Of Sprites and Cobras and Meetings in the Fall

Pretty good show this week. Fred Behning of Austin sent us a nice video walkaround of his still in progress conversion of a 1960 Bug-Eye Sprite in all it's blazing yellow glory. This is the kind of upscale quality build of a much loved classic that I am so fond of. For my money, he has enough motor, controller, and batteries in this thing for about 2 1/2 Sprites. But I think it will go Spritely once completed.

It is coming to light that my prediction of a blood bath for General Motors and for Nissan was prescient. Neither are selling in anywhere near the numbers they had hoped. Both companies are spinning this heroically by the day as the truth becomes apparent to all. General Motors particularly simply readjusts reality in print - it has reached the level of absurd.

My take is that the value proposition on economical electric cars cannot be made, and so we should focus on high end cars that appeal to early adopters. But I've been aware all along that there is a latent desire/demand from those already in the green and electric camp for a viable option. My predication is based on the fact that once that demand is met, THEN who do you sell them to. And just how large a group is this vocal but probably small band.

What I didn't count on was the fact that our viewers are actually the band. Fred Behning awaits delivery of his Leaf. Peter McWade already has his. And a dozen other viewers are in some form or fashion awaiting one of these cars. More so the Leaf than the Volt. Though recall the recent fire of a Volt in a garage - fixing blame was complicated by the fact that he also had a converted Suzuki in the garage at the time.

WE may be the market for these cars. Unfortunately, there is probably not enough WE in WE. But again, gradually as you demonstrate the advantages of electric cars, this will take hold beyond what you realize. You have an impact daily.

Meanwhile, we are in the throes of a fistfight with a Cobra replica. I was initially amazed at how much room I had for batteries. I'm now a little bewildered by how little. The choice of the 11HV leads us to higher voltages, but we still want to be able to make very high currents as well. We've run smack up against the very old and oft quoted EV maxim: You can have range, speed, or price. Pick any two.

In this case, we want range and speed. And the restrictions of gravity and force and inertia are wreaking havoc on my ambitions. But in a way, this project kind of "lets the dog out" in me. We're going to find where it goes. But as usual, battery layout and placement are 90% of the project. Drive train being another 90% and of course wiring and instrumentation represent the final 90%. Due to rounding errors, this may not add up to exactly 100%.


We've decided on Thundersky 90Ah cells for our project. And therein lies a tale. We have the THundersky's in hand but there have been some developments that are a bit soap opera-ish. Winston Chung Hing Ka of course founded Thundersky and developed the originally battery himself. I relocated my battery lab this weekend and am doing some testing now that reminds me how much I admire this cell chemistry. It is just incredible in so many ways.

Apparently there was at some point an IPO at Thundersky because it is traded on the Hong Kong Exchange HKG:0729. This of course leads to disclosure, like the US. The company posted a loss of HK$1.06 billion on sales of HK$69.43 million for the six months ended September 30, 2010. When you factor out the exchange rates, one of the interesting things about the company is a total of less than $10 million USD sales for that period This was up dramatically from $1 million in the same period of 2009. And that brings us to a startling revelation. We are the entire market for these batteries. At $10 million, that's about enough batteries for 1000 very basic car conversions. At $1 million a year earlier, about a 100. I've suspected this for some time. YOU are the market for these cells. All allusions to big projects and OEMs is pure grade B refined bullshit.


Prior to February 22nd, Chung held 79.25% of the stock - an exceptionally high amount of equity in a publicly traded company here in the U.S. He sold about 30 million shares on February 22 and 23rd, 50 million shares on April 29, and 910 million shares on May 3, dropping his ownership to 43%. The majority investors subsequently fired him and have filed a lawsuit over 15 patents it claims it holds through a subsidiary purchased the previous May in 2010.

Meanwhile, Chung used the proceeds to launch Winston Battery Company Ltd., and acquired 48% of Balqon.

Thundersky is facing huge losses in 2011, as Chung apparently took most of the sales with him as well. Thundersky has renamed itself the Sinopoly Battery Company.

Now one of the interesting things about THAT is that one of the factories retained by Sinopoly makes the 200Ah Thundersky cell - not the new Yttrium cell apparently but the earlier LiFePo4 cell. And one of the interesting things about THAT is it is in the 71mm format that previously had been 160Ah cells - and at the same weight of 5.6kg. So in this one specific size and weight, we have the TS-160Ah, the CALB 180Ah, and the TS-200Ah cell.

We had tested these cells last year and they performed very well. So well that we PURCHASED 40 of them from James Morrison/David Kois. They kept the money, and never sent the cells. So we've never really been able to use them. After a year of wrangling, the lawsuit was settled and some recovery of inventory was made from Morrison - estimated at 59% of what the group had purchased. The 200Ah cells were among them, but not a sufficient number for the guys who ordered cells to actually receive them.

Now Sinopoly is apparently offering them - Meanwhile, we're assured by Winston that they do NOT offer this cell.

In any event, that's not the cell we've selected for the Cobra. We're using the 90Ah cell which has been reduced somewhat in physical size. And we've decided that we need 180Ah in order to do 1000 amps and beyond. So we're doing something I've wanted to do for some time = pairing smaller cells to get larger Ah capacities.

Recall that cells vary somewhat in capacity and you would have an easier time with your pack if all cells were the same capacity. In truth, there is no such thing as "cell drift" with these cells because they do not have any internal discharge. But they do vary in capacity. And you are only as long as your shortest cell.

By pairing cells, we could balance all this out. We would naturally want to pair the largest cell (say 94 AH) with the smallest cell (say 89AH), for a total of 183Ah. We would then match the NEXT largest cell with the NEXT smallest cell, and so forth. In this way, the variance between cells is drastically reduced.

That would require us to know the capacity of each individual cell. I wish they came marked. To actually test each cell would require months of effort. But we get some of the effect by just randomly pairing them.

For future reference, this technique works with two cells, works better with three cells, works better yet with four cells, etc. After about 10 cells, it is really subject to the law of diminishing returns. It doesn't improve much after that. We have plans for this bit of knowledge.

But for now, we are going to pair the cells to get what amelioration we can from the capacity difference problem. The problem then becomes, to get 240v, which is what I would like to have for the 11HV, requires 144 cells. 72x 3.35 = 241.2v. This would give us a pack of 43,416 watt-Hours. At about 280 watts per mile, this would give us a max range of 155 miles. But even in this smaller and therefore more granular form factor, 144 cells is a LOT of cells. The most we've done has been the Mini Cooper with 112.

In the video, we also introduce the concept of watts per pound. We have Speedster Redux to thank there. We know we sagged about 22% to 147 volts at 1000 amps using 180 Ah cells. This works out to an input power of 66 watts per pound of the 2385 lbs of Speester weight resulting. The Cobra is going to be a heavier car, perhaps 2800 lbs. And so we would need a 215 volt pack to maintain the same power to weight ratio and so the same 6.5 second 0-60 time. And so I view 215 volts as the minimum and 240 volts the maximum we could get into the car.

As to performance, we do have a couple of kickers in the foot locker to put into play. First, our transmission is FIVE speeds instead of four. We're going to go to a 4.11 limited slip differential on this beauty which should bring it clawing and scratching up out of the hole in fairly persuasive fashion.

And one of the reasons we can do this is that I think the 11HV at the higher voltage will let us move our peak power point out from 3200 rpm - perhaps out as much as 4000 rpm.

Finally, we are looking at controllers that do signficantly MORE than 1000 amperes for a top end.

When we put all that together, I'm starting to get enthusiastic about this car. Brain says the mission with Cobra's is pretty simple: the cars you see in the rear view mirror should always be shrinking in size at an impressive rate. I think we can do that. But it will be interesting to see what we blow up along the way.

Jack Rickard