Re: [EVDL] CALB bolt terminals getting hot -
8 years or UNLIMITED miles as of last week - retroactive and transferrable, too! MW On 20 Aug 2014, at 02:50, Dennis Miles via EV wrote: Peri, Watch the video, You Tube title is: eSamba EP 29 TESLA style fuses The many parallel packs in series depend upon each pack not having multiple failures, one or two in each pack are no problem there are about 50 cells in each parallel group. If a catastrophic failure should happen and a cascade of the cell fuses blow, the car just stops and you get the battery pack replaced under warranty the first 8 years or 100,000 miles. (in a TESLA) Dennis Lee Miles (*evprofes...@evprofessor.com evprofes...@evprofessor.com)* * Founder:**EV Tech. Institute Inc.* *Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US Time)* *Educating yourself, does not mean you were **stupid; it means, you are intelligent enough, **to know, that there is plenty left to learn!* * You Tube Video link: http://youtu.be/T-FVjMRVLss http://youtu.be/T-FVjMRVLss * *NEW You Tube Video link: *http://youtu. be/Pz9-TZtySh8 http://youtu.%20be/Pz9-TZtySh8 On Tue, Aug 19, 2014 at 9:12 PM, Peri Hartman via EV ev@lists.evdl.org wrote: So, if you want individual fusible cells, then a bus bar on both terminals won't work. One side can be spot welded but the other side needs the fuse wire - or something. Not sure how that could be done in this model. Does Tesla really have each cell fused? Part of my idea is to make each module easy to connect and swap out, if needed. Also easy to pack into a tray. Peri -- Original Message -- From: Dennis Miles via EV ev@lists.evdl.org To: Lee Hart leeah...@earthlink.net; Electric Vehicle Discussion List ev@lists.evdl.org Sent: 19-Aug-14 5:29:00 PM Subject: Re: [EVDL] CALB bolt terminals getting hot - The cells in the TESLA pack are a group in parallel then the parallel groups are wired in series for the desired voltage, The key to pack survival when a cell fails is a fusible link (Correctly sized short length of wire) in series with each and every cell then any malfunctioning cell is isolated when the link opens. (Reducing pack capacity about 2%.) Dennis Lee Miles (*evprofes...@evprofessor.com evprofes...@evprofessor.com)* * Founder: **EV Tech. Institute Inc.* *Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US Time)* *Educating yourself, does not mean you were **stupid; it means, you are intelligent enough, **to know, that there is plenty left to learn!* * You Tube Video link: http://youtu.be/T-FVjMRVLss http://youtu.be/T-FVjMRVLss * * NEW You Tube Video link: *http://youtu. be/Pz9-TZtySh8 http://youtu.%20be/Pz9-TZtySh8 On Tue, Aug 19, 2014 at 7:32 PM, Lee Hart via EV ev@lists.evdl.org wrote: Peri Hartman via EV wrote: To take this to a traction pack, I would want to try a similar design where strings of cells are spot welded in parallel for the desired current load. As I understand it, you can put as many in parallel as you want and control them with a single BMS unit. Well... There are those that believe this, and it is certainly done. However, think about failure modes: Sooner or later, a cell will fail. What happens if one of the cells in parallel shorts? All the rest will dump all their stored energy into that one shorted cell. That is very likely to result in a burst cell or even a fire. And packed like this, once one cell starts burning, it can set the rest on fire. When laptop manufacturers connected their cells directly in parallel, there were some dramatic failures and fires. Since then, reputable manufacturers are using cells with *internal* fuses and safety devices. Hobbyists and el-cheapo manufacturers aren't likely to use such cells. -- The principal defect in a storage battery is its modesty. It does not spark, creak, groan, nor slow down under overload. It does not rotate. It works where it is, and will silently work up to the point of destruction without making any audible or visible signs of distress. -- Electrical Review, 1902 -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/ attachments/20140819/de521326/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
Re: [EVDL] CALB bolt terminals getting hot -
Dave, I have a pack like that, 16 cells, 48V. It is heavy and not packed tight as it uses the plastic frames available for these cells. But the threaded holes in the stamped end plates seem to be well made and can take real torque. If they are nickel that explains their high cost. I always assumed they were copper with Ni plating. Weight, cost, and low energy and pack density are probably cons, but maybe the plastc boxed CALB and TS, etc. are similar? I guess nothing is as dense as the laptop style cells. The small packs I have are not specified well, so I can't compare datasheet items. On Tue, Aug 19, 2014 at 10:35 PM, EVDL Administrator via EV ev@lists.evdl.org wrote: On 19 Aug 2014 at 21:18, Jay Summet via EV wrote: The contact/connection may not be as good as bolt on terminals, but for 18650 cells you could probably get away with it without excessive force. Flashlights do it all the time... Does anyone here have experience with the screw-terminal 38140 cells offered by Headway (and perhaps some of their less well known Chinese competitors)? Their vendors even offer complete kits with hardware for grouping and linking cells. But then you might be falling back into the problems of loosening and corroding connections, I suppose. They also seem to be a bit more expensive per watt-hour than some other LiFePO4 cells, but that might be because I don't know where to look. 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/20140820/5d50948b/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)
Re: [EVDL] CALB bolt terminals getting hot -
Jay Summet via EV wrote: The eSamba guy is using a piece of fuse wire to each cell, so that if a single cell shorts out, the fuse wire blows... That's a good plan. Do you know how he tested it, to be sure the fuse wire is sized right to actually work? -- The principal defect in a storage battery is its modesty. It does not spark, creak, groan, nor slow down under overload. It does not rotate. It works where it is, and will silently work up to the point of destruction without making any audible or visible signs of distress. -- Electrical Review, 1902 -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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)
Re: [EVDL] CALB bolt terminals getting hot -
Jay Summet via EV wrote: Why not pressure fit? ...Flashlights do it all the time... Think about how many times you've had bad connections and flickering light, had to shake it or clean the contacts to get it to work. You can make a good electrical connection with pressure alone, but it takes a *lot* of pressure. Corrosion is another problem. The contact surface is completely exposed, and subject to moisture, dirt, and the resulting corrosion. It would help to gold plate the connections, but who would want to spend the money? -- The principal defect in a storage battery is its modesty. It does not spark, creak, groan, nor slow down under overload. It does not rotate. It works where it is, and will silently work up to the point of destruction without making any audible or visible signs of distress. -- Electrical Review, 1902 -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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)
Re: [EVDL] CALB bolt terminals getting hot -
On 08/20/2014 10:22 AM, Lee Hart wrote: Jay Summet via EV wrote: The eSamba guy is using a piece of fuse wire to each cell, so that if a single cell shorts out, the fuse wire blows... That's a good plan. Do you know how he tested it, to be sure the fuse wire is sized right to actually work? I believe he had a discharge tester and turned up the amps output until the wire flashedaround 10 amps Jay ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
I believe he also used insulated wire to contain any molten copper beads from getting loose. On Wed, Aug 20, 2014 at 12:29 PM, Jay Summet via EV ev@lists.evdl.org wrote: On 08/20/2014 10:22 AM, Lee Hart wrote: Jay Summet via EV wrote: The eSamba guy is using a piece of fuse wire to each cell, so that if a single cell shorts out, the fuse wire blows... That's a good plan. Do you know how he tested it, to be sure the fuse wire is sized right to actually work? I believe he had a discharge tester and turned up the amps output until the wire flashedaround 10 amps Jay ___ 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/20140820/8baf0664/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)
Re: [EVDL] CALB bolt terminals getting hot -
Cor, It wasn't the losses I was aghast at it was the thought of having a mini-stove going in my battery box! I was also wondering if the easiest way of measuring the cell terminal connection resistance would be to disconnect the pack and just put a large resistor across it sufficient to draw half an amp or so but what ever it was, very carefully measure the current flow (and keep monitoring it in case it changes as the resistor value changes with heat) and then measure your voltage drops across each connection. Much the same as other have suggested, just a bit more 'regulated', maybe. MW On 19 Aug 2014, at 17:15, Cor van de Water via EV wrote: Martin, Delivering 300A at 120V is 36,000 Watts, so losing 350W in the wiring and terminal connections means only 1% loss in the grand scheme of things. A single traffic light turning red in front of you so you have to stop and again accelerate up to speed is likely a bigger difference in the efficiency of a trip... Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: cwa...@proxim.com Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Lee Hart via EV Sent: Tuesday, August 19, 2014 9:08 AM To: Martin WINLOW; Electric Vehicle Discussion List Subject: Re: [EVDL] CALB bolt terminals getting hot - Cor van de Water via EV wrote: Depends on your current. Typically I would say in the order of magnitude of 0.1 mOhm (milliOhm) because a 300A current will then give 30mV drop, which produces 300A x 0.03V = 9 Watt of power loss as heat. Martin WINLOW via EV wrote: At EVERY connection? In a 120V lithium pack that 's 38 x 9 = nearly 350W of heat! No; Cor has it right. And, 0.1 milliohms is a *good* connection. You will discover that it is damnably difficult to make a connection that good with aluminum terminals! -- You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete. -- R. Buckminster Fuller -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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) ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
From: Roland via EV ev@lists.evdl.org Attach a milliamp meter shunting that one link that was torque... It seems to me that what you mean is a milliVOLT meter. A milliammeter has a low internal resistance that can give you errors if you don't have a good connection between it and the test circuit. A millivoltmeter has high internal resistance, which means it's going to be immune to orders-of-magnitude changes in its probe contact resistance, albeit somewhat balanced by greater sensitivity to electrical noise. Court challenges over cow-share programs and regulatory efforts to further restrict the availability of raw milk have met heavy consumer resistance, in spite of biased media coverage that merely reports government propaganda. -- Ron Schmid Jan Steinman, EcoReality Co-op (Send email to qu...@bytesmiths.com to get a random quote, or quo...@bytesmiths.com to get 50 random quotes. Put a word in the Subject line to filter for that word.) ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
The website is now working. I forgot to save the changes. I am not branching out to more services. Better for me to learn how to use Google and whatever new stuff they have added. I used Google Picasaweb for years without any trouble. The images I linked to were migrated to G+. I am guessing that I am looking at them logged in as me, and the URL is different when others try to go there. I need to figure out how to view G+ as not me. Peri has been able to see this now: https://sites.google.com/site/michaeleross/misc On Tue, Aug 19, 2014 at 4:44 PM, EVDL Administrator via EV ev@lists.evdl.org wrote: On 19 Aug 2014 at 15:57, Michael Ross via EV wrote: I don't have another file service. The following are not official EVDL recommendations, but rather my personal suggestion. They used to be official EVDL recommendations, but a few people found things to gripe about with them. Now my official recommendation is to see the Wikipedia lists of filesharing services. But I personally have used the 3 below and have been satisfied with them within the limits and cautions stated on each one. I like imagebin http://imagebin.org/ pretty well. However, paranoid browsers have fits over it, because apparently a few slimy users have figured out how to post malware there. (My pix there do not have malware.) It requires no signup or login. Just upload what you have and anyone can view it. It has unobtrusive ads, if any. You need javascript to post, but not to view photos. One big downside of imagebin is that your upload is temporary. Their database holds 5000 photos, and new ones push older ones out. Typical life of your photo is around 2 weeks. tinypic.com also requires no signup or login, either to upload or view. However, I think its ads are probably more aggressive. (I don't know, I use various ad-blocking schemes on my computer, so I see none.) It also requires javascript to post and view. Photos on tinypic eventually vanish if they're not accessed now and then. I just checked a photo I uploaded there in 2008, and it's still online, but a video clip I sent around 2002 is gone. uploadhouse.com is a third site which requires no membership or logins, either to upload or view. You do need javascipt to upload, but not to view the uploaded pictures. I don't know what the ads are like there either, but they do push their own hosting service pretty hard. Also, make sure you get the URL right, because they allow (often VERY) NSFW pictures. Hope this helps. Sorry for taking up bandwidth, but it's for EVDL business. 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/20140819/b2b4cafa/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)
Re: [EVDL] CALB bolt terminals getting hot -
On 19 Aug 2014 at 15:48, Willie2 via EV wrote: Please inform me if my Google+ page is not visible to all: https://plus.google.com/102434734002949174273/posts Perhaps one has to be logged on to Google? I didn't think so. I had no trouble seeing your page, and I'm not logged in to Google. When I place the cursor over the pictures, a link to Willie McKernie's photos pops up. If I left-click on that link (presumably to see more photos of that item), I get your entire photo album, not just the item pictured. If I right-click on the link and try to open it in a new tab (the way I prefer), nothing is viewable without a login. Go figure. 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)
Re: [EVDL] CALB bolt terminals getting hot -
On 08/19/2014 04:00 PM, Michael Ross via EV wrote: The website is now working. I forgot to save the changes. I am not branching out to more services. Better for me to learn how to use Google and whatever new stuff they have added. I used Google Picasaweb for years without any trouble. The images I linked to were migrated to G+. I am guessing that I am looking at them logged in as me, and the URL is different when others try to go there. I need to figure out how to view G+ as not me. http://gphangouts.com/googleplusurl.html ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
Sorry, the BMS on this pack is hanging outside the pack. There is an image of another pack (32120 cells) that has the BMS mounted inside its wrapping. The pack is meant to be used by eScooters and such. As these things go it was very economical and seems to be functioning very well - except a crappy spade connection between the pack and BMS. The cost with air shipping included was $450. 20Ah, 48VDC nominal LiFePO4. This included the BMS, a 6A charger, pack and a carrying bag. The mass is 9kg. Here is a link to a torn apart Tesla pack: http://www.teslamotorsclub.com/showthread.php/21850-NHTSA-Opened-Up-the-Model-S-Battery-Pack-Pics Here is an image of guys welding batteries: http://bioage.typepad.com/photos/uncategorized/welding2.jpg On Tue, Aug 19, 2014 at 5:47 PM, Michael Ross michael.e.r...@gmail.com wrote: I think I gave the URL to view when viewed as me logged in as me. I haven't sorted out how to get the public URL. I think it used to be obvious, but I have lost the method :-( This battery was purchased through Alibaba from China. The cells are 18650 size LiFePO4. I believe I saw in image of a Tesla pack opened up and it had multiple thousands of these in it. (I have head they use 6000 or 700 laptop cells) I am sorry I don't recall where I saw that. Maybe EVTV? Seems like welding is the only way to get the sort of reliability you need if there are no threaded connections. Clamping, as with funky old D cell flashlights, is clearly not the way to go. Yes it is a BMS placed inside the pack. Then they duct taped and hot glued their way to a reasonably presentable pack. I did not build this myself - that is what I was wondering - if anyone here has tried this sort of thing. I really don't think it would be too difficult once you knew the recipe. Here is another link that might take you to an album of battery images: https://plus.google.com/photos/100767276460953028406/albums/5857562724939978177?banner=pwa My intention is that it be visible to anyone, and it says that is so, but I may still be sharing the wrong URL. I will put a few more images at the website. On Tue, Aug 19, 2014 at 4:53 PM, EVDL Administrator via EV ev@lists.evdl.org wrote: On 19 Aug 2014 at 16:10, Michael Ross via EV wrote: This should be viewable by anyone https://sites.google.com/site/michaeleross/misc This one works fine for me. (I do have javascript enabled for Google; it might be required for this page.) Thanks for setting it up! The two snipurl links said they were invalid. It's an interesting battery. I take it that's some kind of BMS top right in the first photo? What kind of cells are they? I mean what size, chemistry, brand? Did you assemble the battery yourself? How did you fasten the links? 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 -- 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/20140819/31952fce/attachment.htm
Re: [EVDL] CALB bolt terminals getting hot -
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 08/19/2014 07:54 PM, Ben Apollonio via EV wrote: True enough, but if a 200Ah cell fails shorted, it still has 200Ah to dump all by itself, which is likely to be equally catastrophic. I think the probability of occurrence is higher with 200 1Ah cells than with 1 200Ah cell, but the end result is the same. On the other hand, if you DO take precautions to isolate the parallel cells in a fault, you can limit the total energy released to the amount stored in a single cell (or a handful of small cells). If I recall correctly, Tesla does this, including firewalls between modules, which is how they can get away with using 1000's of cells in a single pack. -Ben The eSamba guy is using a piece of fuse wire to each cell, so that if a single cell shorts out, the fuse wire blows. I believe the assumption is that the then isolated cell won't be able to start ITSELF on fire if it is not drawing current from all the other parallel cells I'm not sure if that is actually the case or not Jay -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAlPz53sACgkQSWJjSgPNbM961wCbB0x2m6wjewcyCkcZw4cWGN1J SW8An374ZGmxqeHKL0SwWPVUNcmoRn+Q =Yxrx -END PGP SIGNATURE- ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
So, if you want individual fusible cells, then a bus bar on both terminals won't work. One side can be spot welded but the other side needs the fuse wire - or something. Not sure how that could be done in this model. Does Tesla really have each cell fused? Part of my idea is to make each module easy to connect and swap out, if needed. Also easy to pack into a tray. Peri -- Original Message -- From: Dennis Miles via EV ev@lists.evdl.org To: Lee Hart leeah...@earthlink.net; Electric Vehicle Discussion List ev@lists.evdl.org Sent: 19-Aug-14 5:29:00 PM Subject: Re: [EVDL] CALB bolt terminals getting hot - The cells in the TESLA pack are a group in parallel then the parallel groups are wired in series for the desired voltage, The key to pack survival when a cell fails is a fusible link (Correctly sized short length of wire) in series with each and every cell then any malfunctioning cell is isolated when the link opens. (Reducing pack capacity about 2%.) Dennis Lee Miles (*evprofes...@evprofessor.com evprofes...@evprofessor.com)* * Founder: **EV Tech. Institute Inc.* *Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US Time)* *Educating yourself, does not mean you were **stupid; it means, you are intelligent enough, **to know, that there is plenty left to learn!* * You Tube Video link: http://youtu.be/T-FVjMRVLss http://youtu.be/T-FVjMRVLss * * NEW You Tube Video link: *http://youtu. be/Pz9-TZtySh8 http://youtu.%20be/Pz9-TZtySh8 On Tue, Aug 19, 2014 at 7:32 PM, Lee Hart via EV ev@lists.evdl.org wrote: Peri Hartman via EV wrote: To take this to a traction pack, I would want to try a similar design where strings of cells are spot welded in parallel for the desired current load. As I understand it, you can put as many in parallel as you want and control them with a single BMS unit. Well... There are those that believe this, and it is certainly done. However, think about failure modes: Sooner or later, a cell will fail. What happens if one of the cells in parallel shorts? All the rest will dump all their stored energy into that one shorted cell. That is very likely to result in a burst cell or even a fire. And packed like this, once one cell starts burning, it can set the rest on fire. When laptop manufacturers connected their cells directly in parallel, there were some dramatic failures and fires. Since then, reputable manufacturers are using cells with *internal* fuses and safety devices. Hobbyists and el-cheapo manufacturers aren't likely to use such cells. -- The principal defect in a storage battery is its modesty. It does not spark, creak, groan, nor slow down under overload. It does not rotate. It works where it is, and will silently work up to the point of destruction without making any audible or visible signs of distress. -- Electrical Review, 1902 -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140819/de521326/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)
Re: [EVDL] CALB bolt terminals getting hot -
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 08/19/2014 09:12 PM, Peri Hartman via EV wrote: So, if you want individual fusible cells, then a bus bar on both terminals won't work. One side can be spot welded but the other side needs the fuse wire - or something. Not sure how that could be done in this model. Does Tesla really have each cell fused? Part of my idea is to make each module easy to connect and swap out, if needed. Also easy to pack into a tray. Why not pressure fit? Have a whole bunch of springs mounted on a board spaced appropriately for your cells. You'd probably need a lot of screws to hold the board flat (unless it was an especially thick and rigid material). You would still have to solder/weld a wire/fuse to each spring..but you could do that at high temperatures without risking cell damage. The contact/connection may not be as good as bolt on terminals, but for 18650 cells you could probably get away with it without excessive force. Flashlights do it all the time(I know, I know...lower current...) Jay -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAlPz928ACgkQSWJjSgPNbM/2FgCfQLu4e9PmtMUUE+CPGDBcytM1 2uwAn0MM0k22L6Q0DxMxmkJYGsTsFMA0 =RdZn -END PGP SIGNATURE- ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
Peri, Watch the video, You Tube title is: eSamba EP 29 TESLA style fuses The many parallel packs in series depend upon each pack not having multiple failures, one or two in each pack are no problem there are about 50 cells in each parallel group. If a catastrophic failure should happen and a cascade of the cell fuses blow, the car just stops and you get the battery pack replaced under warranty the first 8 years or 100,000 miles. (in a TESLA) Dennis Lee Miles (*evprofes...@evprofessor.com evprofes...@evprofessor.com)* * Founder:**EV Tech. Institute Inc.* *Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US Time)* *Educating yourself, does not mean you were **stupid; it means, you are intelligent enough, **to know, that there is plenty left to learn!* * You Tube Video link: http://youtu.be/T-FVjMRVLss http://youtu.be/T-FVjMRVLss * *NEW You Tube Video link: *http://youtu. be/Pz9-TZtySh8 http://youtu.%20be/Pz9-TZtySh8 On Tue, Aug 19, 2014 at 9:12 PM, Peri Hartman via EV ev@lists.evdl.org wrote: So, if you want individual fusible cells, then a bus bar on both terminals won't work. One side can be spot welded but the other side needs the fuse wire - or something. Not sure how that could be done in this model. Does Tesla really have each cell fused? Part of my idea is to make each module easy to connect and swap out, if needed. Also easy to pack into a tray. Peri -- Original Message -- From: Dennis Miles via EV ev@lists.evdl.org To: Lee Hart leeah...@earthlink.net; Electric Vehicle Discussion List ev@lists.evdl.org Sent: 19-Aug-14 5:29:00 PM Subject: Re: [EVDL] CALB bolt terminals getting hot - The cells in the TESLA pack are a group in parallel then the parallel groups are wired in series for the desired voltage, The key to pack survival when a cell fails is a fusible link (Correctly sized short length of wire) in series with each and every cell then any malfunctioning cell is isolated when the link opens. (Reducing pack capacity about 2%.) Dennis Lee Miles (*evprofes...@evprofessor.com evprofes...@evprofessor.com)* * Founder: **EV Tech. Institute Inc.* *Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US Time)* *Educating yourself, does not mean you were **stupid; it means, you are intelligent enough, **to know, that there is plenty left to learn!* * You Tube Video link: http://youtu.be/T-FVjMRVLss http://youtu.be/T-FVjMRVLss * * NEW You Tube Video link: *http://youtu. be/Pz9-TZtySh8 http://youtu.%20be/Pz9-TZtySh8 On Tue, Aug 19, 2014 at 7:32 PM, Lee Hart via EV ev@lists.evdl.org wrote: Peri Hartman via EV wrote: To take this to a traction pack, I would want to try a similar design where strings of cells are spot welded in parallel for the desired current load. As I understand it, you can put as many in parallel as you want and control them with a single BMS unit. Well... There are those that believe this, and it is certainly done. However, think about failure modes: Sooner or later, a cell will fail. What happens if one of the cells in parallel shorts? All the rest will dump all their stored energy into that one shorted cell. That is very likely to result in a burst cell or even a fire. And packed like this, once one cell starts burning, it can set the rest on fire. When laptop manufacturers connected their cells directly in parallel, there were some dramatic failures and fires. Since then, reputable manufacturers are using cells with *internal* fuses and safety devices. Hobbyists and el-cheapo manufacturers aren't likely to use such cells. -- The principal defect in a storage battery is its modesty. It does not spark, creak, groan, nor slow down under overload. It does not rotate. It works where it is, and will silently work up to the point of destruction without making any audible or visible signs of distress. -- Electrical Review, 1902 -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/ attachments/20140819/de521326/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
Re: [EVDL] CALB bolt terminals getting hot -
Flashlights only have a current draw of half an amp. The 18650 cells are typically used at FIVE amps. And I often have to shake my flashlights to clean the contacts before they attain normal brightness. (That indicates they a corroding.) About two years ago I recall seeing a spot-welding system and strapping for the 18650 cells, the welder was only about $200 and for building a $7,000 to $10,000 pack, it would seem a reasonable price to pay. I haven't searched for it yet but it had a video so searching on You Tube for spot weld batteries might lead to a possible solution... Dennis Lee Miles (*evprofes...@evprofessor.com evprofes...@evprofessor.com)* * Founder:**EV Tech. Institute Inc.* *Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US Time)* *Educating yourself, does not mean you were **stupid; it means, you are intelligent enough, **to know, that there is plenty left to learn!* * You Tube Video link: http://youtu.be/T-FVjMRVLss http://youtu.be/T-FVjMRVLss * *NEW You Tube Video link: *http://youtu. be/Pz9-TZtySh8 http://youtu.%20be/Pz9-TZtySh8 On Tue, Aug 19, 2014 at 10:35 PM, EVDL Administrator via EV ev@lists.evdl.org wrote: On 19 Aug 2014 at 21:18, Jay Summet via EV wrote: The contact/connection may not be as good as bolt on terminals, but for 18650 cells you could probably get away with it without excessive force. Flashlights do it all the time... Does anyone here have experience with the screw-terminal 38140 cells offered by Headway (and perhaps some of their less well known Chinese competitors)? Their vendors even offer complete kits with hardware for grouping and linking cells. But then you might be falling back into the problems of loosening and corroding connections, I suppose. They also seem to be a bit more expensive per watt-hour than some other LiFePO4 cells, but that might be because I don't know where to look. 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) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140820/fef73964/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)
Re: [EVDL] CALB bolt terminals getting hot -
What, as a matter of interest, is an acceptable amount of resistance in a battery or cell terminal connection? MW On 17 Aug 2014, at 00:48, EVDL Administrator via EV wrote: On 16 Aug 2014 at 14:04, Lee Hart via EV wrote: The technique has been described many times on the EVDL. It must be in the archives somewhere. Before I type it all in yet again, maybe we can find it? Here's one method. http://www.evdl.org/archive/index.html#nabble-td4657626|a4657642 Just to be clear, he means you should measure voltage drop across the intercell link cable or strap, NOT across the cell or battery itself! I usually measure the voltage drop from the center of the battery post to the clamp itself. That's easy with lead batteries - there's lots of post area for contact. I don't know whether that's the case with your lithium cells. But the principle remains - pass a known current through the connection and measure the voltage drop. Calculate the resistance (if you care) with Ohm's law. Or just look for connections with exceptionally high voltage drop. David Roden - Akron, Ohio, USA EVDL Administrator ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
At EVERY connection? In a 120V lithium pack that 's 38 x 9 = nearly 350W of heat! Sounds a lot and I'm pretty sure my battery box didn't ever get *that* hot! But then, I suppose that would only be under acceleration... my normal cruising current was less than half that but that's still 150W. Still sounds a bit high? MW On 17 Aug 2014, at 09:07, Cor van de Water via EV wrote: Depends on your current. Typically I would say in the order of magnitude of 0.1 mOhm (milliOhm) because a 300A current will then give 30mV drop, which produces 300A x 0.03V = 9 Watt of power loss as heat. Cor van de Water -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Martin WINLOW Subject: Re: [EVDL] CALB bolt terminals getting hot - What, as a matter of interest, is an acceptable amount of resistance in a battery or cell terminal connection? MW ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
Try an IR-Blue, I have one, and have used it at varying distances. https://www.google.com/search?q=ir-blue On August 16, 2014 2:13:23 AM CDT, Martin WINLOW via EV ev@lists.evdl.org wrote: Dan, You should check the instructions for the laser thermometer - I expect that, like mine, it recommends a maximum reading distance (from object of interest to instrument) in single figure inches! MW On 15 Aug 2014, at 02:32, Michael Ross via EV wrote: I am with Jan. The laser thermometers are averaging over the whole patch you see lit up and they are not hugely accurate because of it. If the patch is larger from being farther away or not circular because it is on an angle - it will not report what you are hoping for. They are best for shining inside a uniform container, oven, furnace, etc. Or if at a wall, then you need to take a series of readings. Imagine on one terminal you slide off to one side and average in some temperature from the top of the battery case. Or you have to get very close to one and far from another, and so on. Can you share what make and model of thermometer you are using? Mike On Thu, Aug 14, 2014 at 7:21 PM, David Nelson via EV ev@lists.evdl.org wrote: If this is a change then I would investigate. I have had my pack in for over 4 years and have not had the issue you and others have had and my pack isn't exactly closed to moisture and dust. I have 40 TS-LFP100AHA cells in a 2p20s arrangement. Because the BMS I used to use attached to the heads of the terminal bolts I used brass bolts since they are much easier to drill and tap threads in. This also meant that I could assemble the pack and torque the bolts independent of the BMS connections so they could not interfere with any connections. Before assembling my pack I wire brushed all the terminals to shine them up. I did this with NOALOX on the terminals and SS wire brush so that the NOALOX would seal the metal as soon as possible. I also tapped all the terminal holes again, using NOALOX on the tap though this was probably way overkill. I did find some terminals that didn't get tapped all the way down. I then put NOALOX on the bolt threads before assembling. This was mostly so that the soft Al and Cu terminals wouldn't gall up at all. I used bronze lock washers, too. I have had no terminals come loose or get warm. Some may say that what I did was a waste of time but they can't counter the results. It just works and I'm glad. LiFePO4 has been much simpler than lead acid in many ways. If I were you I would clean all the terminals using a similar process. If I were to do it over, and I have on small 4-8 cell packs, I would use NO-OX-ID A SPECIAL because it doesn't seem to get sticky over time like the NOALOX does. On Wed, Aug 13, 2014 at 2:20 PM, Danpatgal via EV ev@lists.evdl.org wrote: I am using 38x130 ah CALBs in my Lectric Leopard and have had a too hot ( 40C) warning on my BMS come on a few times in the last month or so. Today, after a longer stretch of accelerating uphill to home, I checked some of the battery posts. Measuring with a laser sensor, several of them were around 33C , in a grouping, maybe 6 or 8 posts adjacent on the most positive side of my pack. Posts just a few cells more negative were much cooler, maybe around 26C or cooler. I checked the bolts to make sure they were tight, and didn't notice any real problem with the connections being loose. My only other thought is that perhaps (as has been discussed in other threads), these connections have corroded over time ... adding a little resistance layer (I didn't initially polish or use Noalox on those) that is now finally heating up. I am also using the original copper straps with steels M8 bolts. Are others noticing this kind of heat with the lithium cell terminals? Aside from just cleaning the terminals and putting on some Noalox, might there be other things to do? I installed these in Sep. 2012, so they are not quite two years in service. Thanks - Dan ___ 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) -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140816/bd59f6e5/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)
Re: [EVDL] CALB bolt terminals getting hot -
Danpatgal via EV wrote: I have on my to-do list to clean up the connections. With the BMS modules on there it's just a pain and I have to be very careful (I know - if I had done it at the beginning ...). You can measure the resistance of the connections without taking them apart. Then only clean the ones that have a higher-than-normal resistance. All you need is a normal multimeter and a source of a known current (like your charger). The technique has been described many times on the EVDL. It must be in the archives somewhere. Before I type it all in yet again, maybe we can find it? -- You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete. -- R. Buckminster Fuller -- Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.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)
Re: [EVDL] CALB bolt terminals getting hot -
On 16 Aug 2014 at 14:04, Lee Hart via EV wrote: The technique has been described many times on the EVDL. It must be in the archives somewhere. Before I type it all in yet again, maybe we can find it? Here's one method. http://www.evdl.org/archive/index.html#nabble-td4657626|a4657642 Just to be clear, he means you should measure voltage drop across the intercell link cable or strap, NOT across the cell or battery itself! I usually measure the voltage drop from the center of the battery post to the clamp itself. That's easy with lead batteries - there's lots of post area for contact. I don't know whether that's the case with your lithium cells. But the principle remains - pass a known current through the connection and measure the voltage drop. Calculate the resistance (if you care) with Ohm's law. Or just look for connections with exceptionally high voltage drop. 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)
Re: [EVDL] CALB bolt terminals getting hot -
From: Lee Hart via EV ev@lists.evdl.org You can measure the resistance of the connections without taking them apart... All you need is a normal multimeter and a source of a known current (like your charger)... The technique has been described many times on the EVDL... Pump a fixed known current through the battery, and measure the voltage drop between the terminal and the post. Set your DVM to the lowest range, where you can measure millivolts. If you pump the current through your entire pack, you can quickly move post-to-post, checking them all. Call out the millivolt drop to an assistant for recording. Nothing wastes more energy than worrying. The longer one carries a problem, the heavier it gets. Don't take things too seriously. Live a life of serenity, not a life of regrets. -- Douglass Pagels Jan Steinman, EcoReality Co-op ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
I have on my to-do list to clean up the connections. With the BMS modules on there it's just a pain and I have to be very careful (I know - if I had done it at the beginning ...). I noticed the temperature first while driving from the BMS (Lithimate Lite) telling me one cell was getting over 40C. What was odd was I still got it on a cooler day (in the 70s), so it made me suspect the connections. So I checked a few of the bolt heads with my fingers for comparisons and noticed a few much warmer than others (none hot to the touch, just very warm instead of just warm or cool). I used the laser temperature gun just for some idea on the number ... and my fingers didn't lie ;). Those few were 4-5 C (10-12 F) warmer than the rest. I don't want to make a mountain out of a molehill, just wondered if there might be others having similar issues with CALBs that I should be aware of (bolts, straps, terminals ...) other than just a layer of corrosion on the terminals. Thanks for the comments - Dan - Dan Gallagher http://www.evalbum.com/3854 -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/CALB-bolt-terminals-getting-hot-tp4670981p4671002.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
From: Danpatgal via EV ev@lists.evdl.org ... several of them were around 33C, in a grouping, maybe 6 or 8 posts adjacent on the most positive side of my pack. Posts just a few cells more negative were much cooler, maybe around 26C or cooler. That doesn't seem like much! In fact, that amount could be explained by emissivity error of the tempgun. I've seen them shoot the same mercury-thermometer temperature as much as 10C different between reflective and non-reflective surfaces! Tempguns are notoriously wild, unless you're sure you're measuring things with *exactly* the same emissivity. I'd try it with a contact thermometer before getting too concerned. And then, I wouldn't worry if the differential was 10C or less. Compared to those on pasteurized milk, children who received raw certified milk had better weight gain and greater protection against rachitis. -- Ron Schmid Jan Steinman, EcoReality Co-op (Send email to qu...@bytesmiths.com to get a random quote, or quo...@bytesmiths.com to get 50 random quotes. Put a word in the Subject line to filter for that word.) ___ 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)
Re: [EVDL] CALB bolt terminals getting hot -
I am with Jan. The laser thermometers are averaging over the whole patch you see lit up and they are not hugely accurate because of it. If the patch is larger from being farther away or not circular because it is on an angle - it will not report what you are hoping for. They are best for shining inside a uniform container, oven, furnace, etc. Or if at a wall, then you need to take a series of readings. Imagine on one terminal you slide off to one side and average in some temperature from the top of the battery case. Or you have to get very close to one and far from another, and so on. Can you share what make and model of thermometer you are using? Mike On Thu, Aug 14, 2014 at 7:21 PM, David Nelson via EV ev@lists.evdl.org wrote: If this is a change then I would investigate. I have had my pack in for over 4 years and have not had the issue you and others have had and my pack isn't exactly closed to moisture and dust. I have 40 TS-LFP100AHA cells in a 2p20s arrangement. Because the BMS I used to use attached to the heads of the terminal bolts I used brass bolts since they are much easier to drill and tap threads in. This also meant that I could assemble the pack and torque the bolts independent of the BMS connections so they could not interfere with any connections. Before assembling my pack I wire brushed all the terminals to shine them up. I did this with NOALOX on the terminals and SS wire brush so that the NOALOX would seal the metal as soon as possible. I also tapped all the terminal holes again, using NOALOX on the tap though this was probably way overkill. I did find some terminals that didn't get tapped all the way down. I then put NOALOX on the bolt threads before assembling. This was mostly so that the soft Al and Cu terminals wouldn't gall up at all. I used bronze lock washers, too. I have had no terminals come loose or get warm. Some may say that what I did was a waste of time but they can't counter the results. It just works and I'm glad. LiFePO4 has been much simpler than lead acid in many ways. If I were you I would clean all the terminals using a similar process. If I were to do it over, and I have on small 4-8 cell packs, I would use NO-OX-ID A SPECIAL because it doesn't seem to get sticky over time like the NOALOX does. On Wed, Aug 13, 2014 at 2:20 PM, Danpatgal via EV ev@lists.evdl.org wrote: I am using 38x130 ah CALBs in my Lectric Leopard and have had a too hot ( 40C) warning on my BMS come on a few times in the last month or so. Today, after a longer stretch of accelerating uphill to home, I checked some of the battery posts. Measuring with a laser sensor, several of them were around 33C , in a grouping, maybe 6 or 8 posts adjacent on the most positive side of my pack. Posts just a few cells more negative were much cooler, maybe around 26C or cooler. I checked the bolts to make sure they were tight, and didn't notice any real problem with the connections being loose. My only other thought is that perhaps (as has been discussed in other threads), these connections have corroded over time ... adding a little resistance layer (I didn't initially polish or use Noalox on those) that is now finally heating up. I am also using the original copper straps with steels M8 bolts. Are others noticing this kind of heat with the lithium cell terminals? Aside from just cleaning the terminals and putting on some Noalox, might there be other things to do? I installed these in Sep. 2012, so they are not quite two years in service. Thanks - Dan - Dan Gallagher http://www.evalbum.com/3854 -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/CALB-bolt-terminals-getting-hot-tp4670981.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. ___ 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) -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com ___ 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
Re: [EVDL] CALB bolt terminals getting hot -
On Aug 13, 2014, at 2:20 PM, Danpatgal via EV ev@lists.evdl.org wrote: I am using 38x130 ah CALBs in my Lectric Leopard and have had a too hot ( 40C) warning on my BMS come on a few times in the last month or so. Do you get it when driving? I have the Elithion Pro BMS. My to hot warning comes on sometimes when the cells sit in the direct sun. I don't have a cover over them; just plexiglass. corbin Today, after a longer stretch of accelerating uphill to home, I checked some of the battery posts. Measuring with a laser sensor, several of them were around 33C , in a grouping, maybe 6 or 8 posts adjacent on the most positive side of my pack. Posts just a few cells more negative were much cooler, maybe around 26C or cooler. I checked the bolts to make sure they were tight, and didn't notice any real problem with the connections being loose. My only other thought is that perhaps (as has been discussed in other threads), these connections have corroded over time ... adding a little resistance layer (I didn't initially polish or use Noalox on those) that is now finally heating up. I am also using the original copper straps with steels M8 bolts. Are others noticing this kind of heat with the lithium cell terminals? Aside from just cleaning the terminals and putting on some Noalox, might there be other things to do? I installed these in Sep. 2012, so they are not quite two years in service. Thanks - Dan - Dan Gallagher http://www.evalbum.com/3854 -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/CALB-bolt-terminals-getting-hot-tp4670981.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. ___ 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)
