Marcus, Thanks for taking the time to engage on this. If I ever flame call me on it.
1. & 6. Yay!! Consensus! 2. I would amend to "some" battery joints are impossible... I was saying that a properly designed joint will not loosen. They need to be clean, dry and flat. Hard materials and torqued right. 5. I consider this apocryphal. And my complaint was with split washers (and, god's forbid, star washers) Not all washers are created equal. A quality washer meats a flatness spec. If it is hardened it won't flex. The washer has to be thick enough. (Any flat washer can prevent galling of the surfaces below the spinning head which is nice, but not all can make the joint more effective from a force perspective.) Those qualities make for a better joint. The idea is to give the force exerted by the bolt head a broader and uniform area of pressure. The clamping force propagates into the compressed parts as a frustum of a cone. everything about the joint is netter if that cone has a larger diameter. 3. Screwing round conductors together in a polaris clamp is a bit different than clamping flat parts together. I think clean, dry and flat are primary, then, as I said you might want some conductive grease to exclude condensing moisture. Noalox? I don'e see what that particular formulation brings, but I am willing to investigate further. Someone here at work has a copy of the NEC handbook, and that often has nice commentary on stuff like this. I will report back. There are actually several different electrical codes. I would like to know which one in particular we are talking about. I was interested to see that Jack Rickard builds battery packs and pots then into an insulated box after bottom balancing. That ought to keep the moisture out. 4. I think Nordlocks ought not to be unnecessary. If I can achieve proper torque and the joint is designed well, I would pass on them with confidence. Maybe they are useful like Bellevilles, I am curious now. Split washers are basically usleess. On Wed, Jan 8, 2014 at 1:01 PM, Marcus Reddish <[email protected]>wrote: > Interesting points made in this thread: > > 1. Properly torqued joints do NOT loosen over time. TRUE! I have wrenched > on a lot of rigs and you can always tell a factory-tightened joint by the > "snap" it gives when it loosens. Even when I have tightened something to > what "seems" really tight, come in later and that joint is noticeably > easier to remove than when factory. > > 2. Battery joints are IMPOSSIBLE to tighten properly. TRUE! As those > with experience have pointed out, on some designs the terminal begins to > rotate BEFORE proper torque is reached. I didn't run into this on the M10 > Thundersky 260's, but plenty of others seem to have... Calb's 60's have > TEENY TINY M5 hardware. > > 3. Noalox is snake oil. Bullshit! The electric code REQUIRES that it be > used when joining aluminum and copper wires. Remember when aluminum wire > was causing house fires? That's what happens when you don't use noalox. > Your joints may seem fine for 5-years, 10 years, but I build things to > last 100+ years. Ever look at what happens in a marine environment? Even > tinned coating goes bad. Use a THIN coat of noalox or equivalent or > oxidation WILL occur. > > 4. Nordlock is snake oil. Bullshit! It is obvious by looking at the > design that a Nordlock washer will help secure a low-torque joint. All > these battery terminals are extremely LOW torque compared to a regular > steel bolt. The Nordlock also "bites" into the material, ensuring a good > connection. However, this leads to a second question about whether > conductivity is better or worse with washers. > > 5. Washers make a connection worse. TRUE! I saw a guy in Canada do a > series of conductivity tests using lots of different bus bars, washers, no > washers, etc. The BEST connection was a LARGE aluminum bus bar with NO > washer, using noalox and proper torque. > > 6. Sand/file those terminals. Noooooooooo... the machined surface is > flat. Give Billy-Bob 30 seconds with a file and now you have a completely > Non-flat surface with lots of etches and grooves in it. YIKES!. POLISH > the terminals with a cleaner and or use a Very fine emery cloth. Do NOT > use a flat file or other rude implements on your expensive batteries! > > Ok, enough ranting.. > > > On Wed, Jan 8, 2014 at 9:32 AM, Peter Gabrielsson < > [email protected]> wrote: > > > Here's a picture of what Toyota use in their prius battery terminals: > > http://techno-fandom.org/~hobbit/cars/batbox/80corropen.jpg > > > > Notice the nut with the captive bellville washer. They used the same type > > in their RAV4 EVs. > > > > > > > > On Wed, Jan 8, 2014 at 7:48 AM, Michael Ross <[email protected] > > >wrote: > > > > > Martin, > > > > > > I have no experience with the aluminum post cells. But it is just > > > aluminum. Aluminum is elastic and will not take a set, so it is just > > fine > > > for torquing to a level that will not give up. From my POV there is > not > > > much more to be said about it. The use of split washes concentrates > the > > > clamping forces and make the joint less effective. They are a waste of > > > money and stack height from a design engineer's POV. But if you use > them > > > it is probably not a problem. They only work as a lock after the joint > > is > > > completely loose, however; and they don't actually stop the joint from > > > loosening before that point. The loss of joint clamping force is > caused > > by > > > materials in the joint stretching or compressing. You won't find a > > split > > > washer on a Cat, Deere, Toyota, Ford, you name it product. However > they > > > are popular no denying that. With Al for a threaded member you don't > > need > > > hardened washers, because you can't clamp hard enough to get utility > from > > > them. But you do want flat, clean, metal only, parts in the stack. > > > Belleville washers are not a bad idea, they help maintain clamping > force > > > as a joint loosens. Maybe the Norlocks do some of that too. > > > > > > > > > Dave Roden, > > > > > > Head bolts have hardened flat washers. They use large fasteners as and > > > torque them VERY high to completely take any compliance out of the head > > > gasket, and many use a torque to yield technique where you don't even > > > measure the torque* per se *- you torque until the bolt stretches > > > permanently. With good steel and high quality manufacture you can > take a > > > head bolt into the plastic range and it will not be damaged to cause > > > failure, if you do this you get the maximum force possible. > > > > > > > > > Lot's of nice replies, but I just hit these two for commenting in the > > short > > > time I have right now. > > > > > > > > > On Wed, Jan 8, 2014 at 11:09 AM, EVDL Administrator <[email protected]> > > > wrote: > > > > > > > On 8 Jan 2014 at 6:03, tomw wrote: > > > > > > > > > And while you are at it, remove those lock washers! :^)) > > > > > > > > I'm really surprised to hear people say this. I've used split > washers > > > and > > > > Bellville washers on batteries for 25+ years, and they've done me > well. > > > > > > > > I also can't recall ever encountering any bolted battery connection > on > > > any > > > > commercial product that didn't have a lockwasher. And think about > it - > > > > have > > > > you ever seen any case in a vibrating, lurching vehicle where there > > > wasn't > > > > something resilient (a head gasket for example) that lockwashers > > weren't > > > > used? > > > > > > > > One thing to be careful of is that you want your lug in direct > contact > > > with > > > > the battery terminal itself, with no washers between them to add > > > > resistance. > > > > You add the washer(s) between the fastener and the lug. > > > > > > > > Some discussion too of terminal glop. With flooded batteries, I > > normally > > > > use petroleum jelly to exclude air and moisture. Many years ago I > got > > a > > > > free can of some kind of Cosmolene-like spray with an order of USBMC > > golf > > > > car batteries. That stuff worked well too and was easy to use. The > > > key, I > > > > think, is that I put the goo on AFTER tightening the connection, not > on > > > the > > > > mating contact surfaces. (Though I've known people who DID use grease > > on > > > > mating surfaces.) > > > > > > > > I don't think I've ever bothered with grease when using valve > regulated > > > > batteries, however. Maybe I should have, but nothing bad has yet > > > happened. > > > > > > > > To get back to the point, I'm pretty skeptical about washerless > battery > > > > connections. If you try this, please make sure you keep us updated > on > > > how > > > > it's going over time. For now, though, I'm sticking with > lockwashers. > > > > > > > > David Roden - Akron, Ohio, USA > > > > EVDL Administrator > > > > > > > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > > EVDL Information: http://www.evdl.org/help/ > > > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > > Note: mail sent to "evpost" and "etpost" addresses will not > > > > reach me. 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Ross > > > (919) 550-2430 Land > > > (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google > > > Phone > > > (919) 631-1451 Cell > > > (919) 513-0418 Desk > > > > > > [email protected] > > > <[email protected]> > > > -------------- next part -------------- > > > An HTML attachment was scrubbed... > > > URL: < > > > > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140108/bc05de28/attachment.htm > > > > > > > _______________________________________________ > > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > > For EV drag racing discussion, please use NEDRA ( > > > http://groups.yahoo.com/group/NEDRA) > > > > > > > > > > > > -- > > www.electric-lemon.com > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140108/512cfd4b/attachment.htm > > > > > _______________________________________________ > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > For EV drag racing discussion, please use NEDRA ( > > http://groups.yahoo.com/group/NEDRA) > > > > > > > -- > Marcus Reddish > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140108/91255cf7/attachment.htm > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison<http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140108/253e017e/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
