Elescalade LiftOff and the A123 LiFePo4 Cell Puzzle

It’s almost peaceful at EVTV. The EleCobra project is done and gone and by all accounts from Granby quite a hit points west and south.

This frees up room and time and we are at the end part of November when it is appropriate to stop and give thanks for our really crummy miserable weather of this time of year. Steel grey skies, spitting half-hearted precipitation and chill damp temperatures in an uncertain wind.

It makes the man cave kind of cozy with our enormous gas heaters filling the shop with the homey smell of my money going up in flames of natural gas.

As you know from last week’s show, we have taken on a small project for Lee Morehead with the Swallow. We’re finding a spider under each rock but have the chassis bare and on the lift and Brain is in more familiar territory with VW brakes and clutches and so forth. We’re ordering a lot of little inexpensive piece parts and should receive both batteries and boxes this week.

[jwplayer file=”news112511 – iPhone.mov” hd.file=”news112511-1280.mov” image=”http://media3.ev-tv.me/news112511.jpg” streamer=”rtmp://s3einxnpkaij93.cloudfront.net/cfx/st/” provider=”rtmp” html5_file=”http://media3.ev-tv.me/news112511 – iPhone.mov” download_file=”http://media3.ev-tv.me/news112511-1280.mov”]

We’ve also put Elescalade on the lift and we are carefully beginning the tear down process We had sent Elescalade to Slingblade for a hydroboost ectomy. Many GM vehicles have diesel motors of course and so they have developed a power brake and power steering system based on a hydraulic pump rather than vacuum. We already had a pump for the power steering on the Elescalade but for some reason they had a vacuum brake system on the vehicle. We have never done a car with the noisy intermittent vacuum pump and reservoir and I frankly do not want Elescalade to be the first. So we had Slingblade convert Elescalade to the hydroboost brake system.

This was a bit more involved than I thought. I had been told all we had to do was swap out the hydroboost unit. As it turns out there is a SEPARATE master cylinder and reservoir that also has to be replaced and in fact, the system uses a different pump with more fittings for the hydroboost. I have actually seen conversion photos where they use the same pump and simply hose it up differently. But there might be some advantage to stock hoses from GM. As the pump will be placed on the front of our 34 and 3/4 inch long motor assembly anyway, we might have to redo the hoses. But we START the conversion with a power steering and brake system that works off a quiet pump we can run with the electric drive motors and it should all work just fine.

The system did provide a couple of vacuum sensor inputs to the engine control unit. Hopefully, our HP Tuners system will let us turn off that fault code permanently.

The other area where I’ve taken some time to examine and burned down a few of the cells of course has been the A123 MD-H1 20Ah prismatic cell. This is kind of an interesting area, but fraught with new challenges I’m afraid.

Essentially ALL the OEM’s have opted for these small form factor soft pouch cells with tabs OR in the case of Tesla, an even more challenging small cylinder of the 26550 variety and in vast numerical quantity. The implications of all this keeps me awake nights.

For one thing, the residual value of electric cars has historically been, and most likely will be, very different from ICE cars and not in a positive sense. As most of the components SHOULD be more durable than the ICE version, the cars should last longer and so depreciate more slowly, than ICE vehicles.

That said, the history is that they become near valueless on delivery. This is because most of the cars are orphans, with either bankrupt parents or an abandoned product line. In any event orphans.

But behind every electric car lies a battery and too soon and too often a dead battery. And while the American public is not acculturated at this point to living with an electric car, we ALL know ALL ABOUT batteries. From our first penlight flashlight to our latest cellphone or laptop, we have all paid the price for portability, over and over and over.

If you warranty the battery of a car for 8 years and 100,000 miles, then you have defined the life of the battery, all laws of physics thereafter held in abeyance. In ADDITION to the normal depreciation of the average car, you are also down whatever fraction of that 8 years and 100,000 miles you have used. And the ASSUMPTION we can make in looking for a total pack replacement after 8 years is that you will be screwed into the WALL by whomever sells it to you and TREBLE screwed if it is a proprietary pack.

Long term, I think this is the OEM equivalent of pouring gasoline over their own heads and lighting a BIC. By insisting on a proprietary cell module design and setting a warranty period, they pretty much PROMISE plummeting values the minute the car leaves the showroom floor. How does THIS work for anyone?

In addition to the usual software knots in the car’s computers to make sure it is a Mr. Goodwrench approved battery pack, Tesla has actually gone to the trouble of PATENTING a totally nonsense module connector SHAPE. You can’t really patent shapes. But by patenting the CONNECTOR for the individual modules, they pretty much assure themselves a proprietary pack forever. Third parties MIGHT be able to rebuild these modules, but no new ones could be made by third parties. The shape of the connector is nonsense. It has no merit AS a connector. It just IS a connector with a unique and unusual shape and so patentable. Someone at Tesla I’m sure is celebrating their brilliance on this one. Someone at Tesla should actually be promoted to “street status” and provided a final paycheck over it to my way of thinking. Long term this will haunt them for generations.

In any event, A123 is a battery maker and a MOST peculiar case. In any new and disruptive field there is an urge, certainly by the more advanced players to sort the world out into “good” customers and “bad” customers and the 80/20 rule being what it is, we would all like to focus on the 20. It almost never works that way, and won’t here again. But particularly among the LEAST advanced, it is a mantra. I just had an e-mail conversation with a new electric drive company that is just absolutely FLUSHED with the glow of success from a SEMA showing that caused them a LOT of attention for an exciting NEW product that at this point I think we can rest assured does not exist and never will exist, and he’s already sharpening his pen over which “well funded OEM effort” they will deign speak with. We can assume UNOBTAINIUM forever there.

A123 has a somewhat longer and more gorey history. But it’s actually quite interesting. The company was formed by three people and a scantily garbed fish in 2001. A professor, Yet-Ming Chiang of MIT’s Department of Materials Science and Engineering, an engineer, Bart Riley of American Superconductor, and a serial entrepreneur, Ric Fulop, met for dinner at the Naked Fish restaurant in July 2001. Professor Chiang had been working with a novel set of materials that appeared to self assemble into a very powerful battery.

The three agreed to launch an effort and by December, North Bridge Venture partners had turned their head and coughed $8.3 million. This further inspired Motorola and Qualcomm to join the party at $4 million and the company was off and running.

Along the way, Professor Chiang had also applied for a DOE Small Business Innovations Research grant and was awarded $100,000 for development of a nano phosphate cathode material. The group licensed both the self organizing battery and the nano phosphate chemistry from MIT on an exclusive basis.

As it turns out, the self assembling battery worked. But the batteries lasted a few dozen cycles and died. This was not promising. But the nanophophate material licensed as an afterthought showed unusually high power density. Professor Chiang published a paper on this and it actually caused quite a stir in the battery industry on a wide front.

So the company repurposed for the power cell. Batteries are generally described in two ways of interest – energy density and power density. We tend to be interested in energy density. Energy density is how much total power can be contained in a given weight and volume – the storage capacity if you will. More capacity, more range.

Power density is quite different. Power density has to do with how much INSTANTANEOUS power output can be derived from a given weight and volume. We talk of this as momentary or pulse power and it is often 5C or 10C – meaning 5x or 10x the amp hour capacity. A 100Ah cell that can put out 500 amps momentarily has a 5C power output rating.

This is the central tradeoff in Lithium batteries. More active material on the cathode gives you greater ENERGY density, but it slows the diffusion of lithium ions into and out of the cathode structure, severely limiting the power delivery capability. Thinner cathode materials provide more instantaneous power, but energy density suffers.

Chiang’s nanophosphate cathode material had good energy density, but VERY high power densities of up to 100C. So a 2 Ah cell could momentarily put out 200A. Of course, it couldn’t do that very long as it ran out of capacity very quickly at 100C. 60/200= about 18 seconds.

And where would this be most useful? Power tools like drills and screwdrivers tend to need a lot of power for a few seconds, after which they are often lain on the bench for minutes. A123 showed some cells to Black and Decker and in 2005 the company contracted for some cylindrical cells for their DeWalt Power Tool line. Later they added the main Black and Decker line to the mix as well. As an interesting aside, Black and Decker/Dewalt hold a very interesting patent for BOTTOM BALANCING lithium ion cells.

This gave A123 instant gravitas in the battery world and they were off and running. They eventually raised $131 million in venture capital BEFORE a very successful Initial Public OFfering.

In 2008, they did have a little hiccup. A company in Boulder Colorado had converted a Toyota Prius to an extended range electric by replacing the Prius battery pack with a pack designed by Davide Andrea. The company was Hybrids Plus with Carl Lawrence CEO at the time.

The car had been developed for a utility company and had burst into flames and burned to the ground while driving on the Internstate highway system. The battery pack was removed and sent to A123’s headquarters and a third party company came in to do the forensics and determine the cause of the fire.
It was eventually laid off as an improper hardware assembly of a fuse and cable in the report. But it caused A123 to issue an entire document on proper module design in stellar cover your ass fashion.

The full A123firereport is here.

Davide Andrea went on to design the Elithion Battery Management System and wrote a book that could be titled “Jack is Wrong and you should send me money for my BMS and here is why.”

A123 subsequently refused to sell cells to any conversion shops, one off car builders, custom cars, or hobbyist enthusiast and actually post a derogatory and very nearly actionable description of this on their web site. We questioned them about it and received an answer from the highest levels of management that they believe the incident contributed to their loss of the Chevy Volt contract to LGChem.

Which IS indeed interesting in a way. LG Chem provides GM with an intrinsically LESS safe Lithium Manganese Oxide Spinel cell that the A123 LiFePo4 cell just beats in all directions including life cycle and safety. IN any event, A123 just won’t sell us or any conversion guys batteries.

But snubbed by Chevrolet, and worse, publicly noted as the LOSER in the OEM battle, A123 was desperate to get into electric vehicles. They invested $30 million dollars in Fisker Automotive, and would you believe Fisker found A123 cells to be the PERFECT answer to their battery needs. And so A123 announced they DID have an OEM car maker contract and others should look at their cells as well.

Fisker had promised a very sexy hybrid car. But like many startups, delays were the rule and the car didn’t come out as scheduled. Worse, when they did finally begin shipping a few, it appeared that their all electric range had shrunk to 50 miles and in fact the EPA declared it to be 32 miles – LESS than the Chevy Volt. To suffer insult on indignity, they also found it got 20 MPG on the hybrid engine – worse than almost any economy car. So it isn’t really very green. It isn’t really very electric. And it IS very expensive – originally $95K but now north of $100K. And so beyond a few celebrity movie stars it has placed the cars with, there are no sales of Fiskers. They are currently trying to recast it as some sort of greenish tinted Bentley but there is really no place for this car to go.

So A123 has been working furiously to ramp up production to support Fisker, and now Fisker doesn’t need very many batteries. SINCE we shot this video, A123 has announced layoffs of 125 workers in Michigan of about900 who were working there on the modules. In 2009, when receiving U.S. tax dollars of $259 million and state of Michigan grants and local tax abatements, they had promised 5000 jobs.

This isn’t going well. And worse, it comes on the heals of the Enerdel meltdown. Also publicly traded, Enerdel had invested $59 million in THINKCITY, who miraculously found their ENER1 to be JUST THE TICKET for the THink car. Think didn’t make the cut and has since gone bankrupt and is now apparently the property of a Russian entrepreneur. ENERdel was delisted from the NASDAQ last month.

We would predict Fisker is months away from also turning turtle on A123.

A123 has in the meantime been selected for the Chevrolet Spark program. But this is likely a year or two out in time for actual production – nothing in the next few quarters.

Which is a bit confusing. The company saves about $6.25 million per year by laying off this 125 people – assuming they are costing $50K per year each. They were obviously already trained to make the battery modules. The company has the $259 million in federal money. Why are they risking public ire and parody to save the $6.25 million? I would have probably had them garden, and work with the plants around the building or what not, sit around and train each other instead of cutting them loose. They promise to “call them back later.” They most likely will be in another state later.

In any event, it appears the actual A123 A20MD-H1 prismatic 20Ah pouch cell is manufactured in Korea. The company also does have factories in CHina. And these cells are normally printed MADE IN THE USA incredibly, even though they are NOT made in the USA at all.

We originally bought 16 of these from a company called OSN Power at $50 each. They indicated they could do these in 500 quantity at $46.

We kind of posted a query on Alibaba that would alert us to these cells if they came up. And subsequently we heard from Richard Zhang at Shenzhen VictPower Technology Company They would sell A123 cells for $30 each in sample quantities and take PayPal for payment. AND in quantity 600 they quoted us $23.80 per cell.

$23.80 per cell for 20 Ah cells starts to look competitive. And Like OSNPower, Victpower is just a trading company. They sell birthday candles, flowers, tennis shoes, whatever you want to buy is kind of what they were wanting to sell. So we still haven’t tracked down the SOURCE of these A123 cells, or found the real price for that matter. But it appears A123 is either backdooring production output to Asia, or they have lost control of a Korean factory that is simply selling the cells A123 isn’t taking, anywhere they can.

It’s an interesting problem. ANd an interesting opportunity.

But it goes right back to the original problem that A123 and Hybrids PLus faced, how do you package these pouch cells into a module that is safe and effective at driving a car. We would propose just buying the modules from A123, but it appears they would rather LAY OFF 125 workers than sell us the modules, and we have to guess if they DID, it would be at a ridiculous price to make us go away. So no rational world to deal with here.

So we think a module to use the A123 pouch cell might have life.

And packaging is probably my WORST area of non talent. In this video, I comically and ineptly describe how to make an A123 bomb for your car.

What I would LIKE to do is sponsor some sort of a design contest – something a LOT less work than last year’s battery contest, where we get YOU guys to design the thing rather than ME designing something and all of you elegantly and with such charm e-mailing me about how I SHOULD have done it.

Perhaps we’ll SELL you the cells at $50 each – 20 cells. You then send us the 20 cells in a module. Winning module gets something – 500 cells or something. ALL the cells that entered maybe. And we just buy module hardware from the winner. And of course encourage our viewers to do so as well. Ideas on how to structure this design contest are welcome.

Jack Rickard


86 thoughts on “Elescalade LiftOff and the A123 LiFePo4 Cell Puzzle”

  1. did you delete last weeks blog entry? and why?

    as for the pack design contest, are you suggesting that we pay 1000$ to participate, work to make a pack for you and then give you the pack?
    I’d suggest keeping it a design contest, not a costly implementation.

  2. I think maybe Jack described a prototyping contest instead of merely a design contest just to goad Dan.

    Some mock-up A123 pouch cells ought to be good enough — some cardboard glued up around some metal tabs with a resistor or maybe a coin cell between them. We could start with the design for the mockup which we all could build cheaply and then enter our module prototypes by sending them to Jack. As long as we don’t solder, weld or glue the tabs, Jack could try them out with real A123s.

  3. Sadly, gone. Last weeks input held a lot of wisdom. Anyone got a copy?
    Its a competition. Here is your chance to save ~15,000Euro in the cells you like.
    Jack mentioned people will be correcting his use of Fibreglassing resin on the peanut gallery. Allow me. >:-))

    Going off the colour I think Jacks used the right stuff. Mine gives a pink colour; a polyester resin. It definitely needs protecting from the light. Information on the ‘net.

  4. Man! Enerdel too. Jack,thanks for your very precise analyses of the High “C” rated battery contenders. What is a EV builder to do if they want a high power output battery? This is disheartening.
    Mark Yormark

  5. Hmm.. Dan. Of course. For my sins.

    No, I did not delete the blog entry. I simply failed to repost it. I entered a correction to the text. Nothing nefarious. Valery MITZTAKHOV was misspelled most horribly Mtzikov I think. In any event, they loved the video but not the spelling of the name. I need to pay more attention.

    Yes, Dan. Send me $1000 and I’ll send you 20 cells. You design a module, and send me the module and the cells. Then I have them. Oh, I want the rights to the design as well.

    What do you want if you win?


  6. No, no dummy cells. These have to take a charge and discharge repeatedly. We’re going to vibrate them, hose them down with water, vibrate them some more, draw 2000 amps from them, quick charge them, hose them down some more, vibrate them some more, and try to catch any explosions or fires on camera.

    Kind of like BOTWARS. We dream up horrible indignities to visit upon your design.

    I’m thinking of running it to EVCCON. Testing them all. Then having attendees vote on the displayed entries.

    I’d like to get 20 to 30 really quality entries in this. Now what will it take as a prize to make this happen?

    Jack Rickard

  7. I was using 2:1 epoxy laminating resin.

    Today I tried 1:1 bar top clear resin and hardener.

    I’m a little soft and take too long to cure on the laminating resin.

    I may have to call in the dogs and get Mr. Ball of Porsche 904 fame to weigh in on this one.

    Jack Rickard

  8. Mark:

    It wasn’t a very comprehensive survey if that’s what you thought was attempted. I left out Hyain, Kokam, LG Chem, and several others.

    What I was attempting to point out was the odd route that this “we only sell to OEMs” causes. There is an 80/20 rule in ALL industries that states that 80% of your sales comes from 20% of your customers.

    An obvious way to cut 80% of your sales costs would be to not sell to the 80% that comprise 20% of your sales.

    If life were that simple. And unfortunately, many of the purported business executives at companies such as A123 and Enerdel et al really ARE that simple MINDED. But it never works for them.

    You see, part of your 20% dies, goes out of business, merges with ANOTHER customer in your 20%, etc. I once had three advertisers merge in one fell swoop.

    So you have to have a farm club. And that is a mix of your 80% and your new business. And it is VERY difficult to tell who the players are. First, they have no name tags. And second, THEIR situations change. The small fry struggling for oxygen just DID finally get $12 million in funding. Man, I sure wish I hadn’t told him he was too little, too ugly, and that his mother dressed him funny last week when he was broke. He’s still sore about that.

    In newly emerging industries with disruptive technologies, there IS no scoresheet and you do NOT know who the players are. If you do, when you arise tomorrow morning you will find that it is ALL different now – again.

    It is a bubbling cauldron of innovation, success, failure, money, bankruptcy, bad debt, and windfall profits.

    How do you wend your way through all that? LIsten politely. Sell to whomever sends a check in large or small denominations. Treat the guy buying three cells as if he were GM and GM as if they were buying three cells.

    GM may not be paying for any cells as they go through bankruptcy. The guy with the 3 cells may be working on a design for GM. And in any event, both parties can change places with a phone call. YOU don’t get to pick winners and losers. You get to sell your product. And it is very difficult to tell the players without a program or scorecard.

    Finally, the REAL kook, with the copper foil helmet, goes running down the street screaming that they had ACHIEVED perpetual motion tearing his clothes off. You kind of wish you had never sold him anything. But someone notices, and while they didn’t buy into the perpetual motion thing, they were intrigued by the batteries he was using….. have you got a minute…?

    A simple minded approach to marketing batteries only to large funded OEM’S is a fantasy. Enerdel is delisted and A123 is well under $3 per share. We’re going to lose a few along the way. It doesn’t mean there is no market for the batteries. IT just means there is no market for the stupid and the lazy.

    They view the Toyota fire as a great tragedy. They should have touted it as a feature – “we know more ways of blowing up our batteries and burning cars to the ground with them than another battery manufacturer in the world. We have Davide on our team. And a thousand others just as little and ugly and dressing as funny. We have more burning cars than other battery companies have cars total….

    Etc etc.

    Jack Rickard

  9. there is probably no prize that would make me participate in that.
    even if the prize was so high that it would be interesting from a statistical perspective, you have demonstrated a very strong bias against admitting merit to any of my ideas no matter how good. and letting the audience vote wont help either. they frankly don’t have good enough judgment.
    there is no way that I’m spending 1000$ and a lot of my time to be subject to your fickle whims.
    and I’d be interested to see if anyone else would participate. throwing away 1000$ on a little experiment is not something people with real economies do.
    as I’ve said before you have a somewhat warped sense of financial reality. in your world it’s just poor attitude if people have financial limits. that view is not correct however.

  10. Lets see, Dan. Jack has made and lost and made again more money than you have made in your whole life. I think he has some stellar financial intelligence. You are all talk, Jack backs up his talk with action and has money to prove it. You need to quit yacking and get reading books like “Think and Grow Rich”, “Rich Dad, Poor Dad”, “The Miracle of Right Thought”, and a host of others by people who have done it and then write about it.

    Jack requiring that you spend $1000 on batteries and then send him the module is merely the price of entry. If you want to enter bad enough and think your design is good enough it is a small price to pay for playing the game. Obviously you don’t think you would win because you talk about throwing away $1000 when a winner will see it as investing $1000. There is a big difference.

    Finally, while I don’t have any where the money Jack has, I agree with him that if you have financial limits it IS just poor attitude! The difference between successful people and poor people is ENTIRELY how they think. Nothing else. You are paid EXACTLY how much you think you are worth.

    David D. Nelson

  11. A €650 outlay for a €15,000 prize.
    If you don’t pick fruit from the tree, you’re going to stay hungry.

    I’d like to see a variation of those Zero Insertion Force DIP Sockets. Usually used for eeprom programmers. Remember them? They had a single lever to lock all the pins in place.

    Jack, maybe the winner might prefer your spare 180AH Calbs?

  12. This IS kind of precious. At the “talkin bout” stage and we haven’t even determined what the incentive MIGHT be to enter, here’s Dan…

    “there is probably no prize that would make me participate in that.”

    Well if there is NO incentive that would motivate you to do this, you of course should sit and complain. The state of Arkansas? Mississippi? 1000 cells. 2000 cells. 3000 cells. A Cadillac Elescalade? Nothing would pry you off your porcelain throne in the bathroom to actually DO something?

    even if the prize was so high that it would be interesting from a statistical perspective, you have demonstrated a very strong bias against admitting merit to any of my ideas no matter how good. and letting the audience vote wont help either. they frankly don’t have good enough judgment.

    And you know this because? I cannot recognize a good idea? in fact an entirely unknown audience is likewise disqualified from recognizing your brilliant ideas because “they” don’t have “good enough” judgement? The undiscovered unappreciated genius fantasy again that the world just doesn’t really deserve….

    there is no way that I’m spending 1000$ and a lot of my time to be subject to your fickle whims.

    Got it. THere is NO WAY you are spending money and time to do anything – ever, under any conditions, no matter what the reward. You’ll just sit there doing nothing until someone somewhere recognizes what a genius you are, steals your ideas and makes a fortune from them, leaving you doing nothing and spending nothing particularly of time or treasure. Got it.

    and I’d be interested to see if anyone else would participate. throwing away 1000$ on a little experiment is not something people with real economies do.

    Let’s all join Dan and BOYCOTT the contest before we agree on what it is for or what the motivation might be! That will show that capitalist old fart not to build electric cars around US and bother us with these stupid videos… Yeah. Me too. Yeah. Hubba hubba….

    as I’ve said before you have a somewhat warped sense of financial reality. in your world it’s just poor attitude if people have financial limits. that view is not correct however.

    And you’re basing your estimation on what IS correct and what is NOT correct on precisely what Dan? Have you ever made any financial profit or loss to have the ability to offer us the wisdom of what is correct or what is not correct or are you an adolescent fantasy zone that now also has imagined himself Warren Buffet?

    You have already FAILED in a contest. A contest that hasn’t started, you’re not sure what its for, and you don’t know what the prize is if you win. In fact, we asked you what WOULD motivate you and apparently there is NOTHING on planet that could be dom to induce you to connect 20 of these cells to make 12v????

    Jack Rickard

  13. ANdyj:

    If the winner would prefer CALBs their future in A123 module design is probably limited.

    Now let’s say someone DID have limited resources. But they came up with a cunning design for a module. And we commissioned them to build us some for an 818 World Car build in the spring. And we talked about and used those modules. And we sent them say 1000 cells for their trouble.

    Now if someone wanted to order these modules, they already have the batteries to fill the orders don’t they. By the time they have sold enough modules WITH batteries to use up 1000, I would be thinking they’d be pretty much cash flowing….

    Let’s says $600 for a 13.2v 100Ah module using 20 cells. That’s enough cells for 50 modules or $30,000 in sales. We’ll take the first 22 for the 818 project….

    Or yeah, we can give them a Lamborghini Fiero project car and some wire…..

    Jack rickard

  14. Nice idea Jack. This would be very helpful for low skilled diyers like myself who would like some powerful cells.

    Perhaps only 12 cells is needed to lower the barrier to entry?

    3p4s would be a building block I’d be more interested in.

    15 to 25 of these would be ideal for a light powerful pack teamed up with a Soliton 1.

    Also I gather you could source the cells youself saving some money if you can find a deal.

  15. Hmmm. Not seeing a lot of enthusiasm for it. We’ll muddle along and do the best we can then. But I’m sure I’ll get a lot of e-mail on how we OUGHT to have done it. It would be nice to head that into a productive chanel from the beginning.

    Jack Rickard

  16. Jack – a suggestion on hardware for your A123 module design. You may of course be as aware of it as I am, but all the components you use in your prototype are crying out for laser cutting. Both the slotted insulated carrier and the terminal clamps could be done and if my memory serves me correctly (I had some access panels done in stainless for my 40) the cost should be reasonable spread across a few dozen.

    (PS I guess in fabricating a module like this one might want to avoid inserting one cell the wrong way round…!)

  17. Jack – might I also suggest as an adjunct to the “proper” competition an area of the site where anyone who has a seed-corn idea can post a sketch? That way those of us who don’t have the time/money to participate can make a contribution. I leave it to your good self whether you wanted to offer any kind of incentive to post stuff but I rather think that quite a few would be happy to contribute suggestions without any expectation beyond recognition

  18. Jack, don’t think that I’m saying that what you are doing with EVTV is worthless, far from it. when I speak it is not to tear you down but to increase the efficacy of your efforts.
    It’s a shame that you see my input as attacks that must be viciously deflected. and I fear it taxes you on top of an already large burden.
    there is no conflict but what you make it into. just calmly read what I say, if you disagree, that’s ok. no need for conflict.

    as for motivating me to participate, the size of the prize is not the issue. it is that I have to pay 1000$ to offer you an idea that I can only expect abuse in return of. I have offered you countless very good ideas over the years for free and gotten nothing but bile in return. it should be possible to understand that I am not eager to pay 1000$ to do that.
    as for the audience, a democratic vote is unlikely to find excellence. it’s possible but I have much too great experience with that to bet 1000$, shipping and my time on it.
    if there was a really good judge (let’s call him God for the sake of argument) I might well participate even at the cost of 1000$. but I have every reason to believe you would not be a fair judge of my suggestions. one might point out that I have already offered you my A123 pack design idea… I recall two waves of spitting in my face as a reward despite taking the time to illustrate it with 3D renderings.
    but it was a rather good design. very easy to make and very light.

    you are quite intelligent, but you have some personality elements that you let hamper your intellect substantially at times. with me in particular.

    here it is again. for free.

    fiberglass buckets, fiber glass center cover that could also double as harness to keep the batteries down.
    yes not EVERYTHING has been designed in every little detail. try not to let that make you panic and overlook the merit of the idea.

    that particular layout is 320V 40Ah. it could be others but the design naturally lends itself to series connection.
    for a very efficient car I might even go with a single chain for the elegance of it. say 400V 20Ah.
    and yes I have of course considered that that means controller and motor have to match. and DCDC and charger.

  19. Jack,

    Im count me in.

    I consider myself maybe one of the worst folks to be doing this. I am an Xray/CT tech, former Printing press operator and back yard VW mechanic. I have no CNC machine experience nor do I have any machines at home to create projects except a couple welders. Neither of which I am particularly good at using. My funds are limited somewhat but nothing like 15 years ago and I do have some ideas. I am willing to try. It’s no guarantee but at least I am willing to try. I am also thinking that it may end up being a group thing where a few get together and do the project as a small group. That would help lower the cost and all will have input into the designing process and build process. Each with an ability to make it work. I liked what I saw with Dan’s idea but since he is not wanting to participate I guess I could continue the design to see if it would work. I have a few things that would need to be worked out but It could work if it held together in an abusive environment. Could be made to work for my Flat design too. Mmmmmm. Thanks for the spark Dan. If you want in you must participate and that includes sending money too. You will have a far better chance to win something than if you paid money on a lottery ticket.

    Pete 🙂

  20. Dan I only see the tabs folded. We, (or I mean) the end owner needs them to be EASILY clamped with the means to insulate, cool, service, waterproof (if possible) and attach cables.
    The cells are not very consistent on AH so they don’t lend to being used in series.
    Fibreglass will be rough on the inside (bad for cells) or “unprofessional” on the outside and does not lend itself to any particular lengths or widths required.
    High discharge rates are allowed on these cells because the heat can leech away in singles. En blok they will retain heat according the the cube rule. So the means to attach thermistors will be important.

    What price are the vendors complete battery replete with circuitry and warranted?

    As things stand my future in A123 module design is very limited. I’m sorry but these cannot sensibly fit what I’ve got drawn up but I’d be happy to sit here on the peanut gallery and bounce idea’s for free. :-((

  21. Jack,

    Is there a problem in creating a “module” where all the cells are wired or clamped in series? A twenty cell module might be in the range of 72 volts @15-20 amps with only two external connections. Two modules could then be wired in series for 144 volts and several of these pairs could be wired in parallel to a common bus to the controller. The wires between the 72 volt modules and the bus could be 12 guage and very easy to deal with.

  22. Zak, if just one cell in your configuration is 15AH then the whole pack of 72V will have to be considered to be a 15AH pack. Reckon on 10AH usefulness.

    So mating in parallel ought to come first to average out the runt cells.

    You are right. 12 Gauge is easy to deal with. Using 2×12 gauge is better on a doubled up pack. Cheaper, more flexible and loses heat more efficiently too.
    If each cell was in a cassette like a film slide and connected by sliding it in sideways on a key way to the adjacent cell(s). Then any combination of series and parallel would be accommodated as well as the overall KWH/length.

  23. Around 6 months ago I came across on the visforvoltage forum a Chinese rep hawking a large format cell from CHL and I quote “the best LFP lithium battery from china”


    I looked at their spec sheet and noted 1.5kg for 40ah = 85Wh per kg and thought that was poor.

    Given the recent discussion on higher power density cells I thought I’d revist the thread.

    They now have up a discharge curve showing 6C discharge on a 50ah cell.


    6C continuous is quite impressive. I notice that at the end of the 6C test the curve jumps up which I guess at is faster chemical reaction due to increased heating.

    The voltage drop at 6C is around 0.35V. Without test data I can guess that at sagging to 2.5V the cell will give out temporarily 13 – 14 C. Built into a pack (more sag) and not hitting them so hard maybe 10C can be achieved.

    One of their customers is reselling the cells in Australia. He is claiming, at 2.4C (120 amps), in a scooter a voltage drop of 3V with 24 cells. This works out fairly closely to the above (actually slightly better) but obviously not a very scientific test.

    I can’t find the weight for the 50ah cell or a spec sheet. Their web site only shows the 40ah cell and is in mandarin (use Google translator).


  24. @Dan Frederiksen said…
    “so will you participate David?
    have you put in your order yet? get a head start”

    No, I don’t have the resources (this includes time, machinery, and desire) or skill. I also haven’t complained or asked Jack to pay me either. I have, however, been driving an EV for 5 years, I have upgraded it extensively, and I do some of my own testing. I don’t just talk and parrot back what I’ve read elsewhere on the net. I do learn and don’t think I know everything or that everyone else is ignorant.

    So, have you read and studied any of the books which have been recommended yet?

    Jack, As a contest prize, what about enough cells for the winner to build enough modules for a 30-50kWh pack? The winner could then either use them for his/her own car or sell them.

  25. I don’t think this requires a complex, expensive and dramatic contest. After all, the goal here is to get ideas on how to package these cells simply and elegantly for the benefit of all. How about a simpler contest with a smaller prize?

    I think a drawing contest would suffice. I’m sure everyone here can put pencil to paper or mouse to drawing program.

    As for the prize? How about a J1772 Gas Pump built by the awesome folks at EVTV?

    – Doc

  26. Paper ideas will not proof out the concept. It needs to actually be built with purpose and design. It needs to withstand the rigors of the vehicle and need to not catch fire or fail. No paper idea will prove any of that. I disagree. I am fully on board with a real contest with real batteries and a real punishment test.

  27. This is the heart of the beast guys. And it’s not really because I’m clumsy and stupid. It’s kind of the process.

    I can THINK up a design, and I’ve shown you one. It has pretty good cooling from the big tabls on the end, it’s double ended, it’s compact, and as it doesn’t even have a case it’s pretty lightweight right now.

    So we take that and test it. Well, it’s doing about 90 Ah really. So we need to bump the segments from 5 cells to 6 cells if you really want a 100Ah standard module.

    Then we have to build a vibration table and shake the shit out of it for a week say. Did anyone watch the Nordlock episode?

    Let’s hose em down with water. Let’s drain em at 2000 Amps. Let’s charge them at 300 Amps Chademo style.

    And let’s do a lot of all that.

    Every other day, we have to make a CHANGE to the prototype to put stuff back on that flew off. Or go to a different resin with a slightly higher hardness or higher temperature.

    Let’s use small inserts and some stainless screws.

    We need a little metal comb between the tabs so they make good contact. And so on and on and on.

    Gradually the design gets better until it works pretty good.

    I know this is a much more tedious and Darwinian process – but I’m not really brilliant like Dan and I can’t just sit around and think pretty thoughts until it all works.

    Of course if we had 10 designs all going at the same time? Or 20. The darwinism is somewhat expanded.

    It’s just a concept.

    In any event, Nathan informs me that Enerdel has apparently ALSO sprung a leak in China – 30 AH pouch at about 485 grams – 10 grams lighter than thte A123 20 Ah cell. We’ll see if they can be had as well.

    But suddenly we’re seeing all these pouch cells available from the U.S. , via China, at exactly the same moment when Chinese Sinopoly and Winston batteries appear to be in such disarray?????

    Jack Rickard

  28. Andy:

    If you had 1000 of the cells, and had already designed a module system for them, and had actually won the contest on the TV show, I would think others would want to buy the finished modules from you. And suddenly you would have 1000 cells to work from.

    By the time you filled all the orders, you would kind of be in the battery business.

    Dan of course would still be grumping that it “wasn’t worth it” and the world just doesn’t recognize his genius.

    Now all that is just a what if. I don’t know what or how to do the contest. But it would be nice to get some module designs in the air. I think these pouch cells are going to become something here shortly.

    Jack Rickard

  29. Hey Jack,

    Yes I did watch the Nord-Lock video. Very interesting. I’m starting to use them in other projects. Will probably use them throughout my ranger build.
    Also thought the second video from Sweden was informative. Looked into the small charger he was using to bottom balance the cells. Seems that the RC crowd has been working with their smaller Li and NiMH packs for model planes and helicopters for quite a while. The charger is a buck-boost device that functions for both charging and discharging at up to 1 KW. Might be handy to have around the shop for experimenting with batteries.
    Thought your conceptual design for the A123 pack was a good start. Interlacing the cell packs was innovative and might be hard to improve upon. We shall see what others come up with.


  30. interesting about the enerdel cell but for reasons of safety I might well stick with A123. should be interesting to see tests of them.

    these cells might be available now for unfortunate reasons though. it might be desperate acts by battery makers who have been obtuse.
    A123 is building up to a 240m$ net loss in 2011. that’s bad for an established company.
    enerdel was stupid enough to put a lot of money in Th!nk. big mistake. huge. they seem to be dancing on the edge as well.
    yet despite of this they had the audacity to ask me for financial statement about my company before they were willing to give me a price. I offered to pay in advance in case I would buy any, that didn’t matter..
    double face palm.
    I hope the A123 cells stay available at around 20$. it’s a pretty great cell.

  31. Jack,

    I hope all is well, tell Brian I said hello!

    As you know I have Haiyin Lipo cells coming out of my tail, just completed tests on 1300 pouch cells. Out of 1300 cells I found 16 below the safe level, not a bad percentage. Anyways, I had read this A123 history lesson and love it! I do own stock in A123 (AONE) and always look for additional information. I would like to add buying cells from Alibaba or any other online company claiming to be selling the original cells built by A123, you will find some companies in China will reproduce fake A123 cells and stamp A123 on the pouch. The problem with these copies is the internal resistance will increase over a short period of time and the cell will fail, please be careful when buying from an unknown distributor.

    I have no use for the A123 Pouch cell, because I sell and use Haiyin cells, I am currently building 10P mini blocks that will be installed into lexan boxes, each 10P module will have a thin slice of G10 fiberglass separating the parallel blocks. Each 10P block has a 4000amp burst rate and will provide 3000amps til the cells drop in voltage. This type of pack is used for racing etc…I am installing a copper bus bar piece 15mm height 30mm wide to match each cell tab, the blocks and tabs have a 1/4 hole drilled through on my jig. This large tab and copper connection creates less resistance and heat for the pouch cell tabs.

    I am willing to give anyone advice and opinions on building a pouch cell battery pack, just email me at:

  32. Roger:

    I already have one of those chargers/dischargers on order. I’ve been following the RC guys for years. The LiPoly is actually a very DIFFERENT world from LiFePo4,but still a lot of neat stuff coming out of that venue.

    I use to be a big CBA fan until I blew a pair of their very pricey amplifiers up and fought with them over the software thing for months.

    Jack RIckard

  33. Well that’s the trade isn’t it. Lithium Manganese Oxide for a 50% improvement in weight/energy.

    The A123’s do appear to be a true LiFepo4.

    It’s getting curiouser and cruiser. I expect to hear from Dow Kokam next.


  34. I’m with Dan on this one.. This warning rings hollow to me… Sorry Adam.

    The imprinting on the foil pouch would be harder to counterfeit than actually replicating the cell. And the Chinese are traditionally NOT good counterfeiters as they tend to misspell everything.

    The could easily steal the A123 cell design and sell cells just as good as theirs, but they would be unlikely to be able to accurately reproduce the logo.

    In any event, this sounds like the same old stuff, alluding to the bogeyman as a reason to “trust us.” Sorry Adam. Still from Missouri. Show me evidence of this “counterfeiting”…. The place I have to be careful with that stuff is more HERE in the Good Ol USA.

    IT was with some amusement I noticed the dMADE IN USA with the USA marked out by magic marker, on some cells obviously made in China. A123 claims to be an American battery manufacturer, but they have ALL their cells made in Asia. Less than a thousand employees in Indianna assembling modules from the cells. That’s their concept of an American Made battery feeding off $259Million in federal money to create American jobs, and then laYING OFF 125 workers because Fisker didn’t deliver 7000 cars in 2011.

    If each of those workers made $50K per year, we’re talking about $6.25 million dollars. From a company that just received $259 million tax dollars? The numbers and the talk don’t match.

    So why did Fisker deliver 1500 cars instead of 7000 in 2011? According to their CEO, it was because a shipment of leather was damaged in a flood.

    Later asked how many cars the leather deal affected – 250 cars. ???????

    How can you tell when these people are LYING? Easy. ; You can see their lips moving….

    They don’t know HOW to tell the truth, when to tell the truth, or WHY you would want to. They lie every minute of everyday for a living.

    They think they have to. They don’t have to. They choose to.

    Jack Rickard

  35. Then there is the magical “internal resistance”. Adam, please describe for us what this magical “internal resistance” is, how it develops, and share with us your understanding of all that.

    Having you been playing with those kids on EVDL again? What did your mother tell you about that…..

    Jack Rickard

  36. Perhaps GM will reconsider A123 for their battery now. Posted on the blog about GM willing to buy back the Volts that have been sold due to the crash test fires. Interesting news. Or it will be GM using this to try to close doors on the electric car once again. Or GM’s opportunity to bail out gracefully. We shall see.

  37. It’s a bizarre time. We’re going to go through a bad spell I think, and somewhat needlessly. BUt ultimately you guys are the heroes of this story. At the moment, you’re little, ugly, and your mother dresses you funny. But it it curious that in the end you will be the way the car gets adopted.

    The volt sold a scant 1100 some odd cars in November. Yet, Consumer Reports indicates it LEADS ALL CARS in customer satisfaction.

    Everyone is suffering from RANGE ANXIETY and the NEED FOR INFRASTRUCTURE, except the people with the cars don’t have range anxiety, and charge 99.99% from home.

    There is this great yawning rift between the CONVERSATION and the REALITY about electric cars. And we are living in this bizarre period post MOnica Lewinski where it is ENTIRELY permissible to say ANYTHING regardless of truth or consequences, and we no longer even talk about lying – it’s all just relative point of view.

    The cure is first hand experience and trusted advisors (like your brother, or your son) being the only place you can get information that isn’t twisted and suspect.

    So that’s where we’ll get it. I think the whole thing will grow very well, but again, it is kind of a 10-12 year cycle before we reach the tipping point I’m afraid.

    But we have enough oxygen now to get some more STUFF. As the battery guys go broke, fire sales on cells. Simliarly with the OEMS, lots o parts and drive trains and so forth will be floating around out there.

    So good times in a way.

    Jack Rickatrd

  38. Jack,

    Epoxy resin by itself does not have much strength. I would suggest adding milled glass or colloidal silica to the resin after you mix it up to increase the strength. Another option commonly used is chopped graphite but in this case that would be a bad idea because graphite is conductive. You can add these materials to thicken the mix up to the point where it has the consistency of peanut butter. That may make it easier to work although I am guessing that you just pored the epoxy into the mold and let it flow out to level so making it thick would be more difficult. It is possible you could leave out the inserts and just thread the epoxy if you add enough of the colloidal silica with the correct type of resin.

    Years ago I was given a sample of conductive epoxy (Master Bond) that was copper fill. They also had a silver fill epoxy. The idea was to use these for circuit board assembly. Some creative use of this material might be possible in this situation although the reason I didn’t use it was the resistance was just a little too high for the current levels I was working with on the bond area. With these batteries there is a pretty large surface area on the tabs so it might be possible to use it.


  39. The battery packaging engineering contest sounds like a great idea. My only suggestion would be what about lowering the barrier to entry a bit? Does one have to buy the cells from you at $50/cell, or can one buy them directly for $30 or less? What a about packaging just 4 or so cells as a proof-of-concept rather than 20?

    $1000 is a pretty big entry fee — that would exclude some bright high school and college minds.

  40. David, I’m not sure that wood is actually conductive (I tried indoor pine, beech and mahogany and no matter how close I placed the electrodes I could not get it to register on a 2Mohm scale) and even if it was it could be just the piece under the metal plate that is already quite conductive.

  41. to improve the delorean from the conventionally wasteful design it is you have to rework it so much that’s much better to design a new car from scratch. endless patching on a bad design doesn’t work.
    it’s everything, chassis, wheelhub, brake discs, gearbox, wheels, body material and shape. everything has to be sized for lightness. and the weight reduction should not be to make room for more battery. that’s a mistake. it should even be less battery and then the range remains or even increases.
    something like the 818 could be quite good but for some odd reason Factory Five is ignoring the good designs they got in the competition and designing their own frankly ugly kit car look.

  42. Insofar as internal battery resistance, I believe it exists for real. The chemistry within the battery may not have any resistance but the conductors that carry the electrons inside the battery do. Hopefully these conductors and connections are significant enough to be insignificant resistance wise but it’s possible for them not to be. Skimping on conductor area, poor spot welds, oxide on interconnects, inadequate metal deposition thickness, low purity metals and so on can all lead to real internal resistance in a battery.

  43. Dan,
    Wood has to be treated so it does not absorb water. Knocking out all those centres is expensive. Waste is a great leveller when it comes to profit so why bother with the stuff? It’s not exactly working to auto engineering principles.
    Anyway folks, am I looking at some team-dream site here?:-

    Yes, A123, 20AH at $1-10 apiece!!!

  44. Jack, quite a few things I didn’t agree with in your rant in this weeks show but probably not much gained trying to make the points so I’ll skip past that.

    looking at the VW base I was wondering, how much does that weigh sans batteries?
    and how rigid is it?

  45. Dan:

    You never agree. And you’re consistently wrong. So how come you never really come around to the concept of sentience. I’ve been doing this part for a long time. I’ve been a little uncertain myself. Maybe this IS a different kind of industry and people are different and it’s a different technology, etc.

    NAH. Same Ol Shit. This is so much like 1988 you can’t picture it (mostly because you were very small in 1988). I’ve got me feet under me now. These are VERY familiar patterns.

    Well the car was 1125 pounds. It kind of depends on what you count and what you leave out of the count.

    It kind of doesn’t matter. The battery boxes are bolted to the pan with carriage bolts. The body is ALSO bolted to the pan with bolts. The answer is MORE rigid than without the battery boxes. And it had 550 lbs of lead acid in this hole before, remember?

    We’re looking at 265lbs of cells, plus some aluminum boxes, braided straps, bolts, and nordlocks. A bit of polycarbonate. I think LESS than 300 lbs in its place.

    In addition to the bolts attaching the boxes, they will go through some shims of about 3/4 recycled plastic in some very strong porch decking that additionally distribute the load across the pan.

    How are your options on Tesla stock working out for you?

    Jack Rickard

  46. I regularly use a dry old wooden meter stick or other similarly sized dried out stick to discharge a Van de Graaff globe. If it weren’t at all conductive then it wouldn’t discharge the globe. Also, there is a reason that even with wooden fence posts, plastic or ceramic insulators are used to hold the electric fence wire. It doesn’t matter if it is actually the wood fibers or other things in the wood that conduct. It still conducts and would add to a discharge drain on the batteries. Add to that that it isn’t guaranteed to be an equal discharge and you have a great chance of an imbalanced pack over time.

    David D. Nelson

  47. Jack, I didn’t mean to suggest everything has to be redesigned for that build. it is just enabling knowledge for later. knowing what stuff weighs allows us to talk more intelligently about it.
    as opposed to the conventional 1.5ton black box weight of a car.

  48. Jack and Brian, You guys are doing a hell of a job on the car! Thanks so much for taking on the project.

    I wondered about a couple of things in the video:

    1. Do you think using the rigid copper bars will cause fatigue of the copper with the movement of the battery pack (possible use one of the braided battery connectors to make the connection between the batteries and the box?)

    2. With the 10:1 step down of the traction pack voltage. Couldn’t that be used to power the link pro? Or do you think the current used by the meter would skew the voltage reading?

  49. Lee:

    Copper fatigue is certainly an issue I suppose. However, I have to point out that most people use the copper straps that the battery manufacturer supplies with little ill effect. We are actually building heavier straps to link very short distances between the batteries and the external terminals. I don’t think it’s much of a factor but yes, this could be a failure point in the long term future.

    We have struggled with powering LinkPros in the past. If you draw enough to power it, you are kind of skewing the voltage, but we’ve had worse things yet. At this point, we power by converting our standard 12v with an isolating converter. We then MEASURE via 10:1 through very high resistance – 100K basically. That’s a milliamp or thereabouts for your system.

    Yes, we’ve kind of obsessed on this little project. Should have the other battery box today. As you know, once the batteries come together, everything else moves pretty quickly.


  50. In combination with the first link
    instead of all the metal make a box and fill it with rasine put some tmp. probe in it and mount the PCB on top

    when you make the competition it must bee the winner. if not then for the link (hehehh) !

    regards nfj

  51. Hi Jack,
    I am using 38 200Ah cells with the HPEV50 system. I charge to around 132V. The only issue you may have is if you go to take off too soon after charging. If you are over 130v the car will not move. I once backed out of my driveway and thought I was ok until I was in the middle of the street and dead in the water. I flipped on my ceramic heater and the Pack voltage quickly dropped below the 130V mark and I was good to go.

    I don’t believe the Swallow has a heater though.

    This issue rarely comes up for me but without a way to drain your pack voltage you will need to sit and wait 5-10 minutes for the surface charge to drop off.
    On another note I have a contactor from Gigavac that does work with the Curtis Controller. It’s the GX23-008 description reads HVC-Continental NO w/external PWM I don’t know if I would recommend it as it buzzes more than the Kilovac does. The buzzing is the reason I decided to try Gigavac

  52. GrenEv:

    which is just what I meant !!!
    How in the world can you designe a box with all that metal. I have NEVER seen a batteri build in a metal case.

    My point was, how to asemble all the tabs of the a123 in to a pack, and Jacks way look’s very complicated
    If you look at the metrik mind design and what he explain ABOUT THE ERRORS, IT IS THE DESIGN OF THE METAL CASE, THE STABILITET, AND THE BMS !!!
    I just want to point out, the way to asemble the tabs, is in my opinion, the right way to go
    you have access to all joints visual

    So, make a box the size to fit the batterie’s you want
    fill it with rasine, you could make it so you can change an element,
    put the pcb on top,without all that BMS shit and away you go.

    Make a box that is stable AND isolated INSIDE !!! You get my point ??
    to get the cooling/heat of the box there are several ways to do that


  53. GreenEv:

    build a QUALITY battery box. My ass.

    Building and testing a box. I heard nothing about testing of the design from the designer’s point of wiew, it was build and submitted to the enduser without testing.

    is not quite what you think. maybe not or ???



  54. I was being very sarcastic with my post. So go build your design and see how it holds up. All ideas presented are UNTESTED and UNSUITABLE for use in a vehicle. Build them and test them like Jack is doing. You think his is complicated? Wait until you begin your journey on building a quality box that is simple and will hold up to the rigors of the EV environment.

    Don’t blast anyone else’s design until you have built your own first. Don’t tell anyone else how to build or design until YOURS is built and ready to be implemented into an EV.

    Pete 🙂

  55. We are very open to designs on the A123 modules. Indeed, I would fund a prize and a contest if I knew how to structure that.

    I am kind of obsessing on it myself. I’m at this point convinced urethane cast resins are the way to go for the end pieces. It’s just that there are dozens of formulations to pick from with different characteristics.

    We are going to a six cell segment, as we just can’t get 100Ah out of five cells.

    We’ve dropped the fasteners from 1/4 inch to number 10 screws. I am using a harder stainless screw. I found some threaded inserts that are sort of conical with a smooth face, but we are inverting them in the casting so the broad face on the BACK of the casting. In this way, when you screw down on it, it is trying to pull the largest face through the entire casting. It’s pretty strong.

    The issues are that the tabs have to be pretty securely connected. We’re smashing them flat against each other and the end piece and this is NOT sufficient. I’m adding little copper wire bobby pins between tabs.

    You have to wind up with connections you can connect to. We’re kind of going after the connection style on the GBS batteries, but with larger and more suitable screws – with Nordlocks of course.

    And of course, you want maximum number of cells in the minimum of space. As the connections take up some space, we’ve gone to this alternate end design to allow enough space for the connectors while maximizing the cell density per volume.

    We’re on our third mold design and we’ve bumped the cell count to 24 for a 12v module. 4S6P.

    We are suffering poor tab connection, though our package has gotten to be pretty compact and light weight.

    We continue to test the cells. I confess I like the Chinese prismatics better. But if I encountered these cells fresh off the farm, my reaction would be that I think I might be able to make a car out of these. A slightly softer curve than the Thundersky’s, and no, they do not provide 20Ah in any case I’ve found. But distinctly LiFePo4 like in their reactions and all in all a pretty good cell. We will wind up with NO density gains as they are a little over advertised on their spec – typical gaygin American crap. But they do put out a lot of power. And that provides an option we have not really had available – a smaller pack size with less range but still able to drive the big controllers to the max.

    I think these are going to be available and at ever lower cost. I could be wrong. But if so, it’s an option IF you have a way to package them up in a car. The case material isn’t terribly important – ABS or whatever. I haven’t even looked at that yet I so don’t care. But the end plates where you join the tabs are important as is the geometry of just stacking cells.

    And of course with an eye toward single cells, and multi cell packs of 24v, 48v, 96v and to infinity and beyond.

    Mah..mah…mah.max Headroom.

  56. NFJ:

    I’m not sure if this is some sort of English as a second language humor attempt or what. Victor and the Dow Kokam cells was a disastrous design that arrived on fire apparently on the UPS truck.

    The Dow Kokams apparently were conductive on the edges of the pouch cell and Victor, designing not only a battery module but entire BMS with it, apparently was not sufficiently familiar with the cells to have known this. So they shorted to the metal case. A123 cells do not appear to share this characteristic.

    But it would be unlikely for us to use a metal casing for the cell anyway. Largely due to expense and weight. Plastics again or perhaps fiberglass.

    Jack Rickard

  57. Jack, Kudos on your homemade A123 epoxy prototype. I think the architecture is very creative. Have you tried interposing the batteries at 90 degrees instead of 180 degrees, creating a box with four power sides instead of two and possibly allowing more batteries in a given volume? Have you personally shared your distribution concerns with Winston Chung? Thanks to C. Fischer and P. Eklund for the Nord-Lock and EV insights and refreshing focus. The video(s) left me wondering how the Nord-Locks work and why P. Eklund decided to become involved in EVs, though. It would also be interesting to know the range/performance/cost of the original Renault EV vs the modernized version. Who killed the Renault Cleo? Is there a name for the bolt loosening due to vibration effect? During the test on the video, why was the bolt changed after the ordinary nut failed? Why not leave the bolt in place and simply replace the nut with a Nord-Lock? This looks like one robust hub motor
    Would you have any interest in developing a Tesla-type LiFePo pack? http://www.kldenergy(DOT)com/products/battery

  58. Perin,

    The bolt was changed so that each test starts with the same conditions. Bolts can stretch when tightened. By starting with a new bolt the second test doesn’t “benefit” from the first test’s initial stretching of the bolt.

    David D. Nelson

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Verified by MonsterInsights