[Ken R]

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.

 

[brian_]

3500 extended.

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.

 

[brian_]

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.

 

[brian_]

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.

 

[Ken R]

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

 

[Ken R]

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.

 

[brian_]

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.

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.

 

[Jimbo69ny]

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

 

[funguy49]

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.

 

[Ken R]

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!

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.

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.

 

[Ken R]

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.

 

[Jimbo69ny]

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.

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.

 

[Ken R]

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.

 

[Ken R]

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.

 

[Jimbo69ny]

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

 

[Ken R]

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.

 

[Bmmoffat]

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.

 

[joekitch]

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

 

[brian_]

... 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.