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.....

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

LRR Tires - Worth It

The Aptima Motors eCobra is coming along. We are in the final days of this project. It rolls and drives well.

One of the concerns with this car has been the amount of power required to move it. For a two seat convertible sports model, it is a bit heavy at 2961 lbs - no interior or paint yet at that. But as we have added pieces such as the hood and trunk, the aerodynamics have improved and the power consumption has fallen to more of the expected levels just over 300 wH per mile - about as expected for it's weight.

One of the eyebrow raisers from receipt of this car was the large wide tires that came on it. Lots of rubber looks good and rides well, but it usually means higher rolling resistance. Very early in the program we ordered a new set of lightweight WELD wheels with a carefully calculated offset so we could run Michelin Energy Saver A/S low rolling resistance tires on this car. The issue was having the offset such that the tires still filled the wheel well and didn't look entirely odd on a Cobra.


Recall from our mystery surrounding the Porsche 550 Spyder and the Porsche 356 Speedster that we got a significantly better range and energy use from the heavier and rounder Speedster. Despite installing expensive aluminum rotors, calipers, low rolling resistance tires, and even ceramic bearings, we never did get the Spyder even close to the Speedster's ability to roll much more freely.

As kind of a joke we ran what we called the Soapbox Derby - simply rolling the two cars down the street in neutral to see which rolled further. True to our range results, the Speedster rolled dramatically further than the Spyder.

We can of course do normal range testing but it is quite time consuming and subject to variabilities out of our control. If a tractor trailer blows past you, cuts in front of you, and then slows to 7 miles per hour below your target speed, there's not a lot you can do about it in a small convertible. And the tests take hours and are much more accurate over a significant number of miles - 15 to 25 typically.

So we liked the quick indication of the Soap Box derby. But it didn't actually provide much data - just a distance on a hill. And you have to use the SAME hill. So YOU can't compare YOUR results to ours.

The way this is actually done in automotive testing is with a coast down test. And so we adopted the pretty standard procedure used in such tests - with perhaps less instrumentation and rigeur than is commonly done at the Chrysler Test Grounds. But we think it renders quite accurate information, and is reproducible by anyone anywhere on any car.

Basically, we go to a flat stretch of road sufficiently long to allow an acceleration to 75 mph and a subsequent unpowered roll to a full stop. Ideally, with very little traffic on it. We then accelerate to 75 miles per hour, and then remove all throttle input and place the transmission in neutral.

As the car speed decreases and passes through 70 mph, you take a time mark. As the point where it hits 60 miles per hour, you note the time from the 70 mph start time mark. As it passes through 50 mph, again take a time. And so forth until the car actually comes to a stop, noting the time each 10 miles per hour.

There is a human element using a stopwatch, and the incline of the road will affect the results, no matter how flat. So we run the test THREE TIMES in each direction, giving us six time sets. Then we average the times. We actually had little variation there.

The chart below shows this coast down test for the Michelin Energy Saver A/S tires/wheels, as well as for the Stinger Radial GTS tires that originally came on the car.

As you can see, the results are pretty similar at the higher speeds, where aerodynamics comprises the predominant effect. But as the speed deteriorates, the two curves diverge pretty strongly. Total time was a difference of nearly 30 seconds. That's quite a bit of time and quite a bit of distance differential for two sets of tires.

We also did some actual range testing. Excluding extraneous factors such as hoods and trunk lids, we really only have directly comparable data for 40 mph and 50 mph.

But the results are startling. At 40 mph our max range calculates to 152 miles with the Michelins and 124 miles with the Stinger tires. LRR tires typically provide a 3-5% increase in gas mileage. But in this case, starting with tires that are so BAD for an electric drive application, this was 28 miles further than the Stinger results - a gain in max range of 22.58%. This is frankly just huge. Not precisely apples to apples as they are entirely differently sized tires, but it's a real gain and we'll take it.

The results at 50 mph are less as there is slightly more of an aerodynamic component at the higher speed - predictably enough. But they are still substantial at over 14%.

A number of people have waned us to keep the eCobra cobra like. We don't know precisely what this means. But we think it has something to do with burning rubber. So we installed a line locker on the front brake line. This allows us to spin the rear wheels while applying brake to the front wheels. It worked well enough as you'll see in the video. As an added bonus, it makes a very handy parking brake.

We also did some very preliminary testing of 0 to 60 times using the pretty basics device provided on the GPS speedometer. It would appear we ran 0 to 60 mph in 6.77 seconds and 360 linear feet. We think we can improve on that with practice, probably down to about six seconds.

We hope to get the car over to Slingblade Racing this week for a full dynamometer test.

Jack

Going Down in Flames - It's Just an Expression

Interesting week last week and growing interestingier as we start this one.

Last Monday, we were doing some range testing at 60 mph in the eCobra when the Netgain Warp 11HV let out all its smoke and ceased operation somewhat noisily.

This led to a crusade to swap the motor that I'm more than a bit pleased with as it was pretty much completed in three days. Netgain had a new motor to us in less than 48 hours and our penchant for installing and reinstalling things several times had of course led us to a pretty straight forward replacement from beneath without having to move too many other parts - transmission and drive shaft of course. BUt no batteries or major rewiring.

Unfortunately, we had no video camera operating at the time. So no cool video of the tower of smoke next to the Interstate. Oh well....

The other interesting thing to happen early THIS week is that we put the hood on the car. This is normally a not particularly exciting evolution and always toward the end of the build, when we are doing more driving that building.

In this case, it had a very strong effect. Recall I had been grousing about the rolling resistance, the brakes, and so forth on this car because it was taking between 1.65 and 2.25 Ah of energy at 215 volts to make a mile of distance. This is just horrendous. At the upper end this is like 475 wH per mile or more. And it had shot all my range calculations completely out of the saddle.

Actually, things get better with the hood on. This should be obvious to all, but I didn't think it would account for this much difference. It makes THIS much difference. As soon as the hood was on, we dropped to 1.409 Ah per mile - right in the 300 wH per mile range where this 2961 lb car should be.

I may have mentioned some efforts to develop something more consistent than our soap box derby for a coast down test.

We took the car un to 75 mph on a flat road section and put it into neutral. Time mark 0 was called at 70mph and the time noted at each 10 mph until stopped. We ran this three times in each direction, east and west, and then averaged the results.

The coast down test is conventionally used to determine aerodynamic drag and rolling resistance. But it is difficult to do that with accuracy and requires humidity, temperature, and other factors to be truly accurate. But we think we can do a quick average procedure and have the curve and times as a baseline. This should let us compare to this baseline after changes for example. We'll put on the original tires and rerun it for example to see what the effect is.

This is a bit more trouble than rolling it down the street in front of the shop. But accounts for aerodynamics in addition to rolling resistance and drive train efficiencies.

Jack Rickard

Moore from the Land of Harsh 12v busses and Itty Bitty Batteries

In this week's underdog adventure, we retrace our steps on the Aux battery and the 12volt subsystem.

We have a number of loads that need to be on all the time - parked or running. In fact, the number of these is reaching kind of alarming proportions.

The latest that slipped under the radar was David Kerzels' SAE J1772:2010 Compatible Active Vehicle Side Control Board Module This little device is $37 on eBay and is all you need, besides the inlet itself, to respond appropriately to any commercial J1772 EVSE and charge therefrom.

I love it. Not only does it do the necessary response to the EVSE to both trigger the copilot signal to start the charge process, but it also monitors the proximity switch (the little button on the charge plug) to stop charging if it is pressed. AND it provides a little single pole double throw relay you can use to detect it's state to do such things as interlock your onboard charger, disable the controller while charging, whatever.

The unit draws 20 ma, although we use the SPDT relay to also apply 12v to a string of blue LED lights ringing the billet aluminum fuel port on the Cobra. Good visual at the car that it is charging when the blue LED is on.

But the trick is, it has to have 12v ALL THE TIME, or you can't charge. No 12v to the board, no charging.

We are powering our Xantrex AH meter also with 12vdc. We've tried a number of near disastrous ways of powering this little device and the best seems to be to use an inexpensive (usually $10-$12) DC-DC converter module to take 12vdc from the car, isolate it through the 12v/12v converter, and power the Xantrex with it. Of course, if we are to account for IN amp hours while charging, we have to have it on all the time. Since I can't read it without the backlight, that's on all the time as well. It's a bit of a 24x7 load on the 12v system.

Then there's the ZevaII Fuel Gage Driver. I spend a lot of time exasperated with this device as it is tricky to install and calibrate. But I do love it. It does two things I like. First, it runs an ordinary fuel gage by counting ampere hours. You can use this device to fairly accurately monitor your LiFePo4 pack's state of charge using a familiar and already standard face - an ordinary fuel gage. We have a set of Speedhut Cobra gages for the Cobra and it comes with a fuel gage of course. Might as well use it. Probably NOT as accurate as the Xantrex, but easy to use and everybody knows what it means.

This device also outputs a pulse string representing instantaneous current. We can display this in hundreds of amps on our tachometer from Speedhut. Actually, we installed a small selector switch in the dash that let's us connect this output or the output of a RechargeCar magnetic shaft pickup to our tachometer. In this way, we can read RPM or battery amperes on the tachometer.

This is kind of cool A dancing set of digital numbers for instantaneous current is not really VERY informative. We're changing the current faster than the digital device can sample. But if we put the same information on a large analog needle, it is all different. We get a rougher indication of value, but a kind of more integrated "trend" visual that shows us the current going up and going down in response to our throttle inputs.

Finally, the ZivaII let's us set an alarm level and provides a switched ground output when we reach some low level of charge. We can hook that up to a warning light or power a relay with it.

But to do all that, it is ON for 24x7. In fact, if you remove power from the device, it resets your AH counter and your fuel gage will show full when it's actually had a number of amp hours used This is a worse situation than having no fuel gage at all.

So we tried using an aux battery to the ignition switch, and that voltage to in turn run a contactor that turned on our main DC-DC converter. This quelled the complaints from the Netgain Controls Warp Drive Industrial, but caused endless other problems. Most notably, we kept running down the battery when we charged overnight.

We added a manual bypass switch to bring up the DC-DC converter and recharge our dead battery. But the whole thing was a nightmare and we were going to have a totally destroyed battery within days.

We have tried an aux battery in the past - always to some bad end or other. We've had numerous people point out that if we lose our DC-DC converter, our car won't operate. Duh. What we've found is if we lose our DC to DC converter, we don't know it at first because we have an aux battery. But within a few minutes, the battery runs down anyway and our car won't operate. Plenty of weight, an inherent maintenance item, and same effect.

We're also warned of dire safety issues as a sudden shut down will cause us to lose power brakes and power steering and all manner of ills suddenly while hurtling down the freeway. Same answer really. But most of our cars don't have power steering, power brakes and so forth anyway. For the ones that do, for example the 2009 Mini Cooper Clubman Electric, we have a different solution - redundant DC-DC converters. Indeed the design of the Mini's startup sequence requires 12v of course, and we use one converter to bring it up, and when up it engages a second converter as well. When we shut down, we disconnect the big one, but leave the small one running.

The original problem on the eCobra had to do with the Warp Drive Industrial controller. It threw a series of errors when we shut OFF the controller at the end of the drive. This was very peculiar. But the controller stored the errors and so wouldn't operate the next time we fired it up. We learned to clear the errors with the Interface Module, but once we have all this working, we don't see really using this Interface Module day to day. A great troubleshooting device, it can't count Amp hours and doesn't really add much operationally. Certainly having to clear these errors prior to driving wasn't happening.

Ryan Bohm insisted this was caused by noise on the 12v system and wanted us to scope it. I have a problem with all that. What noise are we looking for? There is noise. And there is noise. And in fact, we find the 12v system in a car a very noisy place, and one of the primary culprits is in rather circular fashion - the controller. So I'm vaguely disinterested in noise in general. Assume we are going to have it in an automotive environment.

In this case, I had another problem with the concept. The controller worked fine - ONCE we had cleared the errors. Indeed, the errors only occurred when we were shutting DOWN the system. If the controller has an issue with "noise' in general on the 12v system, why didn't it throw errors while I'm driving down the street?

Our 12v system does have an unusual number of inductive loads on it. We have a prius pump, for the controller cooling system, a Derale heat exchanger fan of actually some size, again for controller cooling, and an XSTurbos turbocharger we are using as a cooling blower for the 11HV motor. At 435 cubic feet per minute, this fan draws 4.6 amps at 12v.

The windings of a motor are an inductor. An inductor resists changes in current. Current through the windings causes the expansion of a magnetic field around the windings. This field stores energy. When you cut off the current, the field collapses. This collapse induces a current in the same direction. And this can cause relatively huge voltage spikes. The spikes are hard to see on an oscilloscope because while they can be surprisingly high in amplitude, they are very transient. They only appear for a handful of milliseconds. I happened to have a very cool very fast 600v 100 amp diode laying around - about 10,000 X overkill for this test. But we hooked it up between our 12v bus and ground.

It had NO effect.

Ryan Bohm was able to duplicate the problem as he had a Derale heat exchanger as well. What he found was something very different. The fans have a bit of inertia in them. When you shut them off, they keep spinning for a second or two. And when they do, they act as generators. They were maintaining 4-5 volts, quickly decaying of course, on the 12 volt line.

The problem is that the ON digital input to the controller uses this 12v to signal the controller that we are indeed on. So we have shut DOWN our 12v supply to the controller, but the fan is producing sufficient voltage that the ON input is high - for a second or two. This causes the errors to be noted and stored.

We tested this by putting a diode in series with the fan. When it is shut off, the fan does generate, but the diode blocks the feedback into the line.

That pretty much fixes the problem, but as the Derale uses six or seven amps of current, I did not want a semiconductor in that line heating up and inevitably becoming a failure item.

As a workaround, we connected the fans with a relay and used the ignition voltage to energize the relay. In this way, when we turn the ignition off, the fans are simply disconnected physically fro the system. The 3-5v cannot reach the ON input, and the errors do not occur.

This was an interesting problem. But it had us running in circles for days. And it is probably beyond our concept that ANYONE can convert a car to electric drive. in this case, anyone can't, and indeed Jack could not for some period of time. So the "fix" is for the controller to be fixed where this is not an issue.

It does bring up the concept that all such loads ought to be on separate relays with separate fuses. Not a bad practice actually, and you will see this in most modern automotive fuse blocks. Lots of fuses, and lots of relays. There's a reason. But the controller should not depend on that to operate. Put a relay inside the controller if you like.

We also devoted a bit of time to a discussion of the Tesla/Panasonic connection. Tesla makes all this needlessly secretive and confusing with their constant claims of proprietary madness. But that's mostly illusion and press puffery. Panasonic did invest $30 million in Tesla and owns 2% of the stock in the company. And they are working together. But the original concept was for Tesla to use off the shelf cells that are produced in the millions for laptops, cell phones, and flashlights. With the acquisition of Sanyo, Panasonic is the largest manufacturer of those in the world, BYD perhaps excepted. on raw numbers.

In March of 2012, Panasonic begins the production run of a brazillion of their new NNP 3.4Ah cell. This is there New Nickel Platform. It's actually a Lithium Nickel Cobalt Aluminum Oxide cathode material with a carbon anode. And the thing carries 12.24 wH of energy in a 46 gram package. This is something like 266 wH per kilogram. By contrast, the CALB or Winston type cells are more like 109 wH/kg in their optimum size.

This is very nearly two and a half times the energy by weight. And if our 444 lbs of CALB cells were these new Panasonic's instead, we'd be seeing 266 miles instead of 109 in Speedster Duh. As I've actually driven Duh pretty flat at 110 miles, I'm onboard.

Ergo the 300 mile Tesla Model S.

We also learned a bit about cycle life in these cells which is very encouraging.

Cycle life to the industry "traditional" 80% of original capacity is somewhere in the 500-800 cycle range. Not good. But if you look to 70% as the mark, it gets much better as the deterioration curve flattens out in a very unusual fashion. You're looking at well over 2000 cycles to that level. And 70% of 300 is still 210 miles.

These are not here yet. But I do not classify them as unobtanium per se. They have good prospects for being available subsequent to March 2012. Tesla has contracted for enough of these cells to do 80,000 cars over four years. That's 640 million cells. As it will also be the highest energy density of any 18650 form factor cell, it will undoubtedly be popular in a number of other applications - flashlights if no where else. And so we have a truly MASS market battery cell here. That brings in economies of scale. That's the game we need.

I don't relish making modules of all these little cells. But 2.5x energy at potentially a LOWER price within a few years from what we're now paying for CALB/Winsston cells could be a play.

In a much larger sense, there is a perception, espoused by Elon Musk himself, that the Moore's law of PC speed and bandwidth only applies to batteries in a rather sedate form of 8% per year or so. I've never completely bought into this. The creeping advance were in a product that had zero market and no cash flow. As soon as you add oxygen in the form of ducats coming in the door in substantial numbers, innovation in batteries is not that hard. There is tons of cool science laying around with the usual problems of engineering to a product level, but there simply has been no oxygen (money) to drive the productization. Panasonic has already announced plans for 2013 to bump this very 3.4Ah cell to 4.0Ah by using a silicon alloy anode in place of the carbon anode in this cell, for example. But if a fire ensued in the battery market, there are plenty of players and plenty of advances to come. I think Moore's law is alive an dwell in Batteryville. And a car with a 1000 mile range is not inherently a preposterous notion.

Stone Soup

Several hundred years ago, in a war weary and torn rural England, there was a great famine. The war and the weather had conspired to fail the crop entirely and hunger was rampant across the land. So scarce was food that violence was a daily occurrence with the strong taking what they needed from the weak, and the weak imploring God to deliver them from this evil season.

Families hid what food they did have, even from their closest friends and neighbors. Children were warned to say nothing of an onion if there was one on hand for fear someone in need would beg share it. And a bitter, cold wind blew without cease.

A road weary and battle worn knight was trudging horseless across the land toward his home, many days travel by foot away. And as the day grew late, he was relieved to see the smoke from a small village ahead on the rural pathway he trod.

He stopped at the village well to drink and ask food and shelter for the night. He found there an ancient crone who eyed him with suspicion from head to foot. “There’s no need to stop here, Squire” she grumbled. “We’ve been had to the quick and the village is starving. We’ve no food for ourselves, less for strangers.”

The knight knelt drinking deeply from the bucket. “Then thank you mother for this drink from the well. It’s a relief and blessing enough. Tell me true, you’ve really no food in the village?”

“We starve.” snarled the crone. “And if able to grub a single root from the very frozen ground, one of you soldiers offers to trade our own lives in exchange for it. We live under a curse I tell you.”

“Dire!” said the weary soldier. “How you suffer. I can scarcely imagine. It sounds a tribulation beyond belief.”

“Believe it or don’t believe it. We’ve nothing to eat here. So best you move along.”

“That would be a cold and heartless act. With you all starving in front of me, to just move on without doing what I might. I’ll not. I’m a bit short myself, but what I do have I will to share.”

“Share, sire.” The womans chill warmed but slightly. “You have food to share with us?”

“I’ll do what I can, “ replied the weary night. “You’re right enough, it’s a hard season. Fetch me a pot old woman. As large as you can find. I’ll make you soup, meager it is. But nourishing. And you and I shall dine as best we can.”

“I have a pot. It’s fairly large. What soup will you make?”

“Enough of your whining. Fetch me the pot old woman. And hurry. We’re both going to catch our death of cold while standing here starving at each other. Where’s wood for the fire. I’ll get it on.”

“There’s wood aplenty if we could but eat wood. It’s over there by the stalls. I’ll fetch your pot.” Grumbling she shuffled off.

The knight sorted through the wood and found pieces enough not rotted to make a small fire. He knelt and carefully flinted it to life. The old woman returned with a fairly large pot of obvious heritage, but serviceable.

“Let’s fill it perhaps half.” He knelt to ladle the well water into the pot, and carefully positioned it over the fire just beginning to blaze.

“And what’s to go in it?” queried the old woman.

Just then, a thin lad of about fourteen joined them. “What’s doing here Auntie?”

“This stranger is set to make soup. Said he’ll share with us.” replied the old woman.

The knight carefully drew his bag to him and oh so gently withdrew a small bag made of purple velvet from the sack. Carefully, he opened the drawstring and extracted a small smooth stone somewhat lesser in size than a closed child’s fist. He very ceremoniously lowered it over the simmering water and dropped it in.

Carefully, he withdrew a second stone from the sack, and again carefully lowered it over the pot dropping it carefully to the bottom through the simmering water.

“Have you a stir?” the knight inquired.

The lad volunteered “We’ve a ladling spoon in our kitchen. Shall I fetch it?”

“Capitol idea my lad. A large spoon would be ideal. This soup requires a bit of a stir to extract the savor.”

The lad trotted off to his house to fetch the spoon.

“What’s this? Are you daft? You intend to have us eat of a soup made of two stones?”

Casting his eyes down, the soldier sighed. “ I said it was meager enough. But it’s filling and we learned to eat this poor soup at the battles. Hardly a king’s feast, but it will have to do for this day. And I’ll gladly share it with you.”

“Harrumph” growled the old woman. “Stone soup indeed. That IS mighty poor fare. I’m thinking you’ll have little off your hunger with that. And thin. With what flavor at that? And what to gnaw? You’re a poor cook Sire.”
“Perhaps. But I’ve done it enough and I’ll note it does for what it does.”

The lad returned with the spoon. “I’ve found it. A spoon to stir a pot for a king!”

“Aye and a handsome spoon it is lad.” The knight knelt and very carefully stirred the pot with a practiced circular motion.

The boy peered down into the now bubbling water at the two stones in the bottom of the pot. “What nature of stone is this that makes soup?”

“They are quite rare really. Mind you it’s not a mutton stew. But enough to live and quell the pangs. Given me by a ranking knight just before he was slain.”

“For heaven’s sake” cried the old crone. You canna make soup from two rocks I tell you.”

“I fear I have, and perhaps too many times dear mother. I didn’t claim you a royal feast.”

The knight again knelt and drew the now steaming liquid into the spoon and carefully raised it to his lips. “Not as bad as some. I’ve had better. But this will do.” he noted analytically.

“Give me that spoon you idiot. What flavor can a soup made of stones have.” The old woman slurped the hot liquid loudly. “Bah, it has no flavor at all. You know nothing of cooking. This thing hasn’t even the flavor of salt.”

Looking dejected the knight noted. “True enough old woman. It IS much better with salt. But I’ve none.”

“You’re a moron spluttered the old woman. Here, for Christ’s sake. I’ll fetch some salt. How do you think I’m to eat such a thin poor soup without even salt.” Stalking off toward her hut, the woman muttered the whole way. Encountering the town mayor. “He thinks to make us soup! The man hasn’t even salt.”

“Soup?” cried the mayor. “Whose making soup?”

“The stranger in the square there. A poor soldier at that.”

The mayor immediately trotted over to join the lad and the knight at the fire. “What say, you? There is to be a soup? And in these hard times?”

“Stone soup!” piped up the lad. “A BIG pot of stone soup. Needs a pinch of salt but coming along.”

“My word” considered the mayor. “A soup, made of stones?

“Alas, your excellency. It’s what we have. Good enough, I’ll warrant. But for my own tastes, better when a bit of cabbage is in season. It seems cabbage grants it that certain dear flavor of my mother’s soup when I was a lad like this one. Reminds me of home.”

One by one the other villagers trickled over to see what was about.

“Cabbage. I myself like cabbage in my soup. “

“It needn’t be much. And it needn’t be good. In a soup, even a bit of rotting cabbage can take on quite a life of its own.” offered the knight.

“Well I haven’t much. But perhaps there’s a bit of cabbage in my larder. Let me check it.” Off went the mayor.

Just then the old woman returned with a small paper of salt. “Here soldier. If you’re to make soup out of common stones, it should HAVE salt.” she proclaimed emphatically as she dumped the small portion of salt into the water. “Give me that spoon.”

She knelt and swirled the water expertly drawing forth a bit and slurping it loudly. “At least it now tastes salt, as a soup should.”

A thin elderly man stepped forward and peered into the pot. “You say, you’ll share?”

“It’s poor enough. But yes old father. You can join us to dine this night.” Responded the knight.

“He says he’ll share.” Trembled the old man to the woman next. “Me, I’m not so fond of cabbage myself. I like carrots in my stew. I might have A carrot to pitch. I’ll get it”

The suspiciously portly woman noted. “You really cannot bring the flavor of a proper soup out without an onion. I don’t have a whole one. But some shreds to fling. It’ll brighten it quite a bit I think.”


“Aye. And you have to pitch to eat I’ll warrant” noted the stablemaster cynically.

“Not at all mate. We have little in this thin soup. But I know times are hard and you’re welcome to what we have here.” replied the knight. “If you have naught, then naught it is.”

“I didn’t say I had naught. What you must think of me. You twist my own words. Did I say I had naught? It’s a cold time sure enough. But I’m not without entirely. Criminy a few mealy potatoes can be spared. That will offer some body to this thin soup.”

And so the cabbage and the carrot and the onion shreds were added to the pot. And in a short while, potatoes too. The roiling water swirled and scent began to rise from the pot and waft throughout the village.

One by one the villagers crept out into the street with lit pitch torches and the area around the well brightened. “What’s that smell?” exclaimed one.

“It’s stone soup. They’ve made a soup of stones.” Answered another.

“ A soup. Of stones?”

“It is. Smells wonderful. I’m starving here.”

“When will it be done?” yet another.

And again a reply “It’s soup. It’ll be done when it’s done don’t you know.”

The knight bent over the bubbling pot and inhaled deeply. “Ahh. How I long for the days when there was meat aplenty for a fine soup as this.”

“Meat? You must be joking. We’ve had no meat for a moon.” offered a young monk.

“I say. True enough. But a poor old piece of salt pork I’ve kept by and by.” Offered another. “It’s a rind really. And it won’t make a meal for a mouse anyway. I just keep it to look at.”

“I’ve a scrap as well. It’s true not anything to brag on. But it’ll chew.” Offered yet again.

And so into the pot it went. And soon everyone was scrabbling about the village, scouring a pepper here and a mushroom there.

As the torches gathered the night village square took on a lighted cheerful countenance. And someone brought out a fiddle and began to play. Soon there was music and a bit of dancing started.

“Is it soup yet?” and again, “When shall we eat of the soup. The smell is driving me faint.”

Finally the knight ceremoniously tasted the soup with a hundred pairs of eyes watching his every move. Nodding he offered the spoon to the old crone, who nodded with sage approval, having a good claim on very nearly inventing the soup. “It’s fair enough soup, if I do say so. It’ll do right enough on this chill evening.” noted the crone with all due modesty.

The knight carefully fished out the two stones and slowly wiped them dry, carefully placing them back in their velvet bag. “Not to break anyone’s teeth.” to howls of laughter. “Bring your bowls then.” Instructed the knight. “There’s aplenty for all.

And indeed, everyone in the village ate their fill that good winter night.

After everyone was safely asleep and sated, a small group of villagers crept into the loft where the knight lay, and quietly slit his throat and removed the velvet bag.

In the morning, the Mayor thanked everyone for participating in their long developed plan for the first annual stone soup celebration and assured everyone of regular stone soup days in the future.

The grocer ran a special on “stone soup fixins and garnish,” in full compliance with their original “stone soup recipe.”

The butcher too announced that they had special packages of “stone soup” meat cuttings designed to the original specification and traceable back to the exact first stone soup.

The village pharmacist sold salt at two prices henceforth, regular common salt and premium stone soup savory salt.

The blacksmith, under license of the city, would make a sterling silver “stone soup pot and ladle” for anyone wealthy enough to afford it, and of course having the stone soup license.

And the village passed an ordinance severely restricting the ownership of stones of all sizes, and of course requiring that soup be made only of official village approved stones, to prevent any contamination or ill health effects, for the safety and welfare of the villagers. Thus serving as a barrier to random illegal stone soup operations.

A special sherriff’s detail was established to ensure compliance with the stone soup regulations and a standing stone soup court was established to hear cases of stone soup malfeasance. Plaintiff’s and defendants were required to be represented by a qualified stone soup barrister.

And they all lived happily ever after… in the area that came to be know as the land of the stoned. Unlicensed import or export of stones into our out of this area was severely punished.

And travelling soldiers were outlawed entirely.

Follow the Yellow Brick Road

This week we try to catch up a bit on the eCobra project, which I would like to finish sometime in THIS life. This car has been a struggle.

The bad news is it has just featured some really difficult geometry to fit in a 41 kWh battery pack in a small two-seat sports car. I'm very pleased with the power plant. The Netgain Warp 11HV and the Netgain Controls Industrial controller are very strong in this 3000 lb monster. We haven't done any performance testing yet, but I can already tell you the performance will be very strong.

This week we tie up some cooling system issues and some instrumentation. And most of all wire in our Elcon 5000w charger.

The Elcon has emerged as the default charger by virtue of its power and price. It is NOT fully configurable and that poses some problems and the guys selling them have just enough information to be dangerous about the charger and are actually doing some damage out there to cars. Their cocommittant desire to sell battery management systems with them being part of the problem.

We need the Elcon's 5000 watts because we have a 41 kWh battery pack. At full power from 240 vac, this would still take about 8 1/2 hours for a full charge. So we can't really use a smaller charger. And this unit is physically BIG. By lifting the body almost off the car, we managed to squeeze it into the rear trunk area right behind the roll bar.

We also wired it into our J1772 connector and the little AC31 board David Kerzel of ModularEVPower provided. Given the mirroring of the proximity switch pin and the copilot signal pin between the plug and the socket, I can NEVER get them right. Sure enough, I had them swapped in our install and it would not charge. Swapping the wires on the little circuit board solved the problem. The car now charges quite well on the Clipper Creek EVSE we had installed for such testing. Our eCobra should charge smartly from any available SAEJ1772-2010 EVSE.

I prefer fully configurable chargers such as the Brusa, which you can easily change everything about the charge process including the stages, currents, voltages, rest times, etc. But a Brusa is close to $4000 now and this project would have required TWO of them. Eight grand for a charging system seems a little bit much since my first car I drove at age 16 cost me $60 cash money hard come by.

The Elcon at $1695 from Evolve Electrics just seems a better buy. But you have to specify voltage and charge curve algorithm. We've had a lot of questions about these charge curves. In this episode, I talk a bit about why we use curve 502 and how you can add a little bit of "configurability" by having 10 charge curve voltages stored in memory.

Here's an image of the 500 series algorithms they ask you to choose from. We picked 502.

The document basically describes a very simple charge curve, which works well for these cells. Basically, you pump all the current you can into the pack, until it reaches a certain voltage. You then HOLD that voltage by ADJUSTING the current, until the amount of current needed to maintain that voltage diminishes to some set value.

The spec on most of the Thundersky and CALB and Sinopoly cells actually does call out this value - 0.05C. This is 5% of the rated capacity in amps. So a 180 AH pack would cutoff at 9 amperes.

This is not one of the choices. But AH/30 seems to be. Since we are at 180 AH, that would be 180/30 or 6 amperes.

With 69 two-cell pairs, we are looking at a charge VOLTAGE of 251.85 volts. AGAIN and I repeat for the 40th time, this charge voltage has almost nothing to do with the fully charged voltage of the cell, which in all cases will be something less than 3.4 volts if you are indeed using LiFePo4 cells. It is part of a PROCEDURE to get you to that fully charged state. We use 3.65v rather arbitrarily. The original spec on these cells was 4.2v. Then it was lowered to 4.0v. I think it is now 3.8v. It doesn't matter, we developed our OWN procedure that seems to work better. I feel ever more validated as the MANUFACTURERs' procedure is clearly dropping a couple of tenths of volts per quarter as we go along.

In any event, the terminating CURRENT is an important part of this procedure. You do not WANT to keep putting energy into the cell past this point. With 502, we actually ARE overcharging the cell. But since we used 3.65v to UNDERCHARGE the cell, it all works out.

The proof is of course in the pudding. Twelve hours after charging, we are seeing a pack voltage of 230.4v. This works out to a cell average of 3.34 volts - exactly where I like to see it. 3.35 would be good too. But with this many cells, I actually feel better at 3.34.

One thing stressed in the video is to actually observe and measure the end of charge activity before entrusting your pack to ANY charger. This is kind of important - under the rubric that in any product shit happens. You don't want it to happen TO your expensive batteries. So its worth the time to go through the process with the charger a couple of times to make sure it is doing as you THOUGHT you had it configured to do.

In this case, instead of charging to 251.85 volts we actually hit a peak briefly at 253.4 volts. But it settled down quickly to right at 253 volts and maintained that very nicely. The current tapered quickly since we are charging at a low percentage of capacity. We were seeing about 22 amps IN to the pack from this charger and it appeared to be a very nice 95% efficient comparing the current into the cells with the current from the wall AC. I was quite surprised by that.

The current tapered nicely and the voltage was pretty steady, minor wandering in the 0.2-0.4 v range. As the current decreased from 22 amps down to six amps, the charger terminated abruptly at an indicated 6.2 amps. This is actually very good.

Bottom line is that bang for buck, this is an excellent charger operationally. It is a bit of a pain to order and configure. But once installed it works well and is quite powerful for the price.

We also discuss in this week's video the announcement pending from EVnetics of a monster controller they are calling SHIVA. This controller will crank 3000 amps peak and 2500 amps continuous using EIGHT 600 ampere IGBTS. It is pricey at $7500 and they are only going to make 25 of them initially. But it promises to become the immediate darling of the drag race community. It probably has little application in a general electric vehicle UNLESS you happen to be doing a Cadillac Elescalade with twin 11 inch motors. In that event, if you paralleled the connection to the motors and backed it up with some 400 Ah cells, you could probably do 1500 amps into each motor briefly and tear up transmissions all the way between here and Florida.

I think this going to be huge for EVnetics. That the vast majority of their sales will be Soliton Jrs is not the point. Everyone will know the upgrade path to the BIGGEST dc PWM chopper on the block. And I actually think they'll sell out of the 25 run quicker than they think. The Tim Allen/Tooltime riff on MORE POWER worked for that show and that comedian because he hit the nail on the head. Just because I don't USE all the power under the hood, doesn't mean I don't want it there. At $7500 it's just beyond the reach of most builds. But I would goess the drag racing community will waste no time neatening up their wiring with this little controller. As always, the package SEB does is just gorgeous.

The IGBT's have an interesting feature. They have internal temperature sensing. What this means is that the coder guy, Martin, can actually throttle this thing back very quickly and very accurately based on temperature. ANd what THAT means is the better you are at getting cooling glycol to this beast, the more power you can get out of it. The spec limitations are 4800 amps actually but they've got it cut back to 3000 amps. I don't know the voltage drop, but if it's a volt at 3000 amps you also have a 3000 watt heater. NoGiven the forward voltage drop on six IGBTs, that's still a lot of heat. But there's room there if you beg.... and don't mind blowing a $7500 controller every other race. it's all software...

We did talk a little bit about the Tesla party. What I didn't mention, but am looking into is the Tesla/Panasonic battery. March 2012 will be the first run of a new 18650 cell by Panasonic that is really quite a thing. It uses a couple of innovations. They call it their Nickel New Platform or NNP cell. It is actually a Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2) cathode with a 3.6v voltage and 3.4Ah in a single 18650 cell. This works out to 46 grams and 12.2 watt hours or 265 wH per kilogram. By contrast, our cells are about 106-109 wH per kilogram. That's how you get a 300 mile range.

Interestingly, they have even bigger plans for March 2013. At that point they will do a production run of the same cell, but they intend to replace the carbon anode with a silicon alloy anode. This will boost the Ah rating to a full 4.0 Ah in this cell.

As to cycle life, there's some bad news but then some good news. To the standard quoted 80% of the initial capacity, this little cell will only do 500-600 cycles. But if you can deal with 70% capacity, it will go to 2000 cycles. And so given the 265 wH per kilogram, build in a little extra capacity. It will be a MUCH improved package over the Tesla Roadster battery module. And it explains the Tesla 300 mile range claim.

I found it interesting to note that since acquiring Sanyo, Panasonic may be the world's largest Lithium battery supplier. But it is also interesting to note that they are building factories to produce all this in CHINA. In fact, due to the strength of the Yen, they've dramatically cut back plans on a new factory in Japan.

Bottom line, the cell march goes on. Our 80 mile cars will soon be in the 250 mile range (really). But it will cost you. And of course, all roads lead to China.

Regards;

Jack Rickard