tag:blogger.com,1999:blog-6676835811534572362.post692462737783468587..comments2024-02-06T10:02:20.731-06:00Comments on EVTV.ME: OBSESSIVE COMPULSIVE DISORDER AND A123 BATTERY CELLSJack Rickardhttp://www.blogger.com/profile/15936311474215791697noreply@blogger.comBlogger155125tag:blogger.com,1999:blog-6676835811534572362.post-24689918235341259432012-02-28T00:40:56.127-06:002012-02-28T00:40:56.127-06:00I've seen a variant of my question asked, but ...I've seen a variant of my question asked, but I am left wondering if it would be possible to add something like styrofoam spheres the size of BBs to the resin mix in order to save money and weight?<br /><br />I don't understand what use anyone would have for pouch cells with shortened [cut] tabs?<br /><br />I found this 48V/20AH through drgrieve's DIY forum link:<br />http://translate.google.com/translate?sl=zh-CN&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fitem.taobao.com%2Fitem.htm%3Fid%3D13805031856<br /><br />Is it made up of pouch cells? If so, how are they stabilized and contained?Perin du Buluhttps://www.blogger.com/profile/07948129381637534826noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-40185784181316004752012-02-28T00:27:05.297-06:002012-02-28T00:27:05.297-06:00Destabilizing [to corporate control and profits] i...Destabilizing [to corporate control and profits] is probably a better word than impractical. Watch Comprar, Tirar, Comprar [The Light Bulb Conspiracy] for supporting framework:<br />http://youtu.be/AkBQKSlsNhUPerin du Buluhttps://www.blogger.com/profile/07948129381637534826noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-90137656973117223522012-02-28T00:20:35.893-06:002012-02-28T00:20:35.893-06:00I plugged in an old word processor a few years ago...I plugged in an old word processor a few years ago and was surprised when it began to daisy wheel a letter I sent to a foreign embassy about 20 years ago. Something which hadn't been electrified for more than a decade had perfectly stored a lengthy letter: why couldn't this type of memory be employed in cars, as I'm gathering Dan F. suggests?Perin du Buluhttps://www.blogger.com/profile/07948129381637534826noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-272452493603025202012-02-26T13:47:07.390-06:002012-02-26T13:47:07.390-06:00Flatenun series pack!
Hey I considered that for my...Flatenun series pack!<br />Hey I considered that for my project. It fits my floor pan width. Thought against it after. The reason is if I make 120mm high 50V packs side by side (100v) for 6 sets in parallel, it would be more modular and serviceable.<br /><br />Considered that glassfibre Hexel sheet for batt. support and floor but it's getting expensive.Andyjhttps://www.blogger.com/profile/11910687437796998340noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-43119861106200586552012-02-24T08:01:43.826-06:002012-02-24T08:01:43.826-06:00I would like to think that whatever we tried we on...I would like to think that whatever we tried we only had to do once. Somehow I wind up doing the same thing over and over again until I get it right.<br /><br />We're delighted your first blogging experience was here.<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-15297278787583323272012-02-24T08:01:35.355-06:002012-02-24T08:01:35.355-06:00I would like to think that whatever we tried we on...I would like to think that whatever we tried we only had to do once. Somehow I wind up doing the same thing over and over again until I get it right.<br /><br />We're delighted your first blogging experience was here.<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-1405932289564042942012-02-24T03:39:50.923-06:002012-02-24T03:39:50.923-06:00This is my first blog ever so I might as well jump...This is my first blog ever so I might as well jump in with both feet in my mouth. Please forgive my ignorance, but why not just make a box out of good old-fashioned sheet steel? By casting these cells into a resin block you're eliminating the advantage of easily replacing one bad cell instead of several and adding bulk that makes finding space for additional power more difficult. From everything I've read in this blog the problem is metal fatigue of the conducting tabs from vibration, this is easily solved by making the box small enough to hold the pouches securely. Make the main body as a channel open on both ends and have the end plates attach with bolts and threaded rod to provide pressure to keep the pouches from shifting. You can line the box with some material to keep anything from shorting out and since the structure is in the steel the insulator can be cheap because it doesn't have to have any strength. I I think that I'd try powder-coated, or epoxy-painted steel with pickup bedliner material on the inside to provide electrical insulation. I saw an episode of a TV show called Smash Lab where they planted explosives under the bed of a pickup truck. The bed was mangled, but not as bad as an uncoated control subject truck and the liner did not appear to crack or delaminate. Once you have the cells securely clamped in the case you can secure a plastic bar that fits between the positive and negative terminals of the cell bundles and below the clamp blocks to the steel box and then secure the clamp blocks to this with silicone adhesive to keep them from moving. In this way everything is secured, but can still be disassembled if needed. You'd have to put a lid on the whole thing, but this could be a simple plastic plate or (my personal favorite)more steel with bedliner coating. Any length would be possible without locking yourself into fixed dimensions for 13V blocks. I hope I haven't come across as a total idiot, but whatever I try I can only afford to do once and I'm trying to stay away from anthing too expensive. Let me know what you think.fixallthingshttps://www.blogger.com/profile/15672184264330079799noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-29022066453158663112012-02-22T17:49:37.945-06:002012-02-22T17:49:37.945-06:00This is the most interesting line for me. Model S ...This is the most interesting line for me. Model S has remarkable technical solutions, among which a flat-bed battery stretching across the entire floor. Many of our donor cars simply cannot opt for such solution. Perhaps the other face of the floor, inside the passengers cabin floor space could be used. Making a new hollow floor for batteries, on top of which seats will be positioned, a bit higher then originally.Nenad Jovanovichttps://www.blogger.com/profile/06962609137125824909noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-35152638110757746942012-02-22T14:26:50.988-06:002012-02-22T14:26:50.988-06:00Dan, you go store your stuff in flash memory. Let ...Dan, you go store your stuff in flash memory. Let us know how you overcome everything.<br /><br />I found a lovely little passive low voltage warning circuit. Cheap and simple enough for every cell.<br />When the pack V is high and output is low, it still consumes. Like everything else, these can never be allowed to reside on my cells when I isolate them no matter how minuscule the current.Andyjhttps://www.blogger.com/profile/11910687437796998340noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-28288405342508848632012-02-22T13:55:19.053-06:002012-02-22T13:55:19.053-06:00PY,
Did you balance at the bottom or the top? I...PY,<br />Did you balance at the bottom or the top? I'm reading two different things here.<br />expect these cells to have varying capacities.<br />There is no real world reason to top balance because if you run any low and the others are strong, you WILL kill the weaker cells. They will force the weak cell into a reverse charge. That means cell death.<br /><br />The mantra is never to over or under charge them. When the first cell hits 3.5V, stop. There is nothing to be gained in mileage by upping the stronger ones higher whilst overcharging the weaker cell. If a cell is too weak, consider paralleling stronger with weaker.<br /><br />Your pack is as only as strong as the lowest capacity cell.<br /><br />==================================<br />I've got another joke.<br />Q: How do you know when Dan's cells are running low?<br /><br />A: His bow-tie stops.Andyjhttps://www.blogger.com/profile/11910687437796998340noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-45989839439916374072012-02-22T12:16:31.139-06:002012-02-22T12:16:31.139-06:00Jack, if you don't attack me there is no confl...Jack, if you don't attack me there is no conflict. try to be civil.Dan Frederiksenhttps://www.blogger.com/profile/00506872737104553923noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-52653353851729149212012-02-22T11:24:59.403-06:002012-02-22T11:24:59.403-06:00Hope?
Dan you're delusional. If you say it&...Hope? <br /><br />Dan you're delusional. If you say it's possible it is because you are OFF YOUR MEDS AGAIN. YOU PROMISED TO GO AWAY.....<br /><br />JackJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-616192765010898942012-02-22T10:45:39.299-06:002012-02-22T10:45:39.299-06:00Yes Andy, I know that an exothermic cell reaction ...Yes Andy, I know that an exothermic cell reaction could be synonym of fully charged or heavily discharging cell. <br />But the divergences i've observed for 3 of 16 cells appeared within 2min of charge at 60A, as all the cells were previously uniformly discharged until 2,6v and this after a full charge and top balancement at 3,65v.<br />I precise that the pack is well cooled and the 3 divergent/warm cells are not only situated in the center of the pack.<br /><br />I heard and read that these cells could handle these +C rates without problem... the reality is different ?<br />I will swap the three cells and retry...Piwhyhttps://www.blogger.com/profile/06879667208794783493noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-24686149270612971792012-02-22T09:59:17.311-06:002012-02-22T09:59:17.311-06:00Jack, I want them to store settings in flash memor...Jack, I want them to store settings in flash memory and not volatile memory. I would hope most things do that already.<br />If I say it is possible it is because it isDan Frederiksenhttps://www.blogger.com/profile/00506872737104553923noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-72190242700982468662012-02-22T09:23:00.730-06:002012-02-22T09:23:00.730-06:00Hey PY,
An exothermic cell when charging or discha...Hey PY,<br />An exothermic cell when charging or discharging, from what I can find out is a fantastic indicator of a fully charged or heavily discharging cell. I cannot help but think its a better indicator than voltage monitoring. 3.7V is too much for real world use.<br /><br />These cells when charged, one pole gets warm and discharged the other gets warm instead. Some cell types can take a massive discharge but the chemistry on the other pole might be ordinary hence a more standard charge rate applies. This of course depends on the cells external surface area so it can lose the heat.<br /><br />I hope I'm right. I've only read myself clever on this.Andyjhttps://www.blogger.com/profile/11910687437796998340noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-52049406669940489302012-02-22T08:07:35.999-06:002012-02-22T08:07:35.999-06:00Dan:
It is EASY as a THOUGHT experiment in a FANT...Dan:<br /><br />It is EASY as a THOUGHT experiment in a FANTASY. In the real world it's not even possible. Do you want to reload all stereo presets every time you get in the car? How about your onstar info? Your telephone contact list. We actually have TWO DC-DC converters on the Mini cooper. The car can TELL when I'm close to it IF I have the magic amulet on me. But of course it has to have 12v to do that - and let me into the car. Without it, even the rear cargo door is locked.<br /><br />The list of things is interminable. It would actually be difficult to compile. In your world of heavy thinking, it just all goes away. In my world, it does not.<br /><br />We have tried aux batteries and aux systems. They basically eat batteries. So we run off the big pack. But within days, it would eat the pack if we didn't shut it off or keep recharging it.<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-68883700413061637502012-02-22T06:11:25.681-06:002012-02-22T06:11:25.681-06:00doing away with parasitic loads is easy and that&#...doing away with parasitic loads is easy and that's how you fix this very serious problem.<br />for charging you simply have a momentary button that you push after connecting j1772 that enables the needed systems to come on directly from the pack that is otherwise fully disconnected.<br />for the duration of charging whatever energy counter that needs to count is also powered but not after charging. there is no need for parasitic loads. simpleDan Frederiksenhttps://www.blogger.com/profile/00506872737104553923noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-35953064764695957362012-02-22T05:07:58.445-06:002012-02-22T05:07:58.445-06:00Hi Jack,
I've ordered a bunch of A123 cells f...Hi Jack,<br /><br />I've ordered a bunch of A123 cells few weeks ago in order to make some tests on it and to improve my own experience on Lifepo4 technology.<br />I'm especially looking for a small pack, with very high charging rates abilities.<br /><br />I've started some tests on these cells built in a 1p16s pack (non selected cells) that I've charged at 0.5C, 1C, 2C, 3C and discharged each time at 2C.<br /><br />I've obtained such pretty good results from 0.5 to 2C, but i've noticed huge divergences from 3C.<br />On 16 cells, 3 of them at least seems to have a bad IR as they reach the 3.7v HVC point in few minutes with temperature near to 120°f contrary to other that never rise over 95°f..<br /><br />My initial goal was to verify the best capabilities of these cells at high charging rates compared with Headway cells but now, I've some doubts about reaching a 6C rate with this cells...<br />Does I'm hit up on a bad batch of cells ? I need to verify with an other...<br /> <br />Apart from your high discharge tests at 23C, have you made some similar charge tests on it ?<br /><br />Thanks,<br />PYPiwhyhttps://www.blogger.com/profile/06879667208794783493noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-51836283656108848172012-02-22T02:24:26.668-06:002012-02-22T02:24:26.668-06:00Dan:
What? A useful and contributing blog entry ...Dan:<br /><br />What? A useful and contributing blog entry from Dan Frideriksen? As I live and breathe. <br /><br />You bring up an EXCELLENT point and so does the article. I had no idea that Tesla had this problem, and actually NO IDEA that I DID TOO.<br /><br />But I HAVE killed some cells on a GEM with Thundersky's over a STEREO that always uses a wee bit of power. The problem is, it might be parked for five months with no one using it at all. <br /><br />Worse, plugging in doesn't help on ANY of our vehicles. Unlike Teslas, our chargers are NOT that smart. NONE of them that I know of has a setting for maintenance with the lone exception of the MANZANITA which I routinely turn this feature off. The Elcon's and Brusa do not even support it - or such is my understanding. Perhaps there is a mode somewhere on the Brusa. In most cases, you have to actually unplug the charger and plug it back in to reset it and get it to go through the charge sequence again.<br /><br />And ALL of our cars have parasitic loads Dan. I went through this with the eCobra trying to cater to the owners wish TO have an aux battery. We just killed several batteries within a day or two. They just get bled off to squat immediately. A pack, through the dc-dc converter, simply takes longer.<br /><br />Our solution? A maintenance switch. If you are going to park it for more than a few days, we have a switch to BREAK the pack, disconnecting EVERYTHING. We have had no instances of these cells bleeding down on their own though we DID DESTROY 16 cells on the Mini Cooper with two Cell Log 8s devices. Those tiny meters and the TINY amount they draw, over the course of 3 months of inactivity with the car, or let us say, activity related to rebuilding the drive train, was enough to drain down those cells dangerously below the others.<br /><br />I cannot stress enough that a TINY 10 ma draw, works out to 240 maH per day, which is 1.75 Ah per week, which is 7 Ah per month, which is three months is 21 Ah. <br /><br />ANd unfortunately, what you see in this article is homes being renovated, cars being shipped to Japan, and just inactivity. The Tesla, and our cars for that matter, are mostly toys. And the owners have other cars. And well, things get parked.<br /><br />In my case, if I turn the maintenance switch off, everything goes to zero and holds. But with it on, even the little AVC31 board of Modular EV power draws 12v continuously and it HAS to be on for the plug in J1772 charger to work. It will NOT enable charging with out it.<br /><br />Most meters have the same problem - constant unswitched 12v or they don't count Ah while charging?j<br /><br />PROPERLY DESIGNING an electric car to NOT use such parasitic loads can ONLY be performed in a Dan Frederiksen fantasy world. It is almost impossible in a Jack Rickard reality world from which I do suffer.<br /><br />But I can see that this would be a pretty hairy set back in a production car such as a Tesla with non-technical customers.<br /><br />How WOULD you prevent such a thing? I suppose the ultimate "daughter" mode would be if the pack gets down to 10% state of charge, you disconnect the entire pack????<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-49079278365883905502012-02-21T23:25:05.456-06:002012-02-21T23:25:05.456-06:00speaking of self discharge, some data points.
I t...speaking of self discharge, some data points. <br />I took out some batteries that I've sampled from around the world, mostly around 2008. 3 out of 4 Cens cells had killed themselves below 1 volt and my first 10Ah headway cell was down to 0.8v. never charged or discharged.<br />the A123 cells are still strong at 3.3v and so were all the Valence cells at around 3.2.<br />I had some Ryder 18650 3.7V cells and they were all good at 3.8V I put it in a flashlight and it lit for 2h45m. I charged it to full at 4.25v and it lit for 2h57m. the ultrafire cell that came with the flashlight only lasts 2 hours.Dan Frederiksenhttps://www.blogger.com/profile/00506872737104553923noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-30500240590198845602012-02-21T23:13:23.066-06:002012-02-21T23:13:23.066-06:00I would recommend looking at the dynamics of alumi...I would recommend looking at the dynamics of aluminum composite materials. They are nice to work with. It is a sandwich of foils lining both sides of a remarkably soft plastic. The foil doesn't stretch, so it actually creates a very rigid sheet. A similarly sized and thickness of solid aluminum will bow much more under nothing but it's own weight! The key is that the core material keeps the two lining foils aligned throughout the whole sheet. I'm not sure, but rather optimistic that these principles could yield a very remarkable über flat module. The model S is one fine example.Nabil Hankehttps://www.blogger.com/profile/17576270527985289857noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-65819574979659347292012-02-21T22:57:47.379-06:002012-02-21T22:57:47.379-06:00If you have sex a lot in your car it won't rot...If you have sex a lot in your car it won't rot? That explains everything about my last car.<br /><br />A Tesla style battery belly pan to replace VW pans or made for say, the 818... oooooh Matron. Quick! pass me another hankie.<br /><br />The Volt n Leaf have under slung batts. I guess its down to applying reasonable automotive sensibilities in the design. Gotta make 'em magnetic mice proof.<br /><br />As goes self discharge. Dan, do you know of just one car Jack (or anyone) put together that has no constant parasitic load? Seems its only me who's making up a vehicle with native pack voltage for everything.Andyjhttps://www.blogger.com/profile/11910687437796998340noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-29309276052919086072012-02-21T22:49:40.129-06:002012-02-21T22:49:40.129-06:00Andy, I was amazed when you suggested the idea ori...Andy, I was amazed when you suggested the idea originally. I had already been through a couple iterations of refinement at that point! But indeed, no one gave it much thought. Not even after I posted my video. Im not sure what my low hit counts mean. I'm sure there is a large contingent of viewers who have never given these comments on jacks blog any attention.Nabil Hankehttps://www.blogger.com/profile/17576270527985289857noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-2618347531322116342012-02-21T22:37:30.175-06:002012-02-21T22:37:30.175-06:00http://theunderstatement.com/post/18030062041/its-...http://theunderstatement.com/post/18030062041/its-a-brick-tesla-motors-devastating-design<br /><br />it might not be true but if it is it isn't elegant. <br />in general I wouldn't design an EV with loads when it's off. when it's off it should be off.<br />I remember Martin Eberhard first remarking that the 100 watt water pump ran continuously even when the car was off. that was changed later though but it does lend credence to the idea that TM has been sloppy with parasitic loads. one of the TM pdfs cited in the blog states that the car can drain as much as 7% per day when off. that's pretty terrible with a 53kWh pack. if you can actually kill a 40k$ pack by leaving the car unplugged for a couple of weeks they dropped the ball on the design. that's a nasty vulnerability.Dan Frederiksenhttps://www.blogger.com/profile/00506872737104553923noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-39924537586925827442012-02-21T21:51:23.031-06:002012-02-21T21:51:23.031-06:00Ok. You're crazy. But before you wanted us t...Ok. You're crazy. But before you wanted us to call you Doc Which is it?<br /><br />Yes, and those electric FIELDS and magnetic FIELDS they can do bad things to you too don't they" I mean like, haven't they studied mice and stuff? Didn't they like grow tumors or something?<br /><br />I read that cell phones cause brain tumors in mice - but only those on AT&T who suckered in for that two year contract plan. <br /><br />And what about that dreadful STATIC CLING thing with the dryer. What's that all about?<br /><br />Saltwater certainly does bad things to cars. It rots them out for one thing starting in the wheel wells. But that's how they deal with snow in some areas. Wash your car after having sex is all I can tell you. If you do it often enough, you're car won't rot.<br /><br />JackJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.com