Hi Lee etc:I thought that stainless bolts would be a problem on connections on the Cray-3 supercomputer I worked with Seymour Cray on in Colorado Springs but the actual electrical connection is *not* through the bolt but through the contact surfaces of the terminal top and strap (the power supply was 2000A) - although it was in liquid flourinert - no corrosion. All the LiFePO4 batteries sold T-Sky & CALB batteries have M8 stainless bolts and copper straps supplied which are dissimilar metals with the aluminum threads on the battery terminals. I haven't heard of connection problems from those who actually drive their EV's 10K+ miles per year but first sanding or wire brush them & adding Noalox-probably best or dielectric grease to the contacts elleviates dissimilar metal galvanic corrosion. I noticed that doing nothing in a wet east coast environment leaves some white surface corrosion after 20k miles on the aluminum-copper contact point. I ordered NORD lock washers & Noal ox from Grainger to redo all my connections with the stainless bolts.Have a renewable energy day,mark in roanoke, VA www.REEVAdiy.org From: Lee Hart <[email protected]> To: Electric Vehicle Discussion List <[email protected]> Subject: Re: [EVDL] Keeping LiFePO4 battery terminals tight every 10k miles Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Michael Ross wrote: > It is necessary to have a properly sized torque wrench, the willingness to > look up the proper torque setting for the materials involved, and a > willingness to spend the time getting all of the bolts right. The > alternative is you take a chance on shortening the life of an expensive > pack, or running out of power in transit. It is a choice one makes not > torquing well... http://bit.ly/1dsHSCw Good advice, Michael. Thanks for the reference! (That's a new way to look it up.) It should be noted that sometimes the manufacturer's choice of materials and recommended torque is woefully ignorant. For example, a stainless steel screw in aluminum is a bad design choice. It's likely to be electrically bad, and is also likely to gall and seize in time. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140110/52fa4e88/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)
