THE HOLY GRAIL – circa 2013 AC

Many thanks for your patience last week as I played a bit of hooky to attend my daughter Jacquelyn’s graduation from Colorado State University in Fort Collins Colorado. She received a bachelor’s degree in Journalism and Technical Communication – kind of a chip off the old block. She’s grown into a fine young woman of 24 years.

As a result, this week’s show kind of piled up on us. I cut about half and we are still at 2:41 minutes. Our record was 3 hours but this was still a long hard slog. I finally got it up Monday, for you all a holiday. No rest for the wicked.

Tesla is of course the big news. Their stock closed at $97 Friday and opened at $113 this morning. We are anxiously awaiting their Supercharger announcement, even though it was announced months aga. Perhaps in announcing it again it will get better. More than their car, this fast charge station deployment across the U.S. is actually the disruptive end of Tesla Motors in play. It could potentially devastate the plans of other automakers who will no doubt be left out of the party. That would indicate they can announce their own, and more effectively build their own. Nissan announces their own charging network monthly wiht fast charge stations at all their dealers across the country. Unfortunately, it would appear the dealers never get the word as they are not installing any such thing anywhere. But Nissan does keep announcing it.

This places BMW and General Motors in an interesting but unenviable position.

Although my personal use of electric cars is rather a local affair, and I think that is well and good unto itself. But fast charge enables cross country travel and removes one objection to electric vehicles rather effectively. My change in this came after the realization that virtually ALL the batteries in use can do this very well NOW. We need not wait for better batteries. The problem is getting a point of fueling that provides sufficient power to actually accomplish the feat. These little 25 kW and 50 kW “fast chargers” are nothing of the sort.

While I have waxed poetic on the concept of 500 convenience stores with Tesla superchargers and Ho’ho’s and Ding Dongs, in this episode I talk a bit about the possibility of battery module swapping being part of the announcement. This comes at an ironic time with BETTER PLACE announcing bankruptcy this week. But a 10 minute swap is feasible with the Model S, though not the Roadster of course. THAT would be pretty fast charging, but it is NOT the real import of such a move.

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Tesla has a bit of a problem looming with their battery packs. These packs are made up of 14 modules, each with 7 “blades” and each blade containing a variable number of cells but nominally 69 in an 85 kWh pack. Each cell is now over 3 AH and indeed the latest Panasonic boasts 3.4Ah per cell. And therein lies the rub. In riding the wave of consumer electronics cells with all the advantages of economies of scale, and being able to simply deploy the latest by substituting in the same form factor, pretty strong reasons to do this, there is a little wee difference between pocket flashlights and consumer electronics and the Tesla Model S.

Panasonic gets kudos and undoubtedly increased sales when they bump their energy density to 3.4 Ah per cell. They also get kudos for increased power density when they can then do 10 amps per cell. And of course they gain more sales every time the price goes down. But these cells offer relatively short cycle lives of 800 cycles or so. And no one in consumer electronics really cares. They are the type of cell you replace anyway. The 800 cycles is generous in that context. And no one would pay extra for a 1200 cycle version of the same cell. They undoubtedly WOULD pay a premium if they could get 4AH. Or 15 amps. But because they are both inexpensive and replaceable, nothing for cycle life.

Cars are a bit different. And California is kind of mandating a 10 year 100,000 mile warranty on vehicle battery packs. Can the Tesla Model S meet that? Dubious at best.

From their latest SEC form 10Q filing:

The range and power of our electric vehicles on a single charge declines over time which may negatively influence potential customers’ decisions whether to purchase our vehicles.
The range and power of our electric vehicles on a single charge declines principally as a function of usage, time and charging patterns as well as other factors. How a customer uses their Tesla vehicle, the frequency of recharging the battery pack at a low state of charge and the means of charging can result in additional deterioration of the battery pack’s ability to hold a charge over the long term. For example, we currently expect that our battery pack for the Tesla Roadster will retain approximately 60-65% of its ability to hold its initial charge after approximately 100,000 miles or seven years, which will result in a decrease to the vehicle’s initial range and power. Deterioration of the Model S battery pack is expected to be less than the Roadster; however, such battery pack deterioration and the related decrease in range and power may negatively influence potential customer decisions whether to purchase our vehicles, which may harm our ability to market and sell our vehicles.

Normally, capacity ratings are done to 80% of the initial capacity. That the Roadster could be down to 60-65% of capacity after 7 years would indicate huge warranty claims int the future for very expensive battery packs. The admonition that deterioration of the MOdel S battery pack might be less is more of a function of the Model S being younger and so we can rewrite this later than it is of any change to the cells themselves.

Elon has gone on the hook in an earlier announcement that he is personally guaranteeing resale better than the Mercedes and BMW models. What would happen to the residual value of these cars if it got out that their battery capacity could be as low as 60% after 7 years, with a battery pack price of $40,000 or so? I’m guessing the word DEPRECIATION would no longer be adequate. And so Tesla would face huge claims on this residual value, along with HUGE claims for warranty on the packs themselves. This could total staggering amounts of moolah in getting well.

Were that the total plan, I would view the sale of each Model S as a ticking financial time bomb. This is corporate bankruptcy disaster by engineering design. After punishing the short sellers, does Elon Musk have a secret plan to become one?

Hardly. Let’s take a look at another extract from the same 10Q document:

Other factors that may influence the adoption of alternative fuel vehicles, and specifically electric vehicles, include: …. our capability to rapidly swap out the Model S battery pack and the development of specialized public facilities to perform such swapping, which do not currently exist but which we plan to introduce in the near future;

Tesla’s Hair Club for Men. In doing a battery charging infrastructure announcement, I believe Tesla intends to introduce the concept of a battery swap club. Given that they’ve added a $600 per year fee just for software updates, it is no stretch of the imagination for them to introduce something, even as high as $200 to $300 per month, to join a club where you get unlimited battery swaps.

And that rather neatly ties up the whole battery life cycle problem. The modules can be rebuilt rather easily, more easily off the car. Not only rebuilt with current cells, but even upgraded when newer better cells become available. By having dozens or even hundreds of swap sites across the country, let’s say you do NOT opt in for the swap club and the additional expense. Seven years down the road, if you register a complaint with the company over failing capacity under warranty, the fix is not so terribly expensive. They send you a piece of PAPER allowing a one time swap at a nearby facility. Your pack just goes right into the natural flow of packs that are recharged and if not up to spec, rebuilt. This effectively reduces the cost of warranty claims to about nothing. They could probably even get away with prorating the warranty with full replacement for the first three years, and partial payments required for each year thereafter culminating in full price at 10 years.

With such an infrastructure and program in place, the depreciation is kind of back to normal vehicle depreciation. Indeed the life expectancy of an electric motor and single speed gear drive could be expected to be much greater than an ICE engine and as features are mostly software updates in these cars, you might expect LESS depreciation than normal.

So in celebration of Better Place’s bankruptcy, I rather expect battery swap to be the main surprise in this week’s supercharging network announcement.

We were invited for a test drive of the Model S at the new St. Louis service center. I took two cameras and cameramen but the results looked like the Blair Witch Project during an epileptic seizure and so you are not graced with the results.

I don’t know quite how to react to the test drive frankly. It was mixed. The vehicle is just drop dead gorgeous of course. They actually had six or eight vehicles on hand. A shiny black one with buff interior is virtually the color of my Escalade and I fell swain if not swoon over it on sight. It’s a very pretty car.

It IS as predicted a four door sedan, favored by Lutheran Ministers world wide. Not precisely my style. Worse, it was harder to crawl into than the Speedster 356 with a very low roofline. Inside, the seats were actually quite confortable and visiblity reasonably good – out the front. Not so good to the rear. As we were in an 85K Supersport package, with the 4 second 0-60 acceleration, I guess I was prepared to be astounded by the handlign and acceleration. I have to admit, I was not. It drove like a well powered electric car. But the FEELING was nothing extraordinary compared to the eCabra, the Speedster, or for that matter the Spyder. I have to assume that all the raving is from people who have just never driven an electric car. It was indeed the SAME feel for the most part. Nothing shocking nor notable. Very good of course. But nothing new or different for me. So a little disappointing I suppose.

In fairness, I did not accelerate 0 to 60. More like 0 to 50. I was instructed to do so, on a rainy St. Louis residential side street one block past a 20 mph school crossing. I just looked at the little girl giving us the test drive. Punched it up to about 45 and quickly glided through 50 all quite under control and assuming I would have perfect brakes. Which I did.

So I really have nothing to say AGAINST the car, it was in all respects great. The 17 inch screen was truly a marvel. But I walked away thinking $100K, and it is basically JUST an electric car. With the range, and with a nationwide network of charging stations, undoubtedly worth it. But a car nonetheless. So a tiny, VERY tiny little bit of letdown. Like seeing a movie that everyone has told you would be great and your expectations got JUST a little bit out there past what a movie can do.

On the other hand, I got a little bit of lift as to how we’re doing with OUR builds and how the many viewers are doing with THEIR builds. If you cannot afford a Model S, even after the stock runup. Fear not. For a lot less, you can have most of that feeling, without a 17 inch screen.

A few years ago, a viewer approached us with a build already underway and stopped by to show us the battery boxes he was building for his S10 pickup – wherein he planned some excellent Optima lead batteries. I simply berated him mercilessly until he finally sent $16,000 to James Morrison in Washington for a set of CALB SE180 cells. They were never delivered. And the poor guy was tapped for ANOTHER five or six thousand in legal fees before recovering about $400 total from the “lawsuit” so clownishly handled by some of the other victims. He did purchase some cells AGAIN from US more recently and in fact his truck won BEST BUILD at EVCCON 2012 and now he’s a bit of a celebrity up in St. Louis showing off the vehicle at every opportunity.

But I’ve always felt badly about the expense this fraud cost this retired guy. We’ve been predicting a short squeeze on Tesla stock for OVER TWO YEARS at EVTV. It was most gratifying when he stopped by last week to note that he HAD been watching, and that I was not to worry any longer about the lost battery money. He’d more than made it back. Good on ya Dale Friedhoff.

No, we are not going to rename our show TESLA TV. In fact, I was very excited this week but not really about Tesla. More so about High Performance Electric Vehicles.

I’ve always liked this company and this product. We have done a lot of builds using their AC-50 motor with the Curtis 1238 three phase controller. It offered a 75 kilowatt AC induction motor solution with regenerative braking and a fairly easy to setup controller that was actually very “tunable” to dial in the “feel” of your car in a way that most controllers simply cannot achieve. They work. They drive the car fine. But with the HPEVS system we were really able to make small changes that made SMALL corrections in vehicle control feel. And the motor, dispite lacking liquid cooling, always ran cool. No brushes. No dust. And it was smaller – about 8 inches in diameter. It was just a great little package for anything under 2500 lbs.

The Curtis 1238 controller is nominally 108Votls which is kind of limiting. The 7601 version bumped power up to 650 amps which was welcome. But it was still kind of a weeny AC solution – though also very reasonably priced. A great value for the money. We quickly discovered you could ACTUALLY run it up to about 120vdc without complaints for a smooth 120vX650a or 78 kiloWatts.

Bill Richie, of HPEVS had been teasing us with tales of a new 144volt model that was coming for now TWO YEARS. Every time I asked he told me they were about a month and a half away from being available. Apparently, that’s what Curtis had told HIM. But the months turned into years and I had frankly given up on it. Once word came out that the current was dropped to 500 amps from the 650 amps, I really lost interest. No gain in power and actually a LOSS in low end torque. We can do MPH with transmission gears. I like torque at the bottom.

Well the controller finally arrived last week. And all that time Curtis delayed, apparently HPEVS put into play. The result is an entire SERIES of differing motor windings in a new larger 9 inch frame designed to complement the controller abilities. Better, the Curtis controller always did feature a program written by Brian Seymour of HPEVS in the Curtis Vehicle Control Language or VCL. Concurrent with the introduction of the new motors, was a spanking new version of the program.

And so there are several new features/upgrades of note. You might watch the video for a full rundown – the contactor issue went away. The dedicated 1311 Programmer issue went away. You can now officially IDLE with an automatic transmission. And there is a USEFUL CANBUS connection to get all the motor and controller performance data out so you can design a pretty display. Excellent, excellent, and most excellent.

And all very understandable. But a huge amount of work went into these new motor windings. Even better, and I actually secretly think they GOT this idea from us and our Dyno graphs, Brian Seymour actually BUILT a capable motor dynomometer in their shop to test motors and controllers on. The company always did buy Leeson motor parts but they always wound the motors themselves, almost a family tradition going back 30 years when their Dad was rewinding washing machine motors for the neighbors. So you could ALWAYS get a custom wound AC-50 if you knew to ask, and of course were willing to pay.

But the advent of an inhouse dynomometer brings this to the fine art level. Now they can try different windings and immediately see the results on the dyno.

At this point, that actually makes HPEVS something of a one of a kind jewell. A small custom motor shop that DOES like to sell to DIY home builders, hobbyists, as rainmakers for their more lucrative small run OEM business. They power the WHEEGO for example. They started in custom golf carts. And so they are kind of dominant in a nicely carved out niche of SMALL motors.

But they are kind of branching out into larger power levels, and the news is that this opens the door for HPEVS solutions for cars up to 4000-5000 lb class. That’s exciting. And so I’m predictably enough excited.

But the story is almost hard to tell. I fear many will fail to pick up the import of all this, because the telling of it gets a little technical.

The basis of magnetic drive is that a current passed through an inductor causes the expansion of magnetic lines of flux in what is termed a magnetic field. It actually takes electrical energy to setup this field. When you cut off the current, the field collapses and actually CONTINUES the current through the wire, until the field is gone. So this field stores energy. IT also interacts. OTHER conductors nearby will have currents induced in THEM as well as the field expands and collapses. And this happens ONLY when expanding or contracting, not when fully on or fully off.

This then is HOW we INDUCE currents into windings in the rotor of an AC INDUCTION motor.Those currents, in turn, cause a magnetic field in the rotor. And by manipulating these currents in the stator or “field” windings at an AC rate, and noting that the rotor follows but never quite catches up, the two fields interact causing an axial torque to be applied to the shaft of the motor.

Since this field is invisible, and since we can’t see or feel it, it must be weak and feeble. Actually no. You can feel something similar using some neodymium magnets. As you try to push two fo these magnets closer together, the fields of each magnet interact with the other as a function of distance. The closer they come in proximity, the stronger this interaction FEELS and at a still quite visible distance, you just can’t push them any closer together no matter how hard you try.

Actually, all the locomotives, power plants, and steam ships in the world acting in concert do not make enough power to put those two magnets together. It is almost infinitely powerful at close ranges.

In the case of the AC motor, the rotor and the stator are typically separated by an “air gap” of less than a tenth of an inch.

And so we get almost MAGICAL amounts of power out of a bit of current passed through a coiled wire. I never really get over it.

This power can be felt at stall – zero rpm. But as we turn the shaft, and speed increases, the rotor begins to generate it’s own counter electromotive force (CEMF) sometimes referred to in the vernacular as BACK EMF. Basically, the motor is becoming a generator and offering a counter voltage. The resulting current through the motor is a function of the applied VOLTAGE minus the COUNTER voltage from the spinning motor.

In most motors, it takes quite a bit of speed in the form of RPM for this CEMF to become significant. And so for the first couple of thousand RPM we have a quite stable amount of torque or axial force at play. THIS is what gives electric cars that marvelous feeling of continuous acceleration. And compared to an internal combustion engine, it is truly a HUGELY wide torque band. But it is not infinite. As RPM goes up, at some point the CEMF begins to be felt, and the torque of the motor, and the motor currrent, begins to actually fall.

We call this point the knee of the curve. The point at which torque begins to fall. In most motors, it falls quite rapidly.

Because they have no commutators or brushes, many AC motors are rated for speeds up to about 14,000 rpm. And people become fixated on this largely useless specification. Because the torque often starts falling off in as little as 2500-3500 rpm. And by 6000 rpm there is rarely anything left to do much with. So from 6000 to 14000 the only way to increase rpm is by not having a load on it at all. It is a useless area for electric vehicles.

So torque is almost entirely a function of the amount of current through the motor. But current is almost entirely a function fo the applied VOLTAGE. And if we apply a HIGHER voltage, across higher RESISTANCE windings, we can have the same current, but it will extend out further along the rpm line. Instead of 2000 rpm at 100 volts, lets’ do 3000 rpm at 150v. By using a higher applied voltage, we can change the point at which back EMF is felt and becomes a factor, and so move the knee of the curve out to higher rpms.

This would be a good place to talk about the term HORSEPOWER. Basically the relationship between torque and horsepower is given by the formula HP=ft-lbs X RPM / C where the constant C is a value of 5252.

So if we have 100 ft lbs of torque at 1000 rpm, we have 100,000/5252 or 19 horsepower. But if we have 100ft lbs of torque at 3000 rpm we have 300000/5252 or 57 hp.

And so you can see that your motor will exhibit higher horsepower, for a given torque level, at a higher rpm.

To see the import of what HPEVS et al have been up to, let’s look at some power graphs. Here is the familiar AC-50 motor at the nominal voltage of 108 volts and 650 amps offered by the Curtis 1238-7601 controller:

ac50 108 650 amp imperial peak

In this first graph, you can see the AC-50 at 108 volts. As our current rises to 641 amperes, the torque remains reasonably steady, starting at 120 ft.lbs and declining ever so slightly as the rpm rises to 107 ft lbs at about 3800 rpm. From that “knee” it dives to about 60 ft lbs at 5000 rpm and 40 ft lbs at 6000 rpm By 8000 rpm we have just over 20 ft lbs of torque. Our maximum horsepower occurs just after the knee at about 76 horsepower at 3800 rpm.

ac50 144 volt 500 amp imperial peak

If we take that SAME motor and run it at a lower 500 amps we only get 86 ft lbs of torque. But it is fairly flat out to 5500 rpm. Because of the higher 144 volts we have moved the knee from 3800 to 5500 and so got 80 horsepower out of it despite decreasing the top torque by a third. And we still have over half our torque at 8000 rpm. This is how to get a much higher top speed of course.

The AC-50 had of course been wound specifically FOR the 108v curtis. Let’s take a look at the same frame, still at 144v, but now rewound and relabled the AC-51 to get our torque back up a bit, while still having a little higher RPM value:

ac51 144 volts 500 amps imperial peak graph

By decreasing the number of windings and so their resistance, we can more quickly build up our current and so we start with 108 ft lbs of torque considerably higher than the 86 ft lbs in the AC-50. But we also maintain that torque out to about 100 ft lbs at 4500 rpm for 88 horsepower instead of 80.

HPEVS has also moved up from an 8 inch frame to a 9 inch frame with their AC70 series. Let’s compare the AC75 and AC76 windings at 144v.

ac75-144v-500 amp imperial peak

With the AC-75, we start at 124 foot lbs of torque. We can maintain that out to 119 ft. lbs at 3900 rpm and our peak current actually occurs a bit after that at 4500 rpm. So does our horsepower at 92 hp.

ac76 imperial peak 144 volt 500 amp

When we go to the AC-76, we are wound differently for HIGHER TORQUE and so we start out at a much higher 168 ft lbs of torque which we can hold out to 153 ft lbs but the knee is now back down to 3000 rpm. And our peek horsepower is 88 at 3200 rpm.

So why two different motors? Well, a heavier vehicle or truck for example, you might want more torque like the AC76. A lighter vehicle or sports car would be very spry with the AC-75 and the higher 92 horsepower at 4500 rpm.

Think of the AC76 as a V-8 and the AC-75 as a high compression Porsche flat six or flat four.

They actually have an AC-74 whose graph is as yet untested that they are winding for super torque using the Curtis 1238-7601 at 650 amps.

And so HPEVS is basically developing an entire array of motors and controllers you can use to “tune” your driveline to your vehicle. Since we have already noted that the Curtis Controller is already the most capable controller in the field for tuning performance and feel to the vehicle, HPEVS would seem to be playing that hand to that strength in kind of an act of genius as far as positioning the company. The combinations you can do to tune perormance and feel become astounding.

And just when you think you’ve got a handle on it, look to the past. They used to have a popular motor called the AC-35. Let’s take a look at this remnant of their line:

AC-35 108 volt 650 amp imperial peak graph

Here, we have the motor with the earlier Curtis 1238-7601 108v 650 amp controller. This little motor puts out an impressive 128 ft lbs of torque, actually 7 ft-lbs MORE than the larger AC-50. But the knee is at 3000 rpm instead of the 3800 rpm of the AC-50, and so a horsepower of just 70 at 3100 against the AC-50’s 75 at 3800 rpm.

AC-35 144 volt 500 amp imperial peak graph

But again, if we use that SAME AC-35 at 144 volts and 500 amps, our torque drops to an initial 94 ft-lbs, but now it maintains that all the way out to an even 5000 rpm – still 88 ft-lbs for over 82.5 horsepower.

In fact, if you look at this graph, you see a remarkable thing. An AC induction motor with an almost entirely flat torque curve from 0 to 5000 rpm. You just don’t see that much. In fact, I’ve NEVER seen it anywhere.
In fact, we still have a third of our torque at 8000 rpm!

Oh if only it were not so small.

Ok, how about this. How about we siamese them? Let’s put TWO AC-35’s in ONE case on ONE shaft. What would that do?

Well it would require two controllers for one thing So you wind up with an amazingly compact 20 inch long motor with TWO 3-phase connectors on it. By the book, it should do 170 horsepower and 190 ft-lbs of torque entirely flat from zero to 5000 rpm – the perfect motor for an automobile.

But the graphs have not been published yet and it has not been dynomometered. So let’s go back to the beginning. When we send current through a wire, it causes a magnetic field. And that expanding magnetic field also INDUCES currents in nearby conductors. What happens when I put TWO sets of field windings in one short case, with ONE long rotor with windings in it?

Answer: I don’t know. Never done that before. We’ll see. I’m guessing the resulting graphs will NOT be identical to an AC35 times two. Perhaps close. But not identical.

But I am curious. If only I had a really lightweight car to stick THAT in. Like a carbon fiber Speedster at 1130 lbs for the roller. I would have to give up my dream of keeping it under 1550 lbs I guess. And indeed, I think a roll bar of some heft might be in order here. Instead of the lightweight A123 120v pack, I’m guessing 50 of the CA60FI’s would be in order. But I’m betting that little MF will get up off its ass if I tell it too. I wonder if it could beat an HPEVS Siamese AC-35 Corvette at EVCONN 2013.

I guess we’ll find out. I ordered one Monday.

We have been saying for some time that the holy grail of DIY custom electric cars has been the 150 kw AC induction system at under $10,000. I may have mentioned that to Bill.

Let’s see. 170 x 500 = 85,000. How about 170 kiloWatts at an MSRP of $9700. With chill plates call it a smooth $10K.

Jack Rickard

60 thoughts on “THE HOLY GRAIL – circa 2013 AC”

  1. Great show as usual Jack. It’s only long; because it needs to be. While I certainly missed the show last week, I’m actually a little surprised how infrequently you miss one. That shows a significant amount of dedication to what you do. I agree with you about the dual ac35. In that power range you can actually start thinking about a decently fast single speed drive train, a really sporty car with multiple gears, or any number of other combinations with heavier vehicles, without the difficulties the DMOC/siemens combo presents to the layperson. Not to mention the new ac50 and 70 variants with the new Curtis controller. I can’t wait to see what brain and yourself build with with these new options available.

  2. Bill Richie told me that the AC-74 and 115 volts would be the best of the three for my 914. I can’t wait for the dyno information. All the others look very promising and the AC-70 family of motors opens flood gates for the DIY EV conversions. It is now possible to make some nice hot rods. No longer limited to super light weight vehicles and have the AC motors instead of the DC motors. Dual AC-74 anyone? Mmmmmmm.

  3. Congratulations to Jacquelyn!

    I really like the show this week. Lots of new stuff to think about. I have been having a blast driving the EVThing. It is the most fun I have had with a car since I was 16 with my 1969 Chevelle..

    If you are thinking about doing a conversion, just so it. It is so much fun…

    I did notice some odd behavior from the wife today while watching EVTV on my wide screen TV. She was puttering around the house more or less ignoring the show. However, when Anne came on the show, she set down and attentively watched the segment. When it switched back to Jack and Brian, she got up and went back to what she was doing…. I cannot quit figure out what caused this behavior. She actually missed the most technical parts of the show?????

    The wife did pay enough attention to ask me if it would be possible to build a 1965 mustang EV with an automatic transmission with one of the “new motors that is bigger than yours”…..

    I am really looking forward to EVCCON this year…..

    1. About 97% of our viewership is male. Kind of astounding how NOT chic magnet Brain and I really are. I don’t really know how to account for it. But true in Boardwatch days as well.

      We also apparently fail to adequately convey how deeply satisfying an EV conversion innately IS to perform. Of course, at this point, that’s what we do all day.

      But the best mode is to work on the car for an hour or two after supper in a kind of slow methodical manner. This costs you some television time, but trust me, you won’t miss it. Having the baseball game on in the background on the radio is an accepted EV build technique.

      It’s also ok to have a beer or iced tea going on the bench top.

      The key to success is to take each little “problem” or task one at a time and work them off as best you can before going on to the next. Don’t get in a big rush to see it run or get frustrated at all that remains to be done. Enjoy the process. Treat it as a serial exercise in small problem solving. Build the car you want, not the car you can.

      Pretty soon, you get to where you look forward to the eerie peace of the garage. And I stand back and look at the car a lot.

      If you get to a daunting part – it’s ok to call in some help. There is a lot of expertise on specific car things in every community – air conditioning, machining an adapter, paint, etc. I’ve found almost everyone locally EXTREMELY willing to help, usually for cash of course, but very intrigued to be part of an EV build. In some cases, this leads to a kind of defacto “build club” with people stopping by often to see how it comes and sample one of your beers. They usually bring tidbits of useful and often useless information, all quite entertaining.

      If you set the stage just right with the ball game, the beer, and kind of sweep the floor once in awhile, this can get out of hand where there is an evening party in the garage.

      Wives generally come in and cast about sniffing like a cat to see if they can detect the odor of other women. Once they have ascertained that there aren’t any, they quickly retreat from the man cave.

      And one evening you are standing around admiring the car, and going over your tick list and it dawns on you that you really don’t HAVE any more excuses not to turn the key and spin the wheels. And then the first drive. No matter HOW many times you’ve done it or how stoic you think you are, the inevitable EV grin….

      And driving down the road in a car you basically built from scratch, entirely silently and entirely free of gasoline, emissions, etc. with it driving distinctly NOT like a golf cart, and you just never will be the same. It’s one of the most satisfying moments of my life.

      So I just keep repeating it over and over.

      Jack Rickard

  4. Great show Jack . I am from Perth Australia and found your Show whilst looking into permanent mag generators .I have watched every episode ,in regards to heater in karmann ghia Mid America motor Works have two heaters that connect onto existing heater tubes under rear seat of a VW Beatle I think the karmann might be the same hope this helps , I have a 75 super beetle that I have ac in , just need to go ev one day good luck with heater.

  5. Great Show again 🙂 , all this tall on motors put me guessing about the Siemens/DMOC that at 300V can do 300Nm up to 300 rpm and about 100kW , well at 400V that would be someting like 300 Nm up to 4000 rpm and about 120 kW 🙂
    I think I have to try this 🙂 good power train for my BMW 🙂
    best regards

      1. The eTransit Connect is right at 335 volts which is 100 LiFePo4 cells. It accelerates pretty well for a delivery van at the low end, and does 80 miles an hour at the high end, with a single gear at 8.28:1 ratio.

        This indicates to me that it would be VERy capable with ANY transmission essentially to give it some leverage. I am not personally a fan of single speed gearboxes or direct drive for EVs. I think those transmissions are magic, allowing smaller motors and/or much better performance.

        My absolute favorite is the Getrag 6 speed manual in the Mini Cooper. It’s basically a 3 speed with 3 overdrive gears. I can do 100 mph in 6th at 1700 rpm.

        But I also like a five speed TK5 and rear wheel drive.

        Jack Rickard

    1. Would be a nice addition but there may be room constraints without major cutting of the rear apron and still remain covered. I think it would ruin the clean lines of the Ghia to cut and have a motor poking out the rear. If it fits then by all means go with the Dual AC-35. Anything over the AC50 may require some cutting on the Ghia. Im one to not have to cut at all or cut very little.

      1. From the graphs it looks like the AC-50 with the 144 volt control would be a nice racy match. It would keep the car light and Brian could rev it out to his hearts content. If the CA60s aren’t available are the CA70s an option?

  6. Say Jack, I remember something you said in a video a long time ago about choosing the Speedster for your first conversion. You said you had considered the Karmann Ghia, but rejected it because you didn’t think the VW floor pan/chassis would handle the weight of the batteries very well. Since you’re now talking about putting 50 CA180 cells in the Ghia, roughly 630 lbs, I’m wondering what changed your mind? BTW, my first car was a 1964 Karmann Ghia convertible which, 40 years later, I still miss. Such beautiful lines. Good luck with the conversion, I will be avidly following it.

  7. On the subject of three phase powered chargers like the new Brusa. There’s a company that makes Phase Perfect digital phase converters. Three basic sizes 36, 64, and 96 continuous amps. The latter two can be paralleled to provide 130 and 190 amps of three phase power from a single phase source.

    1. Is this for the VW Bus?

      That would make a great drive for it…… I would even consider a 3:88 (highway Flyer gearing). gear instead of a 3:44 with that combo… I find the 3:44 I have in the EVThing a tad too high. It makes 4th more or less useless….

      1. Looking to use it in my 914 I picked up early in the year. Brakes will be all new in a week. Take video and sell the engine as turn key and get my AC-75. Then I need batteries. Did not make the Tesla run on the stock market. Just don’t have that kind of money yet. Bus will be later. VW Roadster is just about ready to run.

  8. Thinking about Brians new project. It’s got a reasonably streamlined shape which will aid distance driving; higher speeds on less current draw. The likes of the Leaf and Model S have been designed to have very good CD values for this very reason.
    So remember when I mentioned of a T-Zero electric motorcycle rider crossing the USA? Well, he has doubled the pack to 15KWH from its original 43 mile range. And Craig Vetter has done the job streamlining the bike so the maximum mileage is doubled again to 200+ miles.
    Aspects of his build and links to the results can be followed from this link:-
    Right now, the rider is trying to accomplish an all electric three day run from coast to coast. Hope you like. 🙂

    1. Terry has been having a fair amount of difficulties with accident traffic backups on his way across. Streamlining is especially important with motorcycles, Terry’s bike looks pretty streamlined. My company Rifle Fairing won the high mileage contest several times in the ’80s we got up to around 400 miles/gal due to a body shape similar to what Craig has put together for Terry. At least half of that efficiency cam from streamlining.

    2. Dennis Carter

      Thanks for this post. Have been following Craig for a couple of years but had not checked the site recently. I know this isn’t Jack’s style but is a noteworthy accomplishment. California to Florida on a pure battery motorcycle in less than 6 days. No other power. No backup riders. No support vehicles. All by himself.

  9. Raymond Blackburn

    Hi Jack,

    in reference to the low voltage cut off being lowered to accommodate battery sag under acceleration.

    If the controller is set below 2.5 volts per cell, what does protect the batteries from going below 2.5 volts when driving? At what point does the car go into limp mode if the trigger for limp mode is below 2.5 volts per battery? How does this protect the pack on the discharge side? Does this render the low voltage, limp mode, cutoff on the controller useless to protect the batteries?

    Is the answer to add instrumentation, “ie” ah counter?

    Perhaps the remedy is the new CALIB’s that do not sag as much?


    1. Raymond, it doesn’t matter if all the pack is bottom balanced, no cell is forced into reverse voltage, (instant death). Then only the whole pack voltage is taken into account…

      1. Thanks for the reply Andyj.

        My question, however poorly stated, is what good is limp mode if you have your lower total voltage set so low (because of sag) that the car can’t limp anywhere when limp mode is triggered. No one wants to run their batteries below spec.

        I think I will re watch the last episode of EVTV and pay closer attention to the part where Jack says he could make a living out of telling people to lower there low voltage settings on the controller. I will try to find out at what voltage per cell is the low voltage being set so the controller does not limit power due to sag? Once I learn that I can multiply by the number of cells to get the total voltage of any given pack.
        If it is set to 2.75 volts per cell then you won’t limp far. From 2.7 volts to 2.5 probably isn’t much more than a mile at low speeds on the CALIB chemistry, one mile would be better than nothing.

        My cells are Kokams. One car has 80 cells, the other has 88, I did not build them but must repair them to keep them on the road. They charge to 4.2 volts and discharge to 3.28 or 3.28 on the low cell is where the BMS will shut the car down. Actually, on two occasions, when the low cell reached 3.28 volts I went 7 more miles (at low speeds like 25 mph) and took the low cell down to 3 volts by hammering the BMS reset button and made it home. I think the Kokam low spec is 2.5 volts per cell so I am not harming them sagging them to 2.9 in a pinch.

        I am not familiar with the CALIB’s and how far they would go on .25 volts on the bottom of the discharge curve. I will be purchasing them for my first build and thanks to EVTV I do not want a BMS on it.

      2. Ooops! Clarification; my bad English.
        If all the pack is bottom balanced. No cell can be forced into a reverse voltage condition which destroys them. As the guys say, use Jacks JD404 so you know what charge is left from AH used. Or the CycleAnalyst as I do. The pack Voltage can be noted while lightly cruising or at the lights.
        Sure cells can be occasionally forced to a lower Voltage under load. It’s part of the natural life aging process through use.

    2. Jarkko Santala


      It’s quite ok for the cells to go below 2.5 volts while under load, since you can’t determine state of charge from a cell under load anyway. It’s preferable to keep a rested cell above 2.5 volts, but if you push a cell to 2 volts under load it will come back to 2.5 volts after a while.

      You should use an Ah counter to activate the limp mode, since Ah or kWh is the only way to really tell the state of your pack anyway. You can set your limp mode at whatever Ah you like. Let’s say on a 100 Ah pack you could turn it on when you have 10 Ah left, i.e. tenth of your range.

    3. Doug Ingraham


      I have my controller set to limit to 1.6 volts per cell. I have to do this in the winter when the temps of the batteries reach the low teens Fahrenheit or the car doesn’t go too well. The only time you need to worry about the low voltage is if the cells are unloaded. This appears to be something that the BMS proponents don’t understand. The only thing you need to worry about on the low voltage side is cell reversal. And with a bottom balanced pack this just doesn’t happen. In my case the car goes into limp mode when it is cold every time I put my foot into it. I will be adding some heat to the batteries before next winter.


      1. “… the car goes into limp mode when it is cold every time I put my foot into it…” Nice turn of phrase. What kind of cells are you using (brand, capacity, age). I wonder to what extent this problem gets worse with calendar age or cycles (I’m thinking “thicker SEI layer”). Any experience?

        1. Doug Ingraham

          Hi John,

          The Cells are GBS 100AH. Probably made in June of 2011. I think this is typical behavior for LiFePO4 type chemistry. I think they all tend to sag badly at low temperatures under high currents. There may be some way to alleviate this with manufacturing changes but I suspect it would have negative consequences in other areas. It should be easy to warm them a little.


          1. That makes sense Doug. Jacks low temp testing on CA cells suggests that they are pretty strong in this area. I had a small heater in my test shed set to keep the temperature at least 5 degrees C in winter (it rarely gets super-cold hear although night time frosts are common in winter). I am using a resistive load and monitoring temperature so I could look for changes in sag with temperature albeit in a fairly narrow temperature range.

  10. Jack, thanks for the analysis of the new HPEVS offerings. I’ve been thinking about doing AC for my next build, and it looks like I’ve procrastinated long enough to have a whole new set of choices, and good ones at that.

    Let me clarify something I heard in the 5/31 video: you and Brian discussed having lots of 220 volt outlets at the EVCCON site this year, and I think you said NEMA 15-50 plugs? I’ve been looking those up and they appear to be three phase, so would I connect any two of the three hot lines to each of the two hot lines of the NEMA 6-20 input to my charger? Plus ground of course. I want to be prepared with an adapter this year.

    Looking forward to seeing everyone at EVCCON!

    1. Fred, Jack,

      NEMA 14-50 makes a lot of sense to me. You can get either 240V or 120V from it.


      Of coarse Jack can get 3 phase for his shop but at home? Europe is different. We are used to baking our ham and eggs with 400V 3 phase turning so we dont need to turn the pan with our own hands. But we are very limited in amperes over here.

  11. I have one of these ELCON chargers in my vehicle. I opted for the non-CAN model. I don’t really like this charger because it has a preset charge curve that they don’t give any details about. It says that it charges (when enabled) at a constant current (9A @ 1120V and 18A @ 240 volts based on my measurements) until a preset voltage (which they don’t tell you what that is) and then goes to constant voltage till the current reaches a preset value (that’s helpful) and then it shuts off. However, on the website in the FAQ section it says that if the light flashes green it’s in a float stage. My light flashes green. So what’s a float stage? Sounds like trickle charge or allowing a small current the whole time it’s plugged in. So… which one is it? Does it shut off or trickle. I hope it’s shutting doen. I tried to measure the current and I can’t tell if it’s small or off. It reads between zero and 0.1A. Could be my meter. Not sure if it does this same thing with CAB control but I would imagine it does.

    1. Jarkko Santala

      Did you order the charger with a Lithium charging profile? You can get these with a plethora of charge curves and voltages. If you have recycled a charger that has previously been used to charge lead acid you may well have a trickle charging curve in use.

        1. Hiya!
          What is your terminating Voltage per cell? seems the more is learned of these things, the simpler the charge regime.
          Nailing the pack hard as you can on CC until they hit 3.4~3.5V per cell then let go… That’s all I’m off to do.
          Where’s J. when we need him? 😉

    2. Paul:

      The Elcon chargers are really the TC Charger, manufactured by the Shenzhou Tiechen Informatics Company Limited of Shenzhen China.

      They are both a blessing and a curse. They use stored charge profiles to charge batteries to specific voltages, which must be programmed.

      Worse, they have a lead version and a lithiu version. If you are float charging, it is probably a lead version. A guy named Creighton I think in Sacramento is actually the “Elcon” here in the U.S. and he can change the configuration on these for a hundred dollars or so but it takes two months sometime.

      We have done a charge controller for the CANbus version. And we’re looking into ways to use the non-canbus version more usefully.

      Jack Rickard

  12. Those new 70 series motors from HPEVS are interesting but really.. what’s the point? The total cost of an AC-75 plus Curtis controller is pretty close to the current cost of a Siemens motor and DMOC645. One of those combinations has a lot more features and is a lot better constructed than the other. To me it’s not much of a choice. Curtis has long been known as a rather low-end system and it does not seem as if this has significantly changed recently. Still, it is nice to see that more work is going into creating AC solutions for hobbyists. The big downside to the DMOC is that nobody is going to be making any more of them. So, some day something else will have to take over. The DMOC was always a really interesting system where it was around half way between the usual ludicrous prices charged by most AC controller vendors (looking at you RMS) and the DC controllers that hobbyists normally use. I wish that AZD had been a bit more frugal with their money and stayed in business. The DMOC has been basically the only good AC option for people/companies not fortune 500. Now we’re left with Curtis and the over priced vendors. Somebody needs to fill in the middle ground again.

    1. I don’t really agree with your characterization of the Curtis controller Collin. They don’t get very aggressive when it comes to power but for features and proven maturity, they make a very good controller that appears in many tens of thousands of devices. It is quite affordable. And we’ve found them to be quite durable. With the 144v and the AC-7x series qnd the AC-35×2, it opens up a lot of possibilities that just weren’t there before.

      I’m excited about the GEVCU and DMOC645 with Siemens, but when we run out of DMOC they are run out. There IS actually about a 1000 of them floating around out there in fleet vans and such. I’m not sure how to dig em out. But they are out there and should start cropping up.

      I did hear from a fleet operator in Canada, they are looking for somebody to convert the vans BACK to anything but electric. They have had troubles with transmissions, clutches, and electrical connections with the AZD products. And of course now they are orphans.

      Jack RIckard

      1. Jack I’m confused by your statement about the AZD van fleet operator. ?Problems with transmissions and clutches? Does the Borg Warner e gear drive have clutches in it?

  13. Hi Jack

    Great show this week, Especially enjoyed the in-depth look into the HPEV motor range. My AC75 arrived this week from Anne, so the excitement level surounding my build has increased hugely now.

    May I prevail upon your battery expertise for a moment. I have purchased 38 x 200AH Winston cells. I was going to BMS them, however after watching around 50 hours of your video archives I have decided to go BMS free and bottom balance. I am planning to use a charge cutoff voltage on the lovely Elcon charger Anne sent me of 3.65v. Because of the fixed charge profiles I can choose between 3.65v and 3.55v amongst others.

    The Winston batteries have an “IMPORTANT NOTICE” attached to them telling me to charge them to 4.2v for a one off initial charge. You have mentioned in your videos that there is some magic chemistry that happens on the first charge, however 4.2v sounds a bit scary high.. Would you recommend that I do this one off charge to 4.2v


    1. Hi…

      Please forgive me if this is a dumb question, but I was trying to think of a time efficient way of bottom balancing a pack before it goes in the car. From what I gather on the videos Jack is discharging the full series pack -ideally by driving the car- to just over 2v per battery, then discharging each battery to 2.0v individually. This processing of each battery individually takes a lot of supervised time. Is there a reason why you can’t just put the whole pack in parallel rather than series, then do the final discharge to 2v on all the batteries together? In theory you could discharge the whole pack to zero without causing damage, however I guess this is probably not recommended.

      I appreciate this may not be a favoured solution for someone who has installed the batteries in the car, but if they’re all on the bench, as they could be for a new build, this could save a lot of time… Unless of course my plan is flawed. I welcome your comments.

      1. It’s not at all dumb James. But cells in parallel have very small differences in voltage and so very small balancing currents. It doesn’t really get the job done.

        Most of use some automated way to discharge the cell to a specific voltage and disconnect (Powerlab8 springs to mind, but whatever).

        I kind of arrange all the batteries in the lab, and everytime I walk by I move the discharge unit to the next cell. This takes days sometimes, but I”m not actually doing it. I just move to the next cell and hit the button and walk away.

        We never discharge to 2.0v. I will typically discharge a cell to 2.50v and after termination it will usually bounce back up to somewhere around 2.75 to 2.85v. I usually just use a 0.1 ohm 250w resistor with some clips to hand drain each for a few seconds to try to get it to settle around 2.75 v.

        Then install em, strap em up, and charge them.

        In the THING, since they are kind of installed at waste level, I am just doing them in the car.

        If in a working car, I drive until the pack is at 3.0v x N cells. With a 100 cells, drive until you get a static read of 300v.

        THEN go through the pack looking for LOW cells and CHARGE them to 3.00v.

        Then drain it to 275 volts with the heater.

        Then hand trim.

        Jack Rickard

    2. James:

      THis should have been done at the factory. The concept is to fully lithiate the carbon anode at the beginning. I’ have not found this to be important.


  14. I thought I would update you guys on my electrical noise issue with the shunt reading. I was using a Thermocouple input card as it can directly read +-50mv. However, it was not isolated and picked up some noise causing false readings at low amp draw levels for the pack….

    I bought a Phoenix Shunt Isolator for the reading. It can take in several mv reading and convert them into outputs more suitable to micro processors. I chose this one from Mouser:

    I set it to take +-50mv input and output +-10VDC. The analog input card in my PLC can directly read the +-10V and scale is from -32767 to 32678 (16bit with sign) with zero being zero amps. It is an 800A shunt so it car read down to about 50mv accurately. This isolator provides a very stable reading. I fully charger the pack to 125.5VDC and set the capacity total to 180Ahr. I drove the car burning about 100Ahr. After the next charge the totalizer read 179.89Ahr…. So it seem to be keeping good track of the amp in and out of the pack….

    The bad news is that it needs 24VDC to operate. It is not a big deal to me as I need 24VDC for my PLC, 4″ color display and Pack Voltage transducer anyway.

    Anyway I knew some people were interested in the issue…..

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