Intriguing. I know that alodine can be conducive but I wonder how much. I understand that a small change in elements added to a parent material can radically change its behavior. I have no idea as to what the terminal’s alloy is other than that it must be low zinc because it’s weldable. Have you tested a before and after?
Are the eve Double Hole cells anodized and need to be sanded off?
- Thread starter EastFalcon
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Intriguing. I know that alodine can be conducive but I wonder how much. I understand that a small change in elements added to a parent material can radically change its behavior. I have no idea as to what the terminal’s alloy is other than that it must be low zinc because it’s weldable. Have you tested a before and after?
RV10flyer
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“To meet the Class 3 MIL-DTL-5541 standard, parts must have electrical resistance of no more than 0.005 – 0.010 ohms per square inch under nominal electrode pressure of 200 psi with a flat contact.”
No problems so far on aircraft or diy LFP batteries I’ve built. I’ve also used carbon conductive grease and NO-OX-ID Special on my battery connections. Time will tell.
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For my purposes, I’ve found the anti oxidants containing zinc or carbon have no advantage and may be actually detrimental. I have not tried silver. Carbon is flat out one of the messiest substances known to man. NO-OX-ID A special, marine green, or silicone dielectric grease is known to work (in and descending value). This alodine pen I must test, placing an order. It may well keep the aluminum from oxidizing but dissimilar metal like platings tin(lugs) nickel (busses) may still play havoc over time and environments.
RV10flyer
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eBay for $100+Shpg. Watch expiration date. I’ve used mine past expiration.
Sleeper85
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Yesterday I did my own tests with another 16S LF280K pack with flexible bus bar and soldered round terminals.
Terminal with oxidation, a thin white film can be seen.
So, I decided yesterday not to use grease on my terminals.
Measured yesterday with YR1035+, 16S LF280K battery with flexible bus bar. With oxidation (after 20 months) I measure a total resistance between + and - (without BMS) of 4.07 mOhm and without oxidation (rubbing by hand with steel wool then cleaning the bus bar and terminals with alcohol 96%) I measure an IR of 3.92mOhm.
Note that after removing the oxidation I do not see it coming back after 5 minutes. This is in line with the YouTube video explaining that new aluminum alloys no longer oxidize as before.
Test carried out the same day when replacing non-flexible bus bars with flexible bus bars. Nut tightened to 7.5 Nm.
I conclude that it is not necessary to add grease or other high-tech compounds. We are not in aeronautics.
On the other hand, removing oxidation and cleaning the terminals before attaching the bus bars is a good practice.
I'll test it like this and watch the behavior in the coming months/years.
Concerning the official EVE terminals with helicoil and a matte gray appearance. I'm still waiting for EVE's response on this. I will keep you informed.
Terminal with oxidation, a thin white film can be seen.
So, I decided yesterday not to use grease on my terminals.
Measured yesterday with YR1035+, 16S LF280K battery with flexible bus bar. With oxidation (after 20 months) I measure a total resistance between + and - (without BMS) of 4.07 mOhm and without oxidation (rubbing by hand with steel wool then cleaning the bus bar and terminals with alcohol 96%) I measure an IR of 3.92mOhm.
Note that after removing the oxidation I do not see it coming back after 5 minutes. This is in line with the YouTube video explaining that new aluminum alloys no longer oxidize as before.
Test carried out the same day when replacing non-flexible bus bars with flexible bus bars. Nut tightened to 7.5 Nm.
I conclude that it is not necessary to add grease or other high-tech compounds. We are not in aeronautics.
On the other hand, removing oxidation and cleaning the terminals before attaching the bus bars is a good practice.
I'll test it like this and watch the behavior in the coming months/years.
Concerning the official EVE terminals with helicoil and a matte gray appearance. I'm still waiting for EVE's response on this. I will keep you informed.
I think you may want look at that internal resistance number again. Verify that stud torque. That seems high. The oxidation that you found is just by itself, no other metal.
Sleeper85
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I think you don't understand.
The oxidation of the terminal that I show in the photo comes from a cell that was produced on 02/11/2022 so 20 months old.
The 16 cells (the cell with the oxidized terminal that I show in the photo is one of them) were then assembled for the first time with the tinned copper bus bars non-flexible supplied at the beginning of December 2022, so 10 months ago. I did not sand the terminals during first assembly.
Yesterday I dismantled everything to place them in a metal box.
I assembled everything the first time without removing the oxidation with the non-flexible bus bars and measured the internal resistance of the complete 16S pack.
5.25 mOhm
Then I assembled a second time without removing the oxidation with flexible bus bars and measured the internal resistance of the complete 16S pack.
4.07 mOhm
Finally, I removed the oxidation with iron wool (less aggressive than Scotch-Brite) and I reassembled the 16S pack with the flexible bus bars and measured the internal resistance of the complete 16S pack.
3.92 mOhm
If we divide the values of the complete 16S pack by 16, even for the worst result of 5.25 mOhm it gives us 0.328 mOhm per cell including bus bar.
Hoping this is clearer.
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I made up a lapping tool to keep it flat. Your terminal nut torque seems high for that type of terminal. Where did you find that number? You may want to re torque the flexible busses after a few days and then fine an interval to check. Some of those do compress for a while until they settle down.
Your whole pack resistance number is very good.
Your whole pack resistance number is very good.
Sleeper85
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In December 2022, I don't know where but after searching the forums I noted that the maximum tightening torque for this terminal was 8Nm.
We are talking about the welded terminal (2nd generation) and not the tapped aluminum terminal (1st génération) which is much more fragile, the tightening torque of which would be only 4Nm if I remember correctly?
Concerning the terminal welded by EVE with helicoil (3rd generation) what would be the maximum tightening torque?
I assume different from EVE clone terminals 100% tapped aluminum without helicoil. The 8S pack with the LF280K cells supplied by QSO has this terminal and I also tightened the nuts to 7.5Nm perhaps too much?
It’s quite ambiguous about some of these cells as to torques. There’s so many types. I even have one batch with welded terminals and just a taped hole(I actually prefer) instead of a stud. For as much as these things cost you’d think that they could toss a little card in with all that kind of info. I never go over 4Nm on any single hole and 6Nm on the two holes.
Helicoils can have lots of strength much of that depends on the length of the Heilicoil. If its length is only about 1X the diameter then I probably wouldn’t go over 6Nm. If it’s longer, then it becomes more about the fastener’s strength. Edit; Or twisting the whole terminal.
Helicoils can have lots of strength much of that depends on the length of the Heilicoil. If its length is only about 1X the diameter then I probably wouldn’t go over 6Nm. If it’s longer, then it becomes more about the fastener’s strength. Edit; Or twisting the whole terminal.
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Sleeper85
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Here are EVE's answers regarding the double-hole terminal with the helicoil.
Aluminum type: AL1060
That aluminum terminal is not easy to be corroded.
No need to polish oxide.
The surface of the product has not undergone other special treatments.
Aluminum type: AL1060
That aluminum terminal is not easy to be corroded.
No need to polish oxide.
The surface of the product has not undergone other special treatments.
Alkaline
Solar Wizard
Exactly, thanks for the info, no way EVE would be adding costs and making it less conductive by anodizing this thread is so misleading and so is that video, but everyone on the internet is an expert...
The only thing I can say is that that terminal looks like it was made form High Pressure Aluminum Die casting:
Aluminum High Pressure Die Casting: An In-Depth Guide - Moldie
Concept Of High Pressure Die Casting High pressure die casting (HPDC) is a metal casting process used for mass production of complex, high-integrity, and near-net-shape metal parts. The process involves injecting molten metal into a pre-designed mold at high pressure, typically between 1000 to...
moldie.net
it has a matt finish, the only issue with this is that its not the best material for conductivity because of the poores and gaps that are on a diecast part, a forged terminal would be better ... DARE I SAY, the knock off Eve terminals that EEL sells and are machined may actually be a superior terminal in terms of conductivity than the eve official.
Sleeper85
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Exactly, thanks for the info, no way EVE would be adding costs and making it less conductive by anodizing this thread is so misleading and so is that video, but everyone on the internet is an expert...
The only thing I can say is that that terminal looks like it was made form High Pressure Aluminum Die casting:
Aluminum High Pressure Die Casting: An In-Depth Guide - Moldie
Concept Of High Pressure Die Casting High pressure die casting (HPDC) is a metal casting process used for mass production of complex, high-integrity, and near-net-shape metal parts. The process involves injecting molten metal into a pre-designed mold at high pressure, typically between 1000 to...
it has a matt finish, the only issue with this is that its not the best material for conductivity because of the poores and gaps that are on a diecast part, a forged terminal would be better ... DARE I SAY, the knock off Eve terminals that EEL sells and are machined may actually be a superior terminal in terms of conductivity than the eve official.
I don't have the impression that those sold by QSO are machined.
I also spoke about this with Docan and I was told that EVE does not produce the terminals, they buy them and then solder them themselves in their factory.
So we end up with several factories producing different terminals... Which one is the best, good question.
The weld on those delivered by EVE is wider.
The great majority of the prismatic cell terminals are laser welded or electron beam welded. The advantages are minimal heating beyond the work area (terminal post into battery). The heat is very localized. The mounting terminals are not soldered, the heat involved would be detrimental. Terminals are most likely machined from billet/bar stock, not cast because of the high tolerance required would necessitate machining anyway so you can eliminate one process. The hole is a close tolerance for a close fit to the post and to control the proper amount of melt-in/penetration for the weld. The top surface must be flat and the tapped holes must be perpendicular to that surface. Terminals that have a satin finish were blasted with some sort of media, you can see that the weld was also exposed to the same process.
Sleeper85
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Indeed those welded by EVE would perhaps be well machined with a milling cutter. I don't think the matte appearance is due to sandblasting, you can clearly see the streaks. The small chips on the original terminal probably happened during laser welding.
I may send close-up photos of the terminals on the QSO cells another day.
This is the picture I was referring to from post 14. In this enhanced image you can see media impact on the weld and even in the threaded holes. The recent pictures look like they may have been etched perhaps to improve weld quality by less contamination. 
Sleeper85
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It's the QSO terminal.
It doesn't seem sanded or machined to me but can be molded?
This terminal is really shiny like glitter.
I might send more photos of this terminal afterwards, I have to open the battery case for that.
Alkaline
Solar Wizard
the qso terminal seems to be bar stock finish with no processing done on it at all. They could have machined the top surface to a smooth machined surface.
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