the Noalox you speak of. Maybe this one is available in Thailand?
Connecting lots aluminium and copper conductors in coastal environments, the power utility has done some research so I’m going to follow this advice.
 
Alminox is not available here.
The search did pop up other product, "uni-seal"
The site is quite useless...
Only writes it's to prevent oxidation.

Standard Di-electric grease also does the same...

Anyway, I now have 7ml silver paint and 10ml cold solder.
Should be able to seal of enough to prevent any oxigen, or oxidation.
Original formula have chemicals that prevents galvanic corrosion process. If the Chinese put that in there as well... I don't know.
Probably, it's cheap.
Or not as it's more expensive then turpentine :)

Thank you for thinking with me.
I do have di-electric grease.
Sadly it isn't that protective.
Mostly to use for lightbulb ? to make it easier to screw / remove.

For now the silver is there and the best I could find within budget.

When Corona is "over" and I am able to visit Europe again, I for sure will get me a tube of anti oxidation and anti galvanic corrosion paste!!
 
Zinc is not between copper and aluminum. It is at the lowest end of the noble metal chart. Only magnesium is lower. That's why it is sacrificial. It will always be the first to corrode.
Much to my chagrin, you are 100% correct! That's what I get for using memory rather than looking it up.
 
The best thing I have found and used for connections is "Deoxit".
It cleans and deoxidizes the parts. After connecting, I use "Deoxit Shield".
I haven't had a corrosion problem since, and I've been on the water a looooong time :)
 
Has anybody tried Coppercote anti-seize lubricant? There are many manufactures of this and I use it for anti-seize applications, and I know it conducts.
 
You aren't the first to suggest this solution.
In my years in the garage we used that regularly on car breaks to keep them lubricated.
Even when the fat/grease would melt (red hot breaks will burn off all types of grease) the copper particles act like tiny ball bearings as "lubrication".
Really fantastic stuff.
Expensive but not near the price level of the alternative, ceramic grease.

Yes, it's conductive but it's oxidated.
This reduces the conductivity enormous.
For the same reason, solder paste isn't a good idea. (+That the flux might be a problem in the future)

There is one metal I know where oxidation doesn't influence it's conductive behaviour, that's silver!

I learned from professional installers they use silver paste.
I found on Amazon, not cheap!!
And not the few grams we need for our "few" cells.
(Professional installers might do a set of 64 cells, that's one day, next day they have 32 or 128, who knows. They run out of paste before they run out of cells)

One is dupont 4929n silver paste, $335
Other one Silver Paste DGP80 TESM8020
Price probably the same range.

I used silver paint/ink or what you might call it.
It worked like a charm.

Sure, one still needs to thoroughly clean Terminal and bus-bar.
After a few minutes the aluminium terminal is oxidated to a level that it will affect the conductivity (a little)
Acetone is perfect degreaser.

Adding some on the terminal and as I like overkill also on the parallel bus-bar.

Key points are cleanness, and tighten strong enough (but not too firm or you will pull the threads from the terminal)
That goes for all electrical connection.
Clean and tight is the least resistance.
Flat surfaces is larger area for contact, also less resistance.

Back to those threads...
Please do never use the bolts delivered by the cells but get threaded rods/studs/ headless bolts.

You can fixate them with Loctite or other locking agent.
This will give you the optimal way to apply force to the bus-bar to connect with the terminal, without having to worry too much about the weak aluminium threads in that terminal. Epoxy/JB weld will work even a little better for strength, but it's a lot more work to apply.

Back to the contact...
Clean, flat, firm and if you feel like it, additive like oxi-guard or other antioxidation chemical.
Or silver based epoxy or grease/paint/ink, what you can get and afford.

I used the last one.
IMG_20210228_123315_copy_416x999.jpg
Each contain 0.7ml, I bought 12 of them.
After the installation of 70 cells (32+48) I had 2 left.

IMG_20210217_140823_424_copy_320x180.jpgIMG_20210227_000705_161_copy_512x288_1.jpg
IMG_20210228_124716_copy_750x1000.jpgIMG_20210228_124727_copy_750x1000.jpg

Many things went wrong during production of the bus-bar, and the plywood sheets to make compression.
The 152Ah cells got somewhat bloated as they didn't have compression during the first few months.
(Still over 145Ah)
So many small adjustments where made, like the large opening on the bus-bar in the last picture.

That's not what that picture is about.
The edge of the bus-bar, nice line of silver that was pressed out the 2 Bus-bars.
This way there is as much oxigen (air) tight seal as possible. Slightly flexible,it won't crack with the movement of expansion and contraction of the terminals/Bus-bars under different temperatures.
No oxigen is no oxidation.
No oxidation is the best low resistance contact.

And yes, many other products can do the same.
None of them are as high conductive as silver.

If you take a close look at your terminal, you will see cylinder lines. = a non flat surface.
Silver will fill those tiny lines and possible scratches, effectively increase the contact surface.
As result, better contact.

Still.
It starts with cleaning the bus-bar and terminal, to free it from oxidation as much as possible.
Without that, additives won't have much usage.
 
Please explain the link.

I can't say anything good of bad about this product,
Copper based for copper to copper,
Tin based for alu to alu or copper.
And antioxidation..

They tell practically nothing about it.
For all I know it's basic silicone grease with grinded tin or copper.

What doesn't mean it does not work.

Always good to know alterative options, especially if you are in the USA, this might work for you.

I keep to my hard to get in Thailand Ox-gard :)
(And hope it will arrive soon!)
 
Please explain the link.

I can't say anything good of bad about this product,
Copper based for copper to copper,
Tin based for alu to alu or copper.
And antioxidation..

They tell practically nothing about it.
For all I know it's basic silicone grease with grinded tin or copper.

What doesn't mean it does not work.

Always good to know alterative options, especially if you are in the USA, this might work for you.

I keep to my hard to get in Thailand Ox-gard :)
(And hope it will arrive soon!)
I just shared the link as another product out there. I haven't used it so I couldn't comment further. :)
 
I just shared the link as another product out there. I haven't used it so I couldn't comment further. :)
The tiny amount of information makes me think of garage brewed product ?

Again, that doesn't mean it won't work, might even be the best.

Like nothing removes Alu/copper oxidation better than lemon juice/baking soda paste..
(Except metal sponges, but they scratch)
 
Thanks @Maxter .

Good contact is clearly hard to achieve.
Please follow the adventures of our forum member @Off-Grid-Garage on YouTube (search for off-grid garage)

He is having similar challenges I'm facing.

A few days ago my ox-gard arrived, this tube will last me a life time.
It better as purchase plus transport to Thailand was $ 45'- for 8oz.

Neither him or me have used this before.
I read a lot about other members who have used ox-gard or similar with good results.
I don't hear them complain about the troubles Andy and I have.
There are many variations.

I'm now slowly preparing my new setup, that does include capacity test of 48* 152Ah I have over a year now and 32* 280Ah who are about 9 months. (August)

Slowly as capacity test takes time @ 20A, 14 hours for 280Ah :)
Even with 3 capacity testers...
It takes a long time to do it all.
Next step is the recharge...
At 10A, but luckily 4 at a time.

Re-drill the holes, new threads (M8)
(See other post from me about that) cleaning the terminals and give them a thin layer of ox-gard.

After that... They can wait till all their brothers and sisters are finished.

Before re-asamble I will also redo the Bus-bars.
Obvious as many cells go from 6mm to 8, so they need a bigger hole.
Besides this, regular cleaning during the last few installations scraped off little to much of the electroplated tin.

I now will use nickel, stays more shiny :)
 
I've been following all the posts about battery connection problems with great interest. (Soon to be my problem!) I just love Andy's videos and have watched almost all of them. The voltage variance Andy's BMS saw was a real eye opener. (The cell voltage would change as he tightened a battery nut just a tad more.)

I am an Amateur Radio person that has dealt with bad connections, dissimilar metal corrosion and oxidation to some extent before. On my large aluminum multi-band antenna I used a product similar to this: https://www.dxengineering.com/parts/jtl-12555 It seemed to do the job on aluminum to aluminum for me. (A zinc base is probably the best solution for our battery bus problem)
https://www.qrz.com/db/n0wae

The problem we have here is sorta all of the above with more unanswered questions all rolled together. It's great to have a forum to share problems, ideas and solutions. I'll add your ox-gard to my list of possible solutions ! (Thanks fhorst)
 
FWIW, on our airplane, we used a product called ACF-50. (Anti-Corrosion Formula.) I call it "Secret Sauce." It's fixed a bunch of electrical problems in the plane - and the house.
 
Will it make that much of a difference? I have never had to use any grease or paste on connections, unless they were exposed to weather somehow, never had a situation where it was called for. I just make sure that the contact surfaces are clean and flat and torqued down to spec. Every once in while I spray some stuff on our car battery terminals and it keeps them clean. Your application could be different. I normally use copper for bus-bars and terminals.
 
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