[AmaToolBox]

Ok, I am starting from scratch here, and want to learn as much as I can to do a full EV conversion of a 96 ford bronco. I know, before anyone says it, it's a heavy vehicle so it's not going to be easy and it will be expensive... I intend to strip and rebuild the truck with lighter parts from the ground up to save on the weight for the EV.

I want the bronco to be able to cover 200 miles on one charge (or I may have to default to having a backup generator for it for extended trips). I would like to be able to hit highway speeds, but I am not looking to win any races.

I'm in the research phase to understand what my limitations will be and learn as much as I can as to what components are needed and what will fall into my skills and out of my skills.

My conceptual idea right now is to create a 4 wheel drive setup, where I will have a gear box created for each wheel. I'm looking for what I need to research when it comes to a controller that can independently control 4 wheels when in 4wd mode (note that I will design the gear box to engage on the front tires only when enabled) as I still want to off-road with the truck.

The next piece i'm looking to find out about is the proper engines for this type of use. I've seen debates between AC and DC, Brushless and a few other different variations for the actual engine, but haven't found anything that says "best for your use" in what I've read.

When it comes to controllers, I am a clean slate and i'm looking for options. given the model of 4 independent tires/engines i'd like some people's opinions on options to work in that design.

and last, batteries... looking for the best storage options available. I've been tempted to buy a tesla house unit for the build but i'd like to explore what other options may be on the market or something I can build.

 

[dcb]

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

 

[AmaToolBox]

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]

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)?

 

[AmaToolBox]

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]

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

 

[dcb]

the generator design I had equated to about 50mpg.

You must have figured wrong.

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?

 

[AmaToolBox]

You must have figured wrong.




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?

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]

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

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]

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.

 

[Jeremyfc1]

^^^^

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.

 

[AmaToolBox]

^^^^

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_]

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?

 

[brian_]

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.

 

[AmaToolBox]

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]

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

 

[AmaToolBox]

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

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]

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

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.

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

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

accept irradic current like static to charge them

 

[AmaToolBox]

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]

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.