I got 110 copper bar delivered next day to Phoenix from them. I didn't ask or pay for next day, that's just how it worked.Their inventory is insane - I got Titanium bolts from them delivered same day (only in LA area)
I got 110 copper bar delivered next day to Phoenix from them. I didn't ask or pay for next day, that's just how it worked.Their inventory is insane - I got Titanium bolts from them delivered same day (only in LA area)
Stainless steel into Aluminum is not great. It can cause galling.
I am going to just use all brass hardware with and side step the issue entirely. Hardware has been ordered.If turned under load?
Securing a stud with loctite shouldn't have that problem.
Careful about torque, so you don't strip the threads in the battery.I am going to stick with stainless fastening hardware to maximize joint pressure and solid machined copper bus bars.
Definitely - I am worried about that for sure.Careful about torque, so you don't strip the threads in the battery.
John knows.
The terminal-buss bar connection should be carrying most of the current, not the fastener that holds it together.
Galvanic compatibility is more important, which brass and aluminum (battery terminal) are not. The brass will cause the aluminum to corrode
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I have been putting stainless STI type inserts into aluminum and using stainless fasteners in life-critical aerospace applications for a very long time. Admittedly, I never really researched the chemistry at all, but the engineers that specified these fasteners did. My particular cells have stainless inserts in the terminals which is far stronger than the bare aluminum in axial strength and also allows more mating cycles. Not sure if this is common or if I am just lucky.From that chart, it looks like stainless is the worst ... and that is what most of us have been using. Brass is in the middle and may be a good compromise between the hardness and the galvanic response.
Actually, it looks like the cheapest option .... zinc coated steel might be the best option.
Now you tell me. I do still have stainless steel grub hubs. I wish you guys would make up your minds. I am just a poor EE. I skated through this stuff in school.John knows.
The terminal-buss bar connection should be carrying most of the current, not the fastener that holds it together.
Galvanic compatibility is more important, which brass and aluminum (battery terminal) are not. The brass will cause the aluminum to corrode
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Read this.Definitely - I am worried about that for sure.
I am fortunate enough to have the tools to repair a damaged thread if I go too far.
I can't argue with your experience since even though I have an extensive background in electronics ....I am new to these type of factors that come into play with a DIY battery pack.I have been putting stainless STI type inserts into aluminum and using stainless fasteners in life-critical aerospace applications for a very long time. Admittedly, I never really researched the chemistry at all, but the engineers that specified these fasteners did. My particular cells have stainless inserts in the terminals which is far stronger than the bare aluminum in axial strength and also allows more mating cycles. Not sure if this is common or if I am just lucky.
So far, I have never seen any corrosion even in significantly corrosive environments. Stainless seems unlikely to be a problem in this application.
Galvanic corrosion is different than what you are thinking. Aluminum oxide is a very poor conductor, your screws and bolts are not carrying the current, the surface where the busbar and the battery terminal meet carries the current. Galvanic corrosion is the chemical reaction when two dissimilar metals meet, basically any corrosion that would have occurred, will only occur on one of the metals. Basically it means the aluminium will corrode first and at a much higher rate. Aluminum oxide is the result, and it is terrible for an electrical connection, much worse than copper oxide. Just wipe some of the many and cheap compounds specifically designed for copper to aluminium on the terminal face, and the busbar. The stud and nut, don't worry about, they don't conduct current anyway. Basically you just put a very (and I stress very) thin layer on the terminal face and the part of the busbar to exclude oxygen and thus corrosion, the nice tight interface between the battery terminal and the busbar will squeeze and exclude oxygen and corrosion. Unless you get a lot of salt spray into the battery compartment, no problem. I doubt the corrosion of the screws will be a problem until long after the battery has reached end of life. It might weaken the mechanical connection given enough time, but we are talking decades in any environment I would put a battery.Now you tell me. I do still have stainless steel grub hubs. I wish you guys would make up your minds. I am just a poor EE. I skated through this stuff in school.
You also must take into consideration the busbar-fastner compatibility as well, but the aluminum post on the cell being the hardest to replace, is the most important to worry about not ruining The paste is very important at stopping the oxygen getting in and starting the process.
Maybe we need to start talking about using galvinised/zinc plated fastening hardware instead of stainless in/on our battery systems?
Aluminum studs seem extremely weak for this sort of thing.My take on the problem: use aluminium studs, nuts and washers, and aluminium busbars. That way you only have the 2 connections to the loads to worry about galvanic corrosion and it's not on the expensive cells but on some cheap and easily replaceable busbars
Aluminum studs seem extremely weak for this sort of thing.
Is galvanic corrosion a real problem that needs to be solved or a rare corner case in specific applications?
Interesting point.I see it as an advantage, if you break something it's likely to be the stud instead of the cell terminal