Very excited to see progress on this build! Sounds like you have a great car on the way!
Location: Maple Grove, MN (Minneapolis)
Posts: 1,423
My VIN: 05457
Very excited to see progress on this build! Sounds like you have a great car on the way!
David Proehl
Location: Southern MA
Posts: 973
My VIN: 767 (3.0L EFI/EDIS)
I looked into some electric conversion stuff a couple of months ago, although more as a thought project with the idea of doing it myself someday and to get a basic idea of how things worked. I'm very far away from doing this; it'll be my project once key components of my 3.0L swap (that I'm still working on) fails in another decade or so. I've also only done maybe a day's worth of research, so I could be wildly off here...
It seems common in the DIY conversion community to continue to use a manual transmission when using a single electric DC motor. The issue appears to be that you can't necessarily get good performance at both low speeds and high speeds -- you can get lots of torque off the line, but then you can't get over 60 MPH; gear it the other way, and you're holding up traffic at stop lights as you try to accelerate. I don't think this limitation applies if you use a brushless DC motor (very, very expensive) or an induction motor (which is what Tesla uses), but I need to do more research to understand this better.
Shifting gears seems to be much different than when using an ICE, though, and I think you only really use two gears plus reverse. You can even drive the car in 2nd or 3rd all the time, if you want (especially useful when someone who don't know how to shift it borrows your car); you just lose the low/high end. Keeping the transmission simplifies the setup, since you get reverse for free without any extra electronics work.
A work-around is to use at least two DC motors, since you can get enough power at both low speeds and high speeds. At that point direct drive becomes more feasible, and you get a lot more power to boot. I also found a small (but expensive) two-speed-plus-reverse racing transmission modified for electric motor use, should you want access to even more power.
My thoughts so far on doing a conversion would have been one of two options:
- Two motors inlined with each other (the shafts on some motors come out both ends, so you can chain together as many as you like), connected to a differential (probably from another car) that then connected to the DMC's transaxles/hub carriers. The trick there is length -- the electric motors are not small, and while one would comfortably fit in the engine bay, two inlined would probably not fit behind the wheels. If I could do one motor and get good performance at both low and high speeds, that would be great.
- Two motors placed next to each other but pointing in opposite directions, one at each wheel (or some similar arrangement). This is more or less how the Mercedes SLS AMG electric drive works, although they do it on all four wheels with some small reduction gearing on the end of each motor. There's no need for a diff because each motor would operate independently. You would, however, need to have some control software to emulate a diff by varying the speed of the motors based on steering wheel angle or something.
There also seem to be three basic kinds of motors: brushed DC, brushless DC, and induction (AC), each with trade-offs in price, performance and life. I found a quick summary of them here, but I don't know enough to really say which one makes the most sense for a conversion.
I don't think you can just pull a Tesla battery pack out and use it in a DMC. My understanding is that the entire bottom of a Tesla (mostly the space from the back wheels and front wheels) is a battery sled that can be removed as a single unit (and in fact this is how their new battery swap stations work -- a robotic system takes the entire sled out and replaces it in about the time it would normally take to fill a gas tank). But this sled is quite specifically built in a shape specific to this car (very wide, very long, and very flat) and it seems it would be very difficult to put it in another vehicle without a lot of modifications. I'm also skeptical that the electronics can be removed and put in another car easily; I imagine all of it is intended to work together with the rest of the car's systems, but I have no specific evidence of this. It's also not clear to me how the electronics would have to be modified to adapt to another car's specifications, or if that is even an issue.
One of the advantages of my not planning to do this for another decade is that there should be enough wrecked Volts, Teslas and other EVs as to make engines much easier to source, as well as more EV conversions to use as reference. However, the pictures I found of the Tesla Roadster suggests the motor is ~2/3 the width of the car, which I'm not totally sure would fit in place of the DeLorean's engine to where the differential would need to be, but I haven't done any measurements or anything like that. It would be handy if it did fit, since I'm sure they've solved all the relevant engineering challenges.
I was thinking of using lithium ion batteries (like the major car manufactures use) instead of lead acid (which most DIY conversions seem to use) due to increased energy density and reduced weight, although they are trickier to charge and use safely. But I'm not wild about only a 100 mile range, nor am I sure I can fit enough batteries into the DMC, so I was also thinking about a hybrid design with a small, quiet gas generator in the engine bay (or possibly hydrogen, if Toyota's plans succeed over the next decade, although by then batteries might be a lot better too). The existing fuel system would be used to run the generator and charge a relatively small battery pack (also in the engine bay), with maybe 15-30 miles of reserve so you can get home if you run out of gas. The drivetrain, however, would be pure electric. This also gets around the lack of a way to charge an electric vehicle at my condo (which might change in another 10 years as well).
I should note that my primary purpose here is to eliminate the Renault automatic transmission in my car, as I'm getting tired of replacing them, and it seems the Porsche 911 is really the only other option due to the DeLorean's RWD/rear engine configuration. The performance and efficiency improvements of electric drive would just be a bonus, as would the much quieter ride. Amusingly enough, the pictures I found of the Tesla Roadster without the body on suggest that it's a RWD/rear engine car as well -- the electric motor sits behind the rear wheels.
Anyway, I'm very curious to see how this moviman's DeLorean build is done, what motors and batteries they used, and all that. Good luck!
-- Joe
Last edited by jangell; 01-11-2015 at 10:36 AM.
Something around 28-32KWh, if I remember correctly. They'll try to put in as much as possible without compromising the front trunk space or inside of the car.
Electric motors do have all their torque right off the line, yes. It is not true that they keep all that torque through their whole RPM range. Here's the torque curve for one potential motor (it looks low power, but remember we'd have 2-3 together). You can see that after 5k RPM, the torque starts to drop quite a lot. With fixed speed, if the car were geared for good performance off the line, it would have very poor power at high speeds. Gear for good power at high speed, get poor acceleration. And something in the middle just compromises both. Why do it?
A small drop in efficiency through the transmission is fine if it makes the car more fun. A hundred miles of range is fine for me because the places I'm going to be driving it are far less than a hundred miles round trip. If I need to go really far, that's what my hybrid is for. Not as cool as a DeLorean, but oh well.
It's not really possible to put a Model S battery in a DeLorean since it makes up the entire bottom of the car. However, I have thought about putting the body of a DeLorean on top of the whole "skateboard" frame of a Model S. I dunno about that, though... I'd rather have a genuine DeLorean. Besides, the wheelbase of the Model S is 21 inches longer than the DeLorean's. Good luck getting that to fit!
I suppose you could take apart the battery and use the individual modules... I dunno, perhaps. But EV West has never done something like that before (nobody really has yet, actually), so we're just going with the tried-and-true. I have also thought about using a Roadster battery, but I think they're a bit too large. I can always upgrade the batteries in the future 6-8 years down the line when the ones that are going in finally stop working. I'm sure Li-ion battery tech will have improved a lot by then, and if Tesla gets their gigafactory going, battery prices could be super low!
There is somebody who has experimented with the Model S pack, though, and you can check out some of that here if you're interested:
http://www.teslamotorsclub.com/showt...e-battery-pack
http://www.teslamotorsclub.com/showt...l=1#post755546
http://hackaday.com/2014/11/11/draft...-hacker-wk057/
I just noticed that I basically just re-iterated everything that jangell said. So, check out his post, too!
As for supercharger usage... stay tuned, I may have news about that in the future.
I'm not having a time machine conversion done, if that's what you mean. The movie made me aware of the DeLorean and made me fall in love with it.
If you're wondering why not a regular gas-powered one, well, no offense, but they're so, so underpowered. I could get a stage II or III kit, or do an engine swap, and it would be good. But an electric DeLorean is much more unique and cool! I'm willing to accept the compromises (high cost, limited range) for better performance and coolness.
Location: Poland
Posts: 329
My VIN: 6149 plus 2418, 3633, 5030, 17086
You're right. I over simplified when I said that the torque stays the same. Of course it doesn't. But then, there's one thing that comes to mind - use a different motor! Something that will provide higher RPM output and then just gear it down. Again, just what Tesla does.
Well, the drop is not going to be as small as you might think. You're right that having a manual trans is more fun so you have to decide if you want efficiency and range or fun. That's what it's all about, isn't itA small drop in efficiency through the transmission is fine if it makes the car more fun.
On the other hand with the limited energy storage I would go with efficiency and I would get rid of the transmission.
No, that's not what I was thinking about. That "skateboard" is way to big to fit the DeLorean. Besides, it would make the car a lot taller and that would kill the overall appearance of the car.It's not really possible to put a Model S battery in a DeLorean since it makes up the entire bottom of the car. However, I have thought about putting the body of a DeLorean on top of the whole "skateboard" frame of a Model S. I dunno about that, though... I'd rather have a genuine DeLorean.
That is exactly what I was thinking about. Since their battery is modular (kind of) I was thinking about taking it apart and then stuffing those "modules" wherever they would fit - above the motor and under the trunk floor. That might actually work.I suppose you could take apart the battery and use the individual modules...
I think you'll have to talk to Tesla. First you'll have to get their permission, second you'll need a way to "talk" to the SC.As for supercharger usage... stay tuned, I may have news about that in the future.
Good luck with the project. Sounds like fun! I really wish I had more time...
Greetings from Poland!
Tom
http://www.deloreana.com
Please excuse my typos... and watch this: Ben Champion - That Auto-Correct Song
Location: Hillsboro, OR
Posts: 476
My VIN: 4099
Club(s): (PNDC)
As an owner of two EVs (Tesla Model S and Fiat 500e), I'm curious as to how this will turn out. I would love to convert my D as well, but it's just not cost effective for me at this time because it would need to support DC quick charging so I could take it on road trips. To be practical there, you need at least a 50kWh battery and support for 100+kW charging. Needless to say, I take the Tesla for most road trips. :-) But I can always dream of having a D with the driving pleasures of an EV!
Please post lots of pics when they start working on it. Do you know the size of the AC charger they'll install? Try to get at least 6.6kW. Anything less will just be painfully slow if you need to use a public charger during the daytime.
Welcome to the future of driving!
Posts: 5
Whoa, this sounds awesome! Love the bare body + frame -- what a great way to start a project.
If you don't mind my asking, what's your budget for this project?
Excited to see what happens next!
I've driven a Tesla Roadster and a P85D. They're definitely a ton of fun! My DeLorean won't be that fast, unfortunately. But then again, not else much is!
I'll have them put in the most powerful charger they have. I definitely want high charge rates.
I'll post more pictures as they come to me from DMCH, but I have nothing else for now!
It's definitely exciting. The frame it's sitting on is not mine, by the way, just a shop frame on wheels to make the body easier to move around.
I'm not sure I want to give out exact numbers on the cost. It's probably a lot higher than most here would approve of.
Let me just say that getting a DMC-12 built from scratch is very expensive. Electric conversions like this are also definitely not cheap.
Posts: 5
Location: Maple Grove, MN (Minneapolis)
Posts: 1,423
My VIN: 05457
I'm sure Mario negotiated his own reasonable price, but back in 2012 DMCH announced a $95k price tag. Granted that was with a different electric motor supplier.
http://www.autoblog.com/2012/04/05/d...-95-000-in-20/
That price doesn't seem out of line considering what other luxury all electrics go for.
David Proehl