This week we formally announce a project I’ve alluded to in the past – the conversion of a 2008 Cadillac Escalade EXT pickup truck to electric drive.
From the get go, we’re going to do this a little differently from what you might expect.
Our first choice is drive train and we’re going a little different direction. Our regenerative braking experiments were less than persuasive to me that this is an absolute requirement for an electric car. We would estimate the finished weight of this vehicle to curb at 7200-7400 lbs if we include sufficient battery power to move this vehicle to a useful range.
Moving that amount of mass is non-trivial. We’ve looked at a number of larger vehicle projects with 150 to 200 kw drive trains and I’m underwhelmed. The Tesla has a 200 kw system in 2800 lbs.
While we do not need to accelerate to 60 mph in 3.6 seconds, my sense is we need a Tim Allen approach with more raw power.
When it comes to raw torque, AC induction motors simply do not have the muscle per mass that a series DC motor has. You are “inducing” a current, and subsequently a field, in the rotor by proximity. It eliminates the brushes and commutator, but it simply does not produce the torque that a series DC motor does.
Permanent magnet motors are indeed interesting. The dirty little secret there is that the permanent magnets are not very permanent, and they become very non-permanent when exposed to heat. Heat is our pernicious and persistent problem area.
Series DC motors have the current flowing through both the stator and rotor. This gives each element a field of proportional power, and the torque developed is simply irresistible.
We’ve asked Jim Husted of Jimerico to do a special heavy duty build of two Netgain Warp 9’s on a single shaft, and mate it to our transmission.
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The transmission is the second rather unusual choice. The Escalade has a fascinating transmission in it already – a 6 speed automatic termed a 6L80E coupled to an All Wheel Drive unit. The 6L80E is very strong, and has the unusual characteristic of having manual shift built into the tranmission controller, which is contained within the transmission. This allows you to manually shift this automatic transmission with a little up/down arrow button on the shift lever.
Unfortunately, it really needs the engine ECU to do all this, and to handle torque converter lockup. We’re removing the engine. We have very limited and not very successful experience fakijng signals from an ECU, and apparently NO ONE makes a stand alone controller for the 6L80E as yet.
We did hear quite a bit from our viewers on this and Tom ALvarey keyed us to the problems with the 6L80E. At his suggestion, we looked at the LENCO racing transmission series. In fact we contacted them and found them curiously uncooperative in this project.
Matthew Hauber, originally from Grand Junction Colorado was out in San Diego and had worked at a transmission rebuild shop for some time. He e-mailed us with some suggestions that became increasingly, and impressively detailed. They centered on a company from Ashland Mississippi called TCI and their 6X transmission. This is a 4L80E, a four speed GM transmission to which they have added a third control solenoid to activate overdrive clutches for the first two gears – effectively a six speed transmission. They also use some hardened parts and best of all, they have their own controller which is quite programmable. The net result is a transmission that almost bolts on in place of the 6L80E, has paddle shift manual control, and which can run entirely without an ECU including torque converter lockup.
This will give us enormous leverage, in fact torque multiplication, with a soft fluid drive that allows us to start the motors from 500 rpm instead of from stall. I think this is the way to initiate motion in a 7200 lb vehicle.
It still requires a lot of power. WE are going to try a pair of EVnetics Soliton1 controllers in this project – 1 controller per motor. No series/parallels switching. We are going to individually drive the two motors. This will let us idle on one motor at 500 rpm and go to both motors in tandem on acceleration. EVnetics has experimented with, and included an “idle” range for automatic transmissions and is the only controller maker we know of to do this. That’s not precisely correct actually. The Curtis 1238 does indeed have a “creep” mode that effectively does the same thing.
In this way, we can apply up to 1000 amps at up to 192v to EACH motor. We’re actually going to do a pack voltage somewhere around 180v. So with two controllers and two motors, we could in theory generate 360kW into this system. Netgain 9;s are probably not going to do that very long. But if we do NOT start them at stall, but rather from 500 rpm, we buffer it with the slip in the torque converter, and rather quickly get them up to our lockup RPM of 1900, I THINK they’ll do it for the 4 or 5 seconds necessary to get this vehicle firmly in motion. At that point, the power requirements should drop dramatically to continue acceleration.
That in turn requires a power pack that can deliver 180v at 2000 amps. We have not made final battery selection at this point, but if we DID parallel two strings of 52 CALB 180AH cells, they are ostensibly capable of 4C continuous or 1440 amps and of course 12C briefly.
To my mind, frankly, this sounds like the perfect storm – a superb opportunity to actually cause a lithium ion iron phosphate battery to explode. And as we all know by now, I DO like melting down batteries. But I prefer to do it in a controlled shop environment, not on the road.
So we are currently constructing a capacitor module of 72 Maxwell 3000F Ultracaps for a total pack of 42.66 farads and 194.4 volts. We are probably NOT going to encumber this with the byzantine trail of boost circuits so much the darling of the cap crowd. Rather, we are just going to parallel this pack with the cells. In this way, they will buffer our batteries, and should be able to produce the 2000 amps for about 4.5 seconds.
I’ve studied about six different papers on the use of capacitors to extend the LIFE of batteries, and I’m convinced that this buffer pack will extend the life of our battery pack to somewhere between 3 and 4 times their normal life span. And we’ll essentially negate the inherent voltage sag, in this case about 15-20% pack voltage, for a brief period.
The result should be dramatic improvement in acceleration, and dramatic improvement in battery life.
Unfortunately, it probably will NOT result in any extension in range. This is why capacitors never quite make the cut. This pack will cost just over $10,000 to construct, and will weigh over 100 lbs, and will be three feet long and 20 inches wide. The Elescalade will be the first vehicle we’ve done large enough to even carry a cap bank. For the same weight and cost, we could do another 40 miles of range. In this case, we’ll forego that in favor of life extension of our 60kWh battery pack, and to feed our Solitons to their maximum.
Yes, I know the Solitons can be configured to do 1400 amps. We won’t. The 1000 amp limit is there to protect the 1400 amp rated IGBTs. We WILL have a pretty serious liquid cooling system for the controllers, and indeed I’m planning a kind of monster blower system for the motors. But we want this system to last for a half million miles, and keeping that pad is an important element to do that.
I love the Escalade. And many Anmerican drivers just feel safer and more comfortable in a larger car. Our mission is to prove you can have all that, give up nothing, and still eliminate the gasoline and the emissions – and drive TOTALLY electric.
Could we go further with a hybrid? We don’t do hybrids. We do electric cars. It’s a line we don’t cross. No compromises. If you find yourself at a gasoline station pumping gas into your car, you are NOT driving an electric car. Period. That’s your first clue.
We think this will be a fun project. We think we’ll learn a lot. And we’re going to share it all, including the mistakes, quite publicly. Please do join us.
Jack Rickard
This Escalade project sound fun. I’m looking forward to seeing the progress. Not that it matters much, but I agree with using the transmission, and I believe the TCI unit is an excellent choice. I’m not convinced you NEED capacitors, but it sure will be fun to see them installed and should really allow for maintaining maximum power to the motors during launch.
I was really hoping to see a post on you A/C segment. The timing could not have been better. I was within days of ordering a Tecumseh a/c compressor and controller when I saw the segment. After viewing I searched the internet and sent an email and got a response from Tony Sun. I’m going to purchase the 144v 3000rpm unit to install into my EV. It should be a fun project. I am using the compressor with a custom A/C system that is being built by Jerry West at http://www.europeancoolerair.com/ He builds custom A/C systems for older Porsches and Volkswagens. I’m sure he could do a system for one of the 356’s if you were interested. Mine is going into a 914.
Hey Jack. I have to hand it to you for taking on such an ambitious and “out of the box” EV project. It will be very interesting to watch (from a safe distance)! I look forward to seeing the influence from the bank of caps on board.
You won’t be surprised to know I think you are missing a big opportunity for regen, especially with a heavy vehicle and that really cool bank of caps ready to soak up a huge amount of energy in a short time! I firmly believe that with this heavy vehicle you will be forced into more regen opportunities than ever, and even your ultra-efficient driving style won’t be able to avoid it. I know you hate Hybrids, but putting that aside for the moment do you find it interesting that the new MKZ Hybrid is rated at 127% better gas mileage in the city and 33% on the highway than the same vehicle with a conventional setup? Is that due to regen or some other magic?
Dan
Did I miss a link section? I’d like to order an A/C kit as well. But I’m unsure who the real MFG/Dealer is as I see about 10 listings for what looks like the same setup.
Hey Jack:
Matt seems like the perfect addition to your team. There are a couple of things I brought up with you that he’s probably better prepared to deal with:
1. I’ve been concerned about the strength of the TC lockup clutch, and whether it will really hold up to the torque you’re going to make if you lock it as soon as you can and leave it locked, especially during power-on downshifts. Its something to be careful with. There’s a reason GM doesn’t let the TC lock in 1st or 2nd or leave it locked in power downshifts- I don’t think it can hold very much torque, and your twin 9s are going to make a LOT of that…
2. I still think the final drive gearing is much too short (numerically high) for electric power. You’re only going to use the top 3 of your gears (which begs the question why you need all that gear-spitting OD from 1st and 2nd in the 4L80, but I digress…) Now that you have a way to smoothly engage all that torque, you could really use taller gears in your diffs- something like 2:41 or the tallest you can get. I think its worth the time and trouble, particularly where your 6X has a slightly shorter top ratio than the 6L80.
3. About idling- you’ll probably want to cycle the idling function back and forth between the motors to manage temperature evenly between them- EVNetics could no doubt handle that in the software. I also don’t think 500RPM is enough idle speed for your accessories. If you stay that low, you’re probably going to want a really small street race pulley on the motor so that the accessories spin faster- I think the A/C wants at least 1000 rpm, and the hydroboost/ps pump will want more, too. Lastly, you’re going to have to bump the idle once to 1500 initially in order to kick the alternator into charging. I don’t know exactly why, but its necessary. If you don’t use the alternator, just make sure your DC-DC setup is robust enough to run the relatively huge (and 13.8V minimum, not 12V) power draws this vehicle demands, from the blower on “MAX COOL” to the ABS, all at once. I would keep the alternator.
4. It will be very interesting to see just how much of your motive power disappears into the “overhead” of this big honking drag device. I’ve seen estimates that it takes 50hp to spin a 4L80, and 15-20hp to run a big air conditioner. The transfer case and diffs has to be another 30+, with another 25 or more for power steering and brakes. Should be fun.
One last think about the wheel motors on the Smart: When you triple the mass of the rear wheel assembly, don’t forget to call Koni or Bilstein and ask them what kind of dampers they can recommend. You’re going to need a LOT more energy dissipation in the shocks to control those rear wheels over bumps. Firmer springs would help some, but the dampers are going to need a serious upgrade.
Love the new shop, except that the new big lift is right under a ceiling beam, not between them. Think of me when that becomes a PITA…
TomA
Actually, a BIGGER pulley on the motors will spin the accessories faster… Coffee clears the head in the morning, yes?
TomA
A/C compressor. I can’t find the link myself at the moment. The guy to talk to is Tony Sun, mailto://motoroem@gmail.com. I was very impressed with their scroll compressor and controller.
An air conditioner in a Porsche 356 Speedster? Actually it gets pretty warm. But it IS a convertible and there just isn’t room for it in the car. The compressor is pretty large – oh about the size of any larger automotive compressor. The controller is about the size of a DC-DC converter. Very nicely designed.
It runs well on the bench. HOw it lasts in a system we just haven’t tested.
Jack Rickard
As always your comments are spot on Tom.
I was planning on loosing the Alternator and probably still plan to do so. I’ve got a pile of 200v to 12v Vicor bricks here and I’ll make us a custom DC-DC converter- probably 1200 or 1600 watts. I think I did 800 watts on the Mini. You can parallel these bricks and you just mount them on a heat sink. They can be switched off and on remotely. A couple of smoothing caps and it works great.
Yes, all that running gear has some overhead. ANd like you, I think we’re going to wind up using 3 through 6 and the overclutch on first and second won’t really matter much. We”ll probably run the car and get a feel for it. I don’t think it will be too short frankly. We have a 3.42 diff if I recall. The Speedster worked a lot better when we went to a 3.44 R&P which would be similar. We found the 0.70 in the Speedster with 3.44 to be TOO TALL. And so I expect the 0.70 in this to be too tall in 6th gear as well. So really it is 3rd, 4th, and 5th gear that we’ll be using almost all the time.
We’ll mind the lockup.
As to idle speed, it’s all in software. We can make it whatever works. Really we’ll make it whatever works the AIR CONDITIONER.
No alternator. We intend to have a power steering pump and an air conditioner compressor on the aux shaft. We do NOT have hydroboost but we’re going to try to convert it to that so the power steering pump will run the brake vacuum as well.
Jack Rickard
Regen. Might be more of a factor with this larger vehicle. But I’ve grown wary of myths and what “everyone knows.”
Our regen tests wound up varied, but not much for me. As I understand the commnents, they eventually degenerated to I could save wear on my $12 brake pads by stressing my $8000 drive train to get 2 wheel braking. Sorry, I’m just not in the regen camp. We’ve done it. We’ve measured it. I don’t think it is what everyone thinks it is.
Here’s ANOTHER little mystery. Wind resistance in the Speedster is a huge issue. Our mileage goes to the floor over 70 mph.
In the Mini, it doesn’t go to the floor. In fact it doesn’t move. It doesn’t move at 90.
No, I don’t know why. MAYBE the cdi is so GOOD on the Mini it doesn’t matter? That doesn’t sound right. So I’m down to mass issues. The Mini is 3500 lbs. A report from Arnul Lardsgaard on a large Ford SUV electric inquires as to why HE isn’t seeing the big drain at highway speeds. Again, heavy vehicle.
We have to look at this further, but it appears that the heavier the vehicle, the less effect wind resistance appears to have.
Jack RIckard
The need for capacitor bank. No, we don’t need it. We don’t even need another car.
We’re going to do more on this this week if I get the capacitor module done. I’ve already built it and blow it up. But I should have the problems ironed out this week and hopefully we’ll film it.
I’ve found about four articles on battery life extension using supercaps. These are all about SMALL batteries of course, camera batteries and power tool batteries and so forth. They appear to extend the life of the batteries 3 to 4x. There is actually a company now titled ULTRABAT that is building hybrid lead acid/capacitor batteries – again with claims of extraordinary life cycles.
So that’s what the caps are about – buffering the batteries to potentially 8000 or 10000 cycles.
In the process, I expect our simple parallel arrangement to “stiffen” the batteries as well, holding up the voltage sag for a few seconds while supplying current for that initial acceleration. I’ve got this worked out to about 4.5 seconds as a strongly calculated guess. The actuals are all integral functions and I would have to relearn that math to actually do it.
But the basic math is 1/2 C V2. (squared). If we look for a 30 volt sag at 2000 amps on a 180v pack, it is 1//2 x 42.66 x 900 or 19197 joules (amp seconds). That’s a little less than 10 seconds of 2000 amps available from the cap bank during that sag.
So the cap bank and the batteries together should be able to hold about 180v for maybe 3 or 4 seconds providing a true 360kw for that period.
These battery and controller “ratings” can be a little misleading. But I’m hopeful that the Soliton’s can really DO 1000 amps into these motors and I have to make sure the batteries can DO that as well. A cap bank buffer is my best shot at that.
We’re also going to liquid cool the controllers and I’m going to try to come up with something innovative to blow air up the skirt of these motors at an impressive rate. It’s always all about heat heat heat and more heat.
More on caps in next weeks video.
Jack Rickard
Hydroboost is indeed what Matt is talking about and trying to spec.
You will use a different brake booster altogether. You throw out the big diaphragm-powered vacuum booster and use a fluid powered pressure booster instead. This pressure booster is fed by the power steering pump, and has a small pressure vessel accumulator on it for 3-4 stops without new fluid, which attenuates the uneven supply of power steering fluid with engine rpm.
This is the only power brake system that will work on a vehicle that generates no vacuum (diesel) or not enough (hot rod with big lumpy camshaft) and its even been done purely for space consideration by Ford on one of the Mustangs with an engine that wouldn’t fit with the vacuum booster. Hydroboost power units are much smaller, about the size of the master cylinder.
So, you are going with hydroboost, but you’re going to need a good GM parts man to pick your way through the numbers to get the parts from the systems on the ’02-’07 diesel trucks (or maybe even earlier parts) working together with the ’08 Escalade body and pedals. Give Matt my emails to you with the links to the truck hot rod sites where this has been done before. Its a detective project, really. You’re on the right track, though.
As for final drive, remember the contribution of the tire circumference. You can very easily drop to a shorter or taller wheel/tire package on this truck, which gives you a little adjustment you wouldn’t have on a car with tighter wheelwells. This is going to be cool…
TomA
If you had a hard top for the Speedster you’d see the problem with convertible aero in back-back tests. It is otherwise pretty slippery, but I suspect the Mini is still smoother.
TomA
Tom:
I’m TOLD that this Cadillac Escalade EXT was a split year and some vehicles actually HAD hydroboost. If we can find that part number, I think we’ll be good to go. But yes, it’s a little bit of a detective story.
Hi Jack et al.
It will be a fine battery pack the Escalde will be packing 🙂
Regarding the poor “milage” at 70 mph, your might recall that the power drain from the pack i proportional to the speed _cubed_ ! Since the speed tends to be constant for long durations, the energy drain will also be proportional to the speed cubed. There is also another factor and that is the airflow. It migth go from something resembling a laminar flow to a turbulent flow at higher speeds and thereby increasing the drag coefficient.
The 72 Maxwell 3000F seems to be a good conservative choise for 52 CALB cells. The lifetime on the caps are very temperature dependent. The 3000F are rated for 150A continous and 2170A peak (1 sec) so you might have to consider the duty cycle of your application.
Will you be using passive (resistive) balancing or the active balancing circuit from maxwell ?
Martin.
Hi Jack,
How do you imagine you will be verifying any lifetime extension of the cells due to the caps ?
Martin.
Jack:
You’ve hit on a curious aerodynamic phenomenon Bonneville racers have known about for many years- the heavier car is more efficient through the air.
Its a simple thing- at any given frontal area and shape, the heavier car has more mass with which to shove the air column ahead of it out of the way. Since the aero forces involved are increasing with the cube of speed, and the mechanical forces of carrying the extra weight are only go up basically linearly, the heavier car has a growing advantage as the speed climbs. On the salt flats, the heavier car is significantly faster, even with the same drivetrain!
I’m not sure this is the whole answer for what you’re observing. In fact, I’m quite sure it isn’t because the cockpit and underbody aero on the Speedster is terrible and the Mini is quite good. Still, it would be REALLY interesting to lay 400lbs of iron weights on the floor of the speedster and see what happens. I will bet you a big fat steak it is faster…
TomA
Help Jack! I still can’t get this/last week’s show to load! I even kicked in a couple of bucks to the bandwidth fund!
Wonderful project! I endorse the mythbusting experiment regardinf automatics as unsuitable for EVs.
However, I must admit I am still uncertain as to why you need to idle the motors. Could you please clarify why it is necessary?
I understand asking the motors to work hard at 0rpm is asking for trouble, but that’s why you have a torque converter: It lets your motors spin up to a happier RPM (the stall speed) before asking them to do any real work.
I understand you want your AC compressor to work at stop lights, but you know how to solve that problem without idling your motors: do what you did on the Mini.
The only reason left I can think of is to reduce the time it takes to get your motors spinning at the stall speed, and for that you could get a converter with a lower stall speed.
There’s probably a good reason I’ve overlooked, so I’m hoping you can explain it to me. Otherwise I’m very excited to see how this turns out.
Of course, all this presupposes spinning your motors at idle is an unnecessarily wasteful act. And next to the task of hauling 7200 pounds around, I’m guessing idling is no work at all.
Idling. Well it’s a bit cummulative. We actually plan to use the existing AC compressor, and it is a bit of a monster. I’m not sure what we did in the Mini could keep up.
The biggest reason is to use the internal pump in the transmission for its hydraulic pressure. Yes, there are workarounds there too.
Third of course is to use the power steering pump, in this case to drive power steering and power brakes.
And you’re quite right, we could do away wilh all that. But count it up, a motor and controller for the A/C compressor, a motor and pump for the hydraulics, a motor and pump for the power steering and a motor and vacuum pump for the brakes. With all those little motors, wouldn’t it just be more efficient to idle one of the two big ones?
And so that’s what we’re doing. It should simplify the system, and I don’t think it will be any more power. We’ll be pumping air through our motors without much of a load or current going through them, and that will likely help cool them over just having them stop. And I think it will be a lot easier on them to accelerate from 500 rpm to 2000 rpm than it is to start from a rotor stall.
I haven’t done the math on all those loads, it’sjust sort of a gut check approximation that we’ll bebetter off with one motor turning.
Should be less expensive too.
Jack Rickard
Hi Jack,
>If we look for a 30 volt sag at 2000 amps on a
>180v pack, it is 1//2 x 42.66 x 900 or 19197
>joules (amp seconds).
quick correction, joules are watt-seconds, not amp-seconds.
180v to 150v with a 41.55F cap = 206’217 J
0.5 * (180^2-150^2) * 41.66.
206’217 J = 45kw for 4.5 sec (or 206kw for 1sec).
bring on the data when its built though 😀
So, after all that crap you laid on Jeffrey Jenkins in the past, now you want to buy 2 of his controllers? I see that hypocracy is still your virtue, Jack….
I’m not sure I follow you, but I do see that you are anonymous. I’ve had interaction with Jeff Jenkins both positive and negative in the forums in the past. No, now I don’t want to buy 2 of his controllers, I already have bought two of his controllers. And they look pretty good. We’re still looking at them, and I wouldn’t say I’m committed, but they’re strong candidates fore the Escalade conversion at this point.
Now if you learn how to spell hypocrisy, and there’s a clue here in this message somewhere, perhaps I’ll try to explain to you what it means.
Or not…
Jack Rickard
“Regen. Might be more of a factor with this larger vehicle. But I’ve grown wary of myths and what “everyone knows.””
We are dealing with laws of physics, not mythology! If I did my calculations correctly when you get the beast up to 60 MPH you will be carrying 328 WH of energy. I spoke with the rep at the EV section of the Ford booth at Osh and he said they figure to recapture about 75% of the energy that would have been dumped into the brakes. You might do even better with your super-caps, recapturing 246 WH or more that would have been wasted as heat in the brakes. Of course, this assumes you actually use the brakes which I suspect you will by necessity do more in this heavy vehicle.
Since hybrids get ALL of their energy from gasoline, any improvement in mileage must be primarily from regeneration since the major losses (rolling resistance and wind resistance) are the same for both. Again, the new MKZ hybrid published EPA mileage is 127% better than ICE in city driving.
I’m not trying to say you should put regen in this project or any other for that matter, but I don’t want the community to misunderstand the potential value.
“it appears that the heavier the vehicle, the less effect wind resistance appears to have.”
“the heavier car is more efficient through the air.”
The equation for wind resistance does not have mass in it, and thus mass cannot in any way affect drag. I think this should be intuitively obvious.
Maybe, but where’s your data?
I’m not an aerodynamicist, and I don’t have to be to know what I know. It isn’t really about the math or what is “intuitively obvious.” For all I know, the explanation I’ve been told is aerodynamically incorrect or incomplete, but it doesn’t change the data: racers have been adding weight to go faster at Bonneville since the Daytona Beach days.
Could it all be just more of that “racing religion” and not really true at all? Sure, that’s possible, but racers are pretty keen on observing and replicating results. Could it actually be about increased stability and traction at speed, and have nothing to do with aerodynamic forces? That’s plenty possible, too. Just about everything is POSSIBLE, particularly among “amateurs” unencumbered by a professional opinion about what certainly could not happen. That’s what makes results so illuminating and challenging when compared to what just thinking about something a lot might predict.
Jack threw down some interesting data on his EVs’ energy usage, and a pretty cogent idea about why it might be that way. I added a similar thought from the history of high-speed racing with which I’m familiar, and I proposed a test of both ideas that wouldn’t be too hard to do, and might surprise us both (if Jack survives the hazards of the exercise.)
Are you saying you have an alternative hypothesis for the observations at hand and that you would like him to try something to test your theory, or are you just stating an (intuitively) obvious, but apparently contradictory non-sequitur that neither explains the data, nor advances the inquiry? How does “the equation for wind resistance” matter to Jack’s observations?
Your regen commentary is quite similar. Lots of intuiting, plenty of calculation, and no addressing the data. I don’t see any relationship between the numbers you’re putting down around regen, with ersatz accuracy, and the observations Jack & co. have taken the trouble to document. It just seems like a way to say “you’re wrong” without actually contradicting anything real. Jack hasn’t said regen doesn’t exist, only that “the potential value” people often claim or believe hasn’t really been found in careful observation of the EVTV fleet. What do you think about that?
TomA
Dwoodward:
I am desperately sorry, but while we do a lot of calculations, we do not live by them. I cannot express to you how very MANY things we have learned doing these conversions that makes perfect sense, and is well accounted for by calculations, and just turns out not to be so. We tested regen rather thoroughly, with it on brakes, on throttle, with it, without it, over the same routes, over different routes, and with different drivers.
The BEST I can say for regenerative braking is that it is mixed, and depends heavily on driving style. But as far as I’m concerned, it really is no longer a design consideration in an EV. If you can get it with what you’re already doing, it won’t hurt much. But the efficiency claims you and the gentleman from Ford are citing are simply in your mind, not in the car.
We measured useage out of the pack and into hte pack, we measured kwH when charging, and it pretty much devolved to nonsense in the end. I can show 15% gains and -3% gains with the same car over the same course at will.
The current observation comes from Arnul Laarsgard with a large Ford SUV using a series DC Netgain motor with no regen and an automatic transmission. He sees the SAME AH draw at 70 mph as he’s getting in town at 35. I had kind of noticed the same phenomenon in the Mini Cooper – esssentially the same 1 AH per mile on the highway as I was getting in town.
It is unexplained at this point. Since the much lighter Speedster shows a dramatic increase in power requirements at 70 mph, it’s drag must be much worse than the other two vehicles. That actually doesn’t make a whole lot of sense.
What we are left with is mass. No, the mass has NOTHING to do with the drag. But the ratio of mass to drag DOES have to do with mass. We have to do a certain amount of work to move the mass, and that doesn’t change with wind resistance. So it is possible that the wind resistance simply declines as a percentage of the overall mix of what it takes to move the car, and mass and rolling resistance become DOMINANT in the end. Air resistance does not go away, but it can be marginalized by other factors simply overwhelming it.
By way of contrast, the speedster takes 225wh per mile, while the mini cooper takes 375. It is POSSIBLE that wind resistance gets lost in the rounding errors of the difference.
On closer measurement, I’m sure we can detect wind resistance. But in casual measurement, the observation is that it doesn’t matter much with these two larger vehicles.
We LOVE your theories and calculations. Even better, we love to prove or disprove them. If you want to chant theory as gospel, you’re in the wrong Church. These pews are in Missouri. And you have to SHOW ME in this state.
Jack Rickard
I’m ashamed I didn’t make the SHOW ME connection myself. It all starts to make sense! Touche. 😉
But, the laws of Physics must be obeyed. When test results appear to contradict a law there is some splainin to do. My belief is it should be the responsibility of the one making the claims to provide the complete explanation in a scientific way. Saying “maybe it has to do with this or that” isn’t an explanation. The “myths that people know” that you rail against are propagated by vague theories like the ones I am hearing on regen and now wind resistance. Replicated data in a controlled experiment with sound calculations based on known laws is the only acceptable way to prove a theory.
Regarding wind resistance, consider this quote from Wikipedia.
“Assuming a more-or-less constant drag coefficient, drag will vary as the square of velocity. Thus, the resultant power needed to overcome this drag will vary as the cube of velocity.”
Does it make sense that doubling the speed (35 to 70) which results in 4X wind resistance requiring 8X power to over come it doesn’t even show up on the power readings? The vehicle in question is reportedly an SUV so we know the wind resistance can’t be trivial. I can’t tell you where the error is, but the reported results don’t pass the reasonableness test in my book. How about yours?
BTW – Will we be seeing some trip data from your computer data collection rig and software you mentioned some weeks ago?
Respectfully,
Dan
You remind me of the Phd patiently explaining to me years ago why 2400 bps was the maximum modem speed achievable because of the laws of physics.
The laws of physics are more or less immutable, though our understanding of them is subject to change.
We have an observation at this point. And are looking for an explanation. You’re offering an armchair explanation of why this observation can’t be.
Great. It’s not worth the paper it’s printed on. Go build a car. And have Wikipedia ride around with you in it.
Precisely the same on regen. Your model is not sufficiently complex to be a test of anything. We have tested it, and it isn’t what you believe. I haven’t devoted the resource to follow it further because it’s no longer interesting. It’s not a player as best I can tell. Feel free to go pencil out why. I’ll read with interest.
Simply chanting that it can’t be so and citing to me how very many people KNOW differently is not persuasive. Cloaking yourself in an appeal to the authority of the laws of physics is childish. We already HAVE the observation. We’re puzzling a bit what it MEANS, not whether its valid.
Results do not HAVE to be reasonable Dan. They’re just what they are. And predominantly most discoveries of everything have been the result of the curiousquestion of anomalous results.
Often, and in fact I would say generally, it was not the first to report the anomalous result to fully explore the cause -essentially what it means. And if fact history is replete with people who had the anomalous result, and the WRONG explanation as to why it occurred.
Jack Rickard
Jack Rickard
“And if fact history is replete with people who had the anomalous result, and the WRONG explanation as to why it occurred.”
And so it seems you are adding to this history. Your anomalous result is that on multiple drives with “plenty of regen opportunities” you report negative energy recovery. Your WRONG explanation is that somehow being in regen mode causes the driver to somehow use more energy. So I am here as the one with the “curios question” of these anomalous results. On the one hand you seem to agree that your results were indeed anomalous, but on the other hand you conclude without further explanation that “as far as I’m concerned, it really is no longer a design consideration in an EV”. This is a general and conclusive statement that is not even close to being supported by the physics involved or the volumes of evidence from other sources. Your results as reported DO support the statement, but there are serious questions to be answered before you can rationally call the results conclusive. I’ll say again, it’s your business whether or not you include regen in your projects, but it isn’t intellectually honest to proclaim regen is not useful on EVs if you base it on what you report.
Jack, I’ve beat this dead horse long enough and I am happy to move on and watch your progress on the Caddy. I want to encourage you and your readers to do more research and keep an open mind on regen. I think it is an important part of an important technology. I am VERY confident in the end even you will embrace regen!
Regards,
Dan
Dan:
You’ve beat it SO long and SO lost I would have to refer you to EVDL or DIYELECTRIC. There is nothing they love over there so much as to debate endlessly how many angels can fit on a pin, with absolutely NO data, NO experience, often NO cars, and no clue of course.
The ANOMALOUS result we have has nothing to do with regen. It is an observation that the increase in power required at high speeds in small cars does not seem to exhibit to the same degree in larger cars.
The regen is actually quite definitive. We tested on two entirely different cars in entirely different weight classes. We did it on various routes. And we did it with various drivers. The “baseline” performance was actually remarkably close in results -within a couple of TENTHS of an AMP HOUR.
The results were not anomalous, they are quite definitive. Brian can get a 15% improvement, I can’t get any. But that’s because his natural driving is a lot more wasteful. His “non regen” drive is attrocious. His “regen” drive is very close to my no regen drive. Trace is in the middle. All on the same route and the same car.
The conclusion is also quite definitive. If you want efficiency, learn to drive. The rather largish premium on AC induction systems to gain regen appears to be a solid economic loser and THOSE are the laws of physics.
That is from real tests, on real cars, with real drivers, on real roads.
We have a very friendly detractor, JRP, who claims widely to get 10% efficiency gains from his setup, which uses the same drive train as the Speedster Duh. The problem is he can’t turn it off, lacking the controller programmer to do so. So he “simulates” no regen. I can’t deal with that kind of data.
In your case, no data at all. No experience at all. Armchair theories and again, the tireless dire warnings of all that will be befall me when I finally see it your way.
Again, they LOVE that stuff over on EVDL and DIYELECTRIC. You guys can debate it for WEEKS over there without being hampered by anyone from the reality lane. Party like Rock Stars.
Jack Rickard
By the way, I’ve heard privately from three or four of the latent OEM manufacturer crowd we seem to be quietly attracting.
The answer to my question on regen is remarkably simple. It is so ingrained in the public consciousness that regenerative braking has to be a good thing, that you cannot appear to be doing advanced work without it. It offers some gains in some selected situations, and so it has to be included.
Bottom line – you guys think it works. We have to have it to compete. End of story.
This is the kind of self fulfiling prophecy thing we love to look at with a fresh eye. I need not spend a 50% premium on a drive train to get LESS torque just to have regen? Cool.
So yeah, it’s kind of fallen off the table as a design consideration. Actually it hasn’t, it’s fallen off the table as a design PRIORITY. It’s still a consideration. I actually like regen. But not because of efficiency gains. It’s a lot more mundane than that. I can simulate power brakes without a noisy vacuum pump. On the Mini, the brakes are quite operational without the vacuum power assist, just stiff. With regen, they feel like power brakes, but it is the regen you feel to a certain point. After that, your mashing the real binders. So I like that.
I’ve managed to get it MOSTLY off the accelerator, and we have no regen at all on the Speedster accelerator, only on the brakes.
Jack Rickard
“It is so ingrained in the public consciousness that regenerative braking has to be a good thing”
You really believe this, that there is a “public consciousness” regarding regenerative braking?. Are you kidding? Not 1 in 100 people could tell you what it is, and less than that care. OEMs are selling gas mileage, not regen. The Prius has been around for years and Toyota doesn’t even mention regen in their specs on the web.
You have a habit of ignoring my questions, but let me try this one again. If its not from regen, how does Ford get 127% better fuel mileage in town and 33% better in highway driving from their Hybrid compared with the same care with ICE? This is my data. No, I didn’t do the test but it was done under strict guidelines and procedures and there is no debate that it is reliable.
Dan:
I’m ignoring them to prevent your embarassment when I answer them. I’d like to continue to do so in this case. Do you insist on an answer to question?
ALL electric drive cars, including all series DC cars get better range and efficiency in town than they do on the highway. That it is the reverse with ICE engine cars is more a testament to their INEFFICIENCIES than anything else.
This would certainly be exhibited in a hybrid’s fuel mileage with NO REGENERATIVE BRAKING OF ANY KIND. This is EXTREMELY common knowledge in the EV world and is even RELATED to the parts of this discussion, which you originally jumped into, as to why air resistance shows LESS of an impact at highway speeds on heavier cars.
The only debate is that you don’t know what this testing means at all. You’ve actually got it wrapped up with regen when it would be easily that way with no regen. And so the famous “laws of physics” discourse.
Now quit it. They do this constantly on EVDL and DIYELECTRIC and I would commend you to the children there for further attacks/wrangling.
If you have any QUESTIONS about the regen data we provided, I’ll try to answer them. But for me, regen has been relegated almost to a way to have power brakes without a vacuum pump as to its total utility. We’re past it.
Jack Rickard
Now quit it. Insisting on this nonsense
Jack and everyone else should just ignore this paper pusher.. From all the comments I have read from “Dan” all he does is blabber incessantly and toot his own horn of how he is so right and everyone else is so wrong. So Dan…. Build it, prove it, or shut up already.. It’s great that your so incredibly smart, use that knowledge to better society and show us all how regen is so efficient.. I am so tired of reading your “laws of physics”, show us all how it’s done don’t just cite Ford’s claims.. That’s like reading an advertising brochure and believing everything in it as fact.. Ever heard of “MARKETING”? Good luck Jack and keep up the good work..
Jack,
Your response is indeed embarrassing.
I will sign off with this quote from Martin Eberhard, co-founder of Tesla motors.
“Call me closed-minded, but I’ve come to have a lot of respect for the basic laws of physics. Push them to their limits, bend them to our needs, take every advantage of the corner cases – but don’t count on breaking them.”
Live well, fly safe, good luck!
Dan
Duane:
We’ll try to stay within the bounds of the laws of physics. Indeed, we’re hard pressed to escape them.
Progress is normally made by changing the game. Each time a limit on the laws of physics is reached, the way through it is not usually by brute force, but by “changing the game”, that is changing our assumptions about the “ONLY” way to do it.
Indeed, while I was having the conversation with what truly was one of the leading experts in information theory at the time, as he described how 2400 bps was the absolute limit, I actually had a pair of Dennis Hayes prototypes on my desk in the other room. We’d already tested them and they indeed did 9600 bps quite reliably. I was unable at that moment to discuss it. But you can imagine my reaction.
The tonal changes actually occurred at the same 2400bps rate. But by going from two tones to four, he was able to encode more information in the same tonal rate change – quadrature bit encoding. Later of course, this actually got into phase encoding as well. And ultimately we got to speeds of 57kbps – although 2400 “baud” was really all it ever did. That was the division between the term “baud” and stating data rates at bps instead. You see, the laws of physics did indeed apply. But a little different twist on our understanding of them led to order of magnitude improvements in the result.
We don’t need to change the laws of physics at all. We need to change the game. Look at it in different ways. This is all the harder in a world rife with myth and misunderstanding. If regen is worthwhile, we should pursue it and optimize it. But if it’s a dead end anyway, making it a more efficient dead end at huge expense is not appealing to me.
We do hope you’ll stay with us. There’s much more to come…
Jack RIckard