# ICE on a trailer?



## Ken R (Sep 26, 2018)

Hi,


I live in a small city in a low-population area in the central USA.



I've been interested in electric vehicles since before auto makers started releasing them a few years back. (Don't talk about the early days of autos, I'm talking like Chevy Volt)


My problem with typical EV projects is that they focus on some econobox car, which is impractical for me. I'm 6'4" (193 cm) and those cars just don't hold somebody my size. Not only that, I'm a foster parent and we have some variable number of kids, and then the people in my real family, and then a couple dogs, and whatever fishing/camping gear I want to take with me.


My current vehicle is a 15 passenger van. It's a 2010 Chevy Econoline 3500, extended. There are 4 bench seats and 2 buckets up front. 3 of the bench seats hold 3 people, the last one holds 4. Usually the back seat is out to make room for dogs, but I have literally had every other seat used. The van has a V8 in it, and it's adequate for acceleration but nothing to write home about. The most economic speed is 55-60 mph. My area generally has 2-lane blacktop roads at about 65 mph, and interstate speeds of 80 mph. The existing ICE gets terrible fuel economy in town, usually less than 10 mpg. On the highway it can get close to 20 mph depending on the wind and such.


My normal day involves driving around town a few miles, easy for an EV project. Most days the van just doesn't move at all. But when we take a trip, we use the van. When we take a trip, we WILL go more than 300 miles round trip.


So here's my question finally:
Consider a van conversion, set up for in-town driving. I can't sacrifice a whole lot of weight to batteries as I use the van to carry a lot of people. But they're little people usually, maybe as many as 5 adults but the rest are miniatures. I figure this is a do-able EV conversion and probably straightforward.


The van has an OEM trailer hitch, something like 7500 lbs weight rating.


What I'm thinking of is a trailer for trips. Probably double-axle. It would have:
1. An internal combustion engine, possibly the same one that's in the van now.
2. A big fuel tank.
3. A storage area for luggage.
4. More batteries.
5. Possibly motors to assist with driving force.


My idea is that, in town, the van is a pure EV. When I go on a trip, I hook up the trailer which converts it into a hybrid. I would obviously need a big high-voltage umbilical going up to the van, and a pretty good control unit.


Is this a feasible idea, or are there too many safety or legality concerns? AFAIK there are no laws forbidding a running engine on a trailer, but I haven't really researched it.


Thanks for your time.


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## MattsAwesomeStuff (Aug 10, 2017)

This was a somewhat common thing in the 90s-2010 or so. At least common enough that people knew about it. I don't know that more than a handful ever got built since most people just owned a second vehicle anyway.

You could make a generator trailer, but that means you need the whole engine on there, plus a generator large enough to power the vehicle at highway speeds (maybe 20hp for your van? 25? That's 15-18kw). Then you charge the batteries (or just drive) from the power cables. Meanwhile, you already have a big electric motor under the hood. Kinda redundant. Maybe you get away with a smaller generator, while the bigger motor under the hood can handle accelerating (dipping into battery use for short term as the smaller genny can't keep up), but still redundant.

So what people do is build a "push trailer". Meaning you drive the trailer wheels with the actual engine. The ghetto way of doing this is to just take the front end of a FWD car, stopping just after after the windshield. A little bit of hotwiring and you're done.

If your motor has regenerative breaking, you can still charge the batteries this way too by applying the brakes while being pushed, though your throttle and brake arrangement gets a bit sketchy that way unless you rig the regen on a second system (brakes should prevent engine from pushing, also brake lights will be on). All possible.

Under the hood the easiest and cheapest thing to use is an old forklift motor, maybe two in your case.


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## Ken R (Sep 26, 2018)

I have serious doubts as to whether a 25hp engine could move this thing fully loaded (per my description above, plus trailer) at 65 mph for hours, and if I'm traveling from town to town it would be hours. Even if you're using the on-board electric drive to even out the high-power stretches. I'd go so far as to doubt that a 4-cylinder auto engine could do it without really stressing. I wouldn't mind a little 5L Cummins diesel though. I'm pretty sure you can get those buckled up to an appropriate generator already on a trailer, but the trailer would not be what I had in mind. And it might be expensive.



We have a second vehicle, but it's a little Toyota Corolla. My wife commutes with it. Usually if we travel we have more people than the Toyota can hold, and the van is much more comfortable for everyone anyway. Clearly if the Toyota is adequate for the job it's the vehicle we take, but usually it's not.



This is a more-than-one-ton capacity vehicle. It's not a minivan, it's at least two minivans in one. I figure It's frequently loaded to more than half weight capacity during trips, the way we do it right now. Limiting myself to less than 65 mph top speed would be counter-productive, I don't think I want extra nights in motels with 8 or more people just to accommodate a lower top speed. State law says no more than 4 people in a hotel room per night. If I'm going to do the conversion at all, it will need to perform like it does now. I will accept a 65 or 70 mph top speed, even though it does much better than that right now. But hill climbing and acceleration I would not want to sacrifice.



I could consider having the van's motors capable of pulling the loaded van and trailer combined at highway speed continuously, I can see where this might simplify things a bit and may even save money on build cost. But the pure push trailer idea does not have appeal for me. I'd like to arrive at the destination city fully charged, possibly find a place to drop the trailer off, drive around doing my business and then come back for the trailer. Possibly the trailer would run at night and charge the batteries, unless the place I drop the trailer has EV charging as a service. I haven't seen this at all in my area, at least at motels. At any rate I'd be looking at a pretty good (quiet) exhaust system for the trailer.



I know that typical DIY EV projects use DC motors, and that absolutely every commercial offering uses AC motors. I know that the DC motors can be had cheaper, especially if you look at an old forklift or something. While I can't say what I will actually choose to do at this point, I can say right now that an ACIM appeals much more to me than any DC option. The final decision would have to be left to a price estimate comparison on both options, and a comparison of features possible on each system.


There are lots of hills where the van coasts higher than the cruise speed, both in and out of town. Regenerative braking would be an appealing feature. I currently ride the brakes to keep the speed in check. I know that regen only gets about 10% of the energy back.


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## brian_ (Feb 7, 2017)

Ken R said:


> What I'm thinking of is a trailer for trips. Probably double-axle. It would have:
> 1. An internal combustion engine, possibly the same one that's in the van now...
> 
> My idea is that, in town, the van is a pure EV. When I go on a trip, I hook up the trailer which converts it into a hybrid.


I get the idea of a hybrid spread between the van and trailer, but there's no reason to use the huge original van engine, because that engine is sized for peak load rather than average load.



MattsAwesomeStuff said:


> You could make a generator trailer, but that means you need the whole engine on there, plus a generator large enough to power the vehicle at highway speeds (maybe 20hp for your van? 25? That's 15-18kw)...


The van with trailer will need more power than that. At the same time, there's no point in an 18 kW generator on a 200+ horsepower engine. The generator needs to have more capacity than the average load over the trip, and the engine needs to be sized to operate efficiently at that power level.



Ken R said:


> I have serious doubts as to whether a 25hp engine could move this thing fully loaded (per my description above, plus trailer) at 65 mph for hours, and if I'm traveling from town to town it would be hours. Even if you're using the on-board electric drive to even out the high-power stretches. I'd go so far as to doubt that a 4-cylinder auto engine could do it without really stressing. I wouldn't mind a little 5L Cummins diesel though.


Right, 25 hp isn't enough, but something much less than the van's current engine is suitable. If you're using up to a kilowatt-hour per mile, and averaging a mile a minute (60 mph), that's 60 kw or 80 hp.

A Cummins 5L (the V8 engine in the Nissan Titan XD diesel) is not "little" by any rational measurement. It would be heavier than the van's current engine. If you really like diesel, the GM "baby" Duramax 2.8 from the Colorado/Canyon, or the Ford small Powerstroke 5-cylinder from the Transit would be a better match, but I think an automotive 2-litre would be better.



Ken R said:


> I could consider having the van's motors capable of pulling the loaded van and trailer combined at highway speed continuously, I can see where this might simplify things a bit and may even save money on build cost.


Because this is a series hybrid, and even for pure EV operation without the trailer, the van's motors are going to need to be large.


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## brian_ (Feb 7, 2017)

*Push trailers*



MattsAwesomeStuff said:


> ... So what people do is build a "push trailer". Meaning you drive the trailer wheels with the actual engine. The ghetto way of doing this is to just take the front end of a FWD car, stopping just after after the windshield. A little bit of hotwiring and you're done.
> 
> If your motor has regenerative breaking, you can still charge the batteries this way too by applying the brakes while being pushed, though your throttle and brake arrangement gets a bit sketchy that way...


It has been done, but a lot of unsound things have been done - that doesn't make it advisable. "Sketchy" is the nicest word that I can think of for this scheme.

There are actually articulated buses (essentially a bus towing a passenger-carrying trailer) with the engine in the back (so, the trailer) pushing the whole thing... but they are not nearly as crude as those "push trailers".

By the way, powering one axle with an engine while charging with a generator driven by another axle is called "through the road" hybrid charging. It is a bad idea with both axles on the same vehicle, but with the driver on the trailer and the drag on the tow vehicle it's really bad.


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## brian_ (Feb 7, 2017)

*Van projects*

There are a couple of van projects in the forum:
1967 VW Split Screen Van - "ICE Breaker" (a little VW van)
Tesla powered Mercedes Vito (a Mercedes Metris - a usable van, but still smaller than a full-size)
Neither of these builders plans (as far as I know) any kind of generator trailer.


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## Ken R (Sep 26, 2018)

If I'll need another engine for this, I think I'd rather get something designed for a generator than something designed for an automobile. Given a diesel's maintenance cycle and overall simplicity, I'd rather go that route than with gasoline.


I can see your point about average power. And I was thinking of the inline v6 diesel found in 90s Dodge trucks. My father had one, it would pull like a mule. You're probably right about it being bigger than the original van engine in terms of power and torque, but it was pretty small in terms of physical size per unit power. If there's a 4-liter version of that, or even 3-liter I'd be interested. Not sure if I want to design something that has to run flat out when being operated in the typical use case though, equipment wears out faster when you do that. And of course it would need a matching 3-phase generator on it.



Motors:
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. 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. I'd like to avoid shifting gears and clutches or any of that nonsense if possible. 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. We get ice here, and snow.


It would be interesting to have 4wd, but I'm not sure I can find an adequate suspension and drive train for that size vehicle. And I don't want to sacrifice turning radius, it's already bad enough as it is.


I know most DIYers take off the engine and keep the transmission, putting the motor right where the engine was, but I think that will likely just add a lot of weight and complexity to the drive train and take up a lot of room. I see most people here seem to use just one gear most of the time anyway. I can see how it would be a much simpler conversion that way, just saying I don't like the compromise.


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## Ken R (Sep 26, 2018)

brian_ said:


> It has been done, but a lot of unsound things have been done - that doesn't make it advisable. "Sketchy" is the nicest word that I can think of for this scheme.
> 
> There are actually articulated buses (essentially a bus towing a passenger-carrying trailer) with the engine in the back (so, the trailer) pushing the whole thing... but they are not nearly as crude as those "push trailers".
> 
> By the way, powering one axle with an engine while charging with a generator driven by another axle is called "through the road" hybrid charging. It is a bad idea with both axles on the same vehicle, but with the driver on the trailer and the drag on the tow vehicle it's really bad.



I don't like any of these ideas. The only "through the road" charging I was thinking of is regenerative braking.


I had originally thought to power the trailer wheels only because I was thinking that the van motors would be smaller and aimed at just carrying the van's weight. I've already been convinced not to do that. I have fairly extensive experience with trailers, they can get in enough trouble when they're not pushing anything. The more you guys talk about push trailers the more the hair on the back of my neck tickles me. Enough said on that.


Right now I'm focused on a generator on a trailer, with storage and power cables. And general ideas about driving the van itself.


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## brian_ (Feb 7, 2017)

*Engine options*



Ken R said:


> If I'll need another engine for this, I think I'd rather get something designed for a generator than something designed for an automobile. Given a diesel's maintenance cycle and overall simplicity, I'd rather go that route than with gasoline.


Any modern diesel is certainly more complex than a gasoline engine. If you want an engine designed for optimal efficiency at the desired power level, that would be a gasoline engine from a Toyota hybrid.



Ken R said:


> I can see your point about average power. And I was thinking of the inline v6 diesel found in 90s Dodge trucks. My father had one, it would pull like a mule. You're probably right about it being bigger than the original van engine in terms of power and torque, but it was pretty small in terms of physical size per unit power. If there's a 4-liter version of that, or even 3-liter I'd be interested.


Inline and V are opposite things; I assume that you mean the Cummins B-series inline 6, originally called the 6B (then 6BT when turbocharged). The current version (called the ISB for commercial applications) is still used in 2500 and larger Ram trucks, but it is now much more complex and powerful. The B-series started as a 5.9 litre and has grown (to 6.7 litres). It is not small for its power, by comparison with anything other than an even larger diesel.

There is a 4-cylinder version of the B-series, called the 4B. With the same bore and stroke, it is a 4-litre. It is an enormous and heavy paint-shaker, used in many delivery vans and similar commercial vehicles. There is no version which meets modern emissions standards, but it might be suitable in power output.


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## brian_ (Feb 7, 2017)

*Transmission?*



Ken R said:


> I know most DIYers take off the engine and keep the transmission, putting the motor right where the engine was, but I think that will likely just add a lot of weight and complexity to the drive train and take up a lot of room. I see most people here seem to use just one gear most of the time anyway. I can see how it would be a much simpler conversion that way, just saying I don't like the compromise.


All good reasoning, and especially valid with the weight and complexity and issues of an automatic transmission, but be sure that the overall drive ratio is right. Modern motors need to run faster to get enough power than they would with just the rear axle's final drive ratio for reduction.


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## Ken R (Sep 26, 2018)

That tesla powered mercedes build looks like what I was thinking, only I don't think both of those sides are motors. Not sure what the other can is. But I thought I overbuilt when I weld crap together, this guy is outrageous.



Those are both much smaller vans than I have. I have seen another maxi van project here a couple years back, but it's not an extended van, and it was only built for a small amount of local driving. Small battery pack, small motors for only in-town driving.



I've read enough though to know that the bigger the vehicle the more it's worthwhile to convert it to an EV, even though the conversion cost is higher.





The main point of my query seems to hold water though, the idea of a generator on a trailer that converts a pure EV into a hybrid. Especially attractive is the idea of storing luggage on the trailer too. We always end up with 3 coolers, baby supplies, a couple pack-and-plays and pretty much an entire daycare in the van all folded up.


I'm thinking that the first step is to get a plan to convert the van itself, and price that out. There's a ton of room under the floor of the van, still protected by the frame. Not sure if I could swing actual EV battery packs, but there's lots of room for them if I can. I'd probably need some sort of cover under them to prevent damage from rocks and dirt though. Things have changed a bit since I first started researching this years back.


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## brian_ (Feb 7, 2017)

Ken R said:


> That tesla powered mercedes build looks like what I was thinking, only I don't think both of those sides are motors. Not sure what the other can is. But I thought I overbuilt when I weld crap together, this guy is outrageous.


That's a typical Tesla drive unit. One side is the single motor (which drives a differential through two stages of reduction gearing); the other side is the inverter/controller, housed in a metal can.



Ken R said:


> Those are both much smaller vans than I have.


Yes, they are relatively small. That's a problem in finding a motor - even the large Tesla Model S motor would be marginal for the large loaded van pulling a trailer.



Ken R said:


> I've read enough though to know that the bigger the vehicle the more it's worthwhile to convert it to an EV, even though the conversion cost is higher.


If the benefit of conversion is saving money on fuel, or reducing fossil fuel consumption, then yes there is more to be saved.



Ken R said:


> The main point of my query seems to hold water though, the idea of a generator on a trailer that converts a pure EV into a hybrid. Especially attractive is the idea of storing luggage on the trailer too. We always end up with 3 coolers, baby supplies, a couple pack-and-plays and pretty much an entire daycare in the van all folded up.


One challenge is weight distribution, with the big fixed weight of the engine and variable cargo load. Where do you put things so that the weight distribution is suitable under all conditions?



Ken R said:


> I'm thinking that the first step is to get a plan to convert the van itself, and price that out. There's a ton of room under the floor of the van, still protected by the frame. Not sure if I could swing actual EV battery packs, but there's lots of room for them if I can. I'd probably need some sort of cover under them to prevent damage from rocks and dirt though. Things have changed a bit since I first started researching this years back.


A complete EV pack won't fit, but repackaged modules of production EVs is the current trend in conversions.


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## Ken R (Sep 26, 2018)

*Re: Engine options*



brian_ said:


> Any modern diesel is certainly more complex than a gasoline engine. If you want an engine designed for optimal efficiency at the desired power level, that would be a gasoline engine from a Toyota hybrid.
> 
> 
> Inline and V are opposite things; I assume that you mean the Cummins B-series inline 6, originally called the 6B (then 6BT when turbocharged). The current version (called the ISB for commercial applications) is still used in 2500 and larger Ram trucks, but it is now much more complex and powerful. The B-series started as a 5.9 litre and has grown (to 6.7 litres). It is not small for its power, by comparison with anything other than an even larger diesel.
> ...



I don't know where that v came from. Inline 6 is what I was talking about, from a 90s Dodge Ram truck.


I can't say I've looked at a modern diesel, but the ones from the 90s are much simpler than a gas engine if you discount the mechanical injectors. I know that the newer injectors are computerized, with some sort of actuator instead of a mechanical pump. To me, that means simpler.


With respect to efficiency I'm going to have to ask for proof. My dad's truck frequently pulled a 40 foot trailer with 20+ tons on it, and it still got 15 to 17 mpg. He drove it until it had 300k miles on it with minimal maintenance.


If your claims about gas engines being more efficient were true, or even if the efficiency were close to true, the commercial haulers (big trucks and trains) would be switching over. 



I don't mean to get into a pissing match here. If you show me real-world proof that your gas engine is more efficient and more reliable than a diesel generator then I'll pay attention.


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## Ken R (Sep 26, 2018)

brian_ said:


> One challenge is weight distribution, with the big fixed weight of the engine and variable cargo load. Where do you put things so that the weight distribution is suitable under all conditions?



Put the engine at the desired center of gravity. Put the fuel roughly the same place, just like a commercial trailer generator. Luggage goes around the outside.


Correctly loading a trailer is not complicated, just necessary. The only post-loading variable here is fuel. You pack the trailer with the correct hitch weight, and if the fuel tank COG is right in front of the axle then the trailer maintains correct balance the whole trip.


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## brian_ (Feb 7, 2017)

Ken R said:


> Put the engine at the desired center of gravity. Put the fuel roughly the same place, just like a commercial trailer generator. Luggage goes around the outside.
> 
> Correctly loading a trailer is not complicated, just necessary. The only post-loading variable here is fuel. You pack the trailer with the correct hitch weight, and if the fuel tank COG is right in front of the axle then the trailer maintains correct balance the whole trip.


If the fuel tank is at the centre of gravity, then the engine can't be behind the fuel tank (the trailer would have negative tongue weight without cargo), so it must be ahead of the fuel tank. That's pretty front-heavy. A more practical configuration would put the fuel at the axle, and the engine and generator immediately in front of that.

Of course the fuel could be on top or under the genset, but that's not reasonable for a large tank. It could also go in saddle tanks on each side, I suppose.

Even then, the cargo is all going in front and rear trunks on the trailer. That can work, but doesn't sound like a convenient thing to use, and requires attention to distribution between front and rear. On the other hand, if this is a simple build, the front and rear cargo compartments can just be off-the-shelf cargo boxes.


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## brian_ (Feb 7, 2017)

*Re: Engine options*



Ken R said:


> I can't say I've looked at a modern diesel, but the ones from the 90s are much simpler than a gas engine if you discount the mechanical injectors. I know that the newer injectors are computerized, with some sort of actuator instead of a mechanical pump. To me, that means simpler.


The problem is that a mechanical injection pump is more complex than a complete gasoline injection system plus a complete ignition system. Modern diesels use electronic injection systems which are similar to gasoline injection systems but at much higher pressure; modern ignition systems have no moving parts and routinely go for the life of the vehicle without failure or repair... and a couple hundred thousand kilometres without even changing the plugs.

On top of that, modern diesels have both diesel particulate filter (DPF) and selective catalytic reduction (SCR) emissions control systems which are far more complex and less reliable than the catalytic converter on a gasoline engine. The problems of making a diesel to meet current emissions regulations are so extreme that Caterpillar dropped out of the business of manufacturing these engines for heavy trucks in response to the regulation changes - they just couldn't make it work economically and reliably. And of course most people have heard of Volkswagen's "dieselgate" nightmare. If you use an old engine you avoid all of that, but it's strange to promote EV conversion (which is often chosen for environmental reasons) then run a filthy engine. If you do, a pre-2007 common-rail electronic injection engine from a light commercial application (not something intended only for cars) is probably the most efficient and reliable choice... although I would want to avoid the parts prices of Mercedes engines.



Ken R said:


> With respect to efficiency I'm going to have to ask for proof. My dad's truck frequently pulled a 40 foot trailer with 20+ tons on it, and it still got 15 to 17 mpg. He drove it until it had 300k miles on it with minimal maintenance.
> 
> 
> If your claims about gas engines being more efficient were true, or even if the efficiency were close to true, the commercial haulers (big trucks and trains) would be switching over.


A good diesel run as intended *is* more fuel-efficient than a gasoline engine under similar conditions. I was just pointing out that the engines which are available in light vehicles which are optimized for hybrid operation (nearly constant power at an engine speed unrelated to road speed) are those gasoline engines.



Ken R said:


> If you show me real-world proof that your gas engine is more efficient and more reliable than a diesel generator then I'll pay attention.


Modern gas engines in cars light trucks are more reliable than diesel engines in the same vehicles, due to the problems with current diesel emission controls. Of course heavy diesels are reliable (other than the emission controls), and there is no gasoline comparison (although they would be just as reliable) because diesels are cheaper to fuel - due to both fuel consumption and fuel pricing - so no one builds large commercial gasoline engines.


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## brian_ (Feb 7, 2017)

Ken R said:


> Right now I'm focused on a generator on a trailer, with storage and power cables.


If the van has suitable battery capacity for local use as a pure battery EV (running on battery power only), that capacity will be lots for series hybrid operation with the trailer. A plug-in hybrid car typically has about 16 kWh of capacity; the much bigger van with trailer would be a reasonable plug-in hybrid with about three times that capacity, and you'll want that for routine operation without the trailer anyway. Unless you want long battery-only range with the trailer, I don't see any need to make things complicated (and expensive) by putting more battery in the trailer.

The trailer could be treated as a mobile charging station for the van, but the van will need to accept a charge while driving, which is not normal for EVs. You do need the connection, but there are off-the-shelf connectors for high-rate DC charging of EVs at up to 400 volts and a couple hundred amps.


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## Ken R (Sep 26, 2018)

brian_ said:


> If the fuel tank is at the centre of gravity, then the engine can't be behind the fuel tank (the trailer would have negative tongue weight without cargo), so it must be ahead of the fuel tank. That's pretty front-heavy. A more practical configuration would put the fuel at the axle, and the engine and generator immediately in front of that.
> 
> Of course the fuel could be on top or under the genset, but that's not reasonable for a large tank. It could also go in saddle tanks on each side, I suppose.
> 
> Even then, the cargo is all going in front and rear trunks on the trailer. That can work, but doesn't sound like a convenient thing to use, and requires attention to distribution between front and rear. On the other hand, if this is a simple build, the front and rear cargo compartments can just be off-the-shelf cargo boxes.



The axle has two wheels. Side-to-side balance is not incredibly critical on a trailer but important enough you don't want it too far off. Mount the engine such that with no cargo and no fuel the trailer is correctly balanced. Tanks are either to either side of the engine or higher, is usually how mobile generators work. Mount them so that empty or full, the trailer is balanced properly. Hitch weight should be 10% of total loaded trailer weight. Actually usually the tank goes above the engine, but that would put the gas tank in the rear window of the van; commercial mobile generators for commercial construction tend to be pretty high.


Luggage goes where it fits. The van currently has a 25 gallon tank. I can't imagine needing more than 50 gallons, but probably a pair of tanks with a combined capacity of 40 would be most practical. Once the generator (and I'm thinking of buying a commercial built-to-spec motor/generator already on a trailer for this, whether new or used) is mounted and the tanks are mounted, you can look at your trailer to determine the best place for luggage.


No matter what the trailer, balancing and securing the load is critical. This goes for 18-wheelers as well as the one you put behind your lawn mower. So loading the trailer will ALWAYS require more attention than loading your car, and loading your car when it's going to pull a loaded trailer will ALWAYS require more attention than if you just had the car. It's not complicated, it's just important to pay attention. Good tire pressure, good grease in the bearings, good brakes, proper hitch weight for the trailer weight. Proper load balance front-to-back on the tow vehicle. Good lights. There's a check list just like on an airplane.





brian_ said:


> The problem is that a mechanical injection pump is more complex than a complete gasoline injection system plus a complete ignition system. Modern diesels use electronic injection systems which are similar to gasoline injection systems but at much higher pressure; modern ignition systems have no moving parts and routinely go for the life of the vehicle without failure or repair... and a couple hundred thousand kilometres without even changing the plugs.
> 
> On top of that, modern diesels have both diesel particulate filter (DPF) and selective catalytic reduction (SCR) emissions control systems which are far more complex and less reliable than the catalytic converter on a gasoline engine. The problems of making a diesel to meet current emissions regulations are so extreme that Caterpillar dropped out of the business of manufacturing these engines for heavy trucks in response to the regulation changes - they just couldn't make it work economically and reliably. And of course most people have heard of Volkswagen's "dieselgate" nightmare. If you use an old engine you avoid all of that, but it's strange to promote EV conversion (which is often chosen for environmental reasons) then run a filthy engine. If you do, a pre-2007 common-rail electronic injection engine from a light commercial application (not something intended only for cars) is probably the most efficient and reliable choice... although I would want to avoid the parts prices of Mercedes engines.
> 
> ...



OK what you're saying is at least plausible. I'll look into that, the emissions specs did ping on my brain a few years back, and I remember the dieselgate thing. As I said I had planned to use a diesel generator set, not mate a generator I found to a motor I found somewhere else. Don't particularly want a stinky engine around though either, so it may be that a gasoline or e85 engine may be a more viable alternative. The hovercraft I built awhile back had a VW inline 4 in it, and I kept the computer and the catalytic on it.





brian_ said:


> If the van has suitable battery capacity for local use as a pure battery EV (running on battery power only), that capacity will be lots for series hybrid operation with the trailer. A plug-in hybrid car typically has about 16 kWh of capacity; the much bigger van with trailer would be a reasonable plug-in hybrid with about three times that capacity, and you'll want that for routine operation without the trailer anyway. Unless you want long battery-only range with the trailer, I don't see any need to make things complicated (and expensive) by putting more battery in the trailer.
> 
> The trailer could be treated as a mobile charging station for the van, but the van will need to accept a charge while driving, which is not normal for EVs. You do need the connection, but there are off-the-shelf connectors for high-rate DC charging of EVs at up to 400 volts and a couple hundred amps.



The space under the floor is at least 8 or 9 inches top to bottom and there's a ton of room between the frame members, especially if you can remove the drive shaft. If rear-mounting the motor(s) pans out, then there is easily enough room between the frame rails to put 5x the battery pack of a plugin hybrid in there. Not saying I'll need it, just saying there's room. There would also be all that room under the hood and in the doghouse.


I was thinking of putting raw 3-phase AC through the trailer connector. Thinking now on it that probably won't work so well, a generator set will probably be either 240 or 480, or maybe 400. There's probably no reason to route around that circuitry, and the EV charging circuitry will be set up for one of those too most likely.


What sort of voltage does a highway-capable (65mph) EV run these days? It would be good to avoid unnecessary voltage conversions through all this, which is why I was thinking of 3-phase through the trailer connector.


I was also thinking of gadget power in the vehicle, we have a ton of phone chargers and tablets and whatever crap we need for baby food. How many people run an AC wall outlet in the car? It's either that or a whole crapload of 12v or USB plugs. Or maybe all of the above.


Back in the day, EV builders had a high voltage battery pack and then a 12v battery for the automotive systems. Is this still the practice or do you run an inverter-pwm regulator for that sort of thing?


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## brian_ (Feb 7, 2017)

Ken R said:


> As I said I had planned to use a diesel generator set, not mate a generator I found to a motor I found somewhere else.


That gives you a matched set of engine and generator, but a genset with high enough output is going to be a massive thing, intended for stationary industrial operation.


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## Ken R (Sep 26, 2018)

Go look at a construction site where they're putting up an apartment building, a hotel or some commercial building especially in a remote location. They have generators on wheels that have 4 cylinder automotive-sized engines or even bigger. Most of the ones I've seen are diesels, but the key here is that they are designed to run as a generator: constant speed, reasonably constant load, day in and day out. They'll be there until the power is hooked up to the site.



The trailers they are on are set up to be hauled onto a site when the dirt work is not done yet. So the COG is very high, ground clearance is high too.


If the site has a crane they tend to hook onto the generator and pick it up for the night to prevent theft, so you'll see a louvered box on a trailer 40 feet in the air after hours.


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## Ken R (Sep 26, 2018)

Another thing to keep in mind here is that I rarely travel more than once a month. So this trailer, it's likely to go a long time between uses. My daily driver as it were will be a really big plug-in pure EV that I plug into the wall outlet when I get home. When I get range anxiety, I hook up to the evil ICE trailer and do what I need to do.


I don't see a diesel as a necessarily bad thing here, if they can be as reliable and efficient as I'm thinking. If the pollution regulations are too tight then I'll clearly need to do something else.


I've recently seen articles about opposed cylinder diesels with a common combustion chamber instead of a common crankshaft. They're reaching thermal efficiencies near 60%. I think if diesel were ridiculously over-regulated then there would be less research on improving them right?


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## brian_ (Feb 7, 2017)

Ken R said:


> I was thinking of putting raw 3-phase AC through the trailer connector. Thinking now on it that probably won't work so well, a generator set will probably be either 240 or 480, or maybe 400. There's probably no reason to route around that circuitry, and the EV charging circuitry will be set up for one of those too most likely.


If using a ready-made genset I can see doing this, preferably at 240 volts to match existing Level 2 EV charging standards... but 3-phase Level 2 charging is only used in Europe, as far as I know.

Multiple conversions are annoying and inefficient, which is why it would be nice to do it all on the generator trailer so that there is no conversion on the van side at all. If you can get a 3-phase alternator at a suitable voltage, you could rectify and regulate to the van's voltage without additional conversions. Of course the rectifier and inverter could be in either the trailer or the van.

An old-style generator set runs at a fixed speed to make 60 hertz (or 50 hertz outside of North America) power, and so doesn't run at its most efficient speed for the load of the moment. A current "inverter" generator runs at variable speed, produces high-frequency 3-phase AC (which the vehicle's charger likely won't handle well), and rectifies that to feed an inverter to produce the desired output. Feeding the final output of an inverter generator set to the van means an unnecessary inverter stage.

If you want the option of using the trailer as a mobile generator to power stuff other than the van (such as powering a house in emergencies), you might want to ensure that it has a 240/120 volt 60 Hz output available.



Ken R said:


> What sort of voltage does a highway-capable (65mph) EV run these days? It would be good to avoid unnecessary voltage conversions through all this, which is why I was thinking of 3-phase through the trailer connector.


360 volts (nominal) from a battery with 96 lithium cells in series (and of course some number of cells in parallel at the lowest level) is the current typical production EV practice. DIY EVs using brushed DC motors and AC induction motors sold for conversions necessarily run lower voltage. That's why existing high-rate DC charging standards allow up to 500 volts.



Ken R said:


> I was also thinking of gadget power in the vehicle, we have a ton of phone chargers and tablets and whatever crap we need for baby food. How many people run an AC wall outlet in the car? It's either that or a whole crapload of 12v or USB plugs. Or maybe all of the above.


Low-power 120 V AC outlets are common in the better-equipped trims of even non-hybrid non-EV vehicles.



Ken R said:


> Back in the day, EV builders had a high voltage battery pack and then a 12v battery for the automotive systems. Is this still the practice or do you run an inverter-pwm regulator for that sort of thing?


Current production practice, which DIY builders seem to be following, is to have a converter from high voltage to 12V, but still have a battery on the 12 volt system to smooth out peak demands and provide power before the DC-to-DC converter is powered on.


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## Ken R (Sep 26, 2018)

Interesting stuff I didn't know there.


The generators I've seen run output higher than the official output and then are regulated down to something standard. A 480v generator may well have a raw output of 600v but then get regulated down to something reasonable. I know that the output of these things has gotten much cleaner over the years, so it's possible that there are some pretty sophisticated electronics in there to give clean power.


No matter what the van will need to accept 240v because that's what is likely to be in the garage when I charge it, and that's what is supplied to homes in the USA. But as you mentioned there are reasons to want to send over the raw 3-phase too, if it gets away from an unnecessary conversion.


The regulation and conversion circuitry to go from 3-phase to single-phase needs to be somewhere, and the circuitry to adapt to the charger's raw input voltage needs to be somewhere. Unlike most EVs I don't think space is going to be a problem here, and having the most direct voltage conversion seems to be a good thing.


But I can also say from experience that trailer electrical connections can be problematic, just because they're flexible connections being bounced around, bent, twisted, rained on and sprayed with gravel and mud and part of a racoon. While it would clearly be necessary to put 240v through that connector, it may not be advisable to double it for safety reasons. Either that or I'll need some pretty amazing safety circuitry.


It's my understanding that a commercially built generator will very possibly have 400-600v circuitry somewhere, and it seems like such a shame to not just send it over to charge the pack. But I'm not sure what sort of noise will be on that line, and whether the charger can handle filtering it. Lots more questions than I started with now.


Then there's a distinct possibility that the generators I'm thinking of may be unsatisfactory for some reason and that I would need to build something from scratch. Which is a drag to me.


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## Ken R (Sep 26, 2018)

You know, almost every time I do something nonstandard when there's a standard, I regret it later. You're saying there's a charging standard voltage, so I think the generator needs to supply that voltage. This opinion will be final until I change my mind yet again.


Somebody said something about satisfactory motors being hard to find? AC induction motors is what I'd prefer. Was that with respect to a dual motor system, or a single motor system?


I made a comment about 4 wheel drive earlier, it would be handy but I didn't think it would be workable. Maybe it would be an advantage to try to find some front suspension parts that would work with 4wd? A separate motor for each wheel? Maybe a suburban's front suspension might be adequate?


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. Typically used with drag racing and with off-road vehicles. This would be neither, but I could seriously benefit from 4wd in this area. I think with ACIM motors all I would need to do is turn off the front wheels when driving slowly. I doubt that spinning the motors would be a huge drain on power at low speed.


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## brian_ (Feb 7, 2017)

Ken R said:


> Go look at a construction site where they're putting up an apartment building, a hotel or some commercial building especially in a remote location. They have generators on wheels that have 4 cylinder automotive-sized engines or even bigger. Most of the ones I've seen are diesels, but the key here is that they are designed to run as a generator: constant speed, reasonably constant load, day in and day out. They'll be there until the power is hooked up to the site.


The problem with those is the size: for instance, a roughly 50 kW unit from Kohler weighs two tons. Automotive needs are quite different from stationary industrial needs, so although the underlying technology is the same (including sharing some base engines and using similar generator technology), the details are all different.

Constant-speed operation is a bit of an issue, too. A typical industrial unit will run a 1800 rpm all the time, to produce 60 Hz power. It might not be very efficient (and isn't quiet) at low load, but who cares on an industrial or construction site? That can be okay in a series hybrid, but it can means starting and stopping the genset often so that when it runs it only runs at high efficiency.


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## brian_ (Feb 7, 2017)

Ken R said:


> I've recently seen articles about opposed cylinder diesels with a common combustion chamber instead of a common crankshaft. They're reaching thermal efficiencies near 60%.


The people pushing the most recent opposed-piston diesels are great marketers, but a little short on integrity. This is old technology coming around again, and inherently has no substantial advantage.



Ken R said:


> If the pollution regulations are too tight then I'll clearly need to do something else.
> 
> ... I think if diesel were ridiculously over-regulated then there would be less research on improving them right?


I doubt that anyone will ever even check the emissions of whatever you mount on a trailer, let alone regulate it.

I think that the effect of regulations is exactly the opposite. Something has to drive improvement, and if the only driver is the cost of engines and their operation, they will get ever cheaper, filthier, and less efficient. Automotive (including trucks) diesels are in an unfortunate state at the moment, much like gasoline engines of the dark days of the 1970's: they are dealing with new demands, and don't have it well sorted out yet.

Diesel fans often claim that some unreasonable demands are being placed on their engines, but in fact the nearly free ride they've had for decades is just ending as they are being regulated like gasoline engines.


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## Ken R (Sep 26, 2018)

New engine designs always have enthusiastic marketing. If third-party test results support it though it's not just marketing. Unfortunately I can't find the article I read the other day, so I can't tell who did the tests.


Emissions checks on a trailer:


A few years ago I went to Colombia. The country in South America, not one of the cities in the USA. (those are spelled Columbia anyway)


There are no pollution laws to speak of there. There are way fewer cars per capita, but not a single one of them has a catalytic converter or any other type of emission control. You could be out on a mountain with only one car for a mile around, and when you turn that car on your eyes burn. But go to Bogota, a city the size of NYC, and you think somebody dropped tear gas on you.


FWIW I think the emission controls are a good thing. They're pretty much unregulated in my state, but I think if this thing goes through I'll actually have what emission controls I can get on the trailer regardless of regulations.


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## Duncan (Dec 8, 2008)

brian_ said:


> I think that the effect of regulations is exactly the opposite. Something has to drive improvement, and if the only driver is the cost of engines and their operation, they will get ever cheaper, filthier, and less efficient. Automotive (including trucks) diesels are in an unfortunate state at the moment, much like gasoline engines of the dark days of the 1970's: they are dealing with new demands, and don't have it well sorted out yet.
> 
> Diesel fans often claim that some unreasonable demands are being placed on their engines, but in fact the nearly free ride they've had for decades is just ending as they are being regulated like gasoline engines.


Total nonsense Brian - today's diesels are several hundred times better than the 70's - if anything is getting the "free ride" its the petrol engines - they are permitted to produce actual poisons! - while the diesels are not even permitted to release chemicals that in 97% of the USA are effectively fertiliser


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## MattsAwesomeStuff (Aug 10, 2017)

I kinda want to back up to the start with a couple key questions....

- Why do you want an electric vehicle?

- What is your budget/what are you thinking you'll spend?

You have basically described the worst case scenario for an EV. High weight. No extra weight. Poor aero. Long range. Mountainous terrain. Occasional use.

You gas milage: http://www.fuelly.com/car/chevrolet/express_3500/2010 -- Something in the range of 10-15mpg.



> Most days the van just doesn't move at all.


EVs make the most sense when you want to save money on gas, with frequent daily use, short range.

You need the frequent use to justify the investment in batteries (if not the conversion itself). This is a huge sunk cost up front whether you use the vehicle daily or never. If you were spending $12,000/year in gas, that's financially wasteful and it's easy to say you should invest in electrical. If you spend $300/year in gas, it'll never be worth it.

You need the short range so that you don't need an outrageously-sized, expense, and heavy battery pack. 

You have huge power requirements because you have an unaerodynamic shape pushing lots of air out of the way at high speed. You need to be able to accelerate all that weight at a decent speed. You need to be able to push that weight up a hill, at a fast speed. For a long period of time.

...

I love supporting projects just for the sake of "I want to" or "It interests me", so if that's the case, do as you please.

But even though we're here because we're passionate about EVs, if you came here with your finished EV, a big heavy van with 2-4 huge electric motors, and a hitch with a huge genny and a trailer... 

... I would actually suggest "Why not remove the motors and batteries and put that engine under the hood of the van instead?".

I think your current situation is actually the best solution to your circumstances. If you need a cargo trailer, just go buy a simple, cheap cargo trailer, done.

Another thought, yeah you've got a big family now but when the kids become teenagers they'll drive their own cars (and you can force them to chauffeur their younger sibblings, a time-honored family practice  ), and you won't be making as many family trips. So that means the time before you have to pay off this expensive conversion is narrower that you might imagine.

Just peeing on the parade a little, as a sober-second-thought.


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## brian_ (Feb 7, 2017)

Duncan said:


> Total nonsense Brian - today's diesels are several hundred times better than the 70's...


Duncan, apparently you didn't understand my post. I didn't compare the diesels of today to the diesels of the 1970's (obviously they have changed, to make them cheaper to operate and to meet regulations). I compared the situation of gasoline engines in the 1970's (struggling to meet changing regulations and not working well) to the situation of diesel engines today (struggling to meet changing regulations and not meeting them reliably).



Duncan said:


> ... if anything is getting the "free ride" its the petrol engines - they are permitted to produce actual poisons! - while the diesels are not even permitted to release chemicals that in 97% of the USA are effectively fertiliser


I'll leave an uninformed deep discussion of the effects of pollutants and which emissions are regulated to another forum, since this is supposed to be about EVs... and in this case, hybrids. All that's relevant to this discucssion is

an industrial engine will not meet automotive standards (of performance or emissions)
an old diesel will not even come close to meeting current standards of emissions
a current diesel may not operate both reliably and cleanly at reasonable cost (current systems are routinely bypassed or disabled)
Anyone who wants a mostly-electric vehicle and doesn't care about exhaust emissions can just run any older engine that they find reliable and cheap.


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## brian_ (Feb 7, 2017)

Since the EV with generator trailer thing is difficult to do well, there is another option... two vans:

one converted to EV for local use (maybe buy one which is cheap because it has a dead engine and/or transmission)
one left stock for longer trips - no trailer required


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## Duncan (Dec 8, 2008)

Or a "Battery Trailer" - and use it for your house to load shift to get cheap (night rate) power when it's not needed as a range extender


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## Ken R (Sep 26, 2018)

MattsAwesomeStuff said:


> I kinda want to back up to the start with a couple key questions....


Fair enough, and they're good questions.



> - Why do you want an electric vehicle?


A number of reasons. In the order I think of them:


I've wanted one almost since I heard of the idea.
I believe that, battery pack notwithstanding, they can be more reliable than an ICE.
I want better fuel economy in town. I love to just get in and drive for awhile, and with my current living situation (foster kids) it's difficult because I'm either leaving my wife to take care of kids, or I'm in a big van that gets ~10mpg in town on a good day.
I want to take steps toward a cleaner environment.
I'm sure I can come up with more answers that are still honest. Those are the big ones.
I'd like to point out that while EVs are almost certainly cleaner while operating, it's clear that the manufacturing environmental cost of a converted vehicle is much higher than a standard one, because you manufactured everything in the standard vehicle, took some of the stuff out and then put more stuff in.

I also realize that an EV means a longer tailpipe. I'd like to get some sort of green power at my home, and that will likely need to happen first. What seems to be most practical would be solar with saltwater batteries.



> - What is your budget/what are you thinking you'll spend?


I'm not sure. I know that converting an EV will easily spend all the money you would have spent on gas buying the electric components. I can't imagine a van project (without trailer) to be less than $30k USD. I'm not rich, and this would be a big chunk of cash for me.

That said, vans have been the same thing for decades. Other cars change shape, the van is just a big box going down the road. Mine is in good shape. No rust I can find, no significant dings. If I maintain it I think could keep it as an EV for a long time and not wish for something else.

I've researched DIY cars before. I was looking at small cars back then, but I know that people spend a ton of cash on them and have a lot of problems getting things right. I've also talked to a few DIY EV owners and looked at their cars in person, and I know that once they get them done the guys are usually happy with them.



> You have basically described the worst case scenario for an EV....
> 
> You gas milage: http://www.fuelly.com/car/chevrolet/express_3500/2010 -- Something in the range of 10-15mpg.


Yes. Only it's hilly terrain, not mountainous. I live in the Missouri River valley. Once I'm on top it's the Great Plains. Mostly flat-ish but lots of rivers and occasional relatively sharp altitude adjustments in the in the altitude which are probably on the order of 1000 feet or more. going down any one of these hills on cruise control in this van at 65 mph will overspeed the cruise and I'll be going 75 or 80 by the time I reach the bottom. Probably 7%-8% grade I'm guessing.

Winter in-town mileage is more like 8, 10 in summer. When I drive a distance I choose my route and my speed to get best economy. I have had it as high as 21 mpg round trip economy over about 6 hours total, and it's usually above 18 in summer.

Occasional use: Most of our driving is in town. We both work. I don't need to drive to work. If at all possible we engineer our trips so that one or two adults takes one or two kids in the Toyota to do what we need to do. If we need more people then we take the van.

We like taking everyone if we can, and if the kids are all behaving. If the van would be more economic to drive in town, we would probably take everyone when we go shopping or running around town. It would certainly see much more use than it does right now.



> EVs make the most sense when you want to save money on gas, with frequent daily use, short range.
> 
> You need the frequent use to justify the investment in batteries
> ...
> You need the short range so that you don't need an outrageously-sized, expense, and heavy battery pack.


I guess part of what I'm hoping for is for the van to be more frequently used. I don't see us spending a lot less money driving it, because in my past I tend to have a budget for transportation and I use all of it whether I actually had someplace to go or not.

The van costs $80 to fill up, give or take depending on gas prices. Usually every other week unless we travel. If we're going out of town that gets us almost 500 miles. Per ton mile of people/cargo (not including vehicle weight), loaded full of kids, the van is actually much more economic to drive than the Toyota.

The short range part is why I'm talking about a trailer, so I don't need a literal extra ton of batteries. The trailer is for the infrequently used edge case. Normally a 30 mile daily range for the van is great, and a 60 mile range would be fantastic. So 30 days a month it would be charged from the wall outlet.



> You have huge power requirements because...


True as far as it goes. Again, I'm not looking at pure numbers here comparing economy of a van to economy of a Toyota Corolla. The Toyota gets 35 mpg at 60 mph fully loaded. The van gets almost 20 at the same speed fully loaded. 4 people at 35 or 12 people, 2 dogs, 3 coolers and fishing gear at 20. I'll take the latter. Drop a bit if I have the (existing) trailer pulling kayaks.


> ... I would actually suggest "Why not remove the motors and batteries and put that engine under the hood of the van instead?".
> 
> I think your current situation is actually the best solution to your circumstances. If you need a cargo trailer, just go buy a simple, cheap cargo trailer, done.


I hear you. I really do. "I want to" is a huge part of this, and ever since I was in my 20s that has been an adequate reason to do most of my stupid projects. Many of them have been exactly that--stupid. I don't feel the need to justify projects that satisfy my curiosity to any naysayer. That's not defensive, I'm just saying that somebody else's opinion doesn't matter nearly as much to me as walking my own path or learning something. I'm not a teenager anymore. I'm 53. I have some bit of experience with building things and with having successes and failures, both of which tend to cost much more than I'd anticipated.

I don't feel that "saving money" is an adequate excuse to buy or build any EV or hybrid. So far as I can tell, the statistical numbers don't support saving money when considering the total cost of ownership. Even commercially built EVs don't likely pay back the additional cost. So zero that out of my equation.

That said, the cost of tooling around town or the local countryside DOES matter. I see turning this van into an EV which, ideally, would double the "money economy" of driving (miles per unit cost) as a big deal, and I would still spend at least as much money driving it as I do now.



> Another thought, yeah you've got a big family now but when the kids become teenagers they'll drive their own cars (and you can force them to chauffeur their younger sibblings, a time-honored family practice  ), and you won't be making as many family trips. So that means the time before you have to pay off this expensive conversion is narrower that you might imagine.
> 
> Just peeing on the parade a little, as a sober-second-thought.


 Last statement first. I ask this sort of question to people in other forums. You are NOT peeing on the parade, you're asking questions that need to be asked BEFORE the n00b spends a shit-ton of money on something that won't get them what they're after.

Teenagers: We're foster parents. My wife and I don't have kids of our own. We tend to stick to the under-4 set as far as preferred placements. The number of kids varies from month to month, and is usually somewhere between 2 and 7. There are 3 adults in the house, and will be until somebody dies most likely. It's possible and hopeful that we might be able to adopt a couple of the kids, but I'm not counting on it.

Kids come here, they stay a few days or a few months, and one of them has been here 2 years and is likely to stay longer. Then they go somewhere else, either back with their family or to a new foster home that can better care for their needs. We feel that kids should have a safe place to grow up, and a happy place to live. We hope that their families can pull it together and get through whatever trouble they're having, but sometimes it just doesn't happen that way.

I've had dozens of hobbies over the years. None of them has been as fulfilling as fostering kids. If a kid comes into your house, you can't help but love them. If you don't then you're not doing them any good at all. When they leave they take a piece of me with them every time. We get money for caring for the kids, but if I don't have the kids we make more money by ourselves. We spend our own money on top of what we get to make their lives better.

Those of you reading this, if your life is empty of meaning maybe you should consider being a foster parent. Every part of the world is short of people who will step up and help out. Every kid is worth the time you spend putting a smile on their face. Kids come to you scared and hurting, and sometimes a little thin, and you feed them and make them happy. There is no better feeling.

Sorry for the shameless foster care plug. At any rate our situation is different. We may see a couple of these guys grow up -- we hope to have some over for holidays when they have their own families -- but in general I think we'll have baby seats in the van for many years to come. And if not, the seats come out and there's always a use for a big van.


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## Ken R (Sep 26, 2018)

brian_ said:


> Since the EV with generator trailer thing is difficult to do well, there is another option... two vans:
> 
> one converted to EV for local use (maybe buy one which is cheap because it has a dead engine and/or transmission)
> one left stock for longer trips - no trailer required



I'm not convinced that the generator trailer is difficult to do well. The EV itself would be aimed at 30-60 mile range and I'd use battery packs from a hybrid or commercial EV for it if I can find them. So lighter weight, leaving more of my full capacity for cargo.


The generator trailer, we've had some discussion about how to implement it but the balancing is extremely straightforward. The generator trailer makes the EV itself much easier. While I have been talking about a commercially built genset, I'm not married to the idea. If it's cheaper or significantly lighter to get a reliable generator which is more appropriate for my use case then I'm open to the idea. 



The idea of the trailer is to have it kick on when the battery gets low, run full blast until it's charged and then shut off again. Or, near the end of the programmed trip, have the trailer top off the battery just as I arrive, letting me drop the trailer off somewhere if it's practical so I can park in normal slots found in malls or whatever.





Duncan said:


> Or a "Battery Trailer" - and use it for your house to load shift to get cheap (night rate) power when it's not needed as a range extender



Some of the trips I take are 14 hours each direction. Maybe twice a year. I don't think a battery trailer is adequate for that. But if it were only a few hundred miles, that might be a neat idea.




I don't see long trips as viable for a pure EV. Not in my area. Part of all this is that the vast majority of my driving either vehicle is in town. I see two (or three) projects here:


A short-range EV with big motors because it's a big vehicle.
A generator trailer for trips, to mitigate the fact of a short range EV.
A house installation for solar. (not related to this forum)
The way I see it, I stand to gain miles-per-dollar for short range driving, which is what I really want, and almost certainly will lose a bit of miles-per-dollar when going a distance. If I'm lucky I may break even on that, but an extra axle really bites into fuel economy.


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## Ken R (Sep 26, 2018)

Having done some calculations on the van's cost per mile right now:




Winter in-town driving, fuel costs generally are up in winter for reason, I've had an actual cost per mile of $0.46 USD, probably higher. Based on highest gas prices in the area over the past 3 years I can see $0.50 per mile.
Summer driving in town, with current fuel costs, $0.35.
Best-case economy highway mileage, current gas prices: $0.13
Average case economy highway mileage, current gas prices: $0.15.
If I can double the miles per unit cost in town in pure EV mode, I would consider this a successful project in that respect. There are of course other considerations, but just getting that aspect of it out there.


*Edit:*_ And in the past year, with the minimalist use of the vehicle I described above, I estimate having spent more than USD $2000.00 on gas for in-town driving._


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## MattsAwesomeStuff (Aug 10, 2017)

> 1. I've wanted one almost since I heard of the idea.
> 2. I believe that, battery pack notwithstanding, they can be more reliable than an ICE.
> 3. I want better fuel economy in town. I love to just get in and drive for awhile, and with my current living situation (foster kids) it's difficult because I'm either leaving my wife to take care of kids, or I'm in a big van that gets ~10mpg in town on a good day.
> 4. I want to take steps toward a cleaner environment.


1 - I had a feeling that this was a "because I want to" project. I'm all aboard.

2 - Ehn. You're driving a 2010. It'll last you another 20 years with very minimal work. You'll be 73 by then. You will put more work into your EV than it will ever redeem in bonus reliability.

3 - That you'll get.

4 - 50% of the carbon/energy/whatever footprint of a vehicle is in manufacturing it. All the gas you burn in the vehicle's 20-30-year life only makes up the other half. You're driving a newer vehicle. So be rebuilding it, you're wasting huge amounts of the energy of its life. Roughly speaking, energy use scales with cost. Things have cost proportional to the resources they took to make them, if they didn't take that amount of resources, they would be cheaper. Cost effective is generally environmentally effective, and you're probably net negative on the environment.



> I guess part of what I'm hoping for is for the van to be more frequently used.


That makes sense too. If you'd do a lot more driving if it wasn't so expensive, that adds a bunch of value to you beyond what your past experience would indicate.



> Sorry for the shameless foster care plug.


Naw it's good. It's good to hear about people's passions and what drives them. I'm glad you've found a life that's rewarding for you.

...

I'm going to piggyback on Brian's suggestion from earlier and it's where I was kind of leaning with my questions. I think you need two vans.

At least, temporarily.

It sounds like you _need_ a van. Most EV conversions that people do, especially because they just want to, take way longer than they would have predicted. I'm 15 months elapsed into what could realistically have been a weekend project, but, life gets in the way.

You don't want to be in a rush. You'll run into headaches you didn't anticipate. It might take you a year to get it done.

Since your van is currently in good condition, I would keep it as such. Buy a second, older van, find one with a blown engine if you can, but good bones, and convert that one. Then when it's done, sell the good one. Or, don't, just add a trailer to it and use it for long trips.

In terms of effort, 2 vans is easier. In terms of conversions, not having to worry about a generator and second fuel tanks and all that is way faster and cheaper. Motor and batteries and you're good. Maybe cheap enough to buy the second van carcass. You should be able to get a 15-year-old one for, what, $2k? If you're looking to spend $30k, that's pretty small in comparison. That's what a used genny is going to cost you, minimum.

For long trips you just eat the cost of gas 100% of the time, whether trailer is parked or not. But around town, your 90% use case is electrical.

...

Another option you might like even less...

Don't buy a second van. Don't build a generator trailer. Build an EV push trailer.

You'd need a junkyard diff, probably a single big motor, and minimal batteries. And a trailer skeleton. Done. Mount it however you want, super easy.

The tradeoff being that now when you're tootling around town every day, you've got the trailer with you.

As a bonus, you could charge it by regening while driving. And it's much safer than a gasoline push trailer regening the van up front.

Bonus.. you could hook it up to anything with a hitch. 

It would also be an easy way to get your feet wet with EVs, without taking use away from the van. If you want to cannibalize it later for a full EV conversion down the road, maybe on a second van or whatever, you still can in about 15 minutes.

You could probably get it all done for $5k.

It's probably not what you envisioned, but, food for thought.


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## Ken R (Sep 26, 2018)

MattsAwesomeStuff said:


> 1 - I had a feeling that this was a "because I want to" project. I'm all aboard.
> 
> 2 - Ehn. You're driving a 2010. It'll last you another 20 years with very minimal work. You'll be 73 by then. You will put more work into your EV than it will ever redeem in bonus reliability.
> 
> ...



Agreed, more or less.





> ...
> 
> I'm going to piggyback on Brian's suggestion from earlier and it's where I was kind of leaning with my questions. I think you need two vans.
> 
> At least, temporarily.



Quite possible. I'm investigating if it's worth my effort at this point.





> ...
> In terms of effort, 2 vans is easier. In terms of conversions, not having to worry about a generator and second fuel tanks and all that is way faster and cheaper. Motor and batteries and you're good. Maybe cheap enough to buy the second van carcass. You should be able to get a 15-year-old one for, what, $2k? If you're looking to spend $30k, that's pretty small in comparison. That's what a used genny is going to cost you, minimum.
> 
> For long trips you just eat the cost of gas 100% of the time, whether trailer is parked or not. But around town, your 90% use case is electrical.



I don't see the trailer as the expensive part here. Probably right though that 2 vans might be easier.





> ...
> 
> Another option you might like even less...
> 
> Don't buy a second van. Don't build a generator trailer. Build an EV push trailer.



Nope. Nope. Nope. Nope. 



No push trailer, period. I've pulled trailers for a lot of miles. Enough crap goes wrong with them that I will absolutely not make a push trailer. we discussed it earlier in the thread.


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## MattsAwesomeStuff (Aug 10, 2017)

Ken R said:


> I will absolutely not make a push trailer. we discussed it earlier in the thread.


Well, that was a gasoline push trailer that you'd use to recharge batteries by regen braking on the lead vehicle.

This is just an electric push trailer. No braking, no charging. Unless you want to charge the batteries from the engine, in which case it's just like pulling a slightly heavier trailer.

But, I get it. You want an EV. Not a trailer


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## brian_ (Feb 7, 2017)

MattsAwesomeStuff said:


> Don't buy a second van. Don't build a generator trailer. Build an EV push trailer.
> 
> You'd need a junkyard diff, probably a single big motor, and minimal batteries. And a trailer skeleton. Done. Mount it however you want, super easy.


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.



MattsAwesomeStuff said:


> The tradeoff being that now when you're tootling around town every day, you've got the trailer with you.


That tradeoff is a huge handicap. I can't imagine wanting to be stuck with a trailer for every trip, even short local errands.



MattsAwesomeStuff said:


> And it's much safer than a gasoline push trailer regening the van up front.


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. 



Ken R said:


> No push trailer, period. I've pulled trailers for a lot of miles. Enough crap goes wrong with them that I will absolutely not make a push trailer.


I'm with Ken on this one!



MattsAwesomeStuff said:


> Well, that was a gasoline push trailer that you'd use to recharge batteries by regen braking on the lead vehicle.
> 
> This is just an electric push trailer. No braking, no charging. Unless you want to charge the batteries from the engine, in which case it's just like pulling a slightly heavier trailer.


It is simpler, but it is still a trailer pushing the van. This truly is putting the cart before the horse, in a physical sense rather than as the usual metaphor for lack of planning.


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## Ken R (Sep 26, 2018)

MattsAwesomeStuff said:


> Well, that was a gasoline push trailer that you'd use to recharge batteries by regen braking on the lead vehicle.
> 
> This is just an electric push trailer. No braking, no charging. Unless you want to charge the batteries from the engine, in which case it's just like pulling a slightly heavier trailer.
> 
> But, I get it. You want an EV. Not a trailer



I never contemplated a push trailer of any kind.


The closest I came was in my first post, where I pondered powering the trailer wheels to reduce force on the van's motors. In my mind it would be operated the same as hydraulic trailer brakes: The hitch has a slide which, when the van moves forward, the trailer motor would accelerate to match. The van ball would have zero force for acceleration and stopping. Only turning and the tongue weight would affect the ball.


By my second post I realized just how much of a cluster-fuck that would be if the controls got messed up, possibly killing someone. I also realized by then that it would be simpler and cheaper to put motors on the van adequate for pulling the trailer.




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.


Or you could just run a wire forward from the generator on the trailer and lose maybe 1% max. I see absolutely no reason to throw away 90% of the energy of fuel just so I can use a push trailer, which is a profound safety hazard at best.


Alternately, I could just leave my van as it is, buy a trailer, put a big open drum of diesel fuel on it, light that on fire and drive around town hoping no burning fuel spills out on the streets, the trailer, the van or nearby cars. That would actually be much much cheaper than the push trailer and every bit as effective.


Sorry about the sarcasm. I would actually rather haul around the burning barrel of diesel fuel than use a push trailer.


Hopefully that's settled.


If somebody still thinks it's worth discussion, please post links to at least 20 commercially available push trailers sold in the USA.


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## Ken R (Sep 26, 2018)

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!



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.



 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.
You have two wheels driving the trailer, which when everything works and the van is going straight, would push the van down the road.
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.
The sharper the turn the more the trailer tries to push the rear of the fan off-course.
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.
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.
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.


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## MattsAwesomeStuff (Aug 10, 2017)

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.


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.


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.


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.


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## Ken R (Sep 26, 2018)

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.


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## brian_ (Feb 7, 2017)

Ken R said:


> 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.


The problem is actually that pressure and flow of the transmission's fluid is normally provided by a pump driven by the input shaft, and so if you push the vehicle with the engine not running the transmission isn't properly lubricated or cooled, so it is eventually destroyed. There are ways around this, but it is situation to be avoided.


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## Ken R (Sep 26, 2018)

brian_ said:


> The problem is actually that pressure and flow of the transmission's fluid is normally provided by a pump driven by the input shaft, and so if you push the vehicle with the engine not running the transmission isn't properly lubricated or cooled, so it is eventually destroyed. There are ways around this, but it is situation to be avoided.



Pretty sure my van won't have that problem.


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## brian_ (Feb 7, 2017)

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.


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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## brian_ (Feb 7, 2017)

Ken R said:


> Pretty sure my van won't have that problem.


Well, no, since you're not going to push it, with or without the automatic.


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## Ken R (Sep 26, 2018)

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?





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.


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## brian_ (Feb 7, 2017)

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.


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## brian_ (Feb 7, 2017)

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.


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.


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.


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.


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## brian_ (Feb 7, 2017)

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..


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?


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...


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


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## Ken R (Sep 26, 2018)

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.



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.


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.


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.



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)
> 
> ...



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.


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## Ken R (Sep 26, 2018)

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.


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.


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).



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


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## brian_ (Feb 7, 2017)

Ken R said:


> 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.


Whatever the sociopolitical basis, the popularity of EVs certainly does vary by area. Here in Alberta you can drive for days and not see a single EV, so the salvage supply is essentially nonexistent. Whatever some people say about salvaged components being readily available, for many people they are not locally available.


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## brian_ (Feb 7, 2017)

Ken R said:


> 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 Express has been available in 1500 ("half ton"), 2500 ("3/4 ton"), and 3500 ("1 ton"), corresponding roughly to the load capacity of pickups of the same designations. I assume that they're very similar mechanically, but there will be component differences. Which one do you have?


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## brian_ (Feb 7, 2017)

Ken R said:


> 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.


That maximum speed range is typical for current EVs, which typically run 360 V (nominal) batteries. Motors built for EVs with much lower max speed are typically intended to be an easy swap into a truck for conversions, or to work with lower voltages.


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## brian_ (Feb 7, 2017)

Ken R said:


> 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.


Coils in front... but in an independent suspension, right? The pickup truck and van suspensions are similar, but at GM the pickups usually use torsion bars because the coils are in the way of the axle shafts in the 4WD. I haven't found an illustration of the Express AWD front suspension yet.


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## brian_ (Feb 7, 2017)

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?


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.


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


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## brian_ (Feb 7, 2017)

Ken R said:


> I haven't seen any suspension kits for vans either, because I assumed it was similar to a truck suspension.


It is, but for a bolt-in kit to work the frame and axle need to be exactly the same (at least in the areas where the kit attaches), not just similar in design.


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## Ken R (Sep 26, 2018)

brian_ said:


> The Express has been available in 1500 ("half ton"), 2500 ("3/4 ton"), and 3500 ("1 ton"), corresponding roughly to the load capacity of pickups of the same designations. I assume that they're very similar mechanically, but there will be component differences. Which one do you have?



3500 extended. Seats 15. It has 4 bench seats and 2 buckets instead of the standard 3 bench seats and 2 buckets that a normal 3500 has. I can't remember right off the bat, but the rated carrying capacity is more than a ton.


Also unlike older vans, the extension is between the axles rather than welding something extra on the back. There's no crazy overhang back there. I know from experience driving both versions that the extended wheelbase makes for better control in slippery conditions.


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## Ken R (Sep 26, 2018)

brian_ said:


> 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.



Yes, a traditional solid axle with an engine mounted with the crankshaft parallel to the direction of travel, a drive shaft going back and a ring and pinion gear differential, which turns the rotation 90 degrees. 



As mentioned in my previous post, my van is rated at more than a ton cargo capacity. I believe it's around 3000 lbs. If you count 15 adults with realistic weights you definitely have more than a ton. I don't know if it's the same running gear under there as a regular 1-ton vehicle or if it's heavier.





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


My EV dreams were re-ignited when I was changing oil under there. I looked back at the frame and thought about how many batteries you could put in there if you got rid of the drive shaft and engine/transmission, and have absolutely nothing visible from the outside without crawling under the van to look.


Practical or not, the dream currently is to replace the one-piece axle with 4-wheel independent suspension and a motor on each wheel with a single-speed gearbox. Motors and gearboxes mounted to the frame, with drive shafts with CV joints going out to the wheels. 4wd would be awesome but possibly not practical. The dream (very possibly not practical or within budget) is to have better acceleration than I currently have, especially if the generator trailer comes into play.


If there are commonly available EV-specific motors in the power range that I would need (let's say, 450 hp instead of 350 so 112 hp each wheel) then I would think the whole project could be cheaper that way.


*Edit:*_ I'm pretty sure the existing engine, rated at 350 hp, can't pull that power continuously. The electric motors I would use would only need to match the abilities of the existing engine, or preferably surpass those abilities by a noticeable amount._


In contrast, buying new equipment clearly the more motors and controllers you get the more outrageously expensive this whole thing gets.


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## brian_ (Feb 7, 2017)

Ken R said:


> 3500 extended.





Ken R said:


> As mentioned in my previous post, my van is rated at more than a ton cargo capacity. I believe it's around 3000 lbs. If you count 15 adults with realistic weights you definitely have more than a ton. I don't know if it's the same running gear under there as a regular 1-ton vehicle or if it's heavier.


3,000 pound payload is not much for a 3500-series pickup - that's more like 2500-series, and even an ideally configured 1500 can get close to that. Recent 3500 Express vans have about 3800 pound payload, so we could assume that; the corresponding GVWR is 9600 pounds (three tons of van plus two tons of payload equals five tons of loaded van... about the same numbers as a 3500 pickup. "One ton" (3500-series, or anything GM labels as "HD") pickup components would be fine... if they fit.


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## brian_ (Feb 7, 2017)

Ken R said:


> I'm pretty sure the existing engine, rated at 350 hp, can't pull that power continuously. The electric motors I would use would only need to match the abilities of the existing engine, or preferably surpass those abilities by a noticeable amount.


Engine ratings are essentially continuous, although few people run them that hard, and lifespan would be short (meaning less than the usual 200,000 miles or 300,000 km expected of a modern light duty vehicle, not blowing up in a few minutes!) if worked that way. A high-voltage modern electric motor can run at the rated power over a broad speed range, while the engine only hits that peak at the top of the operating speed range, so the motor rating can be lower than the rating of the engine being replaced, for the same performance.


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## brian_ (Feb 7, 2017)

For the front, it looks like 4WD with the 3500 van's independent front suspension can be done... Quigley does it. You wouldn't want to pay what Quigley would charge (even if they would do your older van), but they seem to have worked out that the parts will fit and how to do it, with a custom front crossmember (because the van and pickup frames are not the same):
DIY: 2500/3500 Van IFS 4WD Conversion

Quigley Products > Quigley 4x4 GM Vans > 4x4 Models
"K-Series" means 4WD GM pickup trucks

If you use a salvaged EV drive unit or some other motor-and-gearbox arrangement, instead of the factory final drive unit, you would want a crossmember to fit that instead... so it would be custom and unique to your van, not just a copy of Quigley's component.


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## Ken R (Sep 26, 2018)

The last van in the list looks to be exactly my setup.


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## Ken R (Sep 26, 2018)

I've done nothing since my last post except browse the quigley page.


It seems to me that if someone were to want one of their conversions the best way to do it is to just deliver them a brand new van. The conversion seems likely to cost several times the new price of the vehicle no matter what, so the van itself would be sort of an afterthought. If you're going to have a company do the conversion I would think you'd want it to last as long as possible, hence a new van. Or maybe a 1-year-old with 2k miles on it.


That sort of thing is out of my reach for sure, just saying though. It would be neat to be able to dig around in a van they converted to see how they did things. They surely know more about it than I do, and while I might want to do some things differently I'm sure I'd learn a lot from what they do.


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## brian_ (Feb 7, 2017)

Ken R said:


> It seems to me that if someone were to want one of their conversions the best way to do it is to just deliver them a brand new van. The conversion seems likely to cost several times the new price of the vehicle no matter what, so the van itself would be sort of an afterthought. If you're going to have a company do the conversion I would think you'd want it to last as long as possible, hence a new van. Or maybe a 1-year-old with 2k miles on it.


I agree.



Ken R said:


> It would be neat to be able to dig around in a van they converted to see how they did things. They surely know more about it than I do, and while I might want to do some things differently I'm sure I'd learn a lot from what they do.


That's why the discussion in the DieselPlace forum would be valuable, because it works through the details of the conversion... or at least it appears to - I didn't register for their forum so I haven't seen the images.


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## Jimbo69ny (Feb 13, 2018)

Sounds like you might be interested in my T-Rex range extending trailer. Here is me and Rich Rebuilds. https://youtu.be/Qb7vg08zluQ


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## funguy49 (Jun 23, 2010)

Ken, I've read most but not all of the conversation. I apologize if any of my comments are redundant.
First, the push trailer and/or the trailer "range extender" have never been very successful. Just not very elegant or effective.

A DC system can only recharge the traction pack if/when the contactors are open. So, open to charge, close to run, open, close. Too much on/off action. This is primarily why most production EVs use AC systems.

One option I didn't see discussed is putting the electric motor inline with the drive shaft. Netgain makes a "trans warp" motor for this setup. Doing this requires very little reworking of the current vehicle. It also runs with a relatively small voltage battery pack; say 96 volts rather than 144 or more. The electric motor is use for acceleration, the most inefficient part of using a gas engine. The gas engine then takes over for the "at speed" running and, of course, recharging the pack.

All in all, a fairly nice hybrid arrangement. Worth a thought anyway.

Good luck!

Ken G./funguy49

Using lithium batteries, they can be mounted in almost any position under the body and can be protected with a small sheet of polymax.


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## Ken R (Sep 26, 2018)

funguy49 said:


> Ken, I've read most but not all of the conversation. I apologize if any of my comments are redundant.
> First, the push trailer and/or the trailer "range extender" have never been very successful. Just not very elegant or effective.



Even if a push trailer were elegant or effective, I wouldn't build it or buy it or even use it if somebody gave it to me. My area has too many scenarios for it to get completely out of control. The only reason I haven't edited the original post to exclude the motors on the trailer is to provide context for the rest of the discussion.


Unfortunately the idea of a push trailer is popular for discussion. My original idea was to put electric motors on the trailer wheels in order to reduce the necessary size of the van motors. In afterthought it would be cheaper, easier, much more benificial and incredibly safer to put bigger motors on the van.





> A DC system can only recharge the traction pack if/when the contactors are open. So, open to charge, close to run, open, close. Too much on/off action. This is primarily why most production EVs use AC systems.



Not interested in DC systems. I'd prefer AC induction motors, in spite of the popularity of PMAC. I'm well-read on the differences and benefits of each system.





> One option I didn't see discussed is putting the electric motor inline with the drive shaft. Netgain makes a "trans warp" motor for this setup. Doing this requires very little reworking of the current vehicle. It also runs with a relatively small voltage battery pack; say 96 volts rather than 144 or more. The electric motor is use for acceleration, the most inefficient part of using a gas engine. The gas engine then takes over for the "at speed" running and, of course, recharging the pack.



That's because the main battery area under the van is right where that driveshaft goes. If I can get rid of the driveshaft, I have the top and sides of a battery container right there. My preference would be to center-mount 2x electric motors to the frame, shafts toward the center line. Shafts go into a single speed gearbox such that my top anticipated speed matches the max RPM of the motors. Output of the gearbox connects to the wheels via CV joint-connected driveshaft/axle.



This arrangement, in my opinion, offers the best possibilities for performance and the best weight reduction. And the most efficient drive system. It's clear that a single electric motor designed for automotive use is unlikely for my needs, so I'm already into it for at least 2 motors if this project actually happens, and possibly for 4 motors.


I would kinda like 4wd anyway, so from a preferences perspective the idea of 4 motors is kinda attractive.





> All in all, a fairly nice hybrid arrangement. Worth a thought anyway.
> 
> Good luck!
> 
> ...



Trying to do it without the hybrid part. The vast majority of my driving is under 30 miles a day, so a pure EV is easy for that. Moreover a large part of my driving this particular vehicle means that I'm taking more people than would fit comfortably in a smaller vehicle. So it's not like this is a super-sized monstrosity for no reason.


Obviously I would like a modern chemistry battery. Also obviously the batteries and possibly the charging system will be replaced a few times before the vehicle is worn out.


While I don't drive it much right now, a converted EV van would be driven much more often.


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## Ken R (Sep 26, 2018)

Jimbo69ny said:


> Sounds like you might be interested in my T-Rex range extending trailer. Here is me and Rich Rebuilds. https://youtu.be/Qb7vg08zluQ



Interesting.


That's a good solid idea for someone who only needs to double their range. In my case, taking the van on a trip may mean 2k miles or more.


That said, my idea is quite similar to your trailer only with an ICE and gas tank(s) instead of batteries.


It's good to see somebody proving a range-extending trailer though. That looks like a solid setup. I like the redundant contactors on the car and the trailer. I assume they disconnect in the event of anything unexpected? I'm thinking of collisions and such. I'd want the trailer to automatically kill the engine and disconnect high voltage when something unexpected happens.


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## Jimbo69ny (Feb 13, 2018)

Ken R said:


> Interesting.
> 
> 
> That's a good solid idea for someone who only needs to double their range. In my case, taking the van on a trip may mean 2k miles or more.
> ...



My next project is to build the same thing out of a Tesla 100kwh pack then build a removable, lightweight, fiberglass, teardrop over top of it. That will allow me to take road trips with the family and remove it to use it as a utility trailer. Either way I can also use it for home energy storage as well.


I can turn on and off the contactors inside of the T-Rex by pushing a button on the side of the plastic box. I cannot control them from inside my car. The onboard controller can open/close them based on temp, SOC, and voltage. I had an intertia switch but the trailer bounced too much for it to work. I think it will be better once I upgrade the suspension and add more weight.


In the car I do have an inertia switch that will close the contactors that I added in the rear of the Rav. There are also fuses everywhere.


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## Ken R (Sep 26, 2018)

Jimbo69ny said:


> My next project is to build the same thing out of a Tesla 100kwh pack then build a removable, lightweight, fiberglass, teardrop over top of it. That will allow me to take road trips with the family and remove it to use it as a utility trailer. Either way I can also use it for home energy storage as well.



I figured it was a work in progress. Your project seems too neat for someone inclined to leave the pack in the open like that.





> I can turn on and off the contactors inside of the T-Rex by pushing a button on the side of the plastic box. I cannot control them from inside my car. The onboard controller can open/close them based on temp, SOC, and voltage. I had an intertia switch but the trailer bounced too much for it to work. I think it will be better once I upgrade the suspension and add more weight.



Is this your first trailer? Bouncing trailers is a symptom of bad loading, or an empty trailer. With your setup the trailer will always be the same weight, so you should be able to match the axle and tongue length to get extremely good handling.



What sort of suspension do you have on the trailer? If it's just leaf springs consider going to a torsion axle. Or get shocks.


Trailers tend to ride best when they're at about 80% of the axle's rated load. And be sure that the hitch weight is 10% of the total trailer weight. And make sure your tires are over-rated for the weight you wind up with.


Pay attention to every load limit in the chain: Your vehicle's max tow weight, the vehicle's max hitch weight, the max rating of the tires, the max rating for the axle and if it's a manufactured trailer the max rating for the trailer itself. And make sure those bearings get packed at least once a year, more if you use the trailer a lot.


You also want the distance from ball to axle to be large compared to the width between tires.



Trailers are simple and reliable, but they need maintenance and attention to detail. If you do this one right you'll be able to go around curves as fast as you do without the trailer, but you need to make sure everything is right. Go into it knowing this and "owning it" and you'll be a lot better off.





> In the car I do have an inertia switch that will close the contactors that I added in the rear of the Rav. There are also fuses everywhere.



Good deal. Maybe there's a way to hook into the car electrical system to detect when the airbags deploy? Not sure if that's a thing. I've been in one airbag deployment, and I know that a significant collision from one angle can be inconsequential from another. There could be a front-end side collision that does almost nothing to the rear of the vehicle, but you'd still want the switch to cut off I think.


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## Ken R (Sep 26, 2018)

Also pay attention to your car. If your car rides nose up when the trailer's on it you'll get significant problems with handling.


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## Jimbo69ny (Feb 13, 2018)

Hello Ken,


Its my first range extending trailer but I have had many regular trailers. I tow a lot. I have rental properties so I am always moving lawnmowers, appliances, tools etc. When I say bouncing, I dont mean regular hopping, I know thats bad. I actually experienced some of that when my ball mount was too tall. I thought it was balanced nicely but nope. Went down about 2.5 inches and its all good now. I still do get some hop on some roads that are trash but as long as the road is good its smooth as silk.


The suspension is stock that came with the trailer. Its cheap, nothing special but it works. On my next build I am going to buy a Timbren independent suspension system. https://www.youtube.com/watch?v=KOFRqS_BbUg
Seems awesome. Expensive but when you have a $15k battery and $4k teardrop whats another $1k. lol


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## Ken R (Sep 26, 2018)

OK then I'm going to stop giving you advice on trailers then, you probably know as much about it as I do. I've hauled a lot of trailers, and about half of that time is highway time. I've built a couple from the ground up too.



With your trailer you have a constant weight and it's always on one vehicle. You should be able to tune that trailer so it rides as well as your car does. And it would be worth it to do so in this case I think.


One thing I saw once that might interest you: I saw a guy who took a mid-sized car. He chopped it into 3 sections, removed the passenger part, pushed the other two sections together and kept the independent rear suspension. Front half of the front wheel well, back half of the back one. Not sure what the original car was but it was older, when the rear window didn't go all the way back to the bumper. He had to do some significant work on the top but it looked pretty good.


You could find a workable car with a blown engine or something, then you have a shell and an actual automotive suspension. Maybe an old Lincoln would for sure have enough room. Or you could get the same car you're driving and try something equivalent with that.


The modified car would probably be a lot more work than what you had in mind, but it would look neat and might give you better suspension.


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## Bmmoffat (Nov 14, 2018)

What if you convert it to more of a hybrid vehicle? You could use a front axle from a 4wd, and hook the ac motor up to that. That would allow you to run a smaller battery pack. 

You could also downsize the motor to a smaller v8. This with the electric motor for acceleration help will net you way better mileage. The pack could be plug in as well as charge off the ice motor. So for short trips you could almost use no gas engine, and the electric motor would help the gas one going up hills. You could still get the benefits of regen going down hills wight would more save your brakes than get u power back but still saves on maintence.

In California you can only tow at 55, So here it would not be feasible to hit the 65-75 cruising speeds. 

I would do this if it were my van, as well as add one of those hitch racks to carry more stuff off the back without using a trailer.


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## joekitch (Sep 13, 2013)

made a long post about using a Volt engine on a trailer 
opted to make a thread on it instead
https://www.diyelectriccar.com/forums/showthread.php/crazy-idea-using-chevy-volt-engine-200407.html


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## brian_ (Feb 7, 2017)

joekitch said:


> ... actually, you know what, i'll make a separate thread on this question


Great, but can you delete your post, or at least the image attached to it, because it forces the page to display very wide (to match the width of the huge image), wrecking the formatting in a web browser so that the the page must be scrolled side-to-side to read text.


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