Simply that the flanged nuts and studs in this photo look to be plated steel - perhaps it is just the light - whereas the material under the nuts appears to be copper. As has already been pointed out in this thread and is already well know, having dissimilar materials in an elctrical connection is not good. If it is steel against copper, it is a dreadful design. If the corrosion is due to leaking electrolyte alone, fair enough (even so, this does not sound good). If it is steel then clearly if the minor - but significant - corrosion in this photo is typical for a Prius battery pack the, again, I would be concerned as to its longevity. MW
On 9 Jan 2014, at 17:42, Peter Gabrielsson wrote: > NiMH batteries tends to leak a litte around the terminals as they get > older. The electrolyte causes some funky fuzz buildup, usually around the > negative terminal IIRC. > > I don't know what you mean by plated steal being bad, nor do I know that > that is what they're using, the mating surfaces are certainly not plated > steel. > > The prius battery packs have an excellent track record as you may know. > > > > On Thu, Jan 9, 2014 at 9:10 AM, Martin WINLOW <m...@winlow.co.uk> wrote: > >> Ye Gads! I wouldn't like to see that same picture 10k miles from now. >> Has this pack been submerged or something? Plated steel is a very poor >> idea! MW >> >> >> On 8 Jan 2014, at 16:32, Peter Gabrielsson 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 <michael.e.r...@gmail.com >>> 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 <evp...@drmm.net> >>>> 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 >>>> >>>> michael.e.r...@gmail.com >>>> <michael.e.r...@gmail.com> >>>> -------------- 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) >>> >> >> _______________________________________________ >> 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/20140109/f3f009c6/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)
