# Researching a conversion - A Bronco



## dcb (Dec 5, 2009)

do you understand the importance of aerodynamics if you don't want to waste the limited energy storage of a portable battery?


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## AmaToolBox (May 11, 2017)

dcb said:


> do you understand the importance of aerodynamics if you don't want to waste the limited energy storage of a portable battery?


Yep, note my opening statement.

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## dcb (Dec 5, 2009)

nope, I don't see anything about comprehending aerodynamics. You want to drive a brick at hiway speeds for 200 miles on battery, got it. 


And when you run out of range with 160 miles to go, you think the best option is to just turn on a generator? So if you were getting 15mpg with the original motor, you would rather get, say, 10mpg (for enough 200 mile trips for it to matter)?


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## AmaToolBox (May 11, 2017)

dcb said:


> nope, I don't see anything about comprehending aerodynamics. You want to drive a brick at hiway speeds for 200 miles on battery, got it.
> 
> 
> And when you run out of range with 160 miles to go, you think the best option is to just turn on a generator? So if you were getting 15mpg with the original motor, you would rather get, say, 10mpg (for enough 200 mile trips for it to matter)?


Actually, if I have no way to meet my range requirements, the engine I was looking at, and the generator design I had equated to about 50mpg. It was a high efficiency engine, not throwing a generac in the tailgate. Specifically a clean burning multi fuel engine. And, that's only if I need it. Given the advancement in both batteries, reclaim technology and capacitor storage, I feel something can be done.

My knowledge gap is noted above, high efficiency generators utilizing clean burning technology is not in the list.

My goal in this thread is to learn enough about the ev technologies above to eliminate a V8, 8mpg burned out engine from the road. If you don't like that, fine, don't reply. To attack the mission rather than provide real responses is just frustrating.

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## Jeremyfc1 (Feb 5, 2016)

I'm Jeremy currently building an electric rock buggy. Using solid axles and dual toyota transfercases along with an e450 air cooled ac motor out of a hybrid shuttle bus. 

Realistic range is 30-60 miles for a 4wd vehicle even in 2wd you still have all that drag unless you build in some hubs at the wheels. Even then moving say a 32" mud tire at highway speeds isn't efficient. 

Generator tech can move a long way soon. It just needs to happen. I'm in the same boat as you in my build that I want a better generator for longer trips. 40 miles rock crawling or offroading of any kind is a very long way could take you 6hrs to go 3-4 miles depending on the terrain

Pm me I'd be happy to chat more. I'm in North Carolina how about you


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## dcb (Dec 5, 2009)

AmaToolBox said:


> the generator design I had equated to about 50mpg.


You must have figured wrong.




AmaToolBox said:


> fine, don't reply. To attack the mission rather than provide real responses is just frustrating.


You absolutely figured wrong on that account, what is this "mission" crap anyway? And why are motors and batteries and generators the solution? What magical properties do they have in your mind?


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## AmaToolBox (May 11, 2017)

dcb said:


> You must have figured wrong.
> 
> 
> 
> ...


We did it with a Civic, using old equipment stripped from used cars 5 years ago. I figure with new tech the bronco becomes possible. 

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## AmaToolBox (May 11, 2017)

Jeremyfc1 said:


> I'm Jeremy currently building an electric rock buggy. Using solid axles and dual toyota transfercases along with an e450 air cooled ac motor out of a hybrid shuttle bus.
> 
> Realistic range is 30-60 miles for a 4wd vehicle even in 2wd you still have all that drag unless you build in some hubs at the wheels. Even then moving say a 32" mud tire at highway speeds isn't efficient.
> 
> ...


I am in NY, Hudson valley region.

Actually have a design for a gear box that replaces the front hubs. It has a gear drive direct to the wheel that can detach. Only issue is it must be standing still to enable 4wd, but I am fine with that.

I don't know much about electric motors, and I figure if I drive all 4 I will have a lot of drain on the batteries plus maybe amp issues. So I was even considering 4 separate battery banks with a cross connect that the rear when 4wd is not enabled can use the front power too... I can make the circuit, but without knowing the draw I don't know how to figure it out. I also know nothing about controllers.

On mobile at the moment, don't have pm abilities.

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## madderscience (Jun 28, 2008)

I'm sorry there was a bit of hostility / incredulity in some of the prior posts, but they do make a point - a full size bronco 4x4 isn't efficient and you are making a very ambitions range goal for any DIY EV given the current state of the world. A good rule of thumb for an EV conversion looking at the MPG of the original vehicle is you will get about the same amount of range from 10kwh nominal battery capacity as you did from 1 gallon of gas. I'm omitting the math here but it factors in the energy density of gasoline and the relative efficiency of an EV drive vs. the ICE.

This means for a 200 mile EV range in a vehicle that originally got 15mpg, you would need about a 130kwh battery. To put that in perspective, the biggest battery pack available in a Tesla model S right now is 100kwh. (and weighs about 1000lbs) 

You are right, battery tech is improving. In another 3-5 years tesla might be manufacturing 130kwh batteries, and in 10 years, I would not be surprised to see a 200kwh battery in that same size/weight range. 

As for motor and inverter technology, there isn't much room for improvement. those systems are already well over 90% efficient and capable of much more power density (HP per pound) than any gasoline engine.

I wouldn't bother trying to do motor-on-each-wheel. It requires complex control systems that are too much trouble for the gain for most DIYs. If you have or could upgrade to a shift-on-fly capable transfer case I'd just bolt up the motor to that (removing original engine and transmission) and keep the rest of the driveline intact. A part time 4x4 drive with freewheeling front half would help with rolling resistance.

Right now, your best bet for an economical conversion to something getting better mileage is a diesel conversion and some of your aforementioned weight reduction, and some subtle aerodynamic improvements, like belly pans and such that don't detract from its 'truck' factor.

If you do want to do a 200 mile EV (and you don't want to just buy a bolt or tesla model 3) best to start with a more appropriate chassis (1st gen insight or such) and you will need probably 2 healthy nissan leaf packs to get the range even in a chassis like that.

Good luck.


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## Jeremyfc1 (Feb 5, 2016)

^^^^ 

If you want to build a 4x4 ev go for it. Just know that range is always going to be an issue. I went with one big motor coupled to dual toyota transfercases. O did this for a few reasons. One simplicity. Only one motor controler combo. I was going to directly drive the differentials woth it but decided I want some gear of options. I plan on running 37" tires so making it crawl was important. But also want high speeds as well. I have two more of the same motor as well as a slew of smaller ones. Get up with me if you want to go that route.


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## AmaToolBox (May 11, 2017)

Jeremyfc1 said:


> ^^^^
> 
> If you want to build a 4x4 ev go for it. Just know that range is always going to be an issue. I went with one big motor coupled to dual toyota transfercases. O did this for a few reasons. One simplicity. Only one motor controler combo. I was going to directly drive the differentials woth it but decided I want some gear of options. I plan on running 37" tires so making it crawl was important. But also want high speeds as well. I have two more of the same motor as well as a slew of smaller ones. Get up with me if you want to go that route.


I like the layout you have. The only reason I am considering the separated motors instead of a single drive is I feel I can programmatically control the differential better than an axle with drag.



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## brian_ (Feb 7, 2017)

I'm not attacking anything - just continuing the converstation - but I do wonder what assumptions went into getting 50 mpg in a series hybrid configuration of a massive and aerodynamically bad vehicle.

If you convert fuel to shaft power with the most efficient truck-sized engine ever made, running at its most efficient point, but then lose about 10% of that as the generator converts it to electrical power, lose more in the charging and discharging of a battery, lose another 10% of what's left converting it back to shaft power, you're not going to end up three times better than just running engine power through nearly zero-loss gearing... even with the engine in a non-optimal speed-load condition. Relatively poor efficiency in series hybrid mode can be acceptable, if that mode is rarely needed - just ask BMW, which builds a reasonable battery-electric car (the i3), which can be ordered with an optional engine to make it a series hybrid which works as either an overly expensive and overweight battery-electric (when the engine is not running) or a wildly expensive gas-engine car with mediocre fuel economy (when running as a hybrid).

So 50 mpg seems unlikely in anything more demanding than an aerodynamically slick compact car. When people - not just in this thread - say things like they "intend to strip and rebuild the truck with lighter parts from the ground up to save on the weight", I wonder why they are starting with an old truck, since none of the parts are light... and if you replace all of the parts, you have just custom-built an entire vehicle. Ford didn't just throw piles of ballast in there for fun; all that weight is doing something that still needs to be done. New vehicles are generally not much lighter than older comparable vehicles, and when they do save weight it is by highly optimized structural design or expensive materials. Essentially, the most effective rebuild is to melt the old truck down, recycle the steel into new material, and build a more appropriate vehicle. If you're not willing to do that, then I suggest accepting the mass and bad aero, and planning realistically around that.

Madderscience had a great energy-based approach to estimating required battery capacity. Another approach to understanding what will be required is to consider the result of billions of dollars of research and development, and ask how you will change from that.

A Nissan Leaf has about the right range. Can the Bronco be made as light as a Leaf, and if not in what way will it have superior efficiency so it can have similar range with more load? If it will be less efficient (yes), and heavier (yes), and have more aero drag (yes), then it will need much greater battery capacity... or it will need to go hybrid, which adds more mass and complication.
A Tesla Model S "dual motor" has adequate range and all-wheel-drive. Every way in which a home-brew Bronco conversion differs from the Model S will increase energy consumption, and so reduce efficiency and range.

I'm not aware of any technical improvement over the last five years which would massively improve the performance of an EV. Is the improvement the availability of decade-old batteries as used parts from salvage vehicles? Availability of aftermarket inverters and controllers which perform like commercial vehicle components of a decade ago?


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## brian_ (Feb 7, 2017)

I understand the appeal of running separate front and rear motors, rather than incorporating a central differential and adding control of that in case of unequal traction. I'm just not sure that disconnecting the front motor is worthwhile, since most of the hardware will keep turning anyway. There are a few hybrids which run one axle only electrically (the hybrid versions of the Toyota/Lexus RAV4/NX and Highlander/RX, Honda/Acura Pilot/MDX and NSX, etc), and as far as I know they all leave the motor(s) connected at all times, idling when not needed.


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## AmaToolBox (May 11, 2017)

brian_ said:


> I understand the appeal of running separate front and rear motors, rather than incorporating a central differential and adding control of that in case of unequal traction. I'm just not sure that disconnecting the front motor is worthwhile, since most of the hardware will keep turning anyway. There are a few hybrids which run one axle only electrically (the hybrid versions of the Toyota/Lexus RAV4/NX and Highlander/RX, Honda/Acura Pilot/MDX and NSX, etc), and as far as I know they all leave the motor(s) connected at all times, idling when not needed.


The gearbox design I have will allow for the front wheels to also be used for regenerative breaking, not let them sit idle.

I understand all your points, and I have no doubt I won't hit my target, but I am shooting high to see how close I can get to it.

As for the weight for stripping the bronco. I do intend to rebuild from the ground up, pretty much only using the original frame. The intent is to replace a large portion with aluminum where strength is needed and a ploy/plastic material for the body. I wasn't looking to do this as a simple engine swap. It's the style I want not the metal.

Thanks for the input for the formulas. I will look more into that. I am also looking at an experimental capacitor based battery from mit as well.



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## Duncan (Dec 8, 2008)

Hi Arma
You need to sit down with some actual numbers

Basic engineering - everytime you convert energy the gods take a bite - so work with minimal conversions - if you have turned diesel into power use it to drive the wheels

Motors produce torque - very very roughly the amount of torque is proportional to weight - so if you want a lot of torque a small motor + a reduction gear is a LOT lighter than a huge motor

A Kg of Supercaps only holds a tiny amount of energy compared to a Kg of Lithium batteries 

After "Why don't you attach an alternator to the wheels" The biggest "Stupid Ideas" in the EV world are

Hybrid
Hub motors
Supercapacitors


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## AmaToolBox (May 11, 2017)

Duncan said:


> Hi Arma
> You need to sit down with some actual numbers
> 
> Basic engineering - everytime you convert energy the gods take a bite - so work with minimal conversions - if you have turned diesel into power use it to drive the wheels
> ...


The point of me creating this thread is so I can learn the numbers and formulas as well as sources for some components.

As for regenerative breaking, the loss on that is when charging batteries. Capacitors take it more efficiently and at faster rates.

I don't know what your issue is with capacitors. The main problem with dealing with them is they aren't batteries. You need to regulate power more accurately in and out than a battery, but they can be charged with a much lower loss and at a far faster rate. The main benefit here is that I can take the voltage regulator off a generator for example and accept irradic current like static to charge them. 



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## dcb (Dec 5, 2009)

AmaToolBox said:


> I don't know what your issue is with capacitors. The main problem...





Duncan said:


> A Kg of Supercaps only holds a tiny amount of energy compared to a Kg of Lithium batteries


I'm guessing you (OP) don't know the difference between energy and power. But that is the major problem for an ev.



Duncan said:


> After "Why don't you attach an alternator to the wheels"


I've not seen "add lightning rods" yet...


AmaToolBox said:


> accept irradic current like static to charge them


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## AmaToolBox (May 11, 2017)

dcb said:


> I'm guessing you (OP) don't know the difference between energy and power. But that is the major problem for an ev.
> 
> 
> I've not seen "add lightning rods" yet...


Seems you only like attacking people instead of having polite and constructive conversations on technology.



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## dcb (Dec 5, 2009)

AmaToolBox said:


> Seems you only like attacking people instead of having polite and constructive conversations on technology.


Lol, just pointing out the obvious. Duncan answered the problem with capacitors, and you either ignored it, or don't know what he means by energy density.

But in either case you can drop the special snowflake routine.


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## AmaToolBox (May 11, 2017)

dcb said:


> Lol, just pointing out the obvious. Duncan answered the problem with capacitors, and you either ignored it, or don't know what he means by energy density.
> 
> But in either case you can drop the special snowflake routine.


Read up on what MIT produced in the last 2 years as it pertains to capacitors and energy storage, charging and density.

Also read up on what a voltage regulator does and how it impacts a gas generators power output in a nominal range.

Also, I strongly recommend you open a book on civil discourse instead of calling people snowflakes because of your communication issues. 

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## dcb (Dec 5, 2009)

You are ignoring basic physics here.


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## AmaToolBox (May 11, 2017)

dcb said:


> You are ignoring basic physics here.


Nope. You seem to assume to much on a goal, and attack someone looking for information.

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## AmaToolBox (May 11, 2017)

dcb said:


> You are ignoring basic physics here.


AND as a side note to your negativity:
http://www.mpgomatic.com/2008/07/27/40-mpg-ford-f-150/


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## dcb (Dec 5, 2009)

were we talking about capacitors?

Do you know the difference between energy and power yet?

Oh, you would rather play butthurt, and if you think something is possible, then it must be so, and anyone who disagrees with you is just a big meanie.


You will never learn anything with that attitude, only reinforcing your countless misconceptions.

BTW, you are welcome, asshole.


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## AmaToolBox (May 11, 2017)

dcb said:


> were we talking about capacitors?
> 
> Do you know the difference between energy and power yet?
> 
> ...


No, we were not talking capacitors, you just decided to insult and act cynical without providing any input. You have yet to provide any constructive input but consistently chose to insult and provide nothing.

You aren't even disagreeing, you are posting nothing but insults and cynicism. 

Go read this book, then come back and discuss:
https://play.google.com/store/books...7g&gclsrc=ds&dclid=CO2lr4nd7dMCFcILDAodyqEErQ

and by the way, learned a lot from the contributors of this forum. picked up lots on batteries, charging systems, controllers and even a few ideas to improve regenerative breaking utilizing capacitors... and guess what, not a slight bit came from your bad attitude posts.


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## AmaToolBox (May 11, 2017)

Duncan said:


> You need to sit down with some actual numbers


 working on learning formulas to apply, that is why I am here 



Duncan said:


> A Kg of Supercaps only holds a tiny amount of energy compared to a Kg of Lithium batteries


I disagree on the Kg level, space wise I do agree (ratio about 1.6 to 1).

Where the capacitors come in handy is for absorbing a burst of energy in a manageable way to charge a battery or provide it to the system itself.

What I've built into my gear box is a method to utilize the regenerative breaking far more efficiently and for an extended amount of time. Figure a typical regenerative breaking at 30mph over a 45' distance will at a high generate around 60kW for maybe a second or two. feeding that straight into a battery results in a negligible return after passing through voltage regulators and such. The system I've built takes that same energy from braking and pushes it into a coil/fly system (prototype) which then provides around 90kW for about 7 seconds on that same stop. that 90kW feeding into a proper capacitor bank will result in a negligible loss (say 10% based on opinion). now the bank can be used to either charge the batteries (so maybe another 10% loss) or be fed through a controller to power the wheels. 

right now, the tesla model S has the most efficient in a vehicle I know of with stat out, which is where I set my baseline to beat of the 60kW. with a few stops, varying speeds, we have exceeded 300kW for 10 seconds (hard stops).

So, in my view, the lost power generated by regenerative breaking is saved by capacitors.

Additionally, another new technology I am looking at around capacitors (note I don't feel capacitors will reach batteries for a while for "storage to space" ratios), but a combination of the two is something that has popped up that is both at MIT for experiments and Intel has started using in new technology around DDR based hard drives. It's basically a "cache" of power to charge the battery at its most efficient rate. Using a technology like that would result in less loss when dealing with inconsistent power feeds (like a generator with a broken voltage controller) or regenerative breaking that has a spin up/down with varying return rates.

Now, back to what's on the market today... I can get a capacitor bank, and hook it to a battery bank, in a charge mode plus wire it to a controller for a feed to the controller itself. the electronics are not that difficult to me. I am more looking at what batteries are ideal and brands are on the market now that people are using in these projects and feel they are good. Manufacturers lie and promote, so I am looking for real use cases/experience.


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## dcb (Dec 5, 2009)

AmaToolBox said:


> I disagree on the Kg level, space wise I do agree (ratio about 1.6 to 1).


http://batteryuniversity.com/learn/article/whats_the_role_of_the_supercapacitor
Specific energy (Wh/kg): lithium 120–240, Supercapacitor 5

Please, get more butt-hurt though. But there is nothing "Polite" about not doing the most basic research before making assertions, and repeatedly ignoring several people who have told you otherwise.

But you have countless misconceptions and it takes several people repeatedly pointing them out, and you still don't learn.


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## AmaToolBox (May 11, 2017)

dcb said:


> http://batteryuniversity.com/learn/article/whats_the_role_of_the_supercapacitor
> Specific energy (Wh/kg): lithium 120–240, Supercapacitor 5
> 
> Please, get more butt-hurt though. But there is nothing "Polite" about not doing the most basic research before making assertions, and repeatedly ignoring several people who have told you otherwise.
> ...


Aww, how cute, you don't seem to even follow what i wrote and continue to act like a child.

From the page you posted:
Specific power (W/kg) 
SuperCap - Up to 10,000
L-ion - 1,000–3,000

The supercapacitor is often misunderstood; it is not a battery replacement to store long-term energy. If, for example, the charge and discharge times are more than 60 seconds, use a battery; if shorter, then the supercapacitor becomes economical.

Not to mention the ones MIT is producing exceed even the stats noted on the page.


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## Duncan (Dec 8, 2008)

Hi Ama
You are still missing the point the power IS NOT A PROBLEM!!!!

If you want a decent range then you need a large enough battery that it can absorb/produce more power than you need!

If you have a 200 mile range battery - 400watthrs/mile = 80Kwhrs - all modern Lithium cells can do 10C - charge/discharge = 800Kw - = 1066Hp
You don't need (and can't use) more power
So Supercaps are totally useless - they cost money and are heavy and do stuff all

Do the numbers - read the threads -


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## AmaToolBox (May 11, 2017)

Duncan said:


> Hi Ama
> You are still missing the point the power IS NOT A PROBLEM!!!!
> 
> If you want a decent range then you need a large enough battery that it can absorb/produce more power than you need!
> ...


Ok, let me clarify, and thank you you've cleared up that battery alone wont get me the 200 miles so i will be stuck with a hybrid when i have to put on some miles.

And i will say it again, i dont know batteries, my knowledge is in gearing, manufacturing, programming and IC engines. We disagree on capacitors being useful in an aspect to collect energy in different ways.

The only thing i really dont understand is how far i can get with battery with the formulas provided and today's modern batteries (and which batteries for that matter). the formula isnt clicking... I can calculate the displacement on an IC engine, but the battery to ev engine calculations just seem to have a lot of assumptions i am not getting it.

also, how can i calculate the battery when i dont even know what motor i am putting in. it's backwards in my world as i typically need to know the IC engine before i can do the gearing or determine the tank needs.


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## dcb (Dec 5, 2009)

Yah those formulas are pretty old, probably for old style batteries.

You can get a ~20kwh pack in the junkyard from a volt or leaf for ~$2000 that can make maybe 200hp for at least 10 seconds (and move a ~3000lb car about 60 miles), weight about 400lbs. You can't touch that with capacitors, not in your lifetime. But don't run out and buy one, always get the battery near the end of a project as who knows how long it will be sitting and possibly degrading.


estimate (well) the coefficient of drag, the frontal area, the rolling resistance, the weight, the maximum anticipated incline, the maximum anticipated speed. The formulas write themselves from there. You may have to refine your anticipated incline/speed/weight as you narrow things down, but those are the key power demand variables. Then factor in (well) all the conversion and inefficiencies, Then move on to range/energy.

But you are on a slippery slope with the generator, and probably too lazy to actually do some figuring (or incapable of learning), or really don't want to know the truth of it, so I don't have any faith at this point that you will build anything less than a crime against humanity that accelerates ok for 2 seconds and then belches out hydrocarbons for 200 miles. While the "mission" of diyelectricar is exactly NOT that.


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## AmaToolBox (May 11, 2017)

dcb said:


> Yah those formulas are pretty old, probably for old style batteries.
> 
> You can get a ~20kwh pack in the junkyard from a volt or leaf for ~$2000 that can make maybe 200hp for at least 10 seconds, weight about 400lbs. You can't touch that with capacitors, not in your lifetime. But don't run out and buy one, always get the battery near the end of a project as who knows how long it will be sitting and possibly degrading.


One thing to clear up, I am not looking to replace the batteries. Capacitors have a place though, and that is fast collection of power at rates batteries cant. Even utilizing solar cells, the tesla solar "powerwall" system they are pitching right now has a pre-collector utilizing capacitors before it feeds to the batteries. Batteries charge at an "optimal" rate, much like a motor has a optimal speed for efficiency. using capacitors to capture rapidly changing volt/amps, then sending in at a constant rate to the batteries increases the life and the charge/discharge frequency of the batteries.



dcb said:


> estimate (well) the coefficient of drag, the frontal area, the rolling resistance, the weight, the maximum anticipated incline, the maximum anticipated speed. The formulas write themselves from there. You may have to refine your anticipated incline/speed/weight as you narrow things down, but those are the key power demand variables. Then factor in (well) all the conversion and inefficiencies, Then move on to range/energy.
> 
> But you are on a slippery slope with the generator, and probably too lazy to actually do some figuring (or incapable of learning), or really don't want to know the truth of it, so I don't have any faith at this point that you will build anything less than a crime against humanity that accelerates ok for 2 seconds and then belches out hydrocarbons for 200 miles. While the "mission" of diyelectricar is exactly NOT that.


The big question i have is identifying the formula's. i see a lot of formulas, but not one that incorporates the variables and i'm not following them.

as for a engine as a generator, look at what LiquidPiston has done with the rotary engine. if i need one, as based on what you guy's are saying, i will adapt one of them to drive a generator (specifically my generator). the rotary speed and power, along with the extremely low emissions. http://liquidpiston.com/technology/x-engines-diesel/

my goal is still, even with the expense, is to get as far as i can with batteries.

if you can share with me a working formula that i can plug numbers into i would greatly appreciate it.


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## dcb (Dec 5, 2009)

AmaToolBox said:


> ... liquidpiston.com/technology/x-engines-diesel/


No, quit with the wild speculation and internet hype, it is ridiculous as it is at least %99.999 bullcrap and none of it is available in useable form to you or is even worth the effort in a bronco. It only raises more questions (which it SHOULD be your responsibility to get REAL figures for, so they are summarily ignored). Start figuring out your power requirements, there are plenty of resources for estimating coefficient of drag and frontal area and rolling resistance. It has nothing to do with generator vs battery per-se.

I'm not gonna play the internet rabbit hole game with you, played it a million times before and it is crap. I mean you go from junk yard parts and a friggin bronco to bleeding edge hyped up concepts that don't really exist, with a neurotic focus on efficiency, to speculate about making up your efficiency goals.

Screw that idiocy.

do the basics first, area, coefficient of drag, weight, rolling resistance. those plug into formulas.


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## Duncan (Dec 8, 2008)

Hi Ama
Motors are pretty damn efficient - so it kind of makes them irrelevant

There are a number of ways of working out how much "fuel" you need - 
A really light super slippery machine may be able to do 1 mile per 200 watt hours
Your average small pick up - 1 mile per 400 watt hours

Replacing the IC stuff with electric saves some weight - then batteries puts it back - at about 80 miles range the two are the same

A hybrid is bad news - you have got to carry the heavy IC stuff as well as the electric 

So how often do you go 200 miles?
If it is "all the time" - then stick to a diesel
If it is "only occasionally" - then think about alternatives
I like the "pusher trailer" idea - effectively the front of a Diesel Golf as a trailer

It's all about the "Fuel Tank" - as dcb said you can get a Volt pack for about $2000 - that is 16Kwhr - or 40 miles - and about 200Kg (you can reduce this a good bit) 

So 80 miles range is two of the above - or a Leaf pack


A generator system is going to eat fuel - you will be lucky to get 15 mpg with a generator system


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## AmaToolBox (May 11, 2017)

dcb said:


> No, quit with the wild speculation and internet hype, it is ridiculous as it is at least %99.999 bullcrap and none of it is available in useable form to you or is even worth the effort in a bronco. It only raises more questions (which it SHOULD be your responsibility to get REAL figures for, so they are summarily ignored). Start figuring out your power requirements, there are plenty of resources for estimating coefficient of drag and frontal area and rolling resistance. It has nothing to do with generator vs battery per-se.
> 
> I'm not gonna play the internet rabbit hole game with you, played it a million times before and it is crap. I mean you go from junk yard parts and a friggin bronco to bleeding edge hyped up concepts that don't really exist, with a neurotic focus on efficiency, to speculate about making up your efficiency goals.
> 
> ...


Actually, i have one sitting in my work shop... so i dont know why you think i cant get one... i drove the test gokart they have too. it's actually pretty cool.

as for the formula's, i have not found one that i can "plug numbers into" and that's what i am looking for and i keep saying i am looking for. everyone says "calculate this" add it to "that", guess on this and you will know that which can be used to guess at this. no formulas and all opinions.


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## dcb (Dec 5, 2009)

AmaToolBox said:


> Actually, i have one sitting in my work shop...


See, every time I follow someones bs link, it turns out to be complete garbage...


http://liquidpiston.com/wp-content/uploads/LiquidPiston-XMini-Specifications.pdf

you want to use a 3.5 hp motor, through a generator, to maintain hiway speeds.
Google for hp required for 60mph.

On top of that it has a peak BSFC of 15%!!!

Or you are horrible at communicating (and/or).


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## AmaToolBox (May 11, 2017)

Duncan said:


> Hi Ama
> Motors are pretty damn efficient - so it kind of makes them irrelevant
> 
> There are a number of ways of working out how much "fuel" you need -
> ...


I agree which is what i am trying to avoid it as best i can.




Duncan said:


> So how often do you go 200 miles?
> If it is "all the time" - then stick to a diesel
> If it is "only occasionally" - then think about alternatives
> I like the "pusher trailer" idea - effectively the front of a Diesel Golf as a trailer


3 weekends a year, during the winter, that is it. typical drive will probably be around 50 miles round trip.



Duncan said:


> It's all about the "Fuel Tank" - as dcb said you can get a Volt pack for about $2000 - that is 16Kwhr - or 40 miles - and about 200Kg (you can reduce this a good bit)
> 
> So 80 miles range is two of the above - or a Leaf pack
> 
> A generator system is going to eat fuel - you will be lucky to get 15 mpg with a generator system


the leaf battery pack (if i am reading it right) is a 30kWh power pack. 

Stripped down (no IC components), gearbox to replace axle, re-fabbed parts (fiberglass/poly/aluminum), my math says the truck will be about 1800lbs

that does not include batteries, ev engine or anything else i have to add (as i dont know what those parts will weigh)

If i estimate the weight of those components, based on the LEAF's specs i am probably going to be adding around 2000lbs in in equipment meaning the Bronco will end up around 4000 lbs (about 800 lbs heavier than the LEAF). i suspect though the ev gear and batteries will be heavier as i am only guessing...


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## AmaToolBox (May 11, 2017)

dcb said:


> See, every time I follow someones bs link, it turns out to be complete garbage...
> 
> 
> http://liquidpiston.com/wp-content/uploads/LiquidPiston-XMini-Specifications.pdf
> ...


ummm... no... the diesel (40hp) link i sent you, they also have a 70hp. the xmini is a replacement for small applications like lawn mowers, go karts and they have some DARPA project for backback generators.


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## AmaToolBox (May 11, 2017)

dcb said:


> you want to use a 3.5 hp motor, through a generator, to maintain hiway speeds.
> Google for hp required for 60mph.


Googled, and it comes back with 19hp if i am following the program right


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## dcb (Dec 5, 2009)

AmaToolBox said:


> the diesel (40hp).


Do you have a bsfc chart for the engine in question? There isn't much else relevant to the discussion about formulating the power/energy budget.


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## AmaToolBox (May 11, 2017)

dcb said:


> Do you have a bsfc chart for the engine in question? There isn't much else relevant to the discussion about formulating the power/energy budget.


No, but on the bench at nominal load and speed it was 0.68. we had a range in the tests from .347 to .68.

I would really rather talk about electric engines and controllers

Sent from my XT1254 using Tapatalk


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## dcb (Dec 5, 2009)

AmaToolBox said:


> ...at nominal load and speed it was 0.68....I would really rather talk about electric engines and controllers


Yah I don't blame you, .68 is a tough sell in a small-ish engine with high surface combustion area vs volume and single stage combustion seals. (edit, actually a lot of the liquidpiston claims don't add up, i.e. Constant-volume combustion?!?
all the combustion with no work being done, but better combustion prolly. edit 2:mixing lubricating oil with the fuel in a 4 stroke?!?), anyway...

So still you need to figure out how much power you need. It is basically permutations of F=MA and a little trig once you isolate the variables (which I have kindly listed for you) vs various driving conditions, or just pick the worst case (instantaneous and contunuous) based on YOUR design choices #coughbroncocough#, and it is a little suspect that you don't know that. THEN you pick a motor (on paper) and a battery/controller etc and start sorting range. Lather-rinse-repeat till you find a combo you like.


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## nucleus (May 18, 2012)

You could easily need 100 HP continous going up a mountain pass at speed.

Towing a trailer you could need two to three times that.

This is why knowing the mission is helpful.

At lot of that is based on speed, because your aero drag is a square function of velocity, so it goes up exponentially. Half your speed and you have one fourth the drag of course.

Assuming you are not going to be towing a trailer up a mountain pass, if you base your motor/controller plans on a relatively fat ballpark number like 100 HP continuous, you should be fine.

Personally I don't understand why people build underpowered conversions - it just reinforces bad stereotypes about electric cars.

The quiet speed is a nice "WOW" factor.


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## nucleus (May 18, 2012)

*A Bronco Rebuilt from the Ground Up*

I just reread your first post about rebuilding from the ground up to lighten it.

I think your time and money may be better spent on more batteries and power!

Here is a concept I have been mulling for a big four wheel drive:

Turn the Tesla motor/controller module ninety degrees. Install a limited slip differential in it (EVTV sells them).

Install it where your transfer case lives now. Some metal modification will likely be necessary.

Now instead of left and right, you have front and rear outputs. Two custom driveshafts connect from the Tesla drivetrain module to your front and rear axles.

You now have a mid-engined Ford Bronco, and between where the engine, transmission, and fuel tanks used to be, you have lots of space for a ton of batteries and perhaps even a frunk.

You should have over 400 HP with this kind of setup.


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## brian_ (Feb 7, 2017)

AmaToolBox said:


> ... I can calculate the displacement on an IC engine, but the battery to ev engine calculations just seem to have a lot of assumptions i am not getting it.


That is frustrating...

With engines, you have a firm power rating available. With electric motors, you typically get no firm value at all, just typical values under poorly defined conditions and entirely dependent on factors such as drive voltage which have no real equivalent in the engine case.
Engine output is a peak value, but can be sustained by the engine as long as you need it. Electric motor output may be a level that can be continuously sustained, or may be a much higher value that will destroy the motor if sustained.
Engine output ratings assume that fuel can be pumped to it at whatever flow rate is required, and it's relatively easy to arrange that. Electric motor output ratings similarly assume that the power source (battery) can provide the voltage and current required, but that is very far from trivial to arrange, and what can be done briefly may not be sustainable for very long.
All I can suggest is to know the conditions associated with any rating.



AmaToolBox said:


> also, how can i calculate the battery when i dont even know what motor i am putting in. it's backwards in my world as i typically need to know the IC engine before i can do the gearing or determine the tank needs.


Just as the engine determines the gearing, the electric motor determines the gearing - not much difference there.

Duncan has explained the battery sizing approach. I think in practice any battery with sufficient energy capacity to provide sufficient range will likely be able to provide enough power... as long as you have matched the voltage of the pack to the voltage needed by the motor. Yes, this means that you need to have chosen a motor to finish configuring the battery.



AmaToolBox said:


> ...
> Stripped down (no IC components), gearbox to replace axle, re-fabbed parts (fiberglass/poly/aluminum), my math says the truck will be about 1800lbs
> 
> that does not include batteries, ev engine or anything else i have to add (as i dont know what those parts will weigh)
> ...


It looks like you're on the right track with your estimation method (even if the stripped vehicle weight is optimisitic).


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## brian_ (Feb 7, 2017)

dcb said:


> ... actually a lot of the liquidpiston claims don't add up, i.e. Constant-volume combustion?!?
> all the combustion with no work being done, but better combustion prolly.


Ideally, any spark-ignition engine has constant-volume combustion, because combustion is modelled (as a first approximation) as an instantaneous process at the time of the spark, which is TDC in the ideal case. No work is done during combustion; the chemical energy is just converted to heat energy, to be used to perform work in the power stroke.

An engine which provides a non-zero time period of unchanging working chamber volume allows a real engine to perform some constant-volume combustion, and so get closer to the Otto cycle ideal.



dcb said:


> mixing lubricating oil with the fuel in a 4 stroke?!?


Sure, for the same reason as the Wankel rotary (which died for automotive purposes a few years ago)... still obviously undesirable, but perhaps not wildly unreasonable.

I agree (with dcb) that Liquid Piston isn't a serious engine design, but I also agree (with AmaToolBox) that this thread is better kept out of engine technology.


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## brian_ (Feb 7, 2017)

nucleus said:


> You could easily need 100 HP continous going up a mountain pass at speed.
> 
> Towing a trailer you could need two to three times that.
> 
> ...


An excellent dose of sanity 

This is an understatement, and worth repeating, almost as a mantra:
*Knowing the mission is helpful*​


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## brian_ (Feb 7, 2017)

*Re: A Bronco Rebuilt from the Ground Up*



nucleus said:


> Here is a concept I have been mulling for a big four wheel drive:
> 
> Turn the Tesla motor/controller module ninety degrees. Install a limited slip differential in it (EVTV sells them).
> 
> ...


Just what we have been discussing in the Samuari conversion thread. One issue:


brian_ said:


> ...
> The extra reduction of "final drive" stages from both the powertrain donor and the actual final drives is an advantage in low-speed use. To improve high speed operation, the tallest (least reduction) ratios available for both stages can be chosen, but I doubt there's much choice for the Leaf transmission.
> ...
> There are apparently several ratios for the Samurai, but of course most owners are interested in the ones with more reduction (over 5:1 is available), not less.
> ...


While I am not a big fan of Tesla Motors, they do have a talent for applying blindingly obvious technical solutions, successfully. They place a motor and gearbox at each axle. Hmmm....


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## brian_ (Feb 7, 2017)

AmaToolBox said:


> From the page you posted:
> Specific power (W/kg)
> SuperCap - Up to 10,000
> L-ion - 1,000–3,000
> ...


The important points here:

Super/Ultra/Mega/Whatever capacitors do have very high power density, but as Duncan explained it doesn't matter because the battery in any EV can handle the full electrical power input of the motor, and therefore can handle the full output of the motor while generating for regenerative braking.
Energy density is entirely different from power density.

I do understand that the intention of having capacitor-based energy storage is to more efficiently capture and return energy from regenerative braking, but it's hard for me to see any gain over lithium batteries being worth the massive increase in complexity.

Also, the 60-second guideline would routinely be violated during EV operation, by regenerative braking to a stop and waiting to move again.


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## Duncan (Dec 8, 2008)

Hi Ama
In an EV the motor is a conversion device - when the question is how much power can it make the answer is how much do you want

The motor in my car is "Rated" at 10Kw - 15Hp - my controller has the capability of delivering 400Kw - 533Hp to the motor
And it really does GO!!
But If I put a huge trailer behind my car and pulled it up a steep hill I would melt the motor PDQ

DC motors - these are all re-purposed forklift motors
An 11 inch motor (like mine) will be about 100Kg - in the forklift it will be rated at about 10Kw - in a car/van you will be using about 3 times the revs and it will be able to develop a continuous 40Kw 
For a short burst - a lot more - 500hp

AC motors like AC50
Less lower - and nothing like the short burst capability

EV car motors - Leaf, Tesla
These will be able to give you the continuous power that you need
The Leaf motor is about 100hp - and I suspect that you would be able to get twice that 
The Tesla motor is more powerful - but probably does not have much extra left for tuning

So for a massively heavy monstrosity like the Bronco - two 11 inch forklift motors or a single Leaf or Tesla motor would do

Two complete Leaf motor/reduction gear units one driving the front wheels and one driving the back would be ideal


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## AmaToolBox (May 11, 2017)

dcb said:


> Yah I don't blame you, .68 is a tough sell in a small-ish engine with high surface combustion area vs volume and single stage combustion seals. (edit, actually a lot of the liquidpiston claims don't add up, i.e. Constant-volume combustion?!?
> all the combustion with no work being done, but better combustion prolly. edit 2:mixing lubricating oil with the fuel in a 4 stroke?!?), anyway...
> 
> So still you need to figure out how much power you need. It is basically permutations of F=MA and a little trig once you isolate the variables (which I have kindly listed for you) vs various driving conditions, or just pick the worst case (instantaneous and contunuous) based on YOUR design choices #coughbroncocough#, and it is a little suspect that you don't know that. THEN you pick a motor (on paper) and a battery/controller etc and start sorting range. Lather-rinse-repeat till you find a combo you like.


I am only talking about the prototype diesel engine I have sitting on my work bench, and what it output. and again, it's only to do extended range. my target is to get as far as I can with electric alone.


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## dcb (Dec 5, 2009)

I will gladly pretend there is no engine for now. You still need to determine what size motor (and battery/controller/etc) you need, based on your requirements, not the other way around. Well, you can do it the other way around, but you are just guessing wildly and repeatedly till you find something that works, or you just overkill it.

I've seen mention of a few spreadsheets, you might want (re)search that. 

But final word on the engine, figure out how to drive a wheel or two with it (ratio optimized for hiway cruise). Pusher trailer is a great idea, no reason to drag an engine and fuel around everywhere 362 days a year.


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## AmaToolBox (May 11, 2017)

dcb said:


> I've seen mention of a few spreadsheets, you might want (re)search that.


 Happen to recommend one? I keep finding ones tied to products with no explanation.




dcb said:


> But final word on the engine, figure out how to drive a wheel or two with it (ratio optimized for hiway cruise). Pusher trailer is a great idea, no reason to drag an engine and fuel around everywhere 362 days a year.


 Interesting idea. curious if a pusher trailer would be strong enough to move a 4000 lb truck.


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## dcb (Dec 5, 2009)

you will want to add some downforce, a bigger engine would be helpful  (or through the hitch somehow, i.e. a pressure cylinder)


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## dcb (Dec 5, 2009)

oh, btw, the main point about researching is the searching.

http://lmgtfy.com/?q=spreadsheet+site:diyelectriccar.com

The more variables accounted for the more accurate.


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## Caps18 (Jun 8, 2008)

I would say go with the AC motor just for the less maintenance they need.

Other than that, it will take a crazy amount of money to convert it successfully. Jack at EVTV converted an Escalade, so it is possible, but might not be very practical to try and get 240 miles (need 20% buffer to not destroy the batteries too quickly)

One crazy idea that I'm sure will get shot down for some reason is to somehow squeeze a bigger electric motor in place of the existing starter motor. I will need to turn the flywheel using the teeth on the outside ring of the flywheel. It would be a version of a plug-in hybrid basically.

It would take the perfect sized gear attached to the electric motor to get the right RPMs and not mangle the teeth of the flywheel.


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## brian_ (Feb 7, 2017)

Caps18 said:


> ...
> One crazy idea that I'm sure will get shot down for some reason is to somehow squeeze a bigger electric motor in place of the existing starter motor. I will need to turn the flywheel using the teeth on the outside ring of the flywheel. It would be a version of a plug-in hybrid basically.
> 
> It would take the perfect sized gear attached to the electric motor to get the right RPMs and not mangle the teeth of the flywheel.


The starter motor has a tiny gear, engaging a huge ring gear on the flywheel, because it is designed to barely turn the engine at full starter motor speed. I haven't counted teeth on any lately, but it's a huge reduction ratio. I suppose you could put a much larger gear on the motor, and replace the starter motor with a much larger motor/generator which would have enough torque to start the engine despite much less torque multiplication.

The normal way to address this is to sandwich the motor between the engine and transmission; Honda calls this Integrated Motor Assist, and various transmission companies (such as ZF) offer this as a way for vehicle manufacturers to add parallel hybrid capability to a vehicle design.


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## cajunfj40 (May 17, 2017)

Hello AmaToolBox,

(caution: wall of text...)

'96 Bronco? Nice. I was looking for a '92-'96 for a while before settling on my '00 Explorer manual trans, but my price range was all rusted out. Fun facts: '92-'93 have an NHTSA 4/4 star crash rating without airbags. '94-'96 are 5/5 star with airbags. The frame changed in '92 to add a nice crumple zone.

Your goals are interesting. Do you have a ballpark budget? Since you are talking about prototype diesel engines, etc. as if they are easy to get ahold of, I hope you do have a big one. My planning showed a really big bill really fast for what I wanted, and that was just the main bits, not including all the ancillary bits and labor and custom parts and whatnot. 

I like this calculator for range/weight/speed/power calcs - start with the F250 for your Bronco as they are about the same frontal area/aero drag, then adjust the weight and gearing to match what you have or guesstimate. You'll need to play with the battery and motor numbers a bit - this has some really old info, and I have not found a newer set of numbers to plug in yet. 

As others have mentioned, repurposing an existing EV motor makes a lot of sense. A Leaf motor, per gov't testing, will do 110hp continuous at 7,000rpm with stock cooling at 360V. That's enough to push an FJ-40 up a freeway grade at 55mph, so it'll probably push a Bronco nearly that fast, maybe as fast or faster with more cooling to offset higher power output. Torque is a constant 206 ft-lbs from 0-~2,600RPM (~230A), then it is 110hp constant from ~2,600-10,000RPM. Available DIY controllers will dump 800A (so guesstimate ~700 ft-lbs?) in at arbitrary voltages, so you get way more peak power - or if you stick with low current and raise the voltage, you get more constant power since the heating mostly goes up with the current, rather than the voltage. Whatever you're comfortable with. 268+hp peak is easy with Leaf/Volt pack voltages and available DIY controllers. 

Figure 500-800wh/mile at 60mph for something that big/non-aero and heavy. (I figured similar for an FJ-40.) For your 50 mile round trip general use-case, figure at least 2 Leaf packs or 3 Volt packs at freeway speeds. Higher if keeping meaty tires/doing faster freeways/more hills/AC/Heat, lower if going LRR tires/aero mods/doing more city speeds/flat terrain/dealing with the temperature via clothing adjustments, etc.

Lighter bodywork won't be easy - there's pre-runner style fiberglass bedsides and front ends, but generally styled for larger tire clearance rather than aero, and probably not much lighter than stock. (Gotta handle the terrain at speed.) At least you can get rid of a cast iron engine, heavy automatic trans, fuel system, etc. If the style is what you want, you won't be able to do much aero modifications, so reducing speed will be your best bet for better range/lower power consumption. Weight really only matters for acceleration and hill-climbing, plus a bit of rolling resistance. Aero matters a lot more at freeway speeds. Mostly weight reduction makes it easier to stay within the chassis GVWR with more batteries. 

As others have stated, a pusher trailer will beat a genset for long distance travel due to less conversion losses, regardless of engine technology used, all other variables being equal. Getting one set up to push without upsetting vehicle dynamics will be interesting, though - you'll want something like a weight-distributing hitch to load the trailer tires for more traction. 

A genset is of course a lot easier to set up (running cables is easier than figuring out drivelines, traction, etc.) if you don't mind paying the fuel bill for the extra conversion losses. About the only engine types that would do better as a genset are ones that have insanely high shaft speeds and very poor part-throttle efficiency (like turbines) or are very temperamental to get to run outside of a super narrow RPM/Load range (like HCCI or similar). With 9-speed automatic transmissions available, most engines will have a wide enough efficiency island to couple to the road with fewer losses than the genset route. 

Another idea I've had for "intermittent hybrid without having to drag it all around when not in use" was to figure out a way to couple an engine/auto-trans on a trailer to the tow vehicle's driveline, rather than to the trailer's wheels. There are transfercases that can be configured with dual rear outputs. If you use an offset rear axle in the Bronco, and use offset outputs on the transfercase for normal drive/4x4 action in the Bronco, then you can use the center rear output on the transfercase as an auxiliary input for your trailer-mounted engine/transmission combo. You'll need a reverser of the sort used on dual counter-rotating propshaft boats if you mount the transmission facing the Bronco though. This gets you direct fuel to wheels (single conversion) efficiency on road trips without upsetting the driving dynamics like a pusher trailer would. You'd need to get a remote control for the transmission, and figure out how to tie the "towed" engine's throttle to the Bronco throttle and mix the power usage (EV vs engine) properly. "Hitch-up Parallel Hybrid". 

Yet another way to do it would be to repurpose a Two Mode Hybrid transmission as your EV prime mover. I've already done the math for a GM 2ML70 (2008-2010 or so Tahoe/Silverado and related) transmission/transfercase combo. Stick the transfercase in low range (2.72:1), figure out how to get 2-low (front output is actuated by a clutch, not sure if motor or coil driven), and with 5.38 gears and 32" tires you get a top speed of ~69mph with both 83hp(continuous rating) Remy HVH250 motors turning a full 10,600RPM inside the transmission in high (1:1) gear. That's enough to pull all US highway grades. In first gear on the transmission (3.71:1) you get an astounding 26,000 ft-lbs (peak) of torque at the wheels from 0 RPM, with an ~18mph top speed. Running on just the "rear" motor in the transmission you still get 13,000 ft-lbs (peak) in 1st-lo, and the front motor is available for genset operation at arbitrary engine speeds for the rare times you need to charge while rock-crawling. 

If you mount that hybrid transmission backwards in the Bronco, so the input shaft is facing rearwards, and you get the axles set up with the correct "reverse rotation" gearing so the transmission is turning the "normal" direction, you can skip the transmission on the trailer and just run a driveshaft from the engine to the input shaft. Tahoe Hybrids got 20mpg highway with a variable-displacement gasoline V8 and this transmission. An optimized diesel should do better, but aero and rolling resistance are your limiting factors, really. Set up a 4, 5 or 6 cylinder VW diesel (depending on the constant power you want vs. reliability) so that at your desired trip speed it is producing enough power at the BSFC sweet spot (maybe need a single speed reduction gearbox between engine and transmission to get RPM vs speed fine-tuned with the Bronco in high gear) and you'll do really well. Use the EV battery for hill-climbing and passing power. 

The rear-facing hybrid trans also makes a really fun idea possible: use a modified liquid-cooled 4-stroke modern outboard motor as the "bolt-on hybrid" engine, using the tailgate as a transom mount perhaps. Mount the works (cooling, fuel, etc.) on a swing-away tire carrier type thing, with a modified lower unit that gives you an easily separable driveshaft connection to the transmission input, and away you go. Bonus points for using a Mercury outboard. Double bonus points for turning the Bronco into a mythical Mercury branded version... 

Forward-facing hybrid trans would also allow having a "engine unit insert" that you could put under the hood in your "frunk", but that sounds less fun. An outboard motor using the core support as a transom mount, though... 

You've got plenty of plans to make and dreams to entertain. Have fun!


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## brianfloridastate (Jul 8, 2017)

Nice to meet you! I too am dreaming of converting my 1996 Ford Bronco! I've been researching the procedure for about 9 years. This is totally doable.
My simple plan is to remove the engine/tranny (in one piece for re-sale), gas tank and exhaust system.
I will add batteries (Tesla Power Packs) to the engine bay and gas tank area that match the weight exactly of the equipment they are replacing. (This will maintain the safe handling of the Bronco.) That means around 500+ pounds in the engine-bay and around 180+ pounds in the gas-bay. For additional range, I will add batteries along the frame wherever I can.
I willl add a "TransWarp" electric motor by Net-Gain where the tranny used to be and attach directly drive shaft. This will maintain the drivetrain as all original equipment. Easy.
For range extenders, I am looking at a small Capstone Micro-Turbine (30kw+) for electricity generation inside the engine compartment. It is very small, very light, runs on super clean propane (light weight gaseous) and zero-maintenance.
Done.
It will be very fast 0-60. It might get 80 miles of range...very optimistic wish.
What's your plan?


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## brian_ (Feb 7, 2017)

brianfloridastate said:


> For range extenders, I am looking at a small Capstone Micro-Turbine (30kw+) for electricity generation inside the engine compartment. It is very small, very light, runs on super clean propane (light weight gaseous) and zero-maintenance.


Sounds cool... but a reality check on the specs for a Capstone C30:


> Width: 0.76 m (30 in)
> Depth: 1.5 m (60 in)
> Height: 1.8 m (70 in)
> Weight: Grid Connect - 405 kg (891 lb)


To be fair, that's in an industrial housing, and the engine with generator is only a fraction of that volume, but it's a good chunk of the mass, and not trivial to package. Intake and exhaust silencers will be bulky. Nothing is "zero-maintenance", but at least it has no cooling system, and only air bearings.

Also...


> Net Heat Rate LHV: 13.8 MJ/kWh (13,100 BTU/kWh)


That's about 300 g/kWh of propane consumption... very good for a small turbine, but nothing special for an automotive engine.

Propane's density is low, but the weight of propane required for a given amount of energy is similar to other hydrocarbon fuels - the contents of the fuel tank for a given range are no lighter than with other fuels, but the tank is heavier and more awkward than a non-pressurized fuel (because it's a cylinder). Many years ago, propane was substantially cheaper than gasoline here in Alberta, but in recent years it has been just as expensive as gasoline on an energy basis.


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## rmay635703 (Oct 23, 2008)

The Workhorse W15 pickup has a 60kwhr battery and an 80 mile range 
(Think about that for a moment)

Your best bet would be a Dodge Sprinter or some sort of more modern minivan 
"Decorated" so it looks like a Bronco 

Here is a Prius decorated to look like something

http://ecomodder.com/forum/showthread.php/1946-chevy-prius-truck-34935.html

Maybe put the Bronco on a Prius?


Or source yourself a V8 capable FWD transaxle and drop in a classic 4.3 liter Cadillac diesel, NA VW diesel or a Kubota diesel.

Then source one of these

http://ecomodder.com/forum/showthread.php/hot-rodding-toyota-mgr-29878.html

Voila efficient front wheel drive Kubota Bronco with an electric rear transaxle for a short range EV scoot

If you try using thought experiment stuff you will never have something reliable you can enjoy in a reasonable amount of time.

Capstones are fun but unreliable, free piston engines will be expensive, low powered and unproven,

If you want to spend millions for a university project proceed as you are, if you want something runnable use components available off the shelf or out of a junkyard.


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## brian_ (Feb 7, 2017)

rmay635703 said:


> Capstones are fun but unreliable...


It is surprising to me that there would be a reliability issue with Capstone's turbine generator sets. They are built and sold for continuous industrial operation, which seems like an extreme in high-reliability applications.


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## brian_ (Feb 7, 2017)

rmay635703 said:


> ... free piston engines will be expensive, low powered and unproven...


Yes... perhaps why no one had proposed using one of them in this discussion thread (unless I missed it, but I just searched the entire thread for "free").


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## brian_ (Feb 7, 2017)

brianfloridastate said:


> ... I will add batteries (Tesla Power Packs) to the engine bay and gas tank area that match the weight exactly of the equipment they are replacing. (This will maintain the safe handling of the Bronco.) That means around 500+ pounds in the engine-bay and around 180+ pounds in the gas-bay.
> ...
> For range extenders, I am looking at a small Capstone Micro-Turbine (30kw+) for electricity generation inside the engine compartment.


Even if we assume that it would be possible to jam a Capstone C30 with associated air and exhaust handling components plus other supporting hardware into the emptied engine compartment of a Bronco, this suggests that the turbine generator set and 500 pounds of Tesla battery modules (plus electronics) are both occupying the same space. How?

Capstone offers two case studies (HEV - North Carolina and Trolza ECObus) about their units mounted in large urban buses (not light trucks); there is a lot of hardware involved, and these things are not so small.

The similar "Fulcrum" small turbine generator set is offered by Wrightspeed as the generator of their series hybrid system for trucks. The smallest configuration (for a delivery truck or "bread van"/"step van") includes a Fulcrum which might put out as much as 150 hp. That's 4 times the power suggested in the proposal above, but even 1/4 of this 150 hp Fulcrum volume would barely fit in a Bronco, let alone leave room for a 1/4 ton of batteries:


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## rmay635703 (Oct 23, 2008)

brian_ said:


> It is surprising to me that there would be a reliability issue with Capstone's turbine generator sets. They are built and sold for continuous industrial operation, which seems like an extreme in high-reliability applications.


In a non moving or very slow object maybe.

I know of only 2 true automotive applications that used them

Both were very unreliable in many ways.

There was a thread here on whether a guy should salvage one of the capstone hybrid buses from the junkyard, you can read about those boondoggle buses elsewhere if you wish.

As for free piston I read that out of the liquid piston mention, another not reliable not efficient design.

Might as well use a DI 2 cycle motor if you want light semi reliable and efficient but a small diesel (3 cylinder or less) is more efficient and reliable than any of the alternatives.


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## brian_ (Feb 7, 2017)

rmay635703 said:


> In a non moving or very slow object maybe.


If movement is the issue, perhaps the air bearings of the Capstone design can only handle a stationary application well?



rmay635703 said:


> I know of only 2 true automotive applications that used them
> 
> Both were very unreliable in many ways.


Automotive applications of the Capstone units certainly appear to be only experimental at this stage - Capstone's case studies make that clear - although with some searching there seem to have been many projects using Capstone hardware... perhaps because it is the only brand of small recuperator-equipped turbine engines with integrated generators.

Wrightspeed apparently started with Capstone turbines (including the C65), but introduced their own - the "Fulcrum" a couple of years ago. The relationship fell apart, and Capstone sued Wrightspeed. There are not many Wrightspeed units on the road, but there apparently are a few (great fleets if you believe the media hype; at least three operating prototypes if you insist on seeing a photo of a complete vehicle ).


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## brianfloridastate (Jul 8, 2017)

ALL,

Regarding Capstone Turbine success with feasibility in a car: It is a tiny turbine. A car does not require all that housing. The car IS the housing.

Check out the articles, pics and vids of Capstone Turbine's super car - the CMT-380 - at the links below. I think that what this power-plant does in a car would provide "Bronco-like performance" in a 1996 Ford Bronco.

https://www.capstoneturbine.com/new...---hybrid-electric-supercar-with-microturbine

http://www.globenewswire.com/news-r...bine-Technology-to-Debut-at-LA-Auto-Show.html

https://www.engadget.com/2009/12/07/capstones-cmt-380-hybrid-supercar-does-150mph-with-batteries-an/

https://www.youtube.com/watch?v=NMe6iikMvsc

Hope this helps to illustrate the idea.


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## brian_ (Feb 7, 2017)

brianfloridastate said:


> ALL,
> 
> Regarding Capstone Turbine success with feasibility in a car: It is a tiny turbine. A car does not require all that housing. The car IS the housing.
> 
> ...


It doesn't need the big cabinet, but the unit itself is not a trivial size, and it still needs an induction path with filtering, and likely an exhaust muffler. Then there are the electronics. In the cars, it takes the entire conventional engine space. In the industrial package, all that other stuff is not just ballast or space-filler.

The dimensional specifications published by Capstone are all for the complete package. It would be interesting to see the specs (length, diameter, weight) for the basic engine-generator unit, and the specs (volume, weight) for both the power electronics package and the controls package.

It's unfortunate that the article published by Capstone refers to it as a "jet" engine... it's not, which is good because jets are idiotic for cars. 

If the plan is still for propane...
In anything but warm summer conditions propane vapour pressure will be inadequate to operate the turbine, so there will also need to be a liquid propane pump and a vapourizer as well. There should also be a "balance of plant" specification from Capstone, for the fuel system and everything else needed to support the turbine set, but I haven't found it yet online.

Whatever the size, weight, or efficiency, the generator set produces 30 kw, or 40 hp. As with any series hybrid, the short-term performance is the result of the sizing of the electric components - it would be just as fast with a 650 cc engine from any Japanese Kei car, and if you were to lap a racetrack you would soon be out of battery and putting around like anyone else with subcompact car power. Of course the Bronco won't need to lap racetracks.  But seriously, the battery should be sized to climb the longest mountain grade expected with the highest load allowed.



brianfloridastate said:


> https://www.engadget.com/2009/12/07/capstones-cmt-380-hybrid-supercar-does-150mph-with-batteries-an/


The Engadget article is as useless as their stuff normally is. They don't mention that the CMT-380 is a Factory Five Racing GTM kit car, which normally uses a V8 engine from a Corvette - the turbine takes most of the engine space. The Truck Trend article shows a photo with the rear hood open, hinting at the challenge that the builder had jamming everything in.



brianfloridastate said:


> https://www.youtube.com/watch?v=NMe6iikMvsc


The video is of a static display and taken from a single viewpoint, zooming in on the placard, and with nothing but random crowd noise for audio. Seriously? Someone needs to tell this person about still photos, and tell them to walk around to the other end!


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## Duncan (Dec 8, 2008)

When using a gas turbine the largest part is the heat recovery system,
This recovers a lot of heat from the exhaust and uses it to pre-heat the intake air

The turbine will run without it but the efficiency falls off a cliff


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## brian_ (Feb 7, 2017)

Duncan said:


> When using a gas turbine the largest part is the heat recovery system,
> This recovers a lot of heat from the exhaust and uses it to pre-heat the intake air
> 
> The turbine will run without it but the efficiency falls off a cliff


Yes, the recuperator is the key to efficiency in the Capstone line, and other non-aeronautical turbines that are efficient enough to be considered as diesel alternatives; recuperators are not used in aircraft due to the bulk and weight. If anyone is trying to understand the engine cycle, it is critical that the heat is delivered into the air after the compressor, but before the combustion chamber; it would be worse than useless otherwise.

The C30 runs at about 26% efficiency under load, which is okay compared to piston engines of the same size. Larger Capstones are slighter better, as expected with turbine engines. Without the recuperator they would all be hopeless.

Although I haven't found the link again, I noticed that one online article claimed that the exhaust (in an automotive installation of a Capstone) was impossibly cool - it appears that they misread the specs and claimed that the exhaust ran 275˚F; in fact, it is 275˚C (530˚F). This seems to have led some people to have unreasonable expectations of a turbine installation. A lot of heat is recovered by the recuperator, but heat only flows "downhill" (to a lower-temperature location), so given the pressure ratio of this engine the exhaust is just not going to get much cooler, even with a perfect heat exchanger. Even at half load, the exhaust is almost as hot. That doesn't sound very hot by engine exhaust standards, but due to the excess air flow of a turbine engine, there's a lot of that hot air.

If even a small (in output) C30 is installed in the front of a vehicle such as a Bronco, it will need an exhaust pipe that looks like it is sized for a 400 hp diesel. The pipe needs to be large due to the high flow volume relative to the power, and due to the sensitivity of the engine to exhaust back pressure. That's one reason that those show cars with turbines have mid-engine configurations, even though there is no mechanical connection between engine and rear wheels so the engine could be anywhere.

Turbines are rarely used outside of aircraft and stationary applications. One of the rare exceptions is the Honeywell AGT1500 which powers the M1 Abrams tanks. The configuration looks much like the Capstone engines, which is no coincidence. Much of the volume of the engine is the recuperator, and although the result is still decently compact and reasonably light, it's big compared to an aircraft turboshaft engine of the same output (1500 hp at 30,000 rpm turbine shaft speed). The fuel consumption is higher than diesels in comparable applications, even though this engine is much larger than the Capstones and therefore has an efficiency advantage; of course a newer design would be a bit better.


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## WolfTronix (Feb 8, 2016)

Back in the late 90's early 2000's Solectria made a Citi van hybrid with the Capstone micro turbine, running on natural gas.

Here is an old press release I found:
https://www.thefreelibrary.com/Time...roturbine-Based+Hybrid+Electric...-a062878757

I can't find any pics of the inside of one.

But if I recall correctly, they had a mini-frige sized unit on one side, with an exhaust stack that went out the top of the roof.

There was also a power controller unit which selected electric, or hybrid mode, and handled when the turbine would come on.

They had two parallel stacks of 23 (12 Volt, 75 Ah) batteries in series.
276V @ 150Ah

Dual AC55 motors, with dual UMOC445 controllers.


Many years ago, I remember 2 or 3 of them on eBay, but they had been stripped of the Capstone micro turbines.


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## brian_ (Feb 7, 2017)

Thanks for the Solectria/Capstone information. It seems like there were a substantial number of Capstone turbines installed in hybrid vehicles, then interest fizzled out. The engine is no different now than it was 20 years ago, but batteries and electronics have improved, so any of those vehicles might be more viable now... but efficiency, cost, and installation are still challenges.


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## dcb (Dec 5, 2009)

another oddity, the power/temp in this model goes from 65kw to 50kw at 100F degrees ambient, about a %25 drop, that might need some reckoning too. 

http://www.regattasp.com/files/460044A_C65_Product_Specification_083007.pdf


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## brian_ (Feb 7, 2017)

dcb said:


> another oddity, the power/temp in this model goes from 65kw to 50kw at 100F degrees ambient, about a %25 drop, that might need some reckoning too.
> 
> http://www.regattasp.com/files/460044A_C65_Product_Specification_083007.pdf


I noticed that in the specs for the C30 as well. 

Technical Reference - Capstone Model C30 Performance
(available online from multiple sources)

It seems quite sensitive to ambient temperature. I can only guess that the engine is limited by the peak internal temperature, so the higher the intake temperature the less fuel it can burn and stay within that limit.

Output is reduced with lower ambient pressure, such as with increased elevation, but no worse than with normally aspirated piston engines. Here in the area of Edmonton, Alberta, it would be down about 10% from nominal output.

On the other hand, efficiency doesn't drop off as much at lower output levels as I would have guessed - it can turn down to about 1/3 of full power without losing a lot of efficiency... although one would still never want to idle it, and the series hybrid would completely avoid idle. Turbines are generally understood to have poor rangeability.


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