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. To send a private message, please obtain my > > > email address from the webpage http://www.evdl.org/help/ . > > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > > > > > > > _______________________________________________ > > > 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. 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