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Discussion Starter #1 (Edited)
I have been looking for articles on this topic, but it seems that most of the stuff is being developed by private industry - not open source, or openly shared information. I have found some threads on this topic but the ones I have found so far have not seemed to lead to completion.
For the past 15 years I have been dreaming about converting a school bus to an rv to live on it full time in retirement - continue to work from it, but travel around. I have been reading a lot about electric buses and am trying to do a preliminary look at what it would take. The kind of bus I am looking for has a 230hp diesel motor that puts out about 550 ft pounds of torque. They usually are sold connected to an Allison 3xxx transmission. I have done some research on the Allison website and it seems that many companies are buying their transmissions to use with electric motors. This tells me that it is feasible (not how much, but it is good for now.) Another twist...I have seen some projects where people have installed a front end from a 5 ton all wheel drive military vehicle to make their bus a 4x4. It is possible - not terribly difficult...but, again, is feasible, which is the goal now. My thought is that the bus:
- would have an electric motor hooked to the front differential and another motor hooked up to the rear differential (exact same kind of motor) this would give me 4x4 without need for drive shafts to run down the middle of the bus.

- each differential would have an appropriate transmission. Preliminary questions suggest that 2 Allison transmissions (maybe all computer controlled transmissions) can be controlled by one controller.

- the bus would have a battery pack. Initially, not a big one because I would need a few years to recover from the $$$ shock of the other components :eek:

- the bus would have a genset. Not a stinky, noisy one but something assembled from a very clean diesel engine (I feel safer hauling diesel around than gasoline) - maybe a recent car engine - and a genset head. These buses normally get 8-9 mpg with their diesel engines. It is my hope to be able to get at least 13 with the battery/generator setup. More, of course, is better.

- possibly have a high voltage capacitor setup to store a 3 or so minute burst of electricity for passing or other temporary situations. I have read of these things. Batteries need a high C discharge rate to power something like this =$$$ and also maybe not good for long battery life. These kinds of capacitors were designed to release electricity quickly indefinitely.


Let's see....I want to be able to cruise at 65mph....also pulling an 8,000 pound trailer would be nice. That is something the diesel could do. That finishes my wish list.



I have seen 3 phase 150 hp traction motors for about $5K each (they are heavy suckers). From what I have read so far, that seems to be the TYPE of motor that I would need. Is that correct? Would the size be appropriate? They are either 230v or 460v. What would be the benefit of choosing one voltage above the other? Other issue - the couple that I looked at are rated for 1,800 rpms. The diesel is 2,200 rpms. This puppy goes faster: https://inventory.powerzone.com/item/58314/used-125-hp-horizontal-electric-motor-siemens but each motor would weight as much as one diesel engine.



So, this is phase one. Please feel free to send me links to useful articles - hopefully on the more technical side.
 

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Those are big industrial motors. They are not what you want to use. Weight is a big issue with those, as you've noticed. The easiest path may be getting a scrapped bus/van for its electronics and drivetrain. Perhaps two vans would yield a drivetrain for each axle and enough batteries? The motors used in these applications are usually liquid cooled AC motors that spin at much higher RPM with a gearbox for torque. I wish I had more info, but I'd head in that direction.

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Discussion Starter #3 (Edited)
Thanks for your input. I just looked at the warp motors. 4 of the Warp 11 at 288 volts would equal the output of the Cummins 8.3l diesel. Two can be connected at each differential - they can be combined end to end, for a total weight of about 800 pounds, or half of the diesel. Combined price would be about $12K for the motors. Cost of a good rebuild of this diesel is $10-12K, so it looks like a fair exchange. I realize there have to be $$$ put into creating motor mounts, etc for these to work, as well as for the controllers.


Any ideas for a transmission? The present transmission is a 6 speed auto designed for a maximum rpm of 2,500 rpms. I would prefer to keep it automatic. I am not that familiar with power curves for electric motors...I have been told that things like extra over drives are not so necessary for electric motors - that perhaps a 4 speed auto with 4th gear of 1 to 1 might be adequate because of the electric motor's ability to draw power according to need? Not sure about this...in my mind, overdrives always = more distance on the same amount of fuel.


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This is a very familiar discussion, repeating the ideas (including the mistakes) of several previous discussions of large vehicles - generally intended as RVs - including at least one specifically about school buses. Heavy vehicle or not, the idea of using a generator to make a homebuilt series hybrid is also common. I think it's worth searching for those previous discussions to save everyone a lot of rehashing.

For a preview, I'll note that no one actually builds these projects (either RVs or series hybrids); they only make plans, discuss them, realize that they are unworkable, and disappear.

For now, I'll just note that the idea that Allison transmissions are commonly used with electric buses seems unlikely to me. Allison has a great line of hybrid transmissions, but for an electric motor the more common choice is a single-ratio reduction gearbox.
 

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Discussion Starter #5
This is a very familiar discussion, repeating the ideas (including the mistakes) of several previous discussions of large vehicles - generally intended as RVs - including at least one specifically about school buses. Heavy vehicle or not, the idea of using a generator to make a homebuilt series hybrid is also common. I think it's worth searching for those previous discussions to save everyone a lot of rehashing.

For a preview, I'll note that no one actually builds these projects (either RVs or series hybrids); they only make plans, discuss them, realize that they are unworkable, and disappear.

For now, I'll just note that the idea that Allison transmissions are commonly used with electric buses seems unlikely to me. Allison has a great line of hybrid transmissions, but for an electric motor the more common choice is a single-ratio reduction gearbox.

Thanks! I have tried searching on "electric bus", electric+bus and a few other variants, but no luck. Can you give me some other suggestions?
 

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Thanks! I have tried searching on "electric bus", electric+bus and a few other variants, but no luck. Can you give me some other suggestions?
It can be tricky to find relevant threads in discussions forums.

There's no point in putting "electric" in the search, since the entire forum is about electric vehicle conversions.
Just "bus" should work (although it will find threads which in Volkswagen vans are discussed, and references to computer communication buses such as CAN). Specifically for school buses I tried just "school", but that gets lots of references to high school projects; with "school bus" I only found the same threads that I found with just "bus".
Just "RV" would work for a Google search, but if you are using the forum's built-in search tool it wants longer search terms, so you could try "motorhome".

Here's what I found, just looking for "bus" and "RV" using Google; there are more:
Bus

RV
... plus some which were already found in the "bus" list.

Motorhome (this isn't the full list; I just wanted to include this particular discussion)

I didn't even search for hybrid project proposals, most of which are for smaller vehicles, but some of these are hybrid ideas.

Some of these discussions are not really connected to reality.
 

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Discussion Starter #7
It can be tricky to find relevant threads in discussions forums.

There's no point in putting "electric" in the search, since the entire forum is about electric vehicle conversions.
Just "bus" should work (although it will find threads which in Volkswagen vans are discussed, and references to computer communication buses such as CAN). Specifically for school buses I tried just "school", but that gets lots of references to high school projects; with "school bus" I only found the same threads that I found with just "bus".
Just "RV" would work for a Google search, but if you are using the forum's built-in search tool it wants longer search terms, so you could try "motorhome".

Here's what I found, just looking for "bus" and "RV" using Google; there are more:
Bus

RV
... plus some which were already found in the "bus" list.

Motorhome (this isn't the full list; I just wanted to include this particular discussion)

I didn't even search for hybrid project proposals, most of which are for smaller vehicles, but some of these are hybrid ideas.

Some of these discussions are not really connected to reality.
Thank you so much! I will begin reading...so the trick is to use google and not the in forum search?
 

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...so the trick is to use google and not the in forum search?
If you want to use the features of the Advanced Search, such as limiting results to posts by a specific member or in a specific forum section, the in-forum search tool is very helpful. Otherwise, most people find a Google search easier to use.
 

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Look for one of the delivery vehicles built with Enova motors... There were some Smith Electric box trucks sold recently, and there are other companies that built trucks in the 2006-2012 timeframe that might be hitting the market soon. The drivetrains from these should have the power you are looking for, and come with reduction gearboxes.
 
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