Some days you are the bug, and some days you are the windshield. And so it goes. We have a busy 2:23 video this week. Last week we saw Damien Maguire install his Siemens 1PV5135 motor and DMOC 645 controller in the BMW 840ci. This week we visit with Ed Clausen and his BMW320i with the Siemens 1PV5135 motor as well as Paulo Alameida in Lisbon and his Mazda RX-8, or more on point this week, his Siemens 1PV5135 drive train.
And so in addition to our own 1974 VW Thing using this Siemens motor, we have now at least three very prominent builds nearing completion using this roughly 100kw drive train and of course our GEVCU controller.
We’re doing a second VW Thing with the UQM Powerphase 100 system from the Coda bankruptcy, and should soon have some video from Collin Kidder on a 1959 Mercedes 190SL convertible with this drive train and the GEVCU.
I think it’s important that we get a number of practical installations on the street and rolling before these OEM quality AC drive systems are accepted as “doable” in the custom electric vehicle community, and so I’m quite pleased with the progress here. We originally purchased 65 Siemens motors from the Azure Dynamics bankruptcy but also incurred a heavy investment in an additional 100 of these brand new in box motors from Siemens themselves after they had been hung with them post bankruptcy.
Indeed UQM suffered the same fate but on an apparently larger scale from the Coda bankruptcy. We purchased 10 of those at a much higher price but the company reports some $7.5 million in stock left over from the event and are none too happy about it.
The GEVCU was of course developed for the Azure Dynamics drive system so we could drive it at all. And it proved simmilarly useful in operating the Coda drive train. But to more advantage, it allows UQM to provide us with drive trains at much lower cost – almost entirely because they don’t have to support it. They won’t warranty it as it works with our GEVCU, but they also don’t have any means of providing product support, as they don’t really know anything about our GEVCU. You can of course purchase brand new fully warranteed products directly from them, at about twice the price, as they then have to provide product support basically for your project.
And so GEVCU is working out precisely as I hoped, not only as a way to operate orphaned equipment, but also to pry open this kind of circular pricing conundrum based on the vendors need to cover rather pricey engineering talent devoted to answering your questions. It’s a real issue. And GEVCU somewhat deflects that issue.
Indeed we are pleased to announce that we shall soon be distributors for the Rinehart Motion Systems line of inverters. This is kind of key for a couple of reasons. While we did obtain 165 Siemens motors, we only got about 70 of the DMOC controllers. Once they are gone, we had nothing to really run the remaining Siemens motors. The Scott Drive from New Zealand has remained strangely elusive as far as going into production in any quantity at all. But Rinehart, which already features “tunings” for more motors than any other, did do one for the Siemens 1PV5135 as well.
While slightly pricey, the Rinehart is also one of the physically smallest and lightest 3 phase inverters you’ll find in that power class. Indeed, their main line of business as it has developed has been in the racing community. They will be in our 2015 catalog, which I’m still working on.
We also received some preliminary test data from John Hardy of the UK. Mr. Hardy, author of the popular EV how-to book ICE FREE has done some interesting work testing cells in the past. This past EVCCON I awarded him six or eight of the CA40FI cells to play with. He has devised a kind of cunning test where he packages all these cells in a single insulated box so their temperature/environment will be the same, and then ran some cycle tests on them. But he runs one set at standard charge and discharge rates, and the other set at fast charge rates of 3C or in this case 120 amperes.
As you can see from the accompanying graph, it would appear my prediction that fast charge would have little ill effect on these cells appears to be in error. It appears from 500 cycles that there is some readily measurable deterioration of the cells in fast charge. The control pack decreased in capacity to 94% of original while the 3C pack appears to have reduced to 90%. As the high charge cells did not exhibit a significant temperature difference, we can only surmise that this is from a degraded anode crystaline structure and perhaps some increased thickening and deterioration of the solid electrolyte inter-phase layer or SEI on the anode.
Worse, if we project the trendline, the resulting decrease to 80% capacity, our usual definition of pack life, would indicate 1600 cycles for the normal charge which is quite to spec for 100% discharge. But this is reduced to 1000 cycles at 3C.
That’s still pretty good cell life largely due to the long cell life enjoyed by LiFePo4 anyway. And it is true that this test uses fast charge for ALL the charge cycles, except for the measurement cycle taken every 50 cycles. It’s unlikely in practice that you would charge ONLY using fast charge and fast charge every time. But while it remains a real factor to be considered, I consider the level of damage both affordable and acceptable in these cells for the convenience of occasional fast charge.
On another topic, I observe that the custom EV crowd pretty much accepts as a given that however well they do their vehicles, they cannot approach the polish and function of a “store bought” electric vehicle.
There is certainly something to be said for the uniformity and quality of a manufactured car. But I actually find them a disadvantage particularly with the deeply proprietary attitude of today’s manufacturers. It is difficult or impossible to modify the operation of a Volt or a Leaf and indeed probably impractical to do anything to repair it.
Indeed, a not yet evident factor in moving to electric vehicles is that I don’t think the manufacturers are making any particular progress in passing repair training effectively to their dealerships. Too often, a fairly straightforward failure requires a visit from the “factory team” to suse out, often engendering days or weeks of delay.
Indeed we were delighted to finally be able to purchase a battery for a factory built SmartED after months of wrangling with the top man in the company. Finally they agreed to sell us the battery for $7880 and even offfered to install it for us as it of course requires a proprietary change to the Vehicle Control Unit to carry the SERIAL NUMBER of the new battery to work at all.
We trailered the car to the Smart dealer in Creve Couer Missouri. WEEKS later they called us to note that the CONNECTOR to the battery was damaged. They have no connector repair replacement capability. All they can do is plug things in. So the motor would have to be replaced and with labor that would be a smooth $7100 additional. We declined that gracious offer and the car is currently in limbo, because it is BEYOND THE CAPABILITY of the Mercedes Benz Smart dealership, which touts the Smart ED, to replace a CONNECTOR????
So as these vehicles age, I see a coming backlash against manufactured electric vehicles that is quite dangerous to the genre. And that again goes to very expensive factory repairs – drastically reducing the resale value of these vehicles. But along the way, my sense is not so much pride of ownership, but rather a new sense of victimhood. I’m a victim of my Tesla Model S and my Smart ED.
As Ed Clausen noted, if he could only use another kWh or so out of the 24kWh IN the Nissan Leaf, his range issue would be done with. But THEY ONLY LET YOU use 20kWh of the pack. Yes, that is what they will ALLOW….on your car.
So more broadly, why can’t his BMW 320i be competitive in features to the Nissan Leaf? The BMW will be a car he has COMPLETE control over, thorough knowledge of, and the ability to repair or modify at whim.
As I said in the video, the motor turns the same direction whether we install the motor or Nissan does. We don’t seem to have any difficulty installing motors, and now we can have OEM grade and style motors anyway.
I actually think we are out AHEAD of LGChem and the OEM’s on batteries in some ways. Our LiFePo4 cells are inherently safer and longer lasting than the chemistries they use. And while they achieve higher energy densities using their more incendiary chemistries, they largely give that back with heavy, huge, and overengineered mounting and heating and cooling and shunting and BMS ridden monstrosities. Over a third of the Better Place pack is extraneous metal. And over half was in addition to the pouch cells themselves. So what is the advantage of lighter pouch cells with more energy dense chemistries. On balance, our lego bricks are easier to deal with and more durable. Net net, we’re getting the same range.
No, the central differentiation goes to instrumentation and displays.
Here are the Volt, Leaf and Tesla displays which show all sorts of useful as well as irrelevant information.
You will find it surprising to learn that I devised what I considered a very pleasing and effective display system three years ago.
It is actually relatively easy to engineer such a display, but it is easy largely because they are doing it for one specific vehicle and so much can be assumed. Applying this same concept generally across a broad ARRAY of vehicles using different drive systems, different battery systems, etc poses some unique problems before we can get to a GENERALIZED display approach for electric vehicles. There are actually two many strategies to pick from.
You will find it surprising to learn that I devised what I considered a very pleasing and effective display system three years ago.
The EVu display actually worked quite well. I used an Arduino and made my own shield with an RS systems bluetooth module on it. The module happened to feature a 16-bit analog to digital converter and of course since it was communicating the data via bluetooth isolation wasn’t terribly important. It used a LEM HAAS hall effect current sensor and then divided the pack voltage down just using resistors.
Two problems. One, I found the 5v powered hall effect device mysteriously drifty. All who deal with these eventually find the same thing. Second, the bluetooth data was transmitted to a Macintosh laptop and required a program designed just for the Macintosh computer to present this display. I would have had to write teh whole thing over in C# for Windoze for most of you, and then maintained two computer programs indefinitely. And THEN you would have to have a laptop in your car – or at least a CARPUTER to display the data. And so I had once again developed the $2500 unweildy solution.
We have done some better with the GEVCU device as it has a built in web site that presents most of this information in fairly attractive fashion. By using any browser, we eliminate the dedicated software release.
The problem here of course is the GEVCU has to drive the car. And so the wireless website is a rather low priority that updates rather slowly. Using the klunky web browser interface, it looks slow and awkward.
But we do have plans. Collin has done some prelimary work on an OBDII interface to the GEVCU. Note the display below was designed for the Orion BMS developed by Ewert Systems. This uses an “application” on an Android mobile phone or tablet. This can be done with GEVCU and we eventually hope to get this running.
I myself kind of think the car ought to be independent of Smart phones and Tablets as I don’t know what they might look like in 10 years, but my car will likely still be driving. I think the car should be self contained with regards to basic display. We mostly pursue this mobile application front because I want to be able to add OBDII generally to older vintage cars.
Paulo Almeida in this episode very impressively shows an existing Mazda RX-8 instrument cluster working perfectly with his Siemens drive train and GEVCU. Like almost all non-digital displays of the last 10-15 years, the Mazda has a conventional gaged display, but most if not all of the gages are driven by Controller Area Network (CAN) commands from the vehicle control unit (VCU). Paulo has adapted our GEVCU to send the appropriate CAN messages to the instrument cluster making it fully functional.
This is eminently doable. But it has a problem. Paulo had to learn the CAN commands for the Mazda instrument cluster. Fortunately, the Mazda has been kind of a popular car to re-engine anyway, and some Mazdonites had already worked out what most of them were. But the key is they are PARTICULAR to the Mazda. My Escalade has a very similar instrument cluster, but of course uses entirely different messages. So it is not practical to simply have these in GEVCU. Indeed, it requires significant C++ beyond Paulo’s range to accomplish and so Collin Kidder wrote him a “special” module just to interface with this legacy, but CAN driven, instrument cluster. There are too many such clusters to generalize this very well.
Or maybe not.
David Seabury, in this week’s episode, describes his very low cost Arduino based device that also does instrument clusters. But it has drivers for the earlier instrument clusters with real steam gages driven largely by sensor voltages for temperature, gas gage, pressure, etc. He also deals with the pulse-per-minute common tachometers used in these systems and the idiot lights.
But he takes a very interesting approach. He assumes the DATA is available from CAN and then translates that into analog signals to drive the gages.
We actually DO have analogue PWM outputs on the GEVCU – again you could do it but it would involve some software development.
David has done that for you allowing you to simply configure the CAN message ID and data format, and which gage you want to drive. He even provides a little system to calibrate the high and low of the gages. As we already have half our GEVCU outputs busy with precharge and brake lights and backup lights and cooling fans and so forth, it would appear David’s solution, which we intend to carry at about $235, would be perfect for these legacy instrument clusters.
This morning, I’ve gone elsewhere – poking CAN messages into Brian Gallagher’s EVIC display and watching the numbers change. This device CAN be interfaced very elegantly to the GEVCU, but also to the JLD505 device we have in work, or the BMS board that Ed Clausen further describes in this week’s show. Or a combination of them. I haven’t gotten all that sorted out as to what makes the best sense yet, but we will start with an object module for GEVCU that will drive the EVIC, and select from GEVCU data, BMS data, and JLD505 data as the source. Probably raw LEM CAB300 current sensor data as well.
In any event, I see it as ENTIRELY practical in the future, to drive the existing instrument cluster in your vehicle, AND add a sexy 8-inch eye-candy digital display very similar to the Leaf or the Volt, probably without turtles but otherwise similar.
In any event, that is kind of the central mission of our component side at this point. We want to provide everything you need to do a car, YOUR car, that you own, control, understand, can repair, can modify, and in all ways actually OWN, but I see no reason to “settle” for something less than you could also buy. Obviously this is only going to make sense for people who LIKE to work on cars and do such things. But we are moving quickly toward a future where you can customize and “program” your car to the same degree you now do your personal computer, laptop, or phone. And you won’t need anyone’s permission to do so.
Unfortunately, the competitive pressures have altered the landscape for America’s automakers. They are now following the airlines into an ADVERSARIAL model with their customer base. Madness to my way of thinking but very real. I actually have Mercedes Benz heroically trying to market a SmartED that is actually a GREAT little car and they have so far had comically inept results selling it. I might be able to help. But instead, they would prefer, if at all possible, to SCREW ME out of $7100 for a bad connector. In public and in real time. They cannot resist it. You should have heard the GLEE in the service reps voice because he was CERTAIN I would just pay it. In for a penny, in for a pound. When I told him we’d pick up the car and seek a refund for the battery, he just refused to believe it. In fact, in desperation he notified me that the battery was non-returnable special order. I pointed out to him that thus far, they had never DELIVERED it, weeks later though it has been, and I paid for it by American Express. I can do it online. Doesn’t even take a phone call.
The GLEE went GLUM. He had it in the BAG and it just went up in smoke while he’s talking it up. How could this be? The man honestly doesn’t know. He does it all day, every day, to every Mercedes customer he can get. And as all the stuff is proprietary, he gets them all. How long can that last? He believes forever. I believe it is over and he’s already the walking dead.
Is Elon Musk an automotive genius.?? I don’t know. Do you mean to compete against Mercedes Benz all I have to do is show up with a good car and declare to people that I will attempt to AVOID SCREWING THEM at every opportunity as my marketing message? And that owners everywhere will know exactly what I’m talking about and flock to it? How hard can it be?
Note that the figures are just in. The average U.S. car has moved from 9.6 years lifetime to 11.4 years lifetime in the past couple of years. Pushback may have already started.
Yes, the vast body of unwashed are destined to be victims until automakers show up to take advantage of the discord with good service and support. Ford is already kind of on a roll these days, for example.
But for those with a bit of tinkerer spirit, it will become ever easier to take any car, convert it to clean quiet electric drive, and wind up with just as good a car, without the victim status. We think we can get the costs down considerably as well, using the OEM’s own parts to do so.
So while suffering bronchial viruses, plagued by staffing issues, beset by sourgrape wannabe competitors and imitators, I’m just about to bubble over. The Internet was NEVER this much fun. I’m in my element and can hardly sleep from excitement. I’m nearly overwhelmed by all the development projects and things laying around the shop begging for attention. It is without doubt the most productive period of my life.
So yes, I’m in the fist fight of my life, entirely unarmed, hopelessly outnumbered and surrounded, beset on all sides. I cannot adequately express how joyfully exquisite all that is, or how it brings out the very best in me every time. With ables such as Collin Kidder and Paulo Almeida and John Hardy and David Seabury and many many others, we actually have THEM surrounded. The outcome is more or less certain. We just have a scant 40 miles of piss, blood, puss, broken glass, and razor blades to crawl over on our hands and knees and batta boom batta bing, victory.
Jack Rickard
I am starting to look forward to your BLOG postings as much as the weekly video! Great job on getting OEM quality wares in the hands of “Joe-Shit-The Ragman” EV builders! No offense to anyone.
All the best,
Aaron Lephart
Jack and John
The CA40 cycle test is very interesting. Jack indicates that one cell is being charged and discharged at 20 amps (0.5C) and the other cell is being charged and discharged at 120 amps (3C). It is clear that the 3C cell has suffered but it is not clear if this degradation is from the charging at 3C or the discharging at 3C. Would it not have been better to have a common discharge rate so that any cell degradation was isolated to just the difference in the charge rate? Or have I misunderstood the parameters of the test?
Doug
TransportEvolved reports on a study (using LiFePO4 cells) that suggests that higher discharge rates may actually be beneficial.
https://transportevolved.com/2014/09/30/comes-electric-car-battery-care-quick-discharging-might-help-battery-life/
I’ll let John Hardy comment on that, but I believe both charge and discharge was performed at 3C.
Discharge of both packs was the same: about 13 Amps or just over 0.3C
At 500 cycles I let the pack sit for a few days at 2.7 volts then measured voltages to check cell drift. I don’t unfortunately have good start data as I bottom balanced the cells before I started to use the screening process for soft shorts, but the cells were all within 100 mV or so. 100 mV at 2.7 volts (albeit under load) represents just over 500 milliAh or a bit over 1% of nominal capacity. So it doesn’t look like fast charge is causing significant cell drift either (I didn’t think it would, but it is useful to check)
I have swapped the software over to fast charge the pack that was previously slow charged and vice versa to control for differences in the packs themselves. I plan to run another 500 cycles which should take me up to April (I’m on cycle 509 and do about 5 cycles a day).
I agree with Jack’s conclusions: if you are using fast charge occasionally for cross country journeys the difference in cycle life is going to be trivial: and even in the worst case 1000 cycles is still three years of daily charging and heavy use.
I’ll try and do a bit of video in the next week or so (workload is a bit high right now)
Credit where credit is due BTW: Jack provided the cells and Jeff Southern the power supply (the two most expensive items on the test rig by far). Jack also made some very useful suggestions in designing the test.
Thanks guys!
My suggestion for Paolo’s Silicon-Carbide project:
SiC Infinit
(So it begins)
I gotta go with the first thing that came to my mind: ‘QuasaR’. You have to know some EVTV history to really get that one.
Thanks Jack; excellent show; chocked full of EV tech information and hope!
Jack,
What is your opinion on the Spira4u flipping? If you hit a bump in a car that can be flipped back with one hand, albeit empty, seems a risk.
Jack, I own a store bought EV – the Rav4ev. Its a nice car. I wanted to convert my own – I’m an embedded software engineer and I’d love to do it. The problem was that I’m not a car guy. I could muddle my way through the conversion, but longer term maintenance scared me away. There are a thousand things that could go wrong on a modern car – even with the engine removed – that I simply don’t know how to fix. At first I thought I could take the car to my neighborhood garage for all that menial stuff – then my Rav4ev had a flat tire. I had it towed to the nearest Toyota dealership, but they refused to help me. They would not even take it off the tow truck. It turns out they were not certified on the EV, and therefore didn’t want to risk a high voltage electrocution. They couldn’t take a nail out of my tire because they didnt know it wouldn’t kill them. When I thought about it, I don’t blame them. What mechanic is dumb enough to help me with my high voltage experiment? They don’t know how it works, what’s safe to touch, or how reliably I’ve built it. Any mechanic irresponsible enough to work on a 400v system they arent familiar with I wouldn’t trust.
So it seems to me your stuck doing 100% of your auto maintenance yourself – not just the fun stuff. There are lots of cool problems to solve in an EV conversion, but I don’t want to be an auto mechanic at the end of it. Batteries, controllers, sensors, CAN bus – I’m in! Transmission fluid and HVAC? Meh. Bring in a grease monkey.
Chris:
You are delivering rather a blanket eulogy from the experience with one Toyota dealer. I would suggest that you rather easily “saw their side of it” and we’re looking for customers such as you.
We ROUTINELY sub out transmission work, machining, almost always air conditioning, certainly tire and wheel stuff. I mean we do this while we’re building it and after as well. The only different reaction we get is admiration for the cars. If we have to mount tires, buy tires, balance wheels, fix tires, anything like that it goes straight over to Campus Auto. Earls Radiator does all air conditioning hosing, charging, evacuating, and often troubleshooting.
The ONLY smart asses we run into are dealers. ALmost all other repair and specialty shops are more than willing to help, have no general fear of electrocution, lightning, nor evil spirits.
Bottom line, we have a LOT of experience in this area, and it simply does not match the one experience you had with a dealer.
Jack Rickard
The deal is getting our cars back in our hands and our command.
My first cars I could do everything (almost everything) on my own. With later cars changing the oil or changing a blown light could mean a days work. With the i-MiEV I cannot even change a wheel. I have to repair it on the road and have my garage get me a new one.
Although I cannot change a wheel because there is no spare one, the i-MiEV has given me a lot back. That is because compared the other cars I owned they did not finish it.
Our first winter in the i-MiEV got us frozen limbs and a frozen nose and lots of wiping the windows. That is how I learned to add insulation to the doors and the lids back and front. Sideeffect of insulation the radio has got much improfed speakers and we dont hear street noises so bad any longer.
Stopping? Why?
I still havent built in a hamradio yet but I have begone disecting the 12V system. Funny, they have the same key switch like a gasser. We do not turn an engine to start the car but the switch still turns lights and radio off to have more power for the starter motor. It looks like the electric was made for adding a comfort battery like in a boat or a mobile home. Adding another 12V battery at the lighter socket worked. The radio no longer mutes when I start the inverter – and I have got more range. How is that?
Some things continue to run that used to be turned off. Be careful, that costs power when the car is parking but my radio stays on and that is nice. The bigger battery means less work for the alternator / dcdc-converter and that means the cooling pump stays off. That is what actually costs power.
Little steps but the car has begone to become a conversion.
Our remote dashboard is next. I have not found a place where to put a 19 inch display that is why it will be a remote dashboard but I still need it to sniff the canbus and other things. In the long run I have to put in a “bigger” battery and a bigger charger and I can only do that if our i-MiEV believes me being original.
Cheers
Peter and Karin
Found a promo video from Solidenergy while browsing my usual sites for PC news. Hopefully it hasn’t been posted here before as it’s one month old…
http://www.solidenergysystems.com/home.html
The partnership with A123 is quite interesting to me. I guess the real question is if we can obtain any of these if/when they come out?
Jack,
Your Mission statement “Converting personal transportation to Magnito-Electric drive” (I hope I’m quoting you correctly), may need to be updated. Seems to me you also want to “Open Source the Auto Industry”. Both worthy ambitions, and I think the second is only possible as a side effect of the first.
Would you say Elon Musk’s famous double-speak statement on “Open Sourcing the Tesla” inspired you?
I think Jack could argue that Jack inspired Musk to come out of closet on that one. Many of the blogs and videos mention cracking the CAN on OEM’s with GEVCU were well over a year before Tesla announced the “Open Sourcing” of their patents.
The open sourcing hand was waving above the table while Elon was hiring Apple employees and black-hat hacker teams left and right under the table.
Paulo,
You want a name for your DC to DC charging device. I know it has been used for other unrelated products, but I think this is quite apropos. “Hot Shot”
Eric Soneson
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I think John B. Goodenough is one of the most significant scientists of the 20th century. Apart from lithium ion batteries he also had a major role in the emergence of solid state memory. He did some of the core work on the early lithium cobalt oxide cathodes about 50 miles south from my home when he was (ahem) head of the inorganic chemistry lab at Oxford university. He is a foreign member of the (British) Royal Society. Quite a guy.
I agree John, it would be good to see him present at EVCCON!
I predict the motor in that Mercedes will last less than 5 months.
10 Megawatts of grid storage being installed at a site in the UK: supposed to be on line in 2016. Apparently uses small cells (probably 18650s). Roughly equivalent to 11 Model Ss
http://leighton-buzzard.co.uk/battery.htm
You may find these recent quotes about stationary storage from Tesla’s leaders interesting:
“Musk said that Tesla’s consumer battery for homes and businesses will be on the market “fairly soon,” adding, “We have the design done.”
Musk expects production to begin in six months.
JB Straubel, Tesla’s CTO, added that the company is “bidding on lots of stationary storage, talking to lots of utilities,” and “getting an increasing amount of attention.””
Well, I’m all ears. Seriously. If you feel it will not work or will fail or that something will go wrong then I’d like to know what you feel the problem is. But, the previous motor was seriously under powered, was pushed well beyond anything the company would condone, and still managed to last over three years. In fact, it still works. So, I’m going to have to doubt your claims of 5 months for a much more powerful motor. Yes, the configuration we’re planning is somewhat unusual but we did do the math and found that it should be viable. So, enlighten me if I am mistaken. What am I missing here? Why would it last less than 5 months?
Okay, the biggest problem with permanent magnet motors is heat. Heat destroys permanent magnets. Once you lose magnetism, the motor will fail, sometimes explosively. While I realize these motors are liquid cooled, I’m already wary of their use in an EV. But to use one in a direct drive application, that’s just crazy. More stress means more heat, more heat means greater wear on the magnets, even with good liquid cooling. I’d very highly recommend using the transmission to reduce the stress on this particular motor. You’re looking at a potentially expensive mistake. Otherwise, I just hope I’m wrong.
Liquid cooling the stator of a PM motor? Good. For racing these motors effectively the winner will also circulate a light transformer oil around the rotor like our AC motor manufacturer is doing on the marine 35×2 induction motor. Then you truly have a giant killer. Engineers traditionally calculated the “propulsive efficiency” of ICE motors. For the electric Frankensteins perhaps we should consider the term torque density instead.
The OEM’s these motors came from were using the similar direct drive as the Azure dynamic e-gear drive albeit with a 6.5:1 ratio. As long as you meet the manufactures spec for cooling there would likely be no problem. They are also deploying this powertrain in Korea to use on small 1 ton delivery trucks as well… https://uqm.com/uqm-technologies-announces-business-relationship-with-south-korean-power-plaza-for-uqm-powerphase-electric-motor-and-controller-systems/
I can’t imagine what you have to worry about. It is driven by a very nice inverter with temp reporting on both the stator and rotor as I recall.
So you can certainly limit drive when it gets to any point that causes you concern.
It is most certainly possible to de-magnatize the motor, just ask Monster Tajima…
But that was a transgression, or perhaps more like an aggression.
Still, I wonder if a powerglide with no TC is an option?
Dont worry. Drive and be happy.
It is like the Seti or Meti debate. Stay on your trees until we know if that is really ground below or just an imagination. We should still be on our trees but we have decided to go down and build cars and drive them.
Now for the trees let us build electric cars to save the trees in case we need to go upstairs again.
There have been cars ending in flames very fast, carburator cars. I have driven one of them. Electric cars are not that dangerous but they can end in flames nevertheless. Try a BMS if they dont.
All I’m saying is bypassing the transmission is an unnecessary risk to take with this motor design.
Hi, Chuck Milliken, CollinK and all 🙂
Yes it is tru, you can destroy your magnets :
1. Corent.
2. Blow to the magnet.
3. Overheat of the magnet.
Well… I have never seen permeant magnets destroy in a motor coursed by overheating. Why ??
First of all, it is water cooled next, in all servo motor applications i made you have the KTY signal which normally comes with the feedback signal and it doesn’t matter if it is Siemens, Fanuk, AKB, ABB or anything else, it is a standard to protect your motor for overheating so there for you cane continue your build. 🙂 By the way NICE Car 😛
What is the gear ratio in the differential ?
So how cane it go wrong…
It will only happen if the parameter is overwritten/tamper with, higher temperature by the fellow who thinks he know better, some controllers it is even possible to do.
If the temperature rises in the motor the controller vill reduce the power.
The most common corse for destroying your magnets is over current, but it is a bit complicated to explain on the blog, it is much easier to do on a video…
Any way bare with me for small mistakes. If you have a Permanent magnetic motor running if following condition :
The motor is abel to run 24-7-365, in that case you have the nominel motor data, from that point you are abel to ”overload” your motor with 4 times the Nm which is on the motor plate. (rule of thump)
Of course you can’t do that forever, but until the temperature rises to maximum limet at that point the motor will need a resting time until the temperature has fallen to a safe limit and then it is safe to run again, this is call S1 S2 S3 S4……
Let’s state that the motor has following data.
Nm = 132
Volt = 665V
Amp= 67.5
Rpm=1500
Polpar = 5
Waith = 40 Kg
This is about 20KW 24-7-365.
Imagine you choose to ignore the Maximum 4 X 132 m and you take 5 X 132 m then you will reverse your permanent magnets which means, you will lose the talk of the motor, if you then try once again, but this time with 4 x 132 m (Which should be inside the safe paremeter) then it is still revising magnetic again due to the lose magnetic the first time, this is a extremely bad circle.
I am writing this because, Jack earlier mentioned that there was someone how had the intention of building a 1MW or 1.5MW controller for the tesla and I would hate to see anyone fail.
If you look at the weight of det motor of the Tesla or the UQM motor, it is light, extremely light in compare of motor which is abel to run 24-7-365, the reason for that is properly that they choose a rating between S3, S4
It make sense…. If you acc at full power and you arrive at your chosen speed the power consumption will drop and you are running with less the S1, so your motor will have time to cool of.
Anyway my point is, if you increase the power on the Tesla or UQM with 1MW it will destroy your magnet and the winding, to achieve that amount of power, you will have to increase the voltage and the amp and it will result in a melt down, lot of magic smoke, but not from the tire !
I have seen special Getty Motor where down the magnet due to peak cornet over a period over some years however it was in the limit of the type plate. This is offen coursed by bad martial for the magnet, then you disassemble the motor and shipped of to company where they have the equipment to reenergize the magnets, and all is well again for a given period of time.
What happens when the magnet is going bad. You will see less talk and the motor will use full power so the efficiency is getting bad, and when you have reached the point where it is just getting worse, at the end, the motor will not be abel to move the machine or the car although it is using fullpower.
As it is right now im setting a machine up with 5 Axis and all Axis is driven by Servo Drive and Servo motors. I don’t know if it is possible for me to make a video of the function of a servo drive and motor.
There is missing some information here about, for instance Volt VS. Hz, number of poles. The ion in the motor and so forthwith, I think it is complex and it is hard to explain, maybe it should be done over 3 – 8 series of video.
If I find the time and Jack find it is relent, the don’t worry I speak a bit better english then I write 🙂
Best Regards
Allan
On the issue of direct drive, I think have an intuitive feel for the issue of driveline shock but a single speed transmission is in my view an unbeatable driving experience as well as being far more elegant from an engineering viewpoint. It will be interesting to see how it develops. A shock absorbing coupling might be well worth considering (e.g. http://www.eriks.co.uk/Fenaflex-Tyre-Couplings/450)
It may not of course be simple shock. It might be that torsional oscillations are the real killer. A friend who used to work in the area tells me that you wouldn’t believe the way that lorry half shafts can wind up under load. If that is the case it may be important that “ramp rate” applies in both directions, so that not only is power not applied too suddenly but also that it isn’t removed too suddenly either.
Emplementing a kludge in software?
virtual pedal accepting (vp +n) or (vp -n) when we move our foot.
real pedal being read via a timer and deciding what value and direction n should be.
Meeting the metal with the pedal does not put a hammer on the transmission but is meant as a suggestion for the torque manager to ask the torque controller if he would might to raise the virtual steam pressure a little bit whenever he has time and feels like it.
Down the same, softer regen breaking and maybe automatique coasting.
Maybe even make the car a little bit unwilling to cross the usual speed limit marks.
Cheap pedals might feel like high engeneered and epensive ones. No more erratic changes and that would conserve energy and the live of our car including the drive train.
Emulating a steam engine might be not that bad after all. Single gear, slow starting …
I understood direct drive best after riding in the Morris Minor at EVCCON 2013. Off the line it was a bit like starting your 10-speed bicycle in 10th gear. The acceleration at starting was acceptable but nothing to write home to Mom about. After the distance roughly equivalent to the average intersection complete with double cross-walks we got into the OMG-katie-bar-the-door performance. Quite impressive, I was grinning.
The rear differential is about 4 to 1 so it’s under the 6.5 to 1 of a Coda transaxle by quite a bit but we’ve done calculations to suggest that it’ll still work. It isn’t ideal and I wish that this project had the budget for a more adventurous solution but it doesn’t. Yes, the starting line performance will be a bit weak but it should do alright once we’re on the road for a bit. We are using a flex disc between the motor and axle shaft. The 190SL always had one between transmission and drive shaft. We’re using one from a 450SL instead because those cars have the sort of torque that a UQM motor can output and so the flex disc is a bit sturdier. Also, the 190SL is a split shaft in the middle with a set of U-joints in the center of the shaft. So, misalignment isn’t as much of a problem as you might think.
But, yes, we’ll be careful and I will be monitoring the motor performance. If 4 to 1 turns out to not be enough then the requisite I told you so’s are to be had and we’ll have to figure out something else.
Hi CollinK
Sounds like everything is in good hands 🙂
The ratio of 1 : 8.2 is quite true, however I think it will run quite nice, and you get rid of the backslash in the gear box and still flexible due to the Flexidisc. Nice thinking.
Look forward to see the build in progress
Best Regards
Allan
I thoroughly enjoyed the Feb 13 episode. Well, not the part about Apple getting into EVs. But, I was interested in seeing you explain the various issues that people need to grasp to get into canbus messages. Yes, it seems daunting at first but it is only 8 bytes and there are only so many ways that values are put together. Unfortunately, the math behind the UQM security byte is a lot nastier. Speaking of which, I fear that we’re likely to see more of that going forward. Auto makers are currently taking a lot of flack over the lack of security in their vehicles. CAN isn’t the easiest attack vector but it is one of them. I’m not sure how long we’ll see raw values being transmitted over the wire. If I were them and looking for security I’d encrypt all the data bytes. Luckily, it isn’t that easy to create good encryption over only 8 bytes. And, so far they have not bothered. I don’t recall a case where the operating parameters of any piece of hardware has ever been actually encrypted. So far it has been only security bytes and validation traffic. But, we’ll see what the future brings. If I quit posting on forums like this and suddenly canbus gets a lot harder to crack you know what happened. 😉 J/K, I am a kidder after all.
Jack and CollinK just found an article in my local paper about a single speed reduction gear box for RWD.
http://www.torquetrends.com/
What do you think?
Steve
Nice find! I have been looking for a small planetary reduction gearbox for some months now without greater luck… thanks for posting!
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This is probably a newbie question, but do batteries need to be mounted upright?
Ed Klaussen (apologies if I’ve misspelled, Ed) has his rear battery box tucked under the parcel shelf. If the batteries were stacked on their sides, with terminals facing the rear of the car, the battery box would just need a drop-down panel for access, instead of needing to slide out and open upwards.
Are we just accustomed to seeing the batteries standing up?
There is no answer to this question as far as I know. I know of no one who has done any definitive testing of this. The manufacturer recommends they be mounted upright. We have OFTEN mounted them on their edge horizontally and flat horizontally and have no observed any ill effects on really not very long driving or many miles.
We do know they should not be mounted upside down as the electrolyte will block the vents.
If anyone knows of any actual test data on this, I would live to hear about it.
Jack Rickard