There is an infinitely easier way to do this - https://www.nde-ed.org/GeneralResources/MaterialProperties/ET/Conductivity_Al.pdf
%IACS means the conductivity relative the International Annealed Copper Standard https://www.nde-ed.org/GeneralResources/IACS/IACS.htm It is a nice easy way to compare materials conductivity. On Mon, Sep 22, 2014 at 12:22 AM, via EV <ev@lists.evdl.org> wrote: > I might well be fighting a losing battle, but for the price of 4 holes in > a strip of material it has been a great education. > > Tonight I tested the different alloys of Al idea. > > Last time, 0.02 x 1.75 in strip of roof flashing aluminum: > ~120 F temperature rise in ~15 seconds, cross sectional area 0.036 in^2 > > Tonight: 0.1 in diameter aluminum welding filler rod > ~30 F temperature rise in ~90 seconds, cross sectional area 0.016 in^2 > > I was rather impressed that < 1/2 the area had ~1/4 the temperature rise! > My guess is the welding rod is a more conductive Al alloy than the roof > flashing is the big difference. > > Sent: Sunday, September 21, 2014 at 11:03 AM > From: "Chris Tromley" <ctrom...@gmail.com> > To: evdragra...@email.com, "Electric Vehicle Discussion List" < > ev@lists.evdl.org> > Subject: Re: [EVDL] Dissimilar metals on Headyways? > > I think you're fighting a losing battle. Different alloys have an > influence, but not enough to overcome the fact that copper has roughly > twice the conductivity (both electrical and thermal) of aluminum. You'll > need twice the cross-sectional area in aluminum as you would need with > copper to achieve similar performance. Your 1.75 inch test shows a lack of > proportionality, but that's likely due to short straps and how the current > flows locally from the bolted joint. > > I'm thinking your best bet is to use copper conductors and be very sure > all connections are thoroughly greased (Noalox, Vaseline, whatever) to > ensure all moisture is excluded from the joint. And I would re-grease them > once a year. > > Chris > > On Sun, Sep 21, 2014 at 2:54 AM, via EV <ev@lists.evdl.org> wrote:I > thought folks would like to hear the results of some of my testing. > > 1/2 inch smashed copper pipe, 200 Amps for a 2S2P pack of 8 Ahr "P" (for > Power") Headway cells: Things stayed cool. > > 1/2 inch by 0.02 inch braided strap with smashed copper pipe at > connections: 5 F rise in 90 seconds at 200 A > > 1/2 inch by 0.01 inch Al: 200A, 80F to 200F in about 15 seconds! This was > done in the oxidized state. > > 1/2 inch by 0.01 inch Al: 200A, 80F to 200F in about 15 seconds! This was > done with sanding and immediate Noalox. > > 1.75 inch by 0.02 inch Al: 200A, 80F to 160F in about 30 seconds. > > The Al performed way worse than theory predicted, then I think I figured > it out. Al roof flashing from Home Depot is apparently not a very > conductive alloy of Al. I'd guess better Al would perform much closer to Cu. > _______________________________________________ > UNSUBSCRIBE: > http://www.evdl.org/help/index.html#usub[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[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) > > -- 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/20140922/d72c3737/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)
