You do not use the washer against the alu! Since a stainless steel bolt is torqued into an alu post, the buildup is: - alu post - copper (nickel plated) terminal - flat washer to distribute force against soft copper - spring/lock washer to give smooth clamp - steel bolt head
The lock/spring washer will only dig into the steel flat washer or steel bolt head, not into the soft copper or alu. Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Michael Ross Sent: Wednesday, January 08, 2014 7:48 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Keeping LiFePO4 battery terminals tight every 10k miles 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. 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/bc05 de28/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) _______________________________________________ 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)
