ICE on a trailer?

brian_ said:

...Pushing the van with a trailer to keep the van moving is not much different from pushing the van with a trailer for through-the-road battery charging (which is not regenerative braking). Pushing the van with a trailer hard enough to accelerate the van is downright scary.


I'm with Ken on this one!

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Sorry for the major edit. I'm cleaning it up but not really changing the meaning.

Pushing the van with a trailer is worse than if you are pulling a trailer and the trailer gets away from you while stopping. Youtube has plenty of examples of that.

1. You have two wheels forming a triangle with the ball. The ball not only allows turning left to right but also up and down or twisting motions.
2. You have two wheels driving the trailer, which when everything works and the van is going straight, would push the van down the road.
3. If you're taking a highway-style turn, the trailer pushes straight forward for it, which means toward the outside of the curve for the van. It's not pushing the front of the van that direction, it's pushing the rear of it.
4. The sharper the turn the more the trailer tries to push the rear of the fan off-course.
5. If you're in a sharp turn with the trailer at 90 degrees to the van, the trailer uses all its force to push the rear of the van toward the outside of the turn. If you're on ice, you have vehicle damage right there no matter what.
6. If you have one trailer wheel with good traction and the other on slippery or lose material, then the ball experiences a force to the left or right, torquing the van's rear again to one side or the other, but you don't know which side until it happens and in 2 feet it might be pushing in the opposite direction. If the van does NOT have good traction on all wheels you're likely to have vehicle damage again.
7. Even using trailer brakes strongly on questionable traction is sometimes difficult to control. Most trailer stopping accidents happen because the trailer pushes the rear of the vehicle off course and to one side or the other. Which means trailers are prone to this type of physics already, just because they have mass.

Most of this occurred to me shortly after I posted my original post here. That's why I backpedaled on it in my second post.



I don't think a generator on a trailer is an inherently bad idea, but any sort trailer with power to the wheels is absolutely positively not going to happen if I'm involved.


Just having a high voltage high current line running between the trailer and the car is going to require some amazing safety gear.

Brian said:

Why would the batteries be "minimal"? It would need the same capacity as any EV for vehicle of this mass... no, more because it is so heavy and has so much drag.

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Lemme clarify...

Because he would only need it for going around town and could even undersize it.

So if he says 95% of his trips are under 30 miles, but 5% of the time he needs (really needs, or it would mess up his day) to go 60 miles. As a pure EV he's gotta have capacity to do 60 miles. With the normal van as-is, big deal, 5% of the time he burns a little gas, it's never an issue and he could cheap out on the median use, rather than have to prepare for the common extreme.

through-the-road battery charging (which is not regenerative braking). Pushing the van with a trailer hard enough to accelerate the van is downright scary.

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Well, semantics. Through-the-road charging is functionally regenerative braking. I mean technically if speed isn't being reduced you're not "braking", so, okay, but otherwise they're the same. You're charging the vehicle by attempting to slow it down (converting kinetic energy into battery juice), you're just balancing that by adding power to maintain the same speed.

EV racers do it all the time (through the road regen), fastest way to charge up between runs. Get towed around in circles and hold the regen brakes. The car doesn't know any different, so, it's just a difference in semantics, not technology.

And, it's a common-ish DIY bicycle thing to have a push trailer, since it makes it transferable among virgin bikes (and cyclists often have a variety of bikes for different uses).

https://ecomodder.com/forum/showthr...ev-pusher-trailer-make-conventional-2975.html - "The guy with the EV porsche pushed by the VW Rabbit trailer claimed no oversteer problems even with (if I remember correctly) full push and the tightest turn radius. No snow in CA, though."

http://www.mynissanleaf.com/viewtopic.php?t=23335

https://www.diyelectriccar.com/forums/showthread.php/electric-pusher-trailer-58656.html

https://www.youtube.com/watch?v=4tJ1D2O1z-o

https://ridekick.com/

http://www.evalbum.com/type/PGTL

Ken said:

Using a push trailer to regenerate from the van... Let's see how well that works. By rule of thumb one can expect regen to recoup about 10% of the energy. So we have all the losses associated to get power to the wheels, and then you push the van forward. And from there you lose 90% of whatever's actually "on the road" by using regen.

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Err, no, that's not what I meant. You're right, if that's all it was.

Using regen you can expect to add about 10% to your range. I think you're mistakenly thinking that you only get 10% recovery of the energy that goes into the regen system as taken away from momentum (normally heat in the brakes). Which isn't true, you get decently high efficiency at turning momentum into battery juice. The reason that regen is not as big as deal is because there just isn't that much energy lost in a typical drive where you actually convert momentum into heat in the brakes.

What I mean is driving with the van (gas engine), and engaging some regen braking on the EV trailer. This will make the gas engine work harder, as it appears like you're towing a heavier or less aerodynamic trailer, but meanwhile it charges up the batteries.

Jackknifing/etc, yeah, if you go ham on the accelerator in a sharp corner and it was your only traction. But that's the beauty of it. You still have a gas engine there, so it's kind of still 6-wheel (4?) drive.

But okay, enough stupid ideas. Just throwing shit out there that as options that would let you get away with a much cheaper and more compartmentalized conversion for your different-er needs.

Genny mounted in a trailer. EV Van up front. Carry on.

I actually thought you meant to push an EV van with an EV trailer.

The van as it is has an automatic transmission. You can't tow a vehicle with an automatic transmission unless you disconnect the drive line or you risk damage to the transmission. Something about the rear shaft turning and flinging all the oil off and messing up the gears.

At any rate the area I'm in has lots of dirt and gravel roads, lots of snow and ice and just plain "stuff" blown by the wind and landing on the roads. You don't have consistent traction. Some farmer hauled hay on the road and bits of it fell off the trailer, or whatever. Or somebody ran cattle across the road and there's fecal matter all over the road but in splotches.

A Chevy Econoline is not a Porsche. Never owned the latter but I did drive a 911 to get a drunk coworker home. It's not the same. The trailer is not the same either. I suspect a Porsche is pretty good at keeping the wheels stuck to the ground with minimal swaying.

If I were 20 or 30 and didn't have a van load of kids I might consider a push trailer. Instead I've hauled trailers often enough that I know a bit of what can go wrong, and I know a whole lot of people who haul them for a living. I actually at this point can't figure out why my original hitch-activated power idea held up long enough for me to actually type it into the browser and post it. It just won't happen. If you bought me brand new motors and controllers, paid for my entire conversion with new parts and just gave it to me, I would turn you down if I had to use a push trailer.



How can you expect power regen through the road to be anywhere near as efficient at transferring electricity as a power cable?


Speaking of which, I found some manufacturers for AC induction motors for automotive use, and a single motor costs as much as I expected the entire van conversion to be. 2 of them would be plenty, but I'm not spending $70k USD on just 2 motors for a van conversion, not counting anything else. I'll go buy a house or something instead. Hopefully something can be found used or maybe not gold plated.

Ken R said:

... I found some manufacturers for AC induction motors for automotive use, and a single motor costs as much as I expected the entire van conversion to be. 2 of them would be plenty, but I'm not spending $70k USD on just 2 motors for a van conversion, not counting anything else. I'll go buy a house or something instead. Hopefully something can be found used or maybe not gold plated.

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A single quantity of an expensive-to-build and obscure component is going to be expensive... EV-related or not. I assume that this is a high-voltage motor; if so it is comparable to motors used in production EVs, although $35K each is wildly high even for premium motors. One problem is that they are sold as premium products in small volumes by retailers which get them from distributors who only carry small volumes of them, and get them from manufacturers who have no interest in quantities in less than the tens of thousands and price small volumes accordingly.

Very few DIY projects use a motor like this (or even half the price), unless they are salvaged from a wrecked production EV. The Tesla Model S or X is the most common source of these, with the most common source of permanent magnet motors of this class being the Nissan Leaf. Both Tesla and Leaf motors are usually used complete with the car's transaxle (for reduction gearing and differential).

Induction motors have fallen out of favour for production EVs and state-of-the-art custom EVs (and few production EVs ever had them); AC synchronous (normally with permanent magnets) motors are usually used instead. Even Tesla has switched to PM motors for the Model 3 and both planned models (new Roadster, Semi). Who is selling an induction motor at this price level?

brian_ said:

A single quantity of an expensive-to-build and obscure component is going to be expensive... EV-related or not. I assume that this is a high-voltage motor; if so it is comparable to motors used in production EVs, although $35K each is wildly high even for premium motors. One problem is that they are sold as premium products in small volumes by retailers which get them from distributors who only carry small volumes of them, and get them from manufacturers who have no interest in quantities in less than the tens of thousands and price small volumes accordingly.

Very few DIY projects use a motor like this (or even half the price), unless they are salvaged from a wrecked production EV. The Tesla Model S or X is the most common source of these, with the most common source of permanent magnet motors of this class being the Nissan Leaf. Both Tesla and Leaf motors are usually used complete with the car's transaxle (for reduction gearing and differential).

Induction motors have fallen out of favour for production EVs and state-of-the-art custom EVs (and few production EVs ever had them); AC synchronous (normally with permanent magnets) motors are usually used instead. Even Tesla has switched to PM motors for the Model 3 and both planned models (new Roadster, Semi). Who is selling an induction motor at this price level?

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https://www.tesla.com/blog/induction-versus-dc-brushless-motors
http://www.acpropulsion.com/index.php/product-service/drive-system/item/7-180kw-end-mount


I admit I just looked at the first google hit where I actually found a price. And that's a motor with a controller. And while I found a few motors that would work as power for one wheel, I found none designed for automotive use that would power the whole van to the same level as what's in there now. I've pulled a light trailer with my van, but not a heavy one. I wouldn't mind a bit more chili sauce in the tank if I'm going to do this. The existing engine is 260 kW.


I'm familiar with the arguments of PMAC vs ACIM. I have a firm opinion of which I like better, but the decision on what I would actually build with may well come down to price and practicality. I'm aware that most DIY enthusiasts will use a forklift motor and a DC controller. If I were looking for a pure get-around-town car I no doubt would do the same. As I've said before I have never been too shy to find my own path.



ACIM has a variable B field, created by the intensity of what comes out of the controller. While the PMAC motor runs cooler and can get a higher peak efficiency, the ACIM can get better average efficiency across the operating range.


I really really don't want to argue the merits of one technology over the other. I understand and appreciate the reasons many find the PMAC motor to be superior, I just don't feel that way. I respect your decisions. In my opinion this is akin to asking what sort of apple is the best, with lots of anecdotal evidence for superiority of one or the other and everyone has their own opinion of how it would shake out.


The push trailer debate really chewed the flavor out of the discussion, I don't want a repeat so soon.

I wasn't arguing for PMAC over induction motors, just pointing out that it would be surprising for the most expensive motors to be induction. As the Tesla blog item explains, PMAC is typically more expensive due to the magnets.

The linked motor is, of course, from Tesla's original motor supplier. I haven't seen a motor advertised as high as "180 kW" available for retail purchase, although at 75 kW continuous it's not really more powerful than the motors found in common current production EVs of just about every brand. This is the sort of thing that few people buy new for DIY projects, using salvaged production EV motors instead; an alternative is to get one of the leftover Siemens motors from the Azure Dynamics bankruptcy... that's US$2,800 for a motor (albeit with no manufacturer support and no warranty) plus perhaps $US5,200 for a Rinehart PM100DX/DZ controller, rather than US$35K for a motor with controller.

The lack of economical availability of larger motors is a challenge for anyone wanting brisk performance with a larger vehicle. Two motors can be combined, but that doubles the price and bulk. Much larger motors are certainly available - TM4 seems to make some good stuff - but I have no idea where you could buy one individually, or what it would cost. TM4 has just been acquired by Dana, and something like Dana's Spicer Electrified eS5700r e-Axle would be a nice direct replacement for the van's rear axle. Back in the real world, perhaps the idea would be to salvage a motor from a light- to medium-duty truck that had been EV converted by one of the conversion companies.

If using two motors just to get enough power, they could be used to separately drive the front and rear axles, which would at least gain 4WD as well as the extra power. Full-size vans of course are rare in 4WD, but it's a common aftermarket conversion using parts from mechanically similar pickup trucks.

Ken R said:

I was thinking that I could replace the rear suspension with independent suspension, run a shaft to the centerline to a gear box mounted on the frame of the van, and then power each wheel from a motor with a fixed gear ratio. Motors sticking out in front or behind the drive shaft.

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This would look roughly like the setup from Quantum in a Fisker Karma... and given the huge size of the Karma's motors, an actual salvaged Karma complete motor and transaxle unit might be suitable. Sorry, the Karma's motors are PM, not induction.
Previous discussion: Fisker Karma motor ?
(photo of Karma's Q-Drive attached)

Ken R said:

I was thinking 3-phase induction motors with a separate controller for each wheel, and some sort of sensor and controller to provide traction control to avoid spinning one wheel on slick roads.

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Although I assumed that the Karma uses each motor to drive a wheel (separately), it's also possible that both motors drive one differential; I've never seen a good internal description.

Ken R said:

By my guess the van wheel will be turning about 780 rpm at 65 mph, so probably 4.6:1 or so ratio if I'm using 3600 rpm motors.

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That's really slow for electric motors of this size. You can use smaller motors for the same power with no loss of efficiency if you turn them faster, and have suitable voltage available. The Karma appears to the motors up to at least 6,000 rpm, and other hybrids and EVs (e.g. Tesla) run up to 12,000 rpm.

Ken R said:

I've looked into the mechanics of 4-link custom suspension, and I was thinking of either building or buying something for the rear (prefer buying!). Maybe I should consider the front as well? 4-link is incredibly better than stock suspension when it's done right..

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For the rear, coil (or air) springs and control links certainly provide better handling and ride than leaf springs. Ram pickups have all gone to coils and control arms at the rear. There are aftermarket kits, from low-riding setups for custom trucks, to jacked-up systems for off-road (or looking like you go off-road ), to heavy-duty solutions with air springs for trucks which tow and haul. Kelderman makes a bunch of bolt-on systems, but I don't see any for vans.

The rear of the GM full-size SUVs have coil springs and control arms, using GM live beam axles like a Chevy van. The frame details are different so it wouldn't just bolt in, but an adaptation would probably be possible

Beam axles with control links and coil springs are common for the front suspension of heavier light trucks, such as Ford SuperDuty, and Ram 2500 and up. That's definitely an upgrade over the leaf springs used on medium-duty trucks, but the front can easily be independent...

Ken R said:

Maybe it would be an advantage to try to find some front suspension parts that would work with 4wd?
...
Maybe a suburban's front suspension might be adequate?

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The Chevrolet Suburban and Tahoe, GMC Yukon, and Cadillac Escalade are all built on the same forward chassis as the Silverado and Sierra pickups. These vehicles all have independent front suspension, both 2WD and 4WD, and all the way up to the "one ton" 3500. This seems like a reasonable donor of parts for a van, but there are also factory AWD models of the Chevrolet Express van - so there's a driven axle front suspension available.

Ken R said:

My current vehicle is a 15 passenger van. It's a 2010 Chevy Econoline 3500...

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I assume this meant Chevy Express 3500 (Econoline is a Ford van model).

brian_ said:

I wasn't arguing for PMAC over induction motors, just pointing out that it would be surprising for the most expensive motors to be induction. As the Tesla blog item explains, PMAC is typically more expensive due to the magnets.

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OK.

The linked motor is, of course, from Tesla's original motor supplier. I haven't seen a motor advertised as high as "180 kW" available for retail purchase, although at 75 kW continuous it's not really more powerful than the motors found in common current production EVs of just about every brand. This is the sort of thing that few people buy new for DIY projects, using salvaged production EV motors instead; an alternative is to get one of the leftover Siemens motors from the Azure Dynamics bankruptcy... that's US$2,800 for a motor (albeit with no manufacturer support and no warranty) plus perhaps $US5,200 for a Rinehart PM100DX/DZ controller, rather than US$35K for a motor with controller.

Click to expand...

That's more like it.

The lack of economical availability of larger motors is a challenge for anyone wanting brisk performance with a larger vehicle. Two motors can be combined, but that doubles the price and bulk. Much larger motors are certainly available - TM4 seems to make some good stuff - but I have no idea where you could buy one individually, or what it would cost. TM4 has just been acquired by Dana, and something like Dana's Spicer Electrified eS5700r e-Axle would be a nice direct replacement for the van's rear axle. Back in the real world, perhaps the idea would be to salvage a motor from a light- to medium-duty truck that had been EV converted by one of the conversion companies.

Click to expand...

I'll look into everyone's links, whether I mention them or not.


Where I live is not exactly an EV-friendly mindset. For some reason unknown to me, the desire for an EV is an indicator of your political leanings, and this is a very conservative state, and not in a particularly educated sort of way IMO.


What I'm getting at is that if I'm going to find a broken EV I'm going to have to go somewhere else to get it. Not sure I'm comfortable buying something sight unseen.

If using two motors just to get enough power, they could be used to separately drive the front and rear axles, which would at least gain 4WD as well as the extra power. Full-size vans of course are rare in 4WD, but it's a common aftermarket conversion using parts from mechanically similar pickup trucks.

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I'm not entirely sure there's a 4wd pickup equivalent to this van. It might be not too far from a 1-ton I guess.


The thing is, 4wd tends to use a pumkin differential. If I'm using electric I don't see how that's beneficial. It seems to me that a frame-mounted motor and single-speed gear set (gears on centerline) with one motor and gearset for each wheel, and then a shaft with CV joint going out to an independent suspension would be the most mechanically efficient. Maybe an aftermarket 4-link?


Following that logic, if I were going one motor per wheel and used 4wd then I would expect standard EV motors to work fine.

brian_ said:

This would look roughly like the setup from Quantum in a Fisker Karma... and given the huge size of the Karma's motors, an actual salvaged Karma complete motor and transaxle unit might be suitable. Sorry, the Karma's motors are PM, not induction.
Previous discussion: Fisker Karma motor ?
(photo of Karma's Q-Drive attached)

Although I assumed that the Karma uses each motor to drive a wheel (separately), it's also possible that both motors drive one differential; I've never seen a good internal description.

That's really slow for electric motors of this size. You can use smaller motors for the same power with no loss of efficiency if you turn them faster, and have suitable voltage available. The Karma appears to the motors up to at least 6,000 rpm, and other hybrids and EVs (e.g. Tesla) run up to 12,000 rpm.

Click to expand...

I hadn't really found any EV-specific motors that size yet. The examples I found of ACIM motors in the higher power ranges looked to be about 11-13k rpm.

brian_ said:

For the rear, coil (or air) springs and control links certainly provide better handling and ride than leaf springs. Ram pickups have all gone to coils and control arms at the rear. There are aftermarket kits, from low-riding setups for custom trucks, to jacked-up systems for off-road (or looking like you go off-road ), to heavy-duty solutions with air springs for trucks which tow and haul. Kelderman makes a bunch of bolt-on systems, but I don't see any for vans.

Click to expand...

When I lived in the Chicago area, people put tons of money into a 4wd rig that had insanely aggressive off-road tires, jacked up so you could almost drive under it, and all sorts of crazy bells and whistles. And the tread on their tires was worn absolutely flat because they only commute from A to B on the same pavement the econoboxes use.


Where I live, we have the same tires and most of the mods that actually do something beneficial with performance, but the truck is dirty and the guy uses that stuff to get out of their driveway, or get to the job.


I haven't seen any suspension kits for vans either, because I assumed it was similar to a truck suspension. Haven't looked, didn't really know I had to. Clearly before I actually make a decision I'll need to clear that up one way or another.

The rear of the GM full-size SUVs have coil springs and control arms, using GM live beam axles like a Chevy van. The frame details are different so it wouldn't just bolt in, but an adaptation would probably be possible

Beam axles with control links and coil springs are common for the front suspension of heavier light trucks, such as Ford SuperDuty, and Ram 2500 and up. That's definitely an upgrade over the leaf springs used on medium-duty trucks, but the front can easily be independent...

The Chevrolet Suburban and Tahoe, GMC Yukon, and Cadillac Escalade are all built on the same forward chassis as the Silverado and Sierra pickups. These vehicles all have independent front suspension, both 2WD and 4WD, and all the way up to the "one ton" 3500. This seems like a reasonable donor of parts for a van, but there are also factory AWD models of the Chevrolet Express van - so there's a driven axle front suspension available.

Click to expand...

I didn't know about the 4wd express van. I believe I have coil springs in front, I know I have leaf springs in back.

I assume this meant Chevy Express 3500 (Econoline is a Ford van model).

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Dammit. Yes, it's a Chevy. I always do that for some reason even though I know better.

Ken R said:

The thing is, 4wd tends to use a pumkin differential. If I'm using electric I don't see how that's beneficial. It seems to me that a frame-mounted motor and single-speed gear set (gears on centerline) with one motor and gearset for each wheel, and then a shaft with CV joint going out to an independent suspension would be the most mechanically efficient. Maybe an aftermarket 4-link?

Click to expand...

I assume what you mean by a "pumpkin differential" is a live beam axle, in which the differential is in the axle housing (in a bulge sometimes called a pumpkin). Yes, that's the tendency for 4WD trucks, but not for the "half-ton" size at Ford (the F-150) or any of the pickup trucks at GM... those use an independent front suspension.

If you do use a live beam axle in the front (which is a common approach for aftermarket 4WD conversions of full-size vans) then a 4-link would work better than leaf springs, and the motor can sit under the cab area floor (to one side of the original transmission location, because the front differential is offset to one side to clear the engine and match up with the shaft coming from the transfer case).

With a driven independent front suspension (from an Express AWD or 4WD GM pickup), if the original differential is used the motor could be mounted directly to the diff input (if diff's ring and pinion gears give enough reduction for the motor chosen), or back further.

Ken R said:

Following that logic, if I were going one motor per wheel and used 4wd then I would expect standard EV motors to work fine.

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I agree that four motors of the size commonly found in compact EVs would suit the van.