Battery bus bars

Can't think of any benefit to making them solid nickel; it's 4 times the resistivity of copper.

 

Can't see why I couldn't have just ordered M5 flange nuts if used for OEM Gen3/4. McMaster-Carr has a good assortment, majority are 5mm height and 11.8mm flange and under $15 for 100 paks.

Not that TMR needs anymore M5 nuts. Super-Corrosion-Resistant 316 Stainless Steel Flange Nuts $12.88 for 100 pak.

 

Thanks, that's the info I needed. Those bars were clean in a few hours in the rock tumbler and the copper ones are still not fully clean after 30 hours. So it makes sense that the nickel plating came off. Ooops... Oh well, time to close the book on alternative bus bar research now that we know that the solid copper OEM ones work the best. Back in 2018 I thought these brand news nickel bus bars were an upgrade, but they corrode just as easily and have slightly more resistance.

 

Given the thinness of the nickel plating on the plated ones, I would scarcely expect any measurable resistance difference between a plated and unplated copper bar (when both are clean).

It's just if you wanted to compare a copper bar to a bar made of nickel that nickel's higher resistivity would be significant.

 

And with all the problems with voltage sensor harness and corrosion on ECU pins, especially in my region, a brand new wire frame means brand new bus bars on one side and with project lithium there's no other side for busbars anymore, so I don't expect to ever have a shortage of copper bus bars on the parts rack anymore.

 

(shrug)

I snuck a peak at my nickel plated bus bars that I did about 2 years ago- gave them a good coat of dielectric grease at the time.

Don't look so bad.


Posted via the PriusChat mobile app.

 

Blasphemy!! A Gen 2 built with a Gen 3 bus bar holder! What is this world coming to?

Also looks like the 7th nut from the left is only torqued to 46 in-lb.

In all seriousness though, I agree. Although I'm a believer in sticking with copper, all the nickel-plated bars I've seen have been either amazingly clean or amazingly easy to clean.

 

Just to throw a spanner in the works, what are the studs made out of that connect the copper busbar inside the module through the plastic case with the "O" ring seal on it? Sure looks like stainless to me, the magnet sticks to it, so I'm guessing it's 304 grade.
So, if stainless creates so much heat when the current passes through it, why doesn't it destroy the "O" ring and melt the plastic case?

In the rather long video at the beginning of this thread, there is a claim that using a wire wheel or coarse sandpaper would create a reduced surface area due to the highs and lows created ...... but wouldn't the copper be soft enough to crush flat when the nut was tightened?

Out of all the stuff I read on this thread, and I have to admit I skimmed through it a bit, no one mentions adding an anti corrosive/electrolytic reaction inhibiting compound such as Alminox paste?
We have been using this stuff with LFP and LYP cells conducting anywhere from mili amps to over 500 amps and everywhere in between, our BMS requires cell voltage measurement to the second decimal place because the voltage is only between 3v and 3.6v, so not a lot of room for error, the actual busbar blocks in the cells are copper at the negative terminal and aluminium at the positive terminal, the bolts are stainless and the busbar links are copper, lots of dissimilar metals, yet 3 1/2 yrs servicing that involves cleaning the links with a Scotchbrite buffer pad (blue) is all that is required to get another 3 to 4 yrs service before the terminal resistance starts to show up.

Here is my theory regarding the terminals leaking and the corrosion issue resulting from it ..... solid busbars. We use very thin copper busbars, 2 layers, each face coated with Alminox and they have a "hump" in the middle to allow them to flex ......
Anyone witnessed what copper jumper lead cable do when big current is passed through them ...... they jump don't they ..... the copper actually flexes as the current passes through it. If the busbar can absorb that flex, the terminal post in the modules gets pushed and pulled causing the "O" ring to release a bit of electrolyte or just the fumes from it as the pressure inside the module increases .....

I'm open for anyone to critique my theory and point out any holes in it ......

T1 Terry

 

I am the seller of B07XNNZ95Q and I am pleased to inform you that the nuts were changed to wide flange nuts with no serrations. The flange is extra wide, like the OEM, and not the typical afterma rket DIN 6923 flange nuts. In addition, there is also an FEA analysis picture of pressure distribution on the battery terminal at 48 lb-in torque which shows how the new flange nut pressure profile is much more uniform. The bus bars themselves are made of C11000 copper alloy, which contains 1% of Silver (Ag), which increases the conductivity and compensates for the thin nickel-plating.

 

I like your kit. Are you having these nuts custom made? Are the heads still 8mm?
I pretty much always use a new wire/sensor/busbar harness from Toyota when I build batteries, but I've tried several different M5x0.8 stainless nuts. The flanges can vary depending on the source. Never been able to find exact matches to the OEM available outside of Toyota. I've had complete success using ones I purchase from one of the larger supply businesses, even though the flange is slightly smaller than OEM. I've also purchased some M5-0.8 that use the 'heavy' style 10mm nut and they provide awesome flange coverage, but the head size prevents the black plastic protection covers from fitting correctly. It looks like you were able to find (or have made?) the heavy flange with a standard 8mm hex head?

 

Yes, they are custom-made. They are made to match the stock ones with wider flange. The head is 8mm just like the OEM. The black plastic protection covers fit as intended.

 

So much for the bus bars from Amazon.com, enlarged the hole in the bus bar and snipped a bit off the end of the bus bar. Don't see any hint of copper. Returning them. Cleaned my existing bars with a mild acid, grey scuff pad and using Ox-Gard Anti-Oxidant

Ox-Gard Anti-Oxidant

bus bars from Amazon.com

 

We use Alminox for much the same purpose when building off grid batteries from individual Winston LYP prismatic cells, it stops the copper link surfaces oxidating cause by the dissimilar metals and the high current creating an electrolytic on the joint faces and that in turn creating high resistance and heating the links.

The other problem is the seals under the terminal studs leaking because the pressure relief valves are stuck sealed closed causing major pressure build up within the cells.

T1 Terry

 

Have you put a magnet to them? Wonder if they're just stamped steel or similar.

 

Haha, didn't think to check.

 

Yes, be careful what you buy on Amazon, there are many sellers now seem to sell the same product from the same supplier in China. I purchased three different sets just to compare them and see for myself, and they all came in the same black small box package with the only difference being SKU labels. Some clearly have pictures advertising nuts with nylon inserts, when in fact they are regular DIN 6923 nuts with narrow flange. The cheaper option is often not the best one.
I sell on Amazon and always include extra hardware in the package, usually 1-2 bus bars extra, I welcome people to cut the extra bus bars in half and clearly see the copper body. Here is one of the bus bars I cut myself

 

@alftoy thanks for that, I actually just ordered that same set today but just cancelled the order right now.

I also read the review that said the same so figure that its you.

May get this other guys kit he sells on amazon and see how it goes.

I like the wider nut feature and discriptions pictured.

 

It is NOT true that "all" aftermarket busbars are plated stainless, even though some are stainless. ACENBAY brand is solid copper with 6 µm of nickel plating, to only create a thin protecting layer against corrosive electrolytes of the NiMH modules.

 

Plated bus bars sometimes have copper underneath, sometimes have something cheaper. The problem is once you remove them and clean them the plating comes off. The other problem is corrosion from batteries is a 1970's problem because Toyota wants to maximize profits by using antiquated batteries that leak NiMH electrolyte. It's outrageous that we're a 1/4 century into the Lithium revolution and Toyota continues to push garbage that hasn't been considered advanced battery chemistry since the lat 1980's.

If you want to upgrade and get better performance by every measure... Use my affiliate link to buy one of these packs: https://projectlithium.com/?ref=9qLPw

 

Project Lithium thoroughly tested all the bus bars on the market and the solid copper OEM ones had the least resistance / best performance.

Also the notion that the plating protects the copper from corrosion is silly because it doesn't prevent the corrosion, just makes it less green... I got plated bus bars that became just as nasty as the solid copper ones in only a few years.