# Best EV motor for 4WD?



## rmay635703 (Oct 23, 2008)

A $500 leaf motor can be driven to about that power level,

OEM controller and gearbox could be adapted with some skill and canbus trickery documented in various places here.

As toward 4wd , I think it easier to keep the drivetrain stock save a manual XMSN conversion , otherwise you will need a motor for each axle which gets complex.


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## motas (Apr 21, 2017)

rmay635703 said:


> A $500 leaf motor can be driven to about that power level,
> 
> OEM controller and gearbox could be adapted with some skill and canbus trickery documented in various places here.
> 
> As toward 4wd , I think it easier to keep the drivetrain stock save a manual XMSN conversion , otherwise you will need a motor for each axle which gets complex.


Would a Leaf motor be reliable if it's driven above the stock power level? Any issues with getting parts/servicing on a repurposed motor? I plan to keep this for a while so long term reliability is a concern.

Keeping the transfer case makes the drivetrain very easy, shouldn't have any issue there, and I expect it to be easy enough to adapt any motor to a transfer case. I also have a fairly wide range of gearing to choose from if need be.

Thanks!


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## rmay635703 (Oct 23, 2008)

motas said:


> Would a Leaf motor be reliable if it's driven above the stock power level? Any issues with getting parts/servicing on a repurposed motor? I plan to keep this for a while so long term reliability is a concern.
> 
> Keeping the transfer case makes the drivetrain very easy, shouldn't have any issue there, and I expect it to be easy enough to adapt any motor to a transfer case. I also have a fairly wide range of gearing to choose from if need be.
> 
> Thanks!


Depends, are you going to continuously draw 150kw?

If not then yes it would be very reliable, they are good with cooling to a continuous 100kw with intermittent peaks above that perfectly acceptable.

You would need to ensure you are geared down enough as these motors are happiest at high rpm.


In terms of parts And service no hobbiest motor has any such support for long, repurposing an OEM solution gives you the largest wrecker yard selection should something break.

DIY = no support


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## motas (Apr 21, 2017)

rmay635703 said:


> motas said:
> 
> 
> > Would a Leaf motor be reliable if it's driven above the stock power level? Any issues with getting parts/servicing on a repurposed motor? I plan to keep this for a while so long term reliability is a concern.
> ...


My gut feel is 100kW constant is going to struggle, but I haven't got any experience with EV so I'm not sure how well it translates to comparing with an IC and gearbox. 

I can gear down to 5.89:1, or with some work down to 7.17:1. The transfer case is 1:1 in high range, but gives me the option of a 3:1 reduction as well. If I had to go all out I could get an Atlas transfer case with multiple reductions for better gear selection. 

What would be the next common step up from a Leaf motor? Are there any "standard" sized motors? 

Thanks!


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## brian_ (Feb 7, 2017)

There have been several extended discussions in this forum of this specific issue (selecting a motor and configuration for a 4WD vehicle); I think it's worth looking for them.



motas said:


> I can gear down to 5.89:1, or with some work down to 7.17:1. The transfer case is 1:1 in high range, but gives me the option of a 3:1 reduction as well.


You may not want to run a transfer case in low range all of the time, and assuming that you want to be able to drive on hard surfaces (not just loose dirt and gravel) you would need to check is your transfer case can be (perhaps with modification to the shift mechanism) run in low range 2WD.
Just the reduction in your axles will be enough for a low-speed motor, but insufficient to take advantage of the speed range available in most EV motor (which run up to 10,000 rpm or more).

An oddball possibility is the motor from the Chevrolet Spark EV, which was designed to run at lower speed in combination with only 4:1 (approximately) gear reduction from motor to wheels. The Spark EV was replaced by the Bolt, which uses a more typical gear reduction ratio, allowing it to use a smaller but more powerful motor.



motas said:


> What would be the next common step up from a Leaf motor? Are there any "standard" sized motors?


No. There are some industrial standards for mounting faces, followed by most of the motors used in industrial equipment (such as forklift trucks) and most of the lower-voltage motors offered by the aftermarket for EV conversions (such as the HPEVS AC-xx series), but there is no set of standards for EV motor sizes.


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## motas (Apr 21, 2017)

brian_ said:


> There have been several extended discussions in this forum of this specific issue (selecting a motor and configuration for a 4WD vehicle); I think it's worth looking for them.
> 
> 
> You may not want to run a transfer case in low range all of the time, and assuming that you want to be able to drive on hard surfaces (not just loose dirt and gravel) you would need to check is your transfer case can be (perhaps with modification to the shift mechanism) run in low range 2WD.
> ...


I have found a few threads, but many are looking for something on an extremely tight budget and are discussing miscellaneous scrapyard motors that I wouldn't necessarily be able to find the same.

A twin stick transfer case is easily available to have low range 2WD but I don't want to run it in low range all the time because then I would lack actual low range for off road use. May not be as big of an issue with EV and no clutch though.

There are a few options for further gear reduction, but all of them come at a cost. The simplest would be a gear reduction module bolted between the motor and transfer case, but it doesn't seem these are very common. An Atlas transfer case can give me 4 gearing options with independent 4WD/2WD selection, but they are expensive and having the 1:1 gear would be a waste. Portal axles would be an amazing addition, but the cost is insane. 

By my calculations a motor running at 5000RPM gives me a speed of 116km/h which is as fast as this will ever need to go, but obviously on the low end of electric motors.

I'll look into the Chev. I should mention I am in Australia, so the selection of EV wrecked parts is slim to none. I would be happy enough to import, but it adds to the costs and complications of finding a wrecked motor.

I take it that forklift and industrial motors aren't overly useful to me? Funnily enough the diesel already in it is most commonly found in forklifts.

Thanks!


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## motas (Apr 21, 2017)

Okay so a bit more research and looks like an Atlas 4 speed isn't a terrible option. It has an additional 2.72:1 reduction on the input of the transfer case, and then has a further gear reduction in low range between 2:1 and 5:1. There are some other advantages of swapping out to an Atlas as they are renowned for the strength and reliability, and it gives the option of RWD, FWD or 4WD in both high and low range.

This would give the Jeep a cruising speed of 108km/h at 8,000RPM with 4.56:1 differential ratios, which work with the factory Dana 44 in the front. Could easily drop this further for a motor with a higher RPM.

Bolting this to a Remy 250 would give me a bit more power at the wheels than the factory motor, about 25% more worst case (considering the diesel at peak torque, no gearbox losses, no gearbox changes and no clutch). 

Unfortunately the cost of this powertrain is about $15,000 USD though, before even thinking about a controller and batteries, so it may be worth some more looking into wrecked EV motors.

Is it possible to split a Tesla motor from the drivetrain and drive it independently? I'm guessing in a few years the Model 3 motors will be easy to get, and seem approximately the right size for this application, but they seem to be sold as a unit with the gearbox, which is useless for me. 

Cheers!


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## brian_ (Feb 7, 2017)

motas said:


> Is it possible to split a Tesla motor from the drivetrain and drive it independently? I'm guessing in a few years the Model 3 motors will be easy to get, and seem approximately the right size for this application, but they seem to be sold as a unit with the gearbox, which is useless for me.


The Tesla Model S/X drive units use the same casting as the drive end housing of the motor and one side of the transaxle; there's nothing wrong with that, but it makes using the motor separately more difficult, so that is rarely done. It is one reason that motors are sold with the gearbox, but other EV motors are also typically sold with the transaxle, even though they can be readily separated.


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## motas (Apr 21, 2017)

brian_ said:


> The Tesla Model S/X drive units use the same casting as the drive end housing of the motor and one side of the transaxle; there's nothing wrong with that, but it makes using the motor separately more difficult, so that is rarely done. It is one reason that motors are sold with the gearbox, but other EV motors are also typically sold with the transaxle, even though they can be readily separated.


Thanks, that makes sense.

I would need to machine an adapter plate between the motor and transfer case regardless, which could potentially be a replacement drive end housing, but obviously that would depend heavily on the complexity of the part. 

The Nissan Leaf looks practically impossible to separate the motor from the rest of the assembly, and my feeling is that it's just a little bit too light duty for this application.


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## brian_ (Feb 7, 2017)

motas said:


> The Nissan Leaf looks practically impossible to separate the motor from the rest of the assembly, and my feeling is that it's just a little bit too light duty for this application.


The Leaf motor simply unbolts from the transaxle. Although I don't know offhand how visible the bolts are, the motor and transaxle have separate housings and the motor has been used with various other transmissions, including by members of this forum.

The Leaf motor was initially limited to only 80 kW to protect the battery, is allowed 110 kW (possibly limited by inverter capacity) with the current base battery, and gets 150 kW with the optional big battery... and I've never heard of a change in the actual motor.


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## motas (Apr 21, 2017)

brian_ said:


> The Leaf motor simply unbolts from the transaxle. Although I don't know offhand how visible the bolts are, the motor and transaxle have separate housings and the motor has been used with various other transmissions, including by members of this forum.
> 
> The Leaf motor was initially limited to only 80 kW to protect the battery, is allowed 110 kW (possibly limited by inverter capacity) with the current base battery, and gets 150 kW with the optional big battery... and I've never heard of a change in the actual motor.


That is great to hear about the Leaf motor. I found this image from Nissan which made it look VERY tightly integrated, but looking around it does seem easily separable.










I was basing my assumptions off the 80kW power rating. 100kW constant and 150kW peak puts it around the same as the Remy and hopefully just enough to not feel like an absolute snail. Coincidentally my current Jeep JK has around 160kW, it is slow, but not unbearable and I expect an electric motor to feel a little faster.

Any advice on where to find used/reconditioned Leaf motors? They aren't overly common in Australia, so I'd be looking at importing one unseen. You mentioned they go for around $500 USD? 

Thanks again for all the help. I feel like I'm relearning everything I know about cars all over again!


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## brian_ (Feb 7, 2017)

motas said:


> That is great to hear about the Leaf motor. I found this image from Nissan which made it look VERY tightly integrated, but looking around it does seem easily separable.


In all but the earliest variation of the Leaf powertrain the motor is highly integrated electrically with the inverter, with terminals from the motor sticking into the inverter case directly, with no external cables. If there is space above the motor for the inverter (and even the PDM which sits on top of the inverter, I think again with no external cables to the inverter) leaving it there is certainly the easiest way to go... and you have to put that stuff somewhere, anyway. Of course, if the motor is in the original location of a transmission, there is likely no room there for the inverter or PDM.



motas said:


> Any advice on where to find used/reconditioned Leaf motors? They aren't overly common in Australia, so I'd be looking at importing one unseen. You mentioned they go for around $500 USD?


That wasn't me... there are essentially no used EV parts around here, either, and I don't know what any of them would really cost. I assume I would need to get one shipped from the U.S.

I doubt that there are any reconditioned motors available, since nothing will have gone wrong with them. I think they'll just be used.


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## motas (Apr 21, 2017)

brian_ said:


> In all but the earliest variation of the Leaf powertrain the motor is highly integrated electrically with the inverter, with terminals from the motor sticking into the inverter case directly, with no external cables. If there is space above the motor for the inverter (and even the PDM which sits on top of the inverter, I think again with no external cables to the inverter) leaving it there is certainly the easiest way to go... and you have to put that stuff somewhere, anyway. Of course, if the motor is in the original location of a transmission, there is likely no room there for the inverter or PDM.
> 
> 
> That wasn't me... there are essentially no used EV parts around here, either, and I don't know what any of them would really cost. I assume I would need to get one shipped from the U.S.
> ...


I'm intending to put the motor where the gearbox currently sits, so if I wanted to keep the inverter mounted above the motor I would need to mount it in the engine bay and run a driveshaft to the transfer case. Easily doable, but not a nice solution in my mind. The other option would be a reverse mount motor just behind the cab, but that would depend on the overall height and clearance to the bed, as well as how short the rear driveshaft would end up. 

Space isn't something I'm short of luckily. The engine bay is huge, and there are two 80 litre fuel tanks to replace with room to spare. Hoping by the time this project is over batteries are cheap enough to fill all the space and have a ridiculously long range. 

I think I've found one wrecked Nissan Leaf here (out of a total of 997 sold), so I'll find out how much the powertrain is if they still have it.


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## rmay635703 (Oct 23, 2008)

You likely need to make lots of calls pay someone to be an inspector/currier but hybrid and EV drivetrain parts have virtually ZERO market here, I expect getting it to you as expensive as a flight and due diligence of personally picking the motor.


Well what do you know (no affiliation unknown rep)

https://www.diyelectriccar.com/forums/showthread.php?t=201083


Shipping from Japan of a full wreck may be cheaper for you in the long run, see below


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## motas (Apr 21, 2017)

rmay635703 said:


> You likely need to make lots of calls pay someone to be an inspector/currier but hybrid and EV drivetrain parts have virtually ZERO market here, I expect getting it to you as expensive as a flight and due diligence of personally picking the motor.
> 
> 
> Well what do you know (no affiliation unknown rep)
> ...



Wow they are cheap!


I do have some business in USA and travel there occasionally and can probably get it shipped back for nothing. For $500-1000 I might grab one to play with even if I don't end up using it.



I've also been looking further into the BorgWarner/Remy motors. Looks like the OEM style housing is a bit more budget friendly, and pretty easily available. eBay has used motors for around the $2,500 USD mark.


The advantages of the BorgWarner is there is better information available since they are sold for industrial use as well, and I expect that parts and service will be easier to obtain through BorgWarner than through Nissan. They use a fairly standard mounting pattern and output shaft, which should be easy to adapt to a transmission. They also seemed to be used in a few different EV cars including this Chev concept:


https://www.carsales.com.au/editorial/details/evil-ev-chevy-camaro-ecopo-makes-520kw-115428/


I'm speaking to a few suppliers to see how much a brand new motor is. I'm guessing somewhere in the $5-10k range.


Has anyone seen a DIY conversion using a HVH motor? Any problems with running 350V+ in a conversion?


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## rmay635703 (Oct 23, 2008)

https://classicmotorsports.com/foru...ly-planning-stage-homebuilt-car/119159/page2/

https://www.diyelectriccar.com/forums/showthread.php?t=160986

https://m.youtube.com/watch?feature=youtu.be&v=DpdHRiAKkAI

Remy much talked about, rarely used by us mere mortals.

Nothing easy about them.


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## motas (Apr 21, 2017)

rmay635703 said:


> https://classicmotorsports.com/foru...ly-planning-stage-homebuilt-car/119159/page2/
> 
> https://www.diyelectriccar.com/forums/showthread.php?t=160986
> 
> ...



I feared that may be the case when I couldn't find a single project using them.


Interesting that much of that thread is discussing building a housing for the cartridge though, it seems that BorgWarner offers a perfectly good housing already. They even offer a lower performance water cooled option, with a ~40% lower continuous rating, which would probably be sufficient assuming ~40kW required for highway driving.


Is there something particularly difficult I am missing?


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## rmay635703 (Oct 23, 2008)

If you buy everything new probably nothing out of the ordinary 

I would ask Frodus and see


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## brian_ (Feb 7, 2017)

rmay635703 said:


> Remy much talked about, rarely used by us mere mortals.
> 
> Nothing easy about them.


I think they're probably as easy to use as any motor that has no available adapter to mount it to a production car's transmission, as long as you can afford a matched controller/inverter. Of course, mere mortals can't afford that...


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## motas (Apr 21, 2017)

brian_ said:


> I think they're probably as easy to use as any motor that has no available adapter to mount it to a production car's transmission, as long as you can afford a matched controller/inverter. Of course, mere mortals can't afford that...


I was guessing adapting an electric motor to a transmission would be one of the easier tasks. BorgWarner do a bolt on transmission as well though which looks easy to adapt to any IFS/IRS car:










I do hope there is a boom coming in aftermarket EV parts, it seems so much simpler than IC with the massive reduction in parts. Electric RC cars are pretty much plug and play interchangeable between hundreds of different motors controllers and batteries. Time will tell I guess. By the time I have the rest of the car ready it may have happened already 

I've contacted Cascadia for a quote, will see what that comes back as.


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## motas (Apr 21, 2017)

Okay so I have maybe been overestimating my power requirements a little. I was sitting here worrying that 150kW peak might be a bit sluggish.

So I looked at the two most popular utes in Australia, the Toyota Hilux which has a claimed 130kW and 450nM, and the Ford Ranger which has a claimed 157kW and 500nM. Both of these are bigger and heavier than my Jeep (although substantially better aero), and obviously have the losses associated with a gearbox and gear changes as well.

Is there a rule of thumb for electric - IC power comparison? I understand 150kW is 150kW, but with the substantially different power curves and lack of gears I'm guessing an electric 150kW feels noticeably faster than a diesel 150kW.


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## brian_ (Feb 7, 2017)

motas said:


> I feared that may be the case when I couldn't find a single project using them.


No DIY projects, but lots of corporate projects. Example:
https://www.diyelectriccar.com/forums/showthread.php/2019-pikes-peak-racecar-200633.html



motas said:


> Interesting that much of that thread is discussing building a housing for the cartridge though, it seems that BorgWarner offers a perfectly good housing already. They even offer a lower performance water cooled option, with a ~40% lower continuous rating, which would probably be sufficient assuming ~40kW required for highway driving.


In the other direction, there are also the AM Racing housings (sold as complete motors), from Cascadia Motion.

An early use of these motors was as components within GM and BMW Two-Mode Hybrid transmissions, long ago, which is one reason they are designed to be a core which continues to be available without a housing.



motas said:


> Is there something particularly difficult I am missing?


With any motor, physically mounting it and connecting it's output shaft to the transmission input is a challenge, so anything for which off-the-shelf adapters and couplers are not available is difficult. That's why there is a significant advantage to using a salvaged EV motor with the transaxle which is designed for it.

The other challenge with any AC motor is matching a controller-inverter to it, so a DIYer has difficulty making mismatched components work... but if you can afford a new controller-inverter which is set up by the manufacturer for the HVH motors, that difficulty goes away.


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## brian_ (Feb 7, 2017)

motas said:


> So I looked at the two most popular utes in Australia, the Toyota Hilux which has a claimed 130kW and 450nM, and the Ford Ranger which has a claimed 157kW and 500nM. Both of these are bigger and heavier than my Jeep (although substantially better aero), and obviously have the losses associated with a gearbox and gear changes as well.


Transmission losses in a manual transmission or modern automatic are pretty low. A single-ratio reduction box will be better, but not noticeably. Gear changes are power interruptions, but in an automatic those interruptions are a small fraction of a second, and the multiple ratios are important to keeping the engine at a speed where it can produce the desired power.


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## motas (Apr 21, 2017)

brian_ said:


> No DIY projects, but lots of corporate projects. Example:
> https://www.diyelectriccar.com/forums/showthread.php/2019-pikes-peak-racecar-200633.html
> 
> 
> ...


I want that!

Interesting, I didn't realize Cascadia/Rinehart was a subsidiary of BorgWarner/Remy. That explains why their controllers are so well matched for the motor.

No matter which way I go I will need to custom adapt the motor to the transfer case as the usual transaxle is useless in this application. Worst case I should be able to make a short adapter shaft with the required spline on each end, and a bell housing between the two. 

I need to do more research into controllers, I kind of assumed it would be a simpler/cheaper part than the motor and batteries. I was pretty wrong there.



brian_ said:


> Transmission losses in a manual transmission or modern automatic are pretty low. A single-ratio reduction box will be better, but not noticeably. Gear changes are power interruptions, but in an automatic those interruptions are a small fraction of a second, and the multiple ratios are important to keeping the engine at a speed where it can produce the desired power.


Ha, you think Australia has modern transmissions! Aussie utes are still stuck with slush boxes, although we must be due for dual clutch tech in the next models. The manual Hilux also has a reduced power output. Anyway the point was 150kW peak I was aiming for puts me at least equal to the most powerful ute in Australia.

I'm guessing there is still a noticeable difference in power due to the torque curves though? IE 150kW electric is faster than 150kW IC?


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## motas (Apr 21, 2017)

So, $5000 for the HVH250-90-DOM in the OEM style BorgWarner cast housing.


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## brian_ (Feb 7, 2017)

*HVH history*



motas said:


> Interesting, I didn't realize Cascadia/Rinehart was a subsidiary of BorgWarner/Remy. That explains why their controllers are so well matched for the motor.


BorgWarner acquired Remy, including the HVH motor line. AM Racing had already been building their housings for HVH cores in the Remy days; Rinehart was building controllers for the HVH motors. More recently, BorgWarner acquired both AM Racing and Rinehart, and placed them into a new subsidiary called Cascadia Motion. So the ownership is the result of the technical relationships, not the other way around.


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## brian_ (Feb 7, 2017)

motas said:


> Ha, you think Australia has modern transmissions! Aussie utes are still stuck with slush boxes, although we must be due for dual clutch tech in the next models.?


Dual-clutch transmissions are not any more efficient than modern "slushbox" torque-converter equipped planetary gear automatics. The efficiency comes from locking up the torque converter with a clutch (common practice for decades now) and minimizing hydraulic drag with intelligent pump management.

Despite the selection of a dual-clutch for the latest generation of Corvette, I don't think dual-clutch transmissions are necessarily the future of multi-speed transmissions.

Anyway, I understand that the desire is to get rid of any multi-speed transmission in this conversion.


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## brian_ (Feb 7, 2017)

motas said:


> I was guessing adapting an electric motor to a transmission would be one of the easier tasks. BorgWarner do a bolt on transmission as well though which looks easy to adapt to any IFS/IRS car:





motas said:


> No matter which way I go I will need to custom adapt the motor to the transfer case as the usual transaxle is useless in this application. Worst case I should be able to make a short adapter shaft with the required spline on each end, and a bell housing between the two.


A common challenge for salvaged motors and uncommon transmissions is adapting their unrelated mounting bolt patterns; however, that BorgWarner transaxle appears to have a bolt-on adapter housing anyway (which BorgWarner called an "adaptable flange" in a presentation), so anyone up to substantial custom fabrication could build a different one for a different motor. That makes some sense, since BorgWarner intends this transaxle to be used by various OEMs with various motors; however, at the OEM level it's practical to just build the transaxle with a specific housing matched to the customer's desired motor.

EV West (and probably others) sell leftover surplus BorgWarner eGearDrive transaxles from the Azure Dynamics (AZD) bankruptcy; they are set up to mate with the Siemens motors used by AZD.

The usual problem with the shaft is simply mismatched splines (and again, an OEM would order the motor and transaxle with mating shafts). Yes, that means custom couplers and enough length in the housing adapter for the long combination of two shafts and a coupler between them, instead of the motor shaft sliding directly into or over the transaxle input shaft.


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## motas (Apr 21, 2017)

brian_ said:


> Dual-clutch transmissions are not any more efficient than modern "slushbox" torque-converter equipped planetary gear automatics. The efficiency comes from locking up the torque converter with a clutch (common practice for decades now) and minimizing hydraulic drag with intelligent pump management.
> 
> Despite the selection of a dual-clutch for the latest generation of Corvette, I don't think dual-clutch transmissions are necessarily the future of multi-speed transmissions.
> 
> Anyway, I understand that the desire is to get rid of any multi-speed transmission in this conversion.


Interesting! I'm guessing a dual clutch transmission shifts quiet a bit faster than a torque converter though? 

To be fair the last auto I owned was a Mitsubishi Triton, which is the cheapest name brand ute here and featured a 4 speed auto. It also holds the title of the only automatic car I've managed to stall.

I can certainly see the advantages of a gearbox though, especially since there needs to be a gear reduction before the transfer case anyway, and since electric motors don't need a clutch. But keeping the 4 speed manual gearbox seems unnecessary, and I haven't seen any great alternatives yet.

In the ideal world I'd make an on the fly shiftable transfer case, but somehow I think the project is big enough already 



brian_ said:


> A common challenge for salvaged motors and uncommon transmissions is adapting their unrelated mounting bolt patterns; however, that BorgWarner transaxle appears to have a bolt-on adapter housing anyway (which BorgWarner called an "adaptable flange" in a presentation), so anyone up to substantial custom fabrication could build a different one for a different motor. That makes some sense, since BorgWarner intends this transaxle to be used by various OEMs with various motors; however, at the OEM level it's practical to just build the transaxle with a specific housing matched to the customer's desired motor.
> 
> EV West (and probably others) sell leftover surplus BorgWarner eGearDrive transaxles from the Azure Dynamics (AZD) bankruptcy; they are set up to mate with the Siemens motors used by AZD.
> 
> The usual problem with the shaft is simply mismatched splines (and again, an OEM would order the motor and transaxle with mating shafts). Yes, that means custom couplers and enough length in the housing adapter for the long combination of two shafts and a coupler between them, instead of the motor shaft sliding directly into or over the transaxle input shaft.


This is the main reason I think an Atlas transfer case is the way to go no matter what else I end up with. They already offer 8 different input splines, and can most likely machine a custom spline if required, or worst case I can have a new input shaft machined. This should mean all that is required is an adaptor plate which is dead simple to make.


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## motas (Apr 21, 2017)

Speaking of gearboxes. In low range the top speed is ~80kmh, so I could theoretically drive around town in low range with spectacular performance, with the catch that I have to stop and change gears before going onto higher speed roads.

Axletech also offers a 2 speed transfer case with synchros for on the fly shifting, looks very heavy duty. Also has full time 4WD and a PTO output for I don't know what. Flange mount would be easy to adapt to anything. Can only withstand 5,250Nm of torque though .


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## motas (Apr 21, 2017)

Alright, now you've sent me down the gearbox rabbit hole.

I was involved in the development of a custom transaxle for a FSAE car. It was a cool concept with a stressed carbon fibre housing which the rear suspension mounted off. The gearbox itself was a very simple sequential, straight geared dog box with 4 gears which worked really well. The carbon housing on the other hand was impossible to manufacture in spec and constantly leaked onto the track. Anyway, the clutch was only used to take off, and shifting was done with a shift cut in the ECU program as you slammed it into gear. Before the shift cut was worked out it was horrible to shift, but afterwards it worked really surprisingly well with very fast shifting. This was obviously on a very small race car with a 450cc motor and short shift gears, but still I was pleasantly surprised.

So my question is, would an EV require synchros, or would a dog box work okay? My thinking is the inertia of an electric motor is far less than a petrol motor, and a shift cut should be easy to implement. It may even be possible to accelerate or brake the motor briefly between shifts to aim for the correct RPM. I imagine an unloaded electric motor would accelerate very quickly.

There are a few tougher transfer cases which are essentially a dog box transmission, and I'm wondering whether these may be able to support shifting when they are attached to an electric motor rather than a gearbox.


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## brian_ (Feb 7, 2017)

motas said:


> I was involved in the development of a custom transaxle for a FSAE car. It was a cool concept with a stressed carbon fibre housing which the rear suspension mounted off. The gearbox itself was a very simple sequential, straight geared dog box with 4 gears which worked really well. The carbon housing on the other hand was impossible to manufacture in spec and constantly leaked onto the track. Anyway, the clutch was only used to take off, and shifting was done with a shift cut in the ECU program as you slammed it into gear. Before the shift cut was worked out it was horrible to shift, but afterwards it worked really surprisingly well with very fast shifting. This was obviously on a very small race car with a 450cc motor and short shift gears, but still I was pleasantly surprised.
> 
> So my question is, would an EV require synchros, or would a dog box work okay? My thinking is the inertia of an electric motor is far less than a petrol motor, and a shift cut should be easy to implement. It may even be possible to accelerate or brake the motor briefly between shifts to aim for the correct RPM. I imagine an unloaded electric motor would accelerate very quickly.


Your thinking has gone exactly the same route as mine. A manual transmission designed for EV use, as part of an integrated system with the motor, has no need for synchros. Even if using a gearbox with synchros, active management of the motor should eliminate any need for the clutch.

The problems DIY conversions have with clutchless shifting result from a lack of any management of the motor speed. Shifting up, the motor coasts freely and (helped by the high inertia compared to just a clutch disk) is too fast for the next gear so the synchros have a hard time slowing it down; shifting down, the motor needs to be sped up and the synchros have trouble accelerating all that motor inertia.

Motor speed management to match shaft speeds for a shift should be easy with an electric motor; Toyota even does it now with the engine in their basic compact car model, the Corolla.

A sequential-shift design has the advantage that if the driver is manually moving the shift mechanism, the controller knows as soon as the drum starts to turn whether it is an upshift or a downshift. Unfortunately, with an H-pattern shifter, the controller doesn't know until the fork is moved toward the next gear which way it is going, so it can't start adjusting the motor speed until then.


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## brian_ (Feb 7, 2017)

motas said:


> Axletech also offers a 2 speed transfer case with synchros for on the fly shifting, looks very heavy duty. Also has full time 4WD and a PTO output for I don't know what.


Don't need to run a winch, or a hydraulic pump for some sort of equipment? 



motas said:


> Can only withstand 5,250Nm of torque though .


The joys of torque multiplication: big low-speed engine's maximum torque output, multiplied by the lowest gear of the transmission... not a concern in this case, of course.


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## brian_ (Feb 7, 2017)

*Shifting automatics*



motas said:


> Interesting! I'm guessing a dual clutch transmission shifts quiet a bit faster than a torque converter though?


Not necessarily. Until recently, automatics with lock-up clutches for the torque converter would go through a long sequence of unlocking, releasing the clutches or brakes for one gear, engaging those for the next, and locking back up. The latest generation leave the torque converter clutch locked, and release the clutch for the current gear while engaging the clutch for the next - they do effectively the same thing as the dual-clutch, and don't even have a preparation stage of moving synchros to pre-engage the next gear.

Older automatics were also hampered by complex hydraulic controls, while modern units are computer controlled. The shift work is still done by hydraulic clutches, but they are triggered more precisely and quickly.


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## coleasterling (Feb 29, 2012)

motas said:


> Alright, now you've sent me down the gearbox rabbit hole.
> 
> I was involved in the development of a custom transaxle for a FSAE car. It was a cool concept with a stressed carbon fibre housing which the rear suspension mounted off. The gearbox itself was a very simple sequential, straight geared dog box with 4 gears which worked really well. The carbon housing on the other hand was impossible to manufacture in spec and constantly leaked onto the track. Anyway, the clutch was only used to take off, and shifting was done with a shift cut in the ECU program as you slammed it into gear. Before the shift cut was worked out it was horrible to shift, but afterwards it worked really surprisingly well with very fast shifting. This was obviously on a very small race car with a 450cc motor and short shift gears, but still I was pleasantly surprised.
> 
> ...


Well hello WWU. 

Agreed with Brian, no need for synchros.


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## motas (Apr 21, 2017)

Thankfully 2 speeds are always sequential! I'm also tipping a 2 speed gearbox is pretty easy to manage automatic shifting, something as simple as shift up at 75km/h, shift down at 55km/h would probably even work fairly well, otherwise manual shifting would be easy as it always knows it's moving to the other gear.


I'd expect there may be some timing issues for clutch less shifting, but possibly a basic program which shifts to neutral, matches RPM, then shifts to gear would be simple, although may be a little slow. The shift cut was much cruder, and as I said worked surprisingly well. 



I'm not sure a 2 speed gearbox would substantially reduce the power requirement of the motor though. The electric motor is at its worst accelerating at high speed, for example 80-100km/h, which would always be in the highest gear anyway. To get the right cruising speed of 110km/h, the electric motor already outperforms an IC at low speeds. Having a lower gear would make the low speed power phenomenal, and is needed for off road work regardless, but doesn't help on say a freeway on ramp or a long high speed uphill. Could be fun dragging sports cars to 60km/h though.



Unfortunately I can't use a transfer case as a gearbox, because I need an additional gear reduction going into it which would make RPM matching more difficult. I could possibly find a 2 speed gearbox and a transfer case without low range. 



Given how simple a 2 speed dog box is, it wouldn't be completely unreasonable to custom make one to suit. The most expensive part would be machining the housing, which would need a massive billet! Coincidentally one of the best aftermarket gearbox manufacturers (Albins) is 10 minutes away and sponsored the FSAE gearbox project, I'm guessing they'd be able to supply off the shelf gears which would work.


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## motas (Apr 21, 2017)

coleasterling said:


> Well hello WWU.
> 
> Agreed with Brian, no need for synchros.



Western Washington University?


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## coleasterling (Feb 29, 2012)

Yep, unless there's another team that did that. I've never seen another one.


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## motas (Apr 21, 2017)

coleasterling said:


> Yep, unless there's another team that did that. I've never seen another one.



RMIT in Australia.


I believe RMIT did well in the US back in ~2004 with one of the first carbon monocoques. The stressed transaxle didn't make it through the Australian comp so no point sending it to the US.


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## coleasterling (Feb 29, 2012)

motas said:


> RMIT in Australia.
> 
> 
> I believe RMIT did well in the US back in ~2004 with one of the first carbon monocoques. The stressed transaxle didn't make it through the Australian comp so no point sending it to the US.


Ahhhh, of course some Aussies would have done it. Sorry...WWU did one with their V8 back in 2001-2002. 

RMIT has always been one of the better teams in my mind. We (Texas A&M) competed against them back in the mid 2000's.


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## motas (Apr 21, 2017)

coleasterling said:


> Ahhhh, of course some Aussies would have done it. Sorry...WWU did one with their V8 back in 2001-2002.
> 
> RMIT has always been one of the better teams in my mind. We (Texas A&M) competed against them back in the mid 2000's.



RMIT really encourages the team to push the boundaries and do things differently. At that stage it was mainly composites, but they're pushing their titanium 3D printing these days. The one I drove had a really cool titanium exhaust plenum.


It ends up really well sometimes, mid 2000s they did exceptionally well and smashed the Aussie competition, but since then there's just been endless reliability issues. They did really well in endurance a week or two ago at comp, but didn't finish some of the other events. 



I noticed you were from Bryan. We were at Texas A&M around this time 2 years ago doing some crash testing on a temporary workzone barrier out on the old airfield. It was f***ing freezing!


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## coenvanwyk (Apr 6, 2014)

I do not know much abiout EV's, but I do know about offroading, and sheer power isn't it. The most capable offroad vehicle I have ever seen was a CJ2, with all of 28hp. With good driver technique that will outclimb and out-dig any 100hp and more monsters. However, once I win the lottery I intend building an electric six wheeler with walking axle at the back, and six in-wheel motors. YOu don't worry about unsprung wheel weight on a real offroader. But we need the high power guys to thow mud and get stuck.


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## motas (Apr 21, 2017)

coenvanwyk said:


> I do not know much abiout EV's, but I do know about offroading, and sheer power isn't it. The most capable offroad vehicle I have ever seen was a CJ2, with all of 28hp. With good driver technique that will outclimb and out-dig any 100hp and more monsters. However, once I win the lottery I intend building an electric six wheeler with walking axle at the back, and six in-wheel motors. YOu don't worry about unsprung wheel weight on a real offroader. But we need the high power guys to thow mud and get stuck.


Absolutely agree. The low range power of this will be ridiculous, but it's just the byproduct of having enough power to get a big, unaerodynamic box up to freeway speeds.

Have to disagree on the unsprung weight though, but that probably applies to Australian off road more than American rock crawling. Driving through the bush here involves a lot of moderate speed bumps and lightweight unsprung makes a big difference to response.


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## coleasterling (Feb 29, 2012)

motas said:


> I noticed you were from Bryan. We were at Texas A&M around this time 2 years ago doing some crash testing on a temporary workzone barrier out on the old airfield. It was f***ing freezing!


Been there, done that! Those runways are dang cold in the winter! Shoot me a message if you're ever back around here!


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## motas (Apr 21, 2017)

coleasterling said:


> Been there, done that! Those runways are dang cold in the winter! Shoot me a message if you're ever back around here!


Will do mate! I don't work for that company anymore but will be crash testing some horse trailers over the next few years so might have some business over there. 

Back onto the old Jeep, am I being too optimistic in power levels? From people who have actually built and driven EVs what kind of power level should I be aiming for? I'm not looking for anything crazy I just want it to feel like a normal ute to drive.

With the Remy 250, PM150DX and a 400V battery I can expect around 120kW. To bump that up to ~150kW I'd be looking at a 600V battery or the PM250DX. 

The PM150DX is already $10k, plus the $5k for the Remy motor, before even thinking about batteries, it's turning in to a very expensive proposition and an LS crate motor is starting to look more attractive. 

Cheers!


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## Frank (Dec 6, 2008)

I've used both flavors of Remy HVH250-090 motors in my motorcycle. The series wound (SOM I think it is) makes more torque but peaks out sooner. Overall power is lower but might be a better choice for you because of the higher torque. It's a good fit with the standard PM100DX controller.

The DOM (parallel wound) makes less torque but carries it out further, resulting in higher power numbers (same controller, modified to the DX"R" version). My logs show 150+kW battery power with a 96S battery sagged to about 360V with the DOM. Ultimate power depends on battery voltage.

Remember that power numbers are only achieved once the motor reaches base speed (and are supposedly constant after that) but you will make less power at lower motor speeds. The DOM's base speed is > 5K rpm and the SOM is somewhere around half that I think. My opinion is that the higher torque version is better for a slower moving vehicle. My original conversion was with the SOM (because that's what I stumbled across) but in my racing life I wanted to go faster and switched to the DOM.


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## brian_ (Feb 7, 2017)

I think that when you get down to the details, the differences between the various HVH motor cores are important, as Frank explained. In addition to the series or parallel wiring (basically to suit system voltage), there's also the size, since there are 250-90, 250-115, and even 250-150 versions ("250" is the rotor diameter in millimetres, and "90", "115" or "150" is the rotor axial length in millimetres). It seems that the -90 size is the most common, and -150 is rare. Current, torque, and power should all vary almost directly in proportion to length.

If you have lots of room for diameter, there's even the HVH 410 series, which is typically used in trucks and buses.


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## brian_ (Feb 7, 2017)

Since an HVH motor is still in the running...

I stumbled across a note in the Remy Hybrid Application Manual which says that the regular Remy (now BorgWarner) housing for the HVH 250 series has "IEC 72 Frame size 160 mounting features". So in addition to their dimensioned drawings, there is a standard specification for the mounting face.


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## motas (Apr 21, 2017)

Frank said:


> I've used both flavors of Remy HVH250-090 motors in my motorcycle. The series wound (SOM I think it is) makes more torque but peaks out sooner. Overall power is lower but might be a better choice for you because of the higher torque. It's a good fit with the standard PM100DX controller.
> 
> The DOM (parallel wound) makes less torque but carries it out further, resulting in higher power numbers (same controller, modified to the DX"R" version). My logs show 150+kW battery power with a 96S battery sagged to about 360V with the DOM. Ultimate power depends on battery voltage.
> 
> Remember that power numbers are only achieved once the motor reaches base speed (and are supposedly constant after that) but you will make less power at lower motor speeds. The DOM's base speed is > 5K rpm and the SOM is somewhere around half that I think. My opinion is that the higher torque version is better for a slower moving vehicle. My original conversion was with the SOM (because that's what I stumbled across) but in my racing life I wanted to go faster and switched to the DOM.


Damn that must be a fast motorcycle! Do you have a build thread?

From my basic calcs (Excel spreadsheet) the most difficult part is decent high speed power. Looking at the torque curve electric motors have heaps of torque at low RPM but drop off substantially as it gets higher. For a speed of 110km/h I can either have the motor running at high RPM with low torque, or low RPM at high torque, which works out basically the same. With a motor powerful enough to be decent at freeway speeds the low speed power will be exceptional. 

This makes me think the DOM might be the better option. 



brian_ said:


> I think that when you get down to the details, the differences between the various HVH motor cores are important, as Frank explained. In addition to the series or parallel wiring (basically to suit system voltage), there's also the size, since there are 250-90, 250-115, and even 250-150 versions ("250" is the rotor diameter in millimetres, and "90", "115" or "150" is the rotor axial length in millimetres). It seems that the -90 size is the most common, and -150 is rare. Current, torque, and power should all vary almost directly in proportion to length.
> 
> If you have lots of room for diameter, there's even the HVH 410 series, which is typically used in trucks and buses.


There is plenty of space, especially axially, so it may be worth considering the 115 model. How does this relate to controller cost? IE what is the limiting factor to controllers, I'm guessing max current?



brian_ said:


> Since an HVH motor is still in the running...
> 
> I stumbled across a note in the Remy Hybrid Application Manual which says that the regular Remy (now BorgWarner) housing for the HVH 250 series has "IEC 72 Frame size 160 mounting features". So in addition to their dimensioned drawings, there is a standard specification for the mounting face.


That's one of the things I like about it over a junkyard motor. In theory I can replace it with an alternative in the future if need be, although in practice I'm not sure if any other suitable motors use that particular standard, but they'd hopefully at least use a round bolt pattern with the shaft in the centre.


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## Frank (Dec 6, 2008)

Well, I went 140 with the SOM (96S pack) and 200+ with the DOM. How fast do you want to go? Land speed is mostly horsepower versus aerodynamics and a motorcycle typically does not use a transmission. A transfer case or gearbox will give you more options as far as torque at the axle goes but I would think more torque is better. Driving down the road at 90 km/h doesn't take that much power and either option can provide ample.

Here's a link to an old build thread http://www.landracing.com/forum/index.php?topic=14403.0 The pictures are lousy but there's some basic info there. I still have the SOM BTW but suspect shipping would be an issue. A project will probably present itself some day.


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## motas (Apr 21, 2017)

I need to be able to comfortably sit at 110km/h (70mph). 80% of driving to get anywhere in Australia is 100 or 110. A max speed of 120-130km/h for overtaking would be handy but doesn't need to be sustainable.

Looking at the torque and power curves here the torque drops substantially to about 50Nm at the higher RPM. My spreadsheet says the factory motor creates approximately 2150N of thrust in top gear, but with the Remy DOM I'm down to around 1800N. For comparison in first gear the stock motor puts out 8260N, while the Remy DOM puts out 9530N, and that's without a two speed. With a two speed it puts out a whopping 19800N of thrust . 

Gearing lower limits the top speed too much, and puts the motor in a lower torque position, and gearing higher reduces the torque anyway. I should probably do some sort of optimization to find the most efficient gearing though.

I can sort out shipping easy enough. My old company freights plastic barriers from America pretty regularly which fill a container, but I'm sure a motor could be squeezed in. I'd be all over it if it was the DOM model


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## brian_ (Feb 7, 2017)

motas said:


> DThere is plenty of space, especially axially, so it may be worth considering the 115 model. How does this relate to controller cost? IE what is the limiting factor to controllers, I'm guessing max current?


Within the same controller design (which implies a voltage limit due to component choices) more current capacity means more cost... and a longer rotor likely means a higher current limit so a more expensive controller if you try to push to that limit. But total power can also be a limit (due to cooling).


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## motas (Apr 21, 2017)

brian_ said:


> Within the same controller design (which implies a voltage limit due to component choices) more current capacity means more cost... and a longer rotor likely means a higher current limit so a more expensive controller if you try to push to that limit. But total power can also be a limit (due to cooling).



That's what I thought, so there is no advantage to going to the larger 115 motor, since the controller is the limiting factor anyway. 



Thinking about this more, I think I need taller gearing to bring the cruising speed down to the peak power at about 6000RPM. This puts me just as the torque starts to plummet. I was originally aiming the cruising speed to be around the constant RPM rating of the motor (8000-10000 RPM) which isn't the most efficient RPM to be running at. This does bring the gearing requirements down a lot which makes life easier.



Frank: Any chance you've done a dyno pull with the DOM motor and the PM100 controller? I'd like to get an equation that somewhat reflects the torque curve so my calculations are a little bit more accurate than a spreadsheet.


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## motas (Apr 21, 2017)

Aha! Gearing was my downfall. I was stuck in the thinking that a lower gear equals higher torque at the wheel.

6000RPM @ 110km/h gives a thrust of 6000N, 2.8 times more powerful than the factory diesel (2160N). With power limited from a P100, that comes down to 3200N, or with a P150 3900kN, still a big boost in performance. 

The downside is only 6600N at launch, compared to 8200N from the factory diesel (although to be fair this would be dumping the clutch at 1800RPM). This is where the 2 speed gearbox comes in, and a new problem presents itself.


With 2 speed ratios of 3:1 and 1:1 the performance is exceptional across the board, but that is a big jump in ratios, equivalent of going from 1st to 3rd and then some. It's probably doable, but it'll be a slow and noticeable shift.



The other options are to run 3 gears, or a close range 2 speed gearbox, and then a separate transfer case for low range.


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## motas (Apr 21, 2017)

Well, I got bored this afternoon and knocked out a quick gearbox concept.


Has 2.67:1 first gear, and 1.2:1 second gear, followed by a further 2.2:1 reduction. It's drawn as a flat layout but it'd be a bit smaller with the gears in a V arrangement. Depending on packaging it would also potentially be possible to have the front and rear outputs off the one side, which would delete one of the two largest gears. There'd need to be a dog clutch on the two shifting gears, as well as on the front output shaft.


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## Frank (Dec 6, 2008)

motas said:


> Frank: Any chance you've done a dyno pull with the DOM motor and the PM100 controller? I'd like to get an equation that somewhat reflects the torque curve so my calculations are a little bit more accurate than a spreadsheet.


I have never made any dyno pulls but I can show you DC power versus Time or Speed versus Time if you think that might help.


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## motas (Apr 21, 2017)

Frank said:


> I have never made any dyno pulls but I can show you DC power versus Time or Speed versus Time if you think that might help.


Would you have DC power vs RPM? If I can guesstimate efficiency between DC power and output power it should be helpful.


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## Frank (Dec 6, 2008)

[/url]Record Run - DC Power versus Time by Frank, on Flickr[/IMG]








[/url]Record Run - Speed versus Time by Frank, on Flickr[/IMG]

The first image is DC power versus time and the second is motor speed versus time, you can easily correlate them. Max power was achieved around 55-6000 rpm (base speed) and that was carried out to the end of the run. Battery selection is obviously important (these were Lonestar "Sleeper" cells).

The data is somewhat noisy, it's logged from the PM100 controller.


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## motas (Apr 21, 2017)

Frank said:


> [/url]Record Run - DC Power versus Time by Frank, on Flickr[/IMG]
> 
> 
> 
> ...


Thanks Frank! That should help a lot. Was that on 400V DC with the DOM wound motor?


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## Frank (Dec 6, 2008)

Yes, 96S pack, 90mm DOM, batteries sagged from a bit over 400 to 350-ish. Max current draw was in the neighborhood of 500A.


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## brian_ (Feb 7, 2017)

Frank said:


> ...
> The first image is DC power versus time and the second is motor speed versus time, you can easily correlate them. Max power was achieved around 55-6000 rpm (base speed) and that was carried out to the end of the run. Battery selection is obviously important (these were Lonestar "Sleeper" cells).
> 
> The data is somewhat noisy, it's logged from the PM100 controller.





Frank said:


> Yes, 96S pack, 90mm DOM, batteries sagged from a bit over 400 to 350-ish. Max current draw was in the neighborhood of 500A.


So it looks like the first 18 seconds or so at the motor current limit (so increasing motor voltage and power) until base speed, then roughly constant power (so increasing motor voltage and decreasing motor current) for the rest of the run.


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## Frank (Dec 6, 2008)

Sounds about right. I should add this was with a PM100DXR (450A) controller. The motor is rated at 600A but would take a larger controller to get that; lots of room to change gearing though if quicker acceleration is required.

Here's a link to a video I took a year later with similar speeds to those obtained for the graphs I posted: https://www.youtube.com/watch?v=aKpPurk5L7k


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## motas (Apr 21, 2017)

Thanks guys. I think the Remy 250 is the way to go.

Out of curiosity, I've heard talk of rewinding industrial motors for EV use. Has anyone seen an example of this around the 100-150kW mark? Any industrial motor I've seen seems heavy and VERY low power.

Cheers.


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## Emyr (Oct 27, 2016)

EV duty cycle is much more peaky than most industrial applications, so you can push a motor way beyond what it could sustain running 24/7.

By modifying the windings you can go even further. This thread is a good story: http://forums.aeva.asn.au/viewtopic.php?f=41&t=1237
(Page 9 recap, they took an AC motor rated 11kw continuous, 33kw peak, and after rewinding it, got it to 17.5kw continuous, 66kw peak.)


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## el_gallo_azul (Nov 22, 2015)

Personally, my own preference is to get rid of all possible weight. I found it quite easy to find an electric motor that had the 0rpm torque that I needed for my own conversion (a small car), which of course meant getting rid of clutch, gearbox, and the original differential.


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## brian_ (Feb 7, 2017)

el_gallo_azul said:


> Personally, my own preference is to get rid of all possible weight. I found it quite easy to find an electric motor that had the 0rpm torque that I needed for my own conversion (a small car), which of course meant getting rid of clutch, gearbox, and the original differential.


That would be both enough torque at zero rpm to work with the available reduction gearing, and able to run as fast as required by that gearing at the car's top speed (while producing enough power). This is normal for modern production EVs with AC motors and high-voltage batteries. It's more of a challenge for a 4WD vehicle intended to be capable off-road.

What motor did you end up with, el_gallo_azul, and what do you have for gearing?


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## el_gallo_azul (Nov 22, 2015)

brian_ said:


> What motor did you end up with, el_gallo_azul, and what do you have for gearing?


Parker-Hannifin GVM210-150R. It seems to have exactly the correct characteristics, with a differential ratio of 5.3 - 6.0:1. I had installed an open diff with about 5.7:1. but have replaced it with an LSD of 5.38:1.

Yes, it is necessary to make a good guess at how much torque is needed to get moving, because there is no longer the ICE's spinning mass and slipping clutch.


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## brian_ (Feb 7, 2017)

el_gallo_azul said:


> Parker-Hannifin GVM210-150R. It seems to have exactly the correct characteristics, with a differential ratio of 5.3 - 6.0:1. I had installed an open diff with about 5.7:1. but have replaced it with an LSD of 5.38:1.


Thanks 

I wondered about the Parker motors after an earlier mention in this forum...
GVM-Series Permanent Magnet Motors for Mobile Applications
This would be the larger diameter (210 mm vs. 142 mm) variant of the complete motor (GVM), rather than the core "kit" (GVK), in a 150 mm rotor length.
Detailed specs are in their catalog.
Even within the GVM210-150 with liquid cooling there are several winding options, to suit supply voltage (-DPW, -JPW, -SPW, -ZPW)... which one did you pick? I'm guessing the DPW, for up to 320 V. I don't know what the "R" code indicates... it's not in the catalog listing.

_Update_: I found a separate brochure which shows single-character winding codes, so this looks like the variant rated at 83 kW @ 4316 RPM and 350V, and 132 kW peak.

For lots of torque output for a 4WD, the longer rotor lengths are an option... but they come with lower rated speed which could be a concern.



el_gallo_azul said:


> Yes, it is necessary to make a good guess at how much torque is needed to get moving, because there is no longer the ICE's spinning mass and slipping clutch.


The rotational inertia of the engine isn't really important (except to the skill required of a person running the clutch and accelerator pedals), and slipping the clutch is only needed because the engine's need to run above a minimum threshold speed, which an electric motor doesn't have. Just take the torque output of an acceptable engine at the speed needed to provide acceptable initial acceleration, and you have the motor torque needed at low speeds from an electric motor driving through the same gearing.


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## el_gallo_azul (Nov 22, 2015)

brian_ said:


> _Update_: I found a separate brochure which shows single-character winding codes, so this looks like the variant rated at 83 kW @ 4316 RPM and 350V, and 132 kW peak.


Yep, that sounds like it. Rotational speed goes to 8,000RPM continuous.



brian_ said:


> The rotational inertia of the engine isn't really important (except to the skill required of a person running the clutch and accelerator pedals), and slipping the clutch is only needed because the engine's need to run above a minimum threshold speed, which an electric motor doesn't have. Just take the torque output of an acceptable engine at the speed needed to provide acceptable initial acceleration, and you have the motor torque needed at low speeds from an electric motor driving through the same gearing.


The momentum of the engine (and other downstream components) certainly smoothes the transition from a standstill as the clutch is (albeit briefly) slipped.

Yes, I used a similar method, guessing the original ICE's speed, and therefore approximate torque, at initial acceleration, multiplied by the gear ratio in 1st gear and the original diff ratio to get the required wheel torque, divided by the diff ratio of the installed diff. It can be guessed quite effectively.


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## leman2112 (Dec 2, 2018)

Atlas has been mated to tesla.

https://www.youtube.com/watch?v=2v-5GB7i10o&t=745s


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## motas (Apr 21, 2017)

brian_ said:


> That would be both enough torque at zero rpm to work with the available reduction gearing, and able to run as fast as required by that gearing at the car's top speed (while producing enough power). This is normal for modern production EVs with AC motors and high-voltage batteries. It's more of a challenge for a 4WD vehicle intended to be capable off-road.
> 
> What motor did you end up with, el_gallo_azul, and what do you have for gearing?



From my calculations the torque at low speed is easy because the torque starts so high, and because IC motors torque starts so low, almost any gearing will beat the IC off the line, and having a transfer case with low range will have insane torque way more than any IC 4WD. The problem I always have is torque/power at high speed because the EV drops off fast where the IC starts to peak. 





leman2112 said:


> Atlas has been mated to tesla.
> 
> https://www.youtube.com/watch?v=2v-5GB7i10o&t=745s



I like that! Although it's interesting they kept the housing of the Tesla drive train which looks to be empty now.


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## brian_ (Feb 7, 2017)

motas said:


> I like that! Although it's interesting they kept the housing of the Tesla drive train which looks to be empty now.


They only kept the motor side of the transaxle housing, because it is also the end housing of the motor. It's not much more than a side plate, so there's not much empty space... but they had to make a plate to match it, and it is really awkward for vehicle packaging to have that pointless thing sticking out to one side.


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## coleasterling (Feb 29, 2012)

leman2112 said:


> Atlas has been mated to tesla.
> 
> https://www.youtube.com/watch?v=2v-5GB7i10o&t=745s


That's not an atlas, but interesting video, thanks. ORD underdrive box mated to an np205, I think.


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## brian_ (Feb 7, 2017)

coleasterling said:


> That's not an atlas, but interesting video, thanks. ORD underdrive box mated to an np205, I think.


Yes, it appears to be an Offroad Design Magnum, and they seem to normally work with the NP205 transfer case. There are other suppliers of equivalent systems, including homebrew adaptations to put two transfer cases in series, using only the reduction gearing of the first one (a design called a "doubler"). Atlas sells a 4-speed transfer case, which is their normal 2-speed transfer case plus a two-speed reduction box on the input, for the same overall effect as shown in the F-450 video. Of course in an electric conversion, the highest ratio (both reduction gear sets in direct drive) would be of no value in any of these systems.


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## gpearce (Feb 9, 2020)

Has anyone suggested this for a more complete swap? I believe they supply a drop in motor/controller etc and you supply batteries. You lose out on some challenges but can get on the road quicker. No idea of cost. Since purchasing and shipping from USA is possible I thought I would suggest it. 
I prefer doing more myself but admit there are times it is worthwhile have someone else figure out what is most compatible. 

www.electricgt.com 

https://www.thedrive.com/tech/30431/electric-v-8-crate-motor-from-electric-gt-is-sema-swap-ready


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## motas (Apr 21, 2017)

Some new research has uncovered some new options for this build. I've been searching everywhere for a simple way to get the gear reduction needed, and have come across the Land Rover LT230 transfer case.

This T/C has a high range gear reduction up to 1.667:1, and a low range gear reduction up to 5:1. With the maximum gear reduction of the standard diffs of 5.89, the maximum possible final drive is a whopping 29.45:1. It is gear driven, so there is a chance that it will be able to be used as a dog box, but I'm unsure on this. It also has a PTO which I suspect could be helpful on an EV. It is a full time 4WD case, but can be converted to part time. Being an OEM off the shelf assembly it should also be easy to service and find parts for in the future compared to an aftermarket or custom gearbox. 

The only downside is the offset rear output, so I'll need to modify or replace the rear axle housing, but I don't expect this to be too much trouble especially since it is the simpler rear, and it'll be a good opportunity to swap to a full float setup and disk brakes.


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## brian_ (Feb 7, 2017)

I had never heard of this transfer case configuration, but I don't know a lot about Land Rovers.

The reduction (instead of the conventional direct drive) is a really nice feature for this EV conversion application, but it is also the result of the inconvenient (for a vehicle which does not normally have it) rear output offset, combined with gear (rather than chain) drive. All of the power has to go though gear sets anyway, so it can have a non-direct ratio.

The PTO is on the rear of the input shaft, running at input speed. It could be handy to connect both and engine (through a transmission) and an electric motor (at the PTO port) in a hybrid; I don't know how it would be useful in an EV.

There is no need to convert this box to part-time, because it includes a centre differential lock. It can't do just 2WD, but there's no need for that because full-time 4WD is better.
https://www.autoexpress.co.uk/land-rover/range-rover/100624/lt230-the-best-ever-transfer-box

I wonder if there are any others like this?


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## motas (Apr 21, 2017)

brian_ said:


> I had never heard of this transfer case configuration, but I don't know a lot about Land Rovers.
> 
> The reduction (instead of the conventional direct drive) is a really nice feature for this EV conversion application, but it is also the result of the inconvenient (for a vehicle which does not normally have it) rear output offset, combined with gear (rather than chain) drive. All of the power has to go though gear sets anyway, so it can have a non-direct ratio.
> 
> ...


From my knowledge a gear set is slightly preferable to a chain. The offset output is a little annoying, but rear axles aren't that hard to modify and having offset pumpkins is an advantage off road, especially in Australia. Thankfully the front axle is already the correct side.

The PTO could be used for a hydraulic winch, but it could also be used for A/C and things which normally run off the motor. Not saying it's feasible or a good idea, but it would potentially be possible. Downside is they'd only run when you're moving. I originally thought brake booster and power steering but that might not be the best idea 

You could definitely use it for a hybrid, but I have no idea how you'd control a hybrid system like that.

There'd be an efficiency advantage to part time 4WD because the front axles have locking hubs, so the whole front driveshaft and axle can be disconnected. 2WD can also be handy (and fun) off road, for example turning around a tight corner. Some of the fancier transfer cases have a front wheel drive option as well, so you can hold the handbrake and turn almost on the spot. Wouldn't make much difference either way though.


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## esk (Feb 24, 2016)

Hi,


from ashcroft-transmissions.co.uk you can get the 1.667 ratio and a part time 4wd kit for the LT 230. 



In my Land Rover Series 109 conversion 

blackcockatoos.wordpress.com


i use the siemens 1PV5135-4WS14 motor direct on the transferbox (from Land Rover Oneton) and the scott drive 200 controller. With the all over ratio 1:7.1 (long) there is a good acceleration to 100 km/h, the highest speed is by 120 km/h. With short ratio the car (2,5t!) will start even in deep sandy patches (may be, that europeen sandy patches are not so bad like the australien one´s).


Jens


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## brian_ (Feb 7, 2017)

motas said:


> From my knowledge a gear set is slightly preferable to a chain.


Both chain and gear work, chain is cheaper, gear is generally preferred for heavy-duty use... but none of that really matters, because the relevance of the all-gear construction is just that in combination with the offset configuration it enables this non-direct-drive high gear.


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## brian_ (Feb 7, 2017)

motas said:


> The PTO could be used for a hydraulic winch, but it could also be used for A/C and things which normally run off the motor. Not saying it's feasible or a good idea, but it would potentially be possible. Downside is they'd only run when you're moving. I originally thought brake booster and power steering but that might not be the best idea


Long ago, it was apparently common for conversions to run accessories from the drive motor, typically from the non-transmission end of a motor with a double-ended shaft; one aftermarket supplier even offers an "accessory plate and pump system" which ends up looking like the accessory ("front") end of an engine with the various belt-driven accessories; with a motor salvaged from a production EV there's no extra motor shaft end so the transfer case PTO port could be used (but it is in a terrible location in the vehicle for that).

As you noted, this means that the accessories would not turn except when the vehicle is moving; they would also turn at a speed proportional to road speed, which is certainly not desirable. The current approach is usually to use electrically-powered accessory systems (such as steering boost and air conditioning), but even if using original belt-driven systems, it would make far more sense to me to drive them from one constant-speed dedicated electric motor than to try to drive them from the main motor; one could even use something like that mounting plate system.

Fundamentally, using an electric motor to drive through the transfer case and PTO clutch to a hydraulic pump to drive a hydraulic motor to drive a winch drum makes much less sense to me than simply using an electric winch. I do get that the vehicle's drive motor is very powerful compared to a typical winch, and hydrostatic drives are relatively compact, but it still seems like an expensive and complex way to pull a cable. If you have a hydraulic winch sitting around or just really want to use one it could be done from the PTO port - just shift the transfer case to neutral, engage the PTO, and engage some sort of constant-speed control in the motor controller (remember - you don't have an idle control like an engine) to winch.


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## motas (Apr 21, 2017)

brian_ said:


> Long ago, it was apparently common for conversions to run accessories from the drive motor, typically from the non-transmission end of a motor with a double-ended shaft; one aftermarket supplier even offers an "accessory plate and pump system" which ends up looking like the accessory ("front") end of an engine with the various belt-driven accessories; with a motor salvaged from a production EV there's no extra motor shaft end so the transfer case PTO port could be used (but it is in a terrible location in the vehicle for that).
> 
> As you noted, this means that the accessories would not turn except when the vehicle is moving; they would also turn at a speed proportional to road speed, which is certainly not desirable. The current approach is usually to use electrically-powered accessory systems (such as steering boost and air conditioning), but even if using original belt-driven systems, it would make far more sense to me to drive them from one constant-speed dedicated electric motor than to try to drive them from the main motor; one could even use something like that mounting plate system.
> 
> Fundamentally, using an electric motor to drive through the transfer case and PTO clutch to a hydraulic pump to drive a hydraulic motor to drive a winch drum makes much less sense to me than simply using an electric winch. I do get that the vehicle's drive motor is very powerful compared to a typical winch, and hydrostatic drives are relatively compact, but it still seems like an expensive and complex way to pull a cable. If you have a hydraulic winch sitting around or just really want to use one it could be done from the PTO port - just shift the transfer case to neutral, engage the PTO, and engage some sort of constant-speed control in the motor controller (remember - you don't have an idle control like an engine) to winch.


PTO is definitely not a deal breaker, or even really a consideration. As you said the main reason people use hydraulic winch is you can have a lot more power, in a lot smaller package. Although that's typically running a low voltage electric motor on the winch. A ~300V winch motor would obviously be MUCH more powerful already.

Anyway back to the drive train options, I've been inundated with suggestions and have found a tonne of new options.

To summarise:

LT320 transfer case is compact, simple, cheap and tough. It is lacking on gear reduction though, and doesn't have synchros for shifting.

An E153 or similar transaxle out of a mid sized FWD car is compact, simple and cheap, with a wide gear range and synchros. It has a little too much reduction though, and the output shafts are typically very small, potentially a week point. A little wasteful having 5 gears and reverse.

An NP435 4 speed transmission with a single speed transfer case is compact, simple, tough and has a wide gearing range and synchro shifting. The reduction can be adjusted at the transfer case to be perfect. But this is an expensive option as it would preferably need an aftermarket or custom transfer case, and it still has more gears and reverse which aren't really necessary.

Having gears means I could maybe move down to something around the 100kW mark, which would save a substantial chunk of money on the motor and controller end. It would still be equivalent or better performance compared to modern utes in this class.


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