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.
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
Tuesday, November 29, 2011
Monday, November 21, 2011
Charges and Counter Charges in the land of the Swallow
Some are spitters. Some are swallowers.
This week, we send the Cadillac Elescalade over to Slingblade for a brake conversion. This will allow us to use the excellent power brakes on this vehicle WITHOUT having to deal with simulating engine vacuum. Muc of GM's truck line of course features diesel engines and they rather fail to produce sufficient manifold vacuum to run such auxiliary devices. The Elescalade already has a hydraulic pressure pump to run the power steering. By replacing the brake pack with the hydroboost version used on the diesels, and swapping out this pump for an identical one with a few more ports, we can run both brakes and steering off the same pump AND keep everything completely stock in a sense. All parts readily available and recognizable. We've already made provisions to mount this pump on the aux shaft of our electric motor pack.
Meanwhile, Lee Morehead of Denton Texas visited at the 2011 Electric Vehicle Conversion Convention. He brought a vehicle, purportedly just needing a new battery set, he called a Swallow. Originally designed
by Bill Bishoprick of Salem Oregon, this is a very lightweight vehicle based on a 1968 VW beetle, with a custom body reminiscent of a Jaguar. In 1922, Wilson Lyons founded the Swallow Sidecar Company to make motorcycle sidecars. That grew into Jaguar and Bishoprick then named the car after them.
Originally 1650 lbs with 523 lbs of Optima Yellow Tops, the vehicle got a scant 30 miles range. We're going to replace all that with 253 lbs of China Aviation Lithium Battery Company 100 Ah cells bringing the curb weight down to just over 1400 lbs.
That was the original scope of the project. Unfortunately, we've gotten a bit into it and found a bad clutch cylinder, some very bad connections between the rear suspension and the pan, and a seized motor.
So we're going to upgrade the motor and controller to an HPEVS AC-50 and Curtis 1238-7601. We'll put in an Elcon charger to charge the cells. A brake line pressure transducer to manage the regenerative braking, and a set of Bridgestone Ecopia LLR tires to replace the low profile Toyos.
The result should be a very lightweight, slightly overpowered but balanced fair-weather vehicle. I think we'll be up in the 80 mile range even using 100AH cells. Lee originally wanted to stuff it with 180Ah cells. We just couldn't' figure a good way to get them all in there, and it would have brought us back up to about the original weight, which we think was a touch bloated. With some new seat work, we think we'll be at 1500 lbs or less and very sprightly. The car is destined for use by Lee's daughter.
Meanwhile, we have had a bit of a development in the land of chargers. This has been a pernicious problem since we first started converting cars.
Our first charger was a Brusa NLG-511 or 513. It is really pretty good at 3000 watts because it is endlessly configurable. You can set up multiple stages and have them cycle on time, amp hours, current level, voltage, really almost anything. It's quite good at measuring voltage and current.
Unfortunately, it comes from Switzerland - no support at all. If you burn one up you get to keep all the charred remains. And with the Euro exchange rate, they reached $4000 each. I was 26 years old before I owned a car that cost over $4000. Much less a charger.
One of the staples of the EV world has been Manzanita. This is a non-isolated charger. You CAN configure the CC/CV voltage but its not very accurate and the point moves around with the current level. You "tweak" this with a kind of blind pot. And the termination is actually done by clock. It's really not designed for LiFePo4 cells. It can be made to work, but you have to do it carefully and it's a bit tricky. They have an add on Rudman Regulator that serves as a BMS and controls this and there have been a number of "incidents" involving fires related to this combination.
They are also a bit pricey with a 30 amp version starting at about $2400 and the big 75 amp model going for $4750. A lot more power per dollar at the expense of configuration and control.
DeltaQ makes a lot of the chargers for neighborhood electric vehicles like the GEM and THINK and so forth. Because of liability issues, they simple will not sell or configure any of their chargers for EV conversions. And they complain bitterly that the Chinese firm Elcon has ripped off their design.
If so, Elcon has presented designs with much more useful and higher voltages than DeltaQ, and it must be pointed out that the reason they were available to be ripped off is DeltaQ was having theirs manufactured in China. This is kind of a double edges sword faced by many companies. You can have your electronics product made in China at much less expense than in America. But when you do so, you often find remarkably similar products showing up to compete with you, with remarkably similar designs, and often a few improvements to boot.
The Elcon is the low priced leader. We can get a 3000 watt version for about $900. We got a 5000 watt version for the Cobra delivered in one week. They will load up to 10 "charge curves" into the machine for you and you do have the ability to pick from these 10 curves. This gives you a little bit of a selection of voltages. And they work well and reliably. But if you change your battery pack or car very much, you are stuck with a charger that just no longer works.
In September 2009, Simon Raferty, a UK engineer started a thread on DIYelectric on a $200 build it yourself charger. This thread has now spanned two years and about 50 pages of comments - one of the more popularly read threads on the service. In it, he describes a simple buck circuit controlled by an Arduino.
The Arduino is an Italian open source project to make a small board with an Atmel multi controller on it. They added an IDE and programming language to it and a USB port so anyone could easily program these in C++ on a PC. They have produced millions of these and it has given rise to a stunning open source community involved in home automation.
Rafferty adapted the Arduino as a controller to switch a pair of IGBTS's to make a functional buck circuit that could charge at 320v and below to any voltage and current desired.
Enter Valery Miftakhov. Miftakhov sports a Phd in Physics from Princeton and has developed an interest in the EV world. He's started a conversion shop called Electric Motor Werks to convert BMW's to electric drive. But he was a little put off by the state of some of the components, and chargers rather immediately fell to view. And so he has set out to "productize" this open source charger system. He has further refined the design and published layouts for printed circuit boards, parts lists, schematics, etc. He sells a kit of components for $849. And he'll even assemble one for you for $1849.
The unit is ENTIRELY configurable, better it is also entirely PROGRAMMABLE if you care to play Arduino, and it will pump out 10kw of power.
Developing such things is actually non-trivial. This week, we test the THIRD version of this we have received, and note that it still has a lot of things hanging on the outside that should be hanging on the inside. But we tried it on Speedster Redux and its' 192v pack and the device worked superbly. The CC/CV switch was accurate and the termination at 9 amperes was spot on. It is reasonably easy to configure. And it was doing over 8000 watts. I think we could have specified a higher power level yet.
Given the product liability issues with chargers, this may be the way to go. Open source charger projects you can build yourself inexpensively, or of course get some one to build for you for a fee. You kind of have to assume the liability, which you really always did anyway.
Finally, we have located a reasonably priced source for A123 cells. These 20 Ah LiFePo4 pouch cells are mildly interesting. They are high power cells capable of 20C outputs and more. This opens the window to small battery backs and LESS range, but still able to deliver the current levels required for high performance.
It's kind of theoretical, and we intend to approach it with a bit of caution. But we're playing around with five cell 100Ah modules and we were charging such a battery at 100 amps. I got involved in a fascinating phone call with Bill Ritchie of HPEVS about their "Secret stuff" coming spring of 2012 and how that might play with an 818 World Car build from Factory Five Racing. In an Alzheimer's moment, I kind of forgot the batteries.
Brain noticed them when the smoke started billowing out of the battery lab. We used the occasion to do a real world test of a new Kidde ABC fire extinguisher that uses a yellow chemical retardant powder. I was impressed.
Reiterating one more time. If you overcharge these cells, they will cause a very hot fire. Fortunately we were HERE to stop it. They weren't enclosed but perched on top of a plastic box. They burned through the box and dropped into it, where they were struggling for oxygen. We're probably going to replace the box and put about a foot of water in it. In this way, future battery fires would burn through the lid,and drop into the water automatically starting the fire and automatically extinguishing it in one smooth motion. I can then just phone in or text in my part in all this.
The interesting thing going on here is that A123 will not sell to us directly. They DO sell through a company called Mavezin who supplies components for electric motorcycles. They quoted us a price of $65 each for these 20 Ah "prismatic" cells. That's 3x the rate of our current batteries thank you.
OSN Power sold us 16 of these at $50 each. But we recently found a source at a much lower price and OSN has lowered their price commensurately. We bought 36 cells at $30 each and they quoted $23.80 in quantity 600. You can get lower yet if you want 2000 of them. And that starts to get down to the going rate for LiFePo4 cells anyway.
What remains is that you have to do your own packaging. Our initial tests indicate some minor heating around the terminals that could become problematic at VERY high current levels. The essential demand for a good Battery Management System appears to be just as valid as it is for the Chinese prismatics - that is not at all. And so we are looking at module designs that would be light weight, volumetrically of advantage, and inexpensive. This is not an area where we excel and any number of our viewers might do better at this than we do.
I'm playing with cast epoxy resin "tops" that host the cell tabs and clamp them using lightweight copper bars/sheet. Once a mold was perfected for this, they could be produced much less expensively I would think than with CNC machined plastic. But I don't know. We may try to design some sort of design contest for this project. If you have any suggestions for how that might work.
This is a VERY interesting development. And timely. Thundersky appears to be self cratering. Sinopoly has not apparently sold ANYONE we know any battery cells. We have received notice from Winston Battery that they will no longer market cells in the U.S. and that this will be taken over by their U.S. agent Balqon. Balqon assures all callers they must purchase a Balqon BMS and in any event cells will be 60 days to delivery with full payment required up front. This leaves CALB about our only source for Chinese prismatic cells.
Meanwhile, despite their obstinate reluctance to sell us cells, A123 is losing oxygen fast. The problem is Fisker Automotive. Fisker is just not ramping up their car sales per plan and so inventories of A123 cells are stacking up. Fisker blames it on floods and bad leather shipments and all manner of things in classic GM fashion. But it would appear that their car gets somewhere between 30 and 50 miles of electric range, and after the gasoline kicks in it is 20 mpg and spewing carbon in all directions - all for $95K. Becoming available pretty much in the same time frame as Tesla's $77K all electric with 300 mile range. And so Fisker is more or less DOA without drastic action.
The A123 cells are actually manufactured in Korea. The manufacturer has their own agenda. And now Chinese traders have picked up the line from Korea and are selling the cells. And they have their own agenda. Methinks A123 is losing control of their design. I think they'll quickly find their price at about $1 Ah where everything else is, perhaps slightly below given the expense of putting them in modules.
We should at least examine the possibility of using these cells as an option. I don't know at this point if they are Chinese, Korean, or from Framinham Massachusettes. Increasingly, it doesn't matter. But it is some work to use them in a car safely. Maybe a plastic battery box with water in the bottom.....
This week, we send the Cadillac Elescalade over to Slingblade for a brake conversion. This will allow us to use the excellent power brakes on this vehicle WITHOUT having to deal with simulating engine vacuum. Muc of GM's truck line of course features diesel engines and they rather fail to produce sufficient manifold vacuum to run such auxiliary devices. The Elescalade already has a hydraulic pressure pump to run the power steering. By replacing the brake pack with the hydroboost version used on the diesels, and swapping out this pump for an identical one with a few more ports, we can run both brakes and steering off the same pump AND keep everything completely stock in a sense. All parts readily available and recognizable. We've already made provisions to mount this pump on the aux shaft of our electric motor pack.
Meanwhile, Lee Morehead of Denton Texas visited at the 2011 Electric Vehicle Conversion Convention. He brought a vehicle, purportedly just needing a new battery set, he called a Swallow. Originally designed
by Bill Bishoprick of Salem Oregon, this is a very lightweight vehicle based on a 1968 VW beetle, with a custom body reminiscent of a Jaguar. In 1922, Wilson Lyons founded the Swallow Sidecar Company to make motorcycle sidecars. That grew into Jaguar and Bishoprick then named the car after them.
Originally 1650 lbs with 523 lbs of Optima Yellow Tops, the vehicle got a scant 30 miles range. We're going to replace all that with 253 lbs of China Aviation Lithium Battery Company 100 Ah cells bringing the curb weight down to just over 1400 lbs.
That was the original scope of the project. Unfortunately, we've gotten a bit into it and found a bad clutch cylinder, some very bad connections between the rear suspension and the pan, and a seized motor.
So we're going to upgrade the motor and controller to an HPEVS AC-50 and Curtis 1238-7601. We'll put in an Elcon charger to charge the cells. A brake line pressure transducer to manage the regenerative braking, and a set of Bridgestone Ecopia LLR tires to replace the low profile Toyos.
The result should be a very lightweight, slightly overpowered but balanced fair-weather vehicle. I think we'll be up in the 80 mile range even using 100AH cells. Lee originally wanted to stuff it with 180Ah cells. We just couldn't' figure a good way to get them all in there, and it would have brought us back up to about the original weight, which we think was a touch bloated. With some new seat work, we think we'll be at 1500 lbs or less and very sprightly. The car is destined for use by Lee's daughter.
Meanwhile, we have had a bit of a development in the land of chargers. This has been a pernicious problem since we first started converting cars.
Our first charger was a Brusa NLG-511 or 513. It is really pretty good at 3000 watts because it is endlessly configurable. You can set up multiple stages and have them cycle on time, amp hours, current level, voltage, really almost anything. It's quite good at measuring voltage and current.
Unfortunately, it comes from Switzerland - no support at all. If you burn one up you get to keep all the charred remains. And with the Euro exchange rate, they reached $4000 each. I was 26 years old before I owned a car that cost over $4000. Much less a charger.
One of the staples of the EV world has been Manzanita. This is a non-isolated charger. You CAN configure the CC/CV voltage but its not very accurate and the point moves around with the current level. You "tweak" this with a kind of blind pot. And the termination is actually done by clock. It's really not designed for LiFePo4 cells. It can be made to work, but you have to do it carefully and it's a bit tricky. They have an add on Rudman Regulator that serves as a BMS and controls this and there have been a number of "incidents" involving fires related to this combination.
They are also a bit pricey with a 30 amp version starting at about $2400 and the big 75 amp model going for $4750. A lot more power per dollar at the expense of configuration and control.
DeltaQ makes a lot of the chargers for neighborhood electric vehicles like the GEM and THINK and so forth. Because of liability issues, they simple will not sell or configure any of their chargers for EV conversions. And they complain bitterly that the Chinese firm Elcon has ripped off their design.
If so, Elcon has presented designs with much more useful and higher voltages than DeltaQ, and it must be pointed out that the reason they were available to be ripped off is DeltaQ was having theirs manufactured in China. This is kind of a double edges sword faced by many companies. You can have your electronics product made in China at much less expense than in America. But when you do so, you often find remarkably similar products showing up to compete with you, with remarkably similar designs, and often a few improvements to boot.
The Elcon is the low priced leader. We can get a 3000 watt version for about $900. We got a 5000 watt version for the Cobra delivered in one week. They will load up to 10 "charge curves" into the machine for you and you do have the ability to pick from these 10 curves. This gives you a little bit of a selection of voltages. And they work well and reliably. But if you change your battery pack or car very much, you are stuck with a charger that just no longer works.
In September 2009, Simon Raferty, a UK engineer started a thread on DIYelectric on a $200 build it yourself charger. This thread has now spanned two years and about 50 pages of comments - one of the more popularly read threads on the service. In it, he describes a simple buck circuit controlled by an Arduino.
The Arduino is an Italian open source project to make a small board with an Atmel multi controller on it. They added an IDE and programming language to it and a USB port so anyone could easily program these in C++ on a PC. They have produced millions of these and it has given rise to a stunning open source community involved in home automation.
Rafferty adapted the Arduino as a controller to switch a pair of IGBTS's to make a functional buck circuit that could charge at 320v and below to any voltage and current desired.
Enter Valery Miftakhov. Miftakhov sports a Phd in Physics from Princeton and has developed an interest in the EV world. He's started a conversion shop called Electric Motor Werks to convert BMW's to electric drive. But he was a little put off by the state of some of the components, and chargers rather immediately fell to view. And so he has set out to "productize" this open source charger system. He has further refined the design and published layouts for printed circuit boards, parts lists, schematics, etc. He sells a kit of components for $849. And he'll even assemble one for you for $1849.
The unit is ENTIRELY configurable, better it is also entirely PROGRAMMABLE if you care to play Arduino, and it will pump out 10kw of power.
Developing such things is actually non-trivial. This week, we test the THIRD version of this we have received, and note that it still has a lot of things hanging on the outside that should be hanging on the inside. But we tried it on Speedster Redux and its' 192v pack and the device worked superbly. The CC/CV switch was accurate and the termination at 9 amperes was spot on. It is reasonably easy to configure. And it was doing over 8000 watts. I think we could have specified a higher power level yet.
Given the product liability issues with chargers, this may be the way to go. Open source charger projects you can build yourself inexpensively, or of course get some one to build for you for a fee. You kind of have to assume the liability, which you really always did anyway.
Finally, we have located a reasonably priced source for A123 cells. These 20 Ah LiFePo4 pouch cells are mildly interesting. They are high power cells capable of 20C outputs and more. This opens the window to small battery backs and LESS range, but still able to deliver the current levels required for high performance.
It's kind of theoretical, and we intend to approach it with a bit of caution. But we're playing around with five cell 100Ah modules and we were charging such a battery at 100 amps. I got involved in a fascinating phone call with Bill Ritchie of HPEVS about their "Secret stuff" coming spring of 2012 and how that might play with an 818 World Car build from Factory Five Racing. In an Alzheimer's moment, I kind of forgot the batteries.
Brain noticed them when the smoke started billowing out of the battery lab. We used the occasion to do a real world test of a new Kidde ABC fire extinguisher that uses a yellow chemical retardant powder. I was impressed.
Reiterating one more time. If you overcharge these cells, they will cause a very hot fire. Fortunately we were HERE to stop it. They weren't enclosed but perched on top of a plastic box. They burned through the box and dropped into it, where they were struggling for oxygen. We're probably going to replace the box and put about a foot of water in it. In this way, future battery fires would burn through the lid,and drop into the water automatically starting the fire and automatically extinguishing it in one smooth motion. I can then just phone in or text in my part in all this.
The interesting thing going on here is that A123 will not sell to us directly. They DO sell through a company called Mavezin who supplies components for electric motorcycles. They quoted us a price of $65 each for these 20 Ah "prismatic" cells. That's 3x the rate of our current batteries thank you.
OSN Power sold us 16 of these at $50 each. But we recently found a source at a much lower price and OSN has lowered their price commensurately. We bought 36 cells at $30 each and they quoted $23.80 in quantity 600. You can get lower yet if you want 2000 of them. And that starts to get down to the going rate for LiFePo4 cells anyway.
What remains is that you have to do your own packaging. Our initial tests indicate some minor heating around the terminals that could become problematic at VERY high current levels. The essential demand for a good Battery Management System appears to be just as valid as it is for the Chinese prismatics - that is not at all. And so we are looking at module designs that would be light weight, volumetrically of advantage, and inexpensive. This is not an area where we excel and any number of our viewers might do better at this than we do.
I'm playing with cast epoxy resin "tops" that host the cell tabs and clamp them using lightweight copper bars/sheet. Once a mold was perfected for this, they could be produced much less expensively I would think than with CNC machined plastic. But I don't know. We may try to design some sort of design contest for this project. If you have any suggestions for how that might work.
This is a VERY interesting development. And timely. Thundersky appears to be self cratering. Sinopoly has not apparently sold ANYONE we know any battery cells. We have received notice from Winston Battery that they will no longer market cells in the U.S. and that this will be taken over by their U.S. agent Balqon. Balqon assures all callers they must purchase a Balqon BMS and in any event cells will be 60 days to delivery with full payment required up front. This leaves CALB about our only source for Chinese prismatic cells.
Meanwhile, despite their obstinate reluctance to sell us cells, A123 is losing oxygen fast. The problem is Fisker Automotive. Fisker is just not ramping up their car sales per plan and so inventories of A123 cells are stacking up. Fisker blames it on floods and bad leather shipments and all manner of things in classic GM fashion. But it would appear that their car gets somewhere between 30 and 50 miles of electric range, and after the gasoline kicks in it is 20 mpg and spewing carbon in all directions - all for $95K. Becoming available pretty much in the same time frame as Tesla's $77K all electric with 300 mile range. And so Fisker is more or less DOA without drastic action.
The A123 cells are actually manufactured in Korea. The manufacturer has their own agenda. And now Chinese traders have picked up the line from Korea and are selling the cells. And they have their own agenda. Methinks A123 is losing control of their design. I think they'll quickly find their price at about $1 Ah where everything else is, perhaps slightly below given the expense of putting them in modules.
We should at least examine the possibility of using these cells as an option. I don't know at this point if they are Chinese, Korean, or from Framinham Massachusettes. Increasingly, it doesn't matter. But it is some work to use them in a car safely. Maybe a plastic battery box with water in the bottom.....
Monday, November 14, 2011
EleCobra - The Thrill of Victory, and the Agony of The Feet.
Sadly and painfully behind on my blogging duties, it is probably poor form to attempt a remedy with one massive update. But we do what we can. We HAVE been a bit busy with the roundup of the EleCobra prototype for Aptima Motors.
Recall, if you will, that I was vaguely disappointed in our performance at the local airstrip with the EleCobra. As it turns out, justifiably so. I'm pleased to report that we had quite a bit stronger car in the box than was immediately evident.
The week before last we took the EleCobra to Slingblade Performance in Anna Illinois to do some dynamometer testing on their Dynojet system. The results there were also disappointing. But we mounted a video camera behind the car and shot the actual gages up close while the acceleration tests were performed.
On return, I did something so gruesome I scarce recommend it. I exported the Winpep data in 100 msec chunks. We shoot our video at 29.97 frames per second and so 1/10th of a second corresponds to 3 frames of video. And so I loaded the videos and cycled through the runs 3 frames at a time, noting amps, volts, temperature,s etc from every gage on the dash, three fluke meters, and the Netgain Warp Drive Interface Module.
This is beyond watching paint dry. It's self abuse.
But it did pay off. We could note, for example, that not only were we NOT getting the calculated power, but apparently we weren't asking for it. The throttle input never exceeded 80% command.
Recall that we had struggled with a type 23 error reported on the Netgain Warp Drive Industrial. Mr. Bohm was prompt in providing us with a firmware upgrade on the controller. Better, the process of updating firmware was actually pleasant. Mr. Bohm sent us an e-mail with an attached file. We pulled the tiny SD micro card from the interface module and mounted it in an SD card adapter, and plugged it into a desktop computer. We could then copy the file onto the card.
We then reversed the process, inserting the card into the Interface Module. A simple menu item allows you to update the firmware to the controller, and in fact you can even update the firmware in the Interface Module itself if need be. The entire process from e-mail to updated controller was probably not eight minutes.
The Interface Module is a very handy way to set configuration items on the controller, but there really aren't very many. You get motor amps and volts limits, in forward and reverse. You can clear errors, and read errors. There's a "frame leak" option. And not very much else.
But you CAN select your throttle type. You don't get to change much on it, but you can select it. Our throttle is the LOKAR PEDAL the last option on the list. We believe when we updated the firmware we reverted to the default, CTS which is the FIRST item on the list.
So we were running the car error 23 free finally, but with the WRONG pedal. This had the unfortunate effect of lopping off the top 20% of our available power.
The scary thing about all that is that without all this testing, we never would have known. We would have been vaguely disappointed in the Netgain 11HV, the Warp Drive Industrial, and the EleCobra. But it ran well, and we could have gone for years. As a first prototype, we would compare it to WHAT? What SHOULD the power have been? My napkin scratch?
The central issue with one-off custom cars and prototypes is you never KNOW when you are done. Now that we've found the pedal issue, is there MORE things we are missing? More tricks that could this dramatically improve performance?
Our zero to sixty time dropped from 6.8 seconds, which isn't as good as Speedster Redux, to 5.8 seconds - making it the fastest car on our lot. That's a 14.7% improvement. What ELSE is in the car that will give me another 10% say? Scarey thought.
This week, we returned to Slingblade and things got better.
You can also see the results in the graphs below and I'll include a link to the actual elecobra.xlsx EXCEL FILE for the Cobra so you can see the data. There's actually a LOT more data in the file than we graphed and you might find some of it quite interesting.
I'm going to hear howls from the Dan Friedricksons and other lesser intellects on the disparity between the data from the fluke meters and the Xantrex and the Interface Module. Here's a clue. Each device has a different "sample rate" and we are snapshotting the numbers in 1/10th second slices. If you slide the numbers, they're all good, just not in precise line in all cases.
Since we insisted on publishing everything we did on the EleCobra, Aptima Motors, which has plenty of secret plans, has avoided making us privy to all of them for obvious reasons. But Bryan ANderson claims they have already put two additional chassis into work. They are going to integrate the battery boxes a little bit better into the new frame. And they are going to do a carbon fiber body for the vehicle. Bryan believes he can slice 400 lbs certainly, and potentially as much as 500 lbs from our 2961 curb weight. With a 5.8 second zero to sixty now, imagine the improvement with a 17% weight decrease. This should also have a dramatic impact on our 120 mile range. And I think he mentioned they are going to sell these cars completely finished at $85,000.
What I found very surprising was a rather significant level of interest from his EXISTING customer base of Cobra owners in the project.
I didn't have any doubt at any point that we could make the car roll forward using batteries and a motor. Frankly, no miracle there. Really anyone CAN do this. If you want to take an existing car and make it drive on batteries, the stuff is there.
Naturally, we wanted to do it with new and interesting components to make it interesting video. But my concern from the beginning was that the resulting car be "Cobra-like". And I struggle to define what I mean by that. Obviously it would be a new and different thing powered by LiFePo4 cells and a magnetic motor. But could it be done incorporating the feel and mystique and sense of this car, which has such a history and such a community of enthusiasts who so deeply feel the Cobra gestaltd?
Bryan Anderson claims to have built 2700 chassis in 25 years, the majority of which are Cobras. He seems to think so.
Our mission was to take an existing car as it was and convert it to a working prototype electric drive car. In this particular adventure, the loop is continued. Now Mr. Anderson can take what we've done, and go BACK to the beginning of the process. By making some fairly dramatic changes to the chassis, he can take off weight and do a MUCH improved positioning of the battery cells. With carbon fiber, he can lighten the body and if he dares, alter the front end to eliminate the aerodynamically perverse open front face of the car - vastly improving the admittedly poor aerodynamics of this particular model.
There are some more refined improvements available as well. If you are disappointed with our horsepower numbers, you probably ill understand what horsepower is. Our torque was very good, but it WAS a little constrained to the lower end of the RPM band - limiting somewhat the HP number you read on the dynamometer. Horsepower is an expression of radial torque RPM corrected. Simply increasing the voltage 20 volts would widen that RPM band substantially. By incorporating the boxes more integrally into the chassis, that is a very possible improvement.
We were at that under 500 ft lbs of torque. The Tremek TK600 transmission is the big guy in that line and rated for 600 ft-lbs. On reflection, it is POSSIBLE that a lighter, lower friction T45 or even T5 transmission MIGHT make the grade - decreasing our drivetrain friction losses as well as overall weight. The same can be said of the entire rear differential and axle assembly.
The production costs of the EleCobra are simply too high to be a viable vehicle in my estimation. But Aptima is intent on it and at $85,000 it would certainly be an interesting offering. With the changes outlined above, this would truly be a performance car by any measure, and I can say the view from the cockpit did grow on me over the course of this project. It will be very interesting to see this develop.
Meanwhile, we're back on the Elescalade and a couple of new projects. As described in the second video, we are taking a close look at Factory Five Racing's 818 World Car concepts. This is a two seat mid engine spyder sports car using the universally and globally available Suburu parts in either left OR right hand drive. David Smith intends to reach a younger customer base with this and enhance his already notable export business - he calls it a "World Car." Better, he is looking to a $9900 kit car price with a completed vehicle possible at a smooth $15,000.
This is very attractive. We can't make it electric and stay within $15,000. But an electric version of this modern, very aerodynamic and lightweight (818 refers to kilograms wet) could be very attractive at $25,000 or even $27,000 all in. If we could find a suitably NEW and interesting motor and controller combination, and perhaps a suitably new and exciting battery architecture to match, this could be the ultimate kit build electric car at a price more of our viewership can afford than say, the Elescalade.
I guess the question we would have is should we go for max range/performance or attempt a dramatic price breakthrough on such a build? Viewer thoughts on this would be welcome.
Jack Rickard
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