Over the Top Porsche 356 Speedster Redux

We’re getting a little carried away here. The addition of Matthew Hauber to the team has given us some mechanical expertise we’ve just never really had before. And that has given us some opportunities – not on anything particularly magical, but on very ordinary physical things.

They count.

As we became accustomed to Speedster Part Duh, I have to tell you I’ve grown very fond of these Speedsters. It goes quite beyond the electric car thing, although obviously enmeshed with it. But we did a lot better job on Part Duh and it is just in all ways a more elegant car.

But my first love is the Corvette Tri-coat red Speedster with the Coker whitewalls. It just really feels good to drive.

Reminds me of Obama’s campaign speech. “My friends and neighbors, we are privileged to live in the greatest country in the history of the world. With your help, we together CAN change it!”

The original Speedster looks a little…..well….home made. We had a garrish assemblage of TWO strings of 90AH Thundersky cells with cells actually piled on top of cells in the back. Of course, the original Speedster only had TWO useful gears, third and fourth. First and second were just useless. We learned on Duh to change to the 3.44 R&P and suddenly all four gears made sense and looked like someone had done them on purpose.

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The wiring kind of goes every which direction. We never did document that TOO well so we’re not particularly certain what any one specific wire DOES and some of them no longer do anything.

So we started talking about what we would do to spruce it up. Unfortunately, the heart of the car is the transmission, everything pretty much bolts onto that. And that was the most obvious improvement.

To change it, we have to remove ALL the batteries, the motor, and a lot of the wiring. So we might as well redo the thing. We have a couple of the NEW Netgain motors. They have larger terminals, stouter brushes, and an improved internal fan design. So what sense does it make to remove the motor and put the old one back on with a better one laying on the floor next to the car?

And as long as we’re doing that, we DID kind of design a new motor adapter that is lighter and much less bulky than the Canadian EV unit we had used on the first round. Cape Precision Machine now makes them for us, so it’s a phone call and a little under $800.

The original Speedster featured a Kelley 1400 amp controller. Kelley showed great promise two years ago with some innovative designs at a very low price. They never quite lived up to their specs, and it is very unlikely we ever saw 1400 amps – in fact, about 550 battery amps was the highest I had seen.

In the meantime, several people have had bad experiences with them – largely by blowing the input caps with clumsy maintenance procedures. But they’ve developed a bit of a bad reputation fairly or unfairly, and have gradually just faded from the scene. You rarely hear anyone propose a Kelly any more. They’re just not a player in this market any longer.

Ours WOULD occasionally and rather mysteriously “kick out” – simply go limp. You can turn the ignition off and back on on this car to reset it and you can do this rolling down the road – so it wasn’t a big deal. And it didn’t happen often. But it was annoying.

EVnetics is sponsoring our contest and indeed we had already ordered and received two of their Soliton1 controllers for our Escalade project (STILL waiting on Jim Husted). This controller purports to do 340volts and 1000 amps. That’s a LOT of power. But the case design is fabulous, it’s water cooled, and appears to be a mate for the Netgain Warp 9. What if we tried one of those?

The Curtis 1238 is hard limited to 130 volts and we have been careful to stay more on the 120v side of all of that. But the Soliton1 doesn’t have this restriction. We can have as high a voltage as we can string cells. Of course, the Netgain is still a commutator motor with brushes and they arc on higher voltages. The “book” on this motor has always been keep it at 170v or below. With the new brush design, the BRUSH vendor claims it can do 192v with NO arcing. George Hamstra doesn’t really want to sign up to that, because he hasn’t tested it. But the brush vendor undoubtedly has reason to believe. In any event, I wouldn’t exceed 200v with this motor.

I confess I like the CALB cells. It’s a close call. The Thundersky Yttrium cells probably DO have a longer life. ANd they are slightly less expensive. But I’ve always marvelled at the flat discharge curve of the CALB’s and have been further impressed at how closely matched the cells are that we receive. I actually had designs on the fairly rare 200 AH cells Thundersky was selling for awhile in EXACTLY the same form factor as their 160AH cells and the CALB 180AH cells. I actually bought 40 of them. That was the James Morrison fiasco and the cells are currently locked in a storage unit in Issaquah Washington while the lawyers wrangle over all that. If it’s finally settled, I’ll probably get to pay for them AGAIN to actually get them.

So we decided to use CALB 180’s for the Speedster.

I’ve actually designed two aluminum “belly pans” to fit underneath the seats between existing cross members and bolt to them. One pan is about 12.5 inches wide and the other a little over 9 inches. They will run the width of the car. This will allow about 11 cells to lay flat underneath the car in a very advantageous position – very low center of gravity and very central polar moment.

The cost is clearance. We have about an inch and a half recess between the crossmembers. The cells are just under 3 inches thick. And we do have to have some material in the game (0.80 aluminum). But it shouldn’t be too bad really.

In Part Duh, we managed 16 CALB 180 cells in the very front of the car, down very low, in a box built by Special Editions. It was a bit of a squeeze as they gimped me a 1/4 inch on the box size. BUt we got them shoehorned in there.

And so I tasked young Hauber and the Brain with devising a similar box for the original Speedster.

They did well. We actually wound up with an aluminum box hanging from the frame that holds the front bumper to the car – very sturdy – with three layers of 0.63 diamond plate interleaved on the bottom. But amazingly, by cutting out a bit more fiberglass and expanding our concept a bit, they manage EIGHTEEN cells instead of sixteen.

THIS week, (after the video was shot) we took on the rear battery boxes. 10 cells on each side of the motor. Again the Hauber/Noto team scored – 11 cells on the small side. We haven’t even done the other side yet.

All this starts to come together with 18 in the front, 22 in the back, and 11 underneath for a 51 cell 171v pack of over 30kWh. The original Speedster has actually driven 110 miles on a single charge with essentially 36 x 180. This implies a theoretical max of 155 miles.

Note that’s NOT safe range – that’s running them OUT. And of course, we have additional weight to consider from the cells themselves. Then too, with additional power available, it would be unlike me not to use some of it occasionally.

But no doubt we wind up with a SAFE range of well OVER 100 miles and potentially 120.

As to acceleration, that remains to be seen. The car will be over 200 lbs heavier. And we’ve never used a Soliton1 before. IF it can actually do 1000 amps from these 180AH cells, at 171 volts, and let’s say that sags to 150, that’s a 150 kW power level – not quite TRIPLE what we have in Part Duh and right at 201 horsepower if that number makes more sense to you.

I think we dyno’d 73 HP in this car with the Kelly. And I found the acceleration more than adequate then.

And so I’m really in this for the range and the exercise at squeezing batteries into this car – how far can it be pushed. But I think with the SOliton1 and a 170v pack instead of 120v, we are potentially looking at a beastie in the performance area as well.

Stay with us.

Jack Rickard


12 thoughts on “Over the Top Porsche 356 Speedster Redux”

  1. Jack,
    I am eager to see what the new and improved Speedster will do with the upgrades. Do you have any estimates on what the curb weight will be once completed? Also, what kind of 0-60mph times did you get with the original setup (73 hp)?
    Great work.

  2. You brought up an interesting point Martin.
    At least one of his speedster’s was better accelerating through the full range than the manufacturers standard.

    I wonder if Jack would like to put up a “wall” of useful conversion numbers and results for easy reference?

    There was watt/miles range and power/weight?

    Performance changes of his cars before and after.
    Idea’s and improvements and alterations.
    I can see a technical build bible coming on here *wink*.

    On Jacks Clocks, I thought a live graph display of battery load against speed. Load (V*A) being the vertical log scale. This way, one can clearly see what is economical. Drawn against the likes of UQM’s motor controller efficiency graphs it should be most impressive.

  3. That’s odd that you would use 51 cells. Thanks to your testing and reporting, I just ordered 51 Calb 200Ah cells, one for a spare. Then I got to thinking about adding it to the string for a couple more miles in my S10.

    I’m running a 9″ Advanced FB1 stock and am sort of nervous about running that much pack voltage with a stock Curtis 1231C that I can’t limit the max V on the motor. Any input on that high a voltage on my stock motor Jack?

    I’m so friggin excited about getting the lead out I can’t stand it!

  4. WT:

    I have not really tested or even examined an Advanced FB1 motor. I just can’t say. With the Netgain 9 inch, the brushes and commutator really were always good for 170v max. Their new model has a new composite brush structure that the BRUSH manufacturer claims will be good to 192v. We’ll be at a nominal fully charged pack voltage of 171. So I think we’re good to go all around. At any significant current, we’ll never exceed 170.

    We’re using 51 cells because it looks like all we can get in the car are 51. If I figure out a way to put in another one, we’ll be at 52.

    If you are accustomed to lead, you have a bit of learning curve, but it will be a delightful one. These cells are so far out from lead that in my point of view, they finally make an electric car actually viable – for the first time. If you’ve been S-10ing on lead, you’ll be riding around in an S-33 now.

    Jack Rickard

  5. Martin:

    The original Speedster was in the 11 second range. Felt good, but nothing impressive. As you recall, we published full dyno data on both Speedsters some episodes back. When we get this one done, we’ll probably go over to Vienna to run on the same Dyno. So it should be pretty easy to compare.

    We were at 2190 pounds on the original Speedster if I recall correctly. I think we’ll be adding right at 225 lbs to that. But we should wind up with a full 30 kWh pack and the ability to put 150kw to the road in a pinch. In addition to the larger number of cells, we’ll be putting in a heavier controller, and a glycol cooling system. About all we lose is the contactor box and two fairly light battery boxes. So the car will be heavier.

    Naturally, we’re hoping for better acceleration and more range.


  6. WT , The limiting factors for increasing battery voltage are capacitor ripple in the controller and commutation in the motor. Typically a 144v controller will use 200v bus caps. Maybe 250v if your lucky. That does not mean you can run a pack that high due to the ripple voltage that the caps will see during operation and the fully charged pack voltage.

    Commutation is more difficult to predict and depends largely on motor design and brush advance. The simplist thing to do is observe the comm during a test drive with a video camera in the engine bay. Ease up the voltage and retest. At the first sign of streamers on the comm back off. This of course assumes that the winding insulation etc can tolerate the higher potential. Every motor is different. In my case I have an 11″ forklift motor rated at 72v now running with 12 degrees advance at 120v with no problems. This is going up to 153v with lithium in the next few weeks…….

  7. THe drop in Tesla? Well, full disclosure, I’m about a million into Tesla at the moment, kind of in and out, but whatever. So I’m a little shy of unbiased.

    I am particularly taken with this company. I have followed technology companies for a very long time, and there is a lot to recommend this one. I think the investment community has seriously underestimated Mr. Musk et al and particularlly et al.

    Tesla had an IPO last June. During an initial public offering, the current shareholders get converted to the common stock, but they usually must agree to a “lockup” period. In this way, shares can be sold to the public, without fear that the large shareholders will “dump” their stock and drive the price down right after the public has bought the newly issued shares. Typically, this is 180 days but sometimes it is actually staged.

    The lockup expired Monday, and the shares did drop about 17%. What is newsworthy here is that they didn’t drop any more, and indeed I was buying all December.

    Why? Part of it is religious fervor. The employees and investors in Tesla rather believe in the concept and the company. Rather than cash out, THEY think it will go higher yet, potentially much higher. A few of the vulture capitalists did dump some shares, but not many.

    Anticipating all this, a LOT of investors not particularly well versed in the company, assumed it would go much as ENERDEL and A123 and others in the space have gone and would drop from $17-20 down to $5 after the unlock. By selling the shares SHORT at $30, they hope to cover by buying them back at $5, and pocket a nifty $25 per share on the transaction.

    I like Musk’s vision. I like everything about the S model. But most importantly, he is doing a superb job hiring people. An excellent example of this would be George Blankenship to head up the Tesla Retail Store concept, which most people in the automotive world don’t quite understand at this point. ANd woe to those who don’t.

    George did Apple’s stores. And now he’s a fervent TEsloid. One of an increasing number of very talented people, who have “bought in” to the Tesla concept and drank fully of the fount of Tesla KoolAid.

    Their balance sheet pretty much doesn’t matter. Execution does but it doesn’t have to be precision, just executed. And I think they’re going to do it.

    Meanwhile, the price bust wasn’t much of a bust. It closed yesterday at $27.75 – up from the $25.50 where I bought back in after selling the week before at $32. I think it will wander and waiver for the next two weeks. But along the way, I think you’ll see the shorts (a huge 16.42% of the stock) start to get uneasy. Then a few will bail. And that will bring the price up some more. Last short out of the pool gets drowned. It shows all the makings of not just a short squeeze, but a short panic. If it goes, it will go hard.

    I’m thinking $325 will be a pretty good exit point all the way around.

    While you laugh, make a note of where you heard it first. The guys who knew me from Boardwatch won’t be laughing much methinks. Unfirst rodeo.

    Jack RIckard

  8. Jack, Brain, and Matt,
    Happy Holidays! Many thanks for all the work/play you do to further the EV cause. It’s been great to see various projects come together, come apart, and come together again. I’m especially impressed that you did a Friday show on Christmas Eve! Do you guys ever sleep? 🙂

    It must be a good feeling to see gas prices creep up and see the former Pres. of Chevron predicting $5/gallon by 2012.

    Hey, we’re getting pounded by snow here in CO right now, which means you got some nasty stuff headed your way. Have you guys driven any of the cars in the white stuff?


  9. Nice stock moves, Jack. My non-investing self completely concurs with your short-term view. I hadn’t considered were it might go in the long run but was somewhat surprised to see your bold $325 prediction. I certainly wouldn’t bet against you. You own more planes than I do. ^_^

    Thanks for the holiday show and best wishes for the New Year to you and your crew.

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