For Winston type cells I recommend to keep them dry and clean and as they are from the factory. Do not use any magic creams to keep the moist out from the poles. One can sand and polish the poles if one wishes but do it right to keep the contact surface good and tight. Battery pack with proper enclosure keeps the poles in perfect condition and they stay so for 10 years (proven). Tightness of the bolts should be checked every few years at least. -Jukka
http://www.google.com/profiles/jarviju#about 2014-07-31 9:48 GMT+03:00 Cor van de Water via EV <[email protected]>: > Michael, > Your last sentence (about asperities) appears to be at odds with our > earlier statement of preferring a flat machined surface. Can you > elaborate? > > 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: EV [mailto:[email protected]] On Behalf Of Michael Ross > via EV > Sent: Wednesday, July 30, 2014 6:26 PM > To: Electric Vehicle Discussion List > Subject: Re: [EVDL] Lithium battery setpoints... > > In air, aluminum oxide forms nearly instantly. You have never seen pure > aluminum, because it does not exist where a human can stay alive to view > it. > > Therefore, sanding is a useless activity, if the goal is to remove > aluminum > oxide. You can do it, but you can't stop it from reforming. I suppose > it > is possible the layer is reduced in thickness, but I am not buying that > that matters. > > I don't like the idea of sanding terminals. You want then to have the > flat > machined surface they have leaving the factory o get a good bolted joint > with as much contact area as possible. If the terminals are clean and > un-corroded I would leave them alone. > > I suppose one might prove whether the resistance is changed for the > better > if you have a really good instrument to check it. But this will not be > your garden variety multi-meter. > > The magic creme noalox, is alleged to pierce the ALO2 crust with zinc > particles improving contact conductance and maintaining it for some time > to > come. I would like to see some sort of evidence of this that is not > anecdotal. But it might be true. > > As discussed here ad nauseum, I believe in clean joints that are torqued > properly with good quality flat washers. I think a conductive grease > that > excludes moisture may be a good idea. I am less fond of dielectric > (high > resistance) greases, but they may not hinder conduction much, as the > current passes predominantly through crushed asperities - metal to metal > contact. > > > On Wed, Jul 30, 2014 at 8:57 PM, EVDL Administrator via EV < > [email protected]> wrote: > > > On 30 Jul 2014 at 17:05, Dennis Miles via EV wrote: > > > > > Silicone dioxide is glass, and aluminum oxide is clay, which when > > > heated becomes ceramic, for example... > > > > Maybe it's splitting hairs, but (even though I took freshman chem a > LONG > > time ago) I don't know that I'd say "aluminum oxide is clay." > > > > If I'm not mistaken, potter's clay contains aluminum compounds > (silicates). > > I think you can chemically extract Al2O3 from it. Maybe you could say > that > > potter's clay CONTAINS aluminum oxide, but aluminum oxide isn't clay > per > > se. > > > > I would further disagree with "Silicone dioxide is glass," for two > reasons. > > > > First, as with clay, glass does CONTAIN silicon dioxide. However, it > also > > contains other compounds, such as sodium carbonate and lime. > > > > And being a language stickler, I should also point out that the words > > "silicon" and "silicone" are not interchangeable. Silicone CONTAINS > > silicon, but silicone is not an element, nor does it occur in nature. > It's > > a synthetic (man-made) chemical compound. There is no such critter as > > "silicone dioxide." > > > > To bring this back on topic, aluminum is not the best conductor, and > > aluminum oxide is a pretty poor one. Unfortunately making al requires > a > > lot > > of energy to reduce the bauxite, and this high embedded energy means > that > > Al > > is always in a big hurry to turn itself into aluminum oxide. > > > > To keep this from happening, you have to keep air away from it. In > > practice, you apply your NoAlOx or other grease within moments after > you > > abrade aluminum terminals (and aluminum wire, if you're using it). In > fact > > the instructions with at least one of those glops tells you to slather > it > > on > > the (aluminum) wire, then wirebrush the wire with the goop already on > it. > > > > As a side note, aluminum's high embedded energy and eagerness to > oxidize > > also makes it potentially (pun not intended) useful to power EVs. In > the > > past, EV projects have tried out aluminum-air batteries. (Unique > Mobility > > teamed up with AlCan for one of them in the 1980s.) > > > > There are big problems with al-air, though. For one thing, they're > primary > > (non-rechargeable) cells - in some ways more similar to fuel cells > than to > > batteries. Thus, you don't recharge them, you replace them, or at > least > > rebuild them in place. > > > > Also, al-air batteries aren't very efficient. They deliver only about > 15% > > of the energy that went into refining the aluminum. I don't think > that > > includes any energy use factors for transporting the alumnum to where > the > > EVs would load it in, so that would make for a further efficiency > hit. > > > > 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/20140730/612c > 2059/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) > > -------------- next part -------------- An HTML attachment was scrubbed... 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