# Introduction and build ideas



## jlangholzj (Nov 7, 2011)

Hey all, 

First post here :woo: and like most its to soak up some information. I've got some different ideas about what "should" be possible but I'll get to that eventually.

First however, some things about me. I'm a college student currently. Double majoring in a BS for Electrical Engineering and Mechanical Engineering. I'm also part/full time employed at a company called Daktronics (seems like you either love us or hate us) and I work with our video products line on a daily basis. I've been in industry for the last 3 years, however only 1.5 in an engineering position. Aside from school, work (and the girlfriend) I'm also highly involved with FSAE (no not the hybrid comp, the regular one). Unfortunately South Dakota State is a small school in respect to other colleges but we've been able to lay down a good foundation that has been working well for us, which is why we're sticking to regular formula for now. 

I'll be graduating in 5 years this next spring (2013) with both majors and as most of you know the Sr. Year typically involves a Sr. design project for a pair of students to basically "show off" the skills we have learned in the last few years. 

I'm wanting to do an EV orientated build but I'm a bit apprehensive to putting some of this information on the internet. It's all stuff that's been done before but at the same time I want to try and cover my butt (who knows, maybe I'll get lucky with a patent). However without any information at all, you guys will all be like...wtf is he talking about 

The basic idea is that I'll have a diesel-electric setup similar to what a train uses. No mechanical drives from the motor, just a pure genset. I'm guessing I'll have to have somewhat of a battery reserve that would help cushion the transient draw of the motors under hard acceleration but the goal here is to have minimal batteries. The platform for the build will be a small truck (ranger, s10, etc)

I've got a few idea's rolling around but since I've no experience in this field I have no way of validating the thoughts which is why I've come here. I've got a kubota or a cummins diesel picked out from approx 60-100 horse based on what i would assume to be about a 50-60kW (100kW MAX peak draw) base needed power usage on the tuck after you figure in conversion losses and so forth. 

Next step is finding all the motors and generators i guess. I figure the output motor would need speeds of about 3k to properly hit 80mph in the vehicle. But now the question becomes do i stick with an AC motor or convert to AC. I'm going to be lucky to see 90% efficiency with a DC/DC converter let alone AC/DC (ROCK ON _\m/) converters. As a mentioned earlier Ive got NO idea whats out there but i DO know that there is stuff out there that fits my specs but I'm just unaware of which of my choices are better than others (kinda like the fact that fords last forever but chevys break down all the time... i kid i kid) 

As far as the controllers and such, I'll have two other EE's working with me and I've got a few prof's available that have experience with control systems. We _may_ have the capability to design our own controllers and tailor them as need be. But there is a lot to do between here and there!

for the TL/DR crowd:
looking for some good companies for motors and generators, I'm in the middle of being book learned and I'm new here


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## gor (Nov 25, 2009)

"for the TL/DR crowd:"
 
welcome 
well, crowd here don't like gas at all, but most will agree - until batts got cheaper, smaller and range - larger (3-4h on highway) - genset of any kind, with weight penalty like passenger and dog, would be a good solution and answer to many people's range fear - at least for a transition period like now.
chevy volt, plug-in prius, extended range ev-hummer - good example


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## jlangholzj (Nov 7, 2011)

gor said:


> "for the TL/DR crowd:"
> 
> welcome
> well, crowd here don't like gas at all, but most will agree - until batts got cheaper, smaller and range - larger (3-4h on highway) - genset (weight penalty like passenger and dog) would be a good solution and answer to many people's range fear - at least for a transition period like now.
> chevy volt, plug-in prius, extended range ev-hummer - good example


from my understanding however the volt and prius are primarily battery source applications. once your battery drains out, you're fubar'd. My knowledge on this could be wrong but a situation as such is what I'm trying to avoid. The only reason i would see needing a battery pack would be for the transient demands of the motor. 

i could be wacky thinking this though 

EDIT:

i did do a quick google-foo on the EV hummer and found some more information on the volt. ignore my ignorance  I also saw that the hummer uses a 100KW genset to run it all. If the hummer can run off of that I'm guessing my shot for 60KW might be a little high? :headscratch:


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## Guest (Nov 7, 2011)

Volt is electric drive primary but can run gas engine in specific cases. Prius is a Gas/Electric but primary gas and neither runs alone in the Prius or other hybrids either. There are some gen set hybrid setups but not many as it is usually better to use one or the other and not both in an on road vehicle. Room being the primary reason. With a hybrid you have the worst of both. If you go ICE do it the best. If you go electric do it the best. Diesel for a hybrid is commonly what many want but weight constraints prohibit a good combination of both as the diesel engines available today are usually large and bulky. Even the ones for automobiles. The industrial ones for tractors and such are even more so. Having a Genset attached to the diesel leaves little room for an electric drive and batteries. Pick one and build an excellent one. I had similar ideas too but with what is available to the average person not much is going to work. I know of some old systems that did work. Most here would not want such an old antiquated system but I feel it would work. I have not ruled out doing a hybrid but I'd shoot for a small ICE and convert to direct injection ethanol or propane or natural gas for its fuel of choice then use the attached generator to power the electric drive. 

No need to worry about posting. Patients would be difficult to get but you might get lucky. If you hold back many can't help if you run into trouble and need help. Information is needed to help asses and diagnose problems and doing such over the web requires information. 

Anyway I like the ideas and think some should pursue that avenue. Remain all electric drive with aux ICE generator power for longer distances but with more environmentally friendly fuels than gasoline. I leave diesel out because the engines are bulky and heavy and that is the only reason. Until they make a small powerful lightweight and available diesel that is affordable the small ICE will be the choice. I prefer to do only electric. I drive only electric for my primary vehicle. I am currently working on two other conversion vehicles. 

Pete


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## jlangholzj (Nov 7, 2011)

http://www.cumminspowerproducts.com/PowerUnits/Diesel/T3/QSB33/weight.asp

the only downside to this is the weight. The particular model I linked to pulls down about 1.5 gal per hour at 50% load. The open powerplant dimensions listed also are with the radiator/air intake that are currently on the system. I would see no concern with fitting this plus a gen into a small truck. 

Also there are other options out there, primarily much smaller than the one I liked to. The qsb3.3 platform will typically put out 100hp. Namely another alternative is the kubota V1505 that puts out 44hp and is MUCH lighter than the qsb3.3 (640kg vs 140 kg)

http://www.kubotaengine.com/products/05/v1505_t_e3.html

this is why I'm trying to get the ball rolling some to figure out where my specs need to be. 

I'm still trying to determine _why_ exactly the batteries are needed. They obviously are because every other vehicle out there has them but is it due to purely transient draw or are they using the batteries to drive the motors (as mentioned in the case with the volt) Why not just run directly from the genset to the motors?

I'm spec'd out so far having a 3.00:1 final drive in the rear differential and with tires that are approximately 30" tall would require about 3000 rpm to kit 80 MPH on the road. 

the real question is how much power do i need to make. this is the one big variable i have right now and once that's answered I'll have some more ideas.


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## gor (Nov 25, 2009)

there been discussion recently - check the thread 
http://www.diyelectriccar.com/forums/showthread.php/why-there-no-board-generatorsi-35557.html

there are a lot of links (powersouces - from biofuel jet (jay leno) to bike, avia, wankel engines); one guy in the very end of the thread has similar to your approach


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## charliehorse55 (Sep 23, 2011)

jlangholzj said:


> http://www.cumminspowerproducts.com/PowerUnits/Diesel/T3/QSB33/weight.asp
> 
> the only downside to this is the weight. The particular model I linked to pulls down about 1.5 gal per hour at 50% load. The open powerplant dimensions listed also are with the radiator/air intake that are currently on the system. I would see no concern with fitting this plus a gen into a small truck.
> 
> ...


Here is a spreadsheet I made for calculating the power you will need to keep a car moving at a steady state speed. You just input the aero, weight, rolling resistance, drivetrain efficiency and accesory power draw, and if you input your battery pack figures it will even calculate range.

Drivetrain efficiency is the power transfer efficiency between input from batteries and output to drive shaft - so include controller, motor and transmission/differential losses.


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## Duncan (Dec 8, 2008)

Hi Jang

I don't see any advantage in your concept - you are trading a 95%+ efficiency gearbox for an 80% efficiency generator/motor combination - why is it a good idea?

Hybrids like the Prius use an increased efficiency Atkins cycle engine and still end up with only about diesel efficiency

As far as patents are concerned - you need to do a bit of searching there are millions of automotive patents going back 100+ years, a hell of a lot of them expired before the technology to implement them was developed

Anyway good luck


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## TomA (Mar 26, 2009)

As Pete and others are suggesting, the central problem is efficiency.

You can absolutely put the very best available components together, with some nifty bits of your own design, and it will no doubt work, but the final product will be overwhelmed with the inefficiencies of carrying the genset around, and the inefficiency stack-up of using fuel to make electricity to power a controller to run an electric motor through a driveline to the road. Any highly developed single system from EV to diesel or maybe even steam is going to be gobs more efficient, and ultimately a better compromise. 

Sadly, there are quite a number of cars like you are envisioning, cobbled together by students to prove a point or win a contest, quickly and completely abandoned, only to quietly weather on or near university lots until they're stripped and sold off. My completely unsolicited advice would be to put all that time and energy into something you'll drive and keep after school, and not walk away from like a bad habit upon graduation.

Instead of taking the "because I can and it seems cool" science-project-to-nowhere approach, you could use available EV components, or even start with a built EV, and really chase after efficiency in a meaningful way, including aero, charging, mechanical losses, gearing, accessory loads, temperature management, wiring, etc. I would think a project like that on your resume would make you far more marketable to industry than your initial approach, which at best seems destined to become a bad idea well executed. 

Your double major ideally suits you for this challenge. The pieces of the efficiency puzzle should all be within the sweet spot of your disciplines. If you could dramatically improve the efficiency of, say, a bone stock Jet Electric 007 or Dodge TeVan, or even one of Wayne Alexander's pickups, you'd really have something all the way around, and likely a keeper for the garage. 

Just my $.02,

TomA


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## dougingraham (Jul 26, 2011)

jlangholzj said:


> I'm still trying to determine _why_ exactly the batteries are needed. They obviously are because every other vehicle out there has them but is it due to purely transient draw or are they using the batteries to drive the motors (as mentioned in the case with the volt) Why not just run directly from the genset to the motors?
> 
> the real question is how much power do i need to make. this is the one big variable i have right now and once that's answered I'll have some more ideas.


You need the batteries for the transient draw. Hard acceleration draws a lot of power. I am planning on up to 192kw into my motor during acceleration. Average draw at 65mph should be 18kw. Why put in a motor/generator set that will do 192kw when you only need one that will just keep the batteries topped off? 

How much power? One rule of thumb I have heard is weight of vehicle in lbs/10 = wh/mile. Yeah, I know it is a very squishy rule of thumb but surprisingly works for typical mixed driving habits over the sizes of EV's people build.


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## jlangholzj (Nov 7, 2011)

i guess you guys here are looking at a different market than myself. That is one little tibit i forgot to mention. 

The reason why I want to do this isn't for the "daily driver" that gets joe shmo from ptA to ptB in their "typical" 40-50 mile daily commute. The application I'm shooting for here is in small to full-size pickups. Since everyone here HATES fuel and i'm not so sure of the demographics (I'm assuming that most are city guys?) I don't expect you to realize it but (we're talking STRICTLY ICE here) diesel engines kick the piss out of gas engines when it comes to getting stuff done. Our F-350 with a 7.3L t-diesel will pull a loaded 10,000 trailer through 6% grades and still get 14 mpg doing 75 mph. For that much weight, thats kickin ass! But you're never going to see a truck that's fully EV because the battery packs won't supply enough sustained torque for large periods of time.

however you do see things like this:

http://www.cat.com/D7E

http://science.howstuffworks.com/transport/engines-equipment/diesel-locomotive.htm

I can't think of much else that requires GOBS of torque and pulling power that would be a better example. Wait a minute though....why wouldn't they just go with a direct drive ICE if its 95%+ efficient. (which by the way the last figures i found GM FWD vehicles are approximately 15-20% loss and RWD cars are upwards of 30% loss) 

one of the reasons is torque. A nephew of a friend of mine is a EE that worked on the D7E project. They sheer'd TWO Allison rear ends in the cat during initial testing that held up fine under they're ICE motors. 

The 100hp cummins i spec'd to pulls 1.5gph. A ranger itself weights approx 3000lbs. If we figure on another 1000 lbs in the ICE and another 1000 in the generator and motors and batteries and go by the rough rule of thumb doug posted, I'm looking at about 40kW for power consumption doing 80mph. where the 100hp genset should produce approx 74kW.

(BETTER YET here's a kubota i found that produces similar power minus 400lbs http://www.kubotaengine.com/products/v3/v3800di_t_e3.html also this motor burns similar to the cummins, 3.6 gph at full load, 1.6 at 1/2 load and 1.1 at 1/4 load)

now all of this is before power loss. I know at work on our boards we hit at least 90% efficiency and that has a dc/dc converter as well as 3 LDO's. Those are also all SMD components and I'm under the impression that generally the smaller things get the harder they are to be efficient. I was seeing higher efficiency rates with our through hole boards than the SMD ones. so if we can hit 15% efficient then I would be happier than a pig in poop. Even 20% would STILL be better than what GM specs out their vehicles at.

so lets say 40kw (which is close to that 1/2 load mark) at 1.5 GPH. that 1.5gph mark works out to be about 41kw if you consider diesel has 139,000BTU/gal and 1kwh=3412 btu so there's about a 3% efficiency loss already (darn). well you figure another 10% if you have to DC/DC convert and we're still doing pretty good. 

Also this is all considering that I'm doing a direct drive from the rear pumpkin to the EV motor. If we put a gearbox in there, the efficiency of use would be smoother across the operational range and it would also be able to pull more. But then add in another 5% loss for the gearbox as well...still not too bad. 

regardless of pulling anything, here's a vehicle that is more efficient than most ICE plus it gets 50mpg (going off that 1.5gph figure) The only super big hole I have so far in piecing information together is how efficient a motor controller really is.


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## jlangholzj (Nov 7, 2011)

charliehorse55 said:


> Here is a spreadsheet I made for calculating the power you will need to keep a car moving at a steady state speed. You just input the aero, weight, rolling resistance, drivetrain efficiency and accesory power draw, and if you input your battery pack figures it will even calculate range.
> 
> Drivetrain efficiency is the power transfer efficiency between input from batteries and output to drive shaft - so include controller, motor and transmission/differential losses.


the "Cd" field is what and also I'm assuming the power usage is output in kW


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## charliehorse55 (Sep 23, 2011)

jlangholzj said:


> the "Cd" field is what and also I'm assuming the power usage is output in kW


Coefficient of drag. 

Frontal area is the area if you look at the car directly from the front. You should be able to find both of these stats for your particular car model on the internet. Remember the frontal area is inputted in square meters, so you may have to convert from square feet. 

For example, I just found stats on the Ford Ranger (2001) model to have a cd of 0.49 with a frontal area of 2.4 m^2

Aero drag = 1/2 * density of air * Coefficient of Drag * Frontal Area * velocity^2

And yes, power output is in kW. 


As for controller efficiency, for a three phase AC motor you are usually looking at 95-97%, with a DC controller around 99 - 99.7%. I'd be looking at an AC motor if you want high amounts of sustained torque. Water cooling will be required to run the motor at high power ratings for extending periods of time, and it is hard to find water cooled DC motors. Additionally, regen will help get those efficiency numbers up. Espescially due to the high weight of the vehicle.


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## dougingraham (Jul 26, 2011)

The rule of thumb breaks down at sustained high speeds and bad aerodynamics of a pickup truck with a trailer.

I've seen dyno data combined with motor controller log files that indicates battery to wheel efficiency of between 70 and 85%. Since it is on a dyno there was no air drag which of course becomes the dominant loss component the faster you go.

http://jackrickard.blogspot.com/2011/04/graphs-is-always-greener.html

This was a Warp9 motor with Soliton 1 controller and 57 cell 180AH battery pack. Includes the losses in the transmission, differential, motor control and motor. Of course this is showing the full power efficiency and not steady state partial throttle efficiency which would most likely be less.

I would rent a 30kw motor generator trailer as a range extender for long trips if such a thing were available. I estimate that it would keep my batteries topped off when driving down the interstate at 75mph. One would hope that the efficiency of such a thing could be better than the dismally bad 15-20% you get from a normal ICE engine.

Doug


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## jlangholzj (Nov 7, 2011)

charliehorse55 said:


> Coefficient of drag.
> 
> Frontal area is the area if you look at the car directly from the front. You should be able to find both of these stats for your particular car model on the internet. Remember the frontal area is inputted in square meters, so you may have to convert from square feet.
> 
> ...


water cooling was going to be part of our design anyway. 

just by using your spreadsheet quick I made a few calcs

i used linear interpolation between the load points to get a smoothed out line of approximate fuel usage in GPH. 

i also found similar specs to what you listed out and used the power used points as the load points. 

i used 90% Drivetrain efficiency and that number seems to be pretty close based on your information.

i also figured on having a 4500lb vehicle (3000lb ranger, + 200 lb motor + 600lb diesel + 200lb gen + batteries)

give or take...I'm seeing about 35-40 mpg max but I've also got a dip in the middle of my curve so it's probably not overly accurate  the MPG I'm seeing is in the speed ranges from 15.5 to 68.7 mph. Covering your typical range of driving speeds.

EDIT::

DT efficiency is still up in the air


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## charliehorse55 (Sep 23, 2011)

Make sure to lower the accessory power usage, I had 4.5kW in there to represent a cold winter drive using 4kW of electric heat. Headlights, sound system and average power draw from vacuum brakes is probably closer to 500W. 

I also had a high rolling resistance value to represent winter tires, it will probably work as is for your vehicle as the truck will have high RRC tires (as most trucks do). 

Finally, the air density was set to 1.4 kg/m^3, which is for -25C air. If this will be driven in a warmer climate, you may wish to change that to 1.3 (0C) or even 1.25 (10C). 

90% drive train efficiency will probably be hard to get, even if you are running direct drive. 

97% controller * 95% motor * 95% gearbox = 87% overall efficiency, and that's assuming a very efficient gearbox/differential. 

If you have skype, you can add me

evantandersen


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## jlangholzj (Nov 7, 2011)

charliehorse55 said:


> Make sure to lower the accessory power usage, I had 4.5kW in there to represent a cold winter drive using 4kW of electric heat. Headlights, sound system and average power draw from vacuum brakes is probably closer to 500W.
> 
> I also had a high rolling resistance value to represent winter tires, it will probably work as is for your vehicle as the truck will have high RRC tires (as most trucks do).
> 
> ...


helical cut gears typically loose 1-2% for each "mesh" so putting a 95% efficiency on the rear end isn't that outrageous. 

Thanks for the help on the spreadsheet too. I already adjusted the rho value for air and the accessory draw as well  

I was actually kind of surprised that as a "rough" estimate i put in a vehicle weight of 9000lbs to kind of simulate pulling a load and it came out to be above 25 mpg for speeds between 30 and 65 mph. if i could get that pulling 4500 lbs I'd be tickled pink! that would be enough for me to pull my '68 mustang on a trailer


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## jlangholzj (Nov 7, 2011)

I've also found that the kubota V3800DI-T-E3B meets tier4 diesel emissions as well. There's an isuzu that meets 4i standards but also has considerably less power output


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## charliehorse55 (Sep 23, 2011)

I am currently working on a system to quickly shift gears without a clutch on a manual transmission. Basically by using an electrically controlled manual gear box (a strong linear actuator pulls on a wire) the gears can be changed by pressing a button. Without a clutch on the motor you would normally have to wait for the motor's speed to fall when shifting up or push on the accelerator a little to shift down. I am working on a microcontroller that knows the angular momentum of the motor side of the gearbox, and then requests the controller to very quickly change the speed of the motor (based on the amount of effort required to change the speed of the motor). I am aiming to be able to shift in under 100 milliseconds. The largest limiting factor will be the limit of the impulse I can put on the transmission components. 


Would you consider using such a system on your car? Right now this will only be tested on a small go kart and potentially a small EV sedan (owner permitting). It would be a great help if I had more vehicles to test the system on. The main advantage is that you get very short shifts, lower the weight of the vehicle by removing the clutch and allow the car to be driven as either a manual or automatic based on a switch on the dashboard.


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## jlangholzj (Nov 7, 2011)

I've got a LOOONNGGG ways to go before i get there but I wouldn't mind trying out a similar system. As of now i was planning on doing a direct drive with the vehicle but there's obvious benefits in having a transmission added to it. You're basically doing with an EV what we do with the ICE's in FSAE. Our shifting is pure electrical thats driven by a dual throw linear actuator. I've got it set up for ignition kill on the shifts, which sounds about like what you're doing. 

out of curiosity what platform are you using for the transmission? gearing? etc. 
I'm looking at getting most of the legwork done over the next semester and summer as far as budget and jumping through hoops and then fall '12 the actual "design" phase of the project will start. (just to give you an idea)


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## jlangholzj (Nov 7, 2011)

also attached are a couple shots of the work I've done so far w.r.t some theoretical calculations that outline genset vs EV performance. There's alot more in-depth stuff that needs to be done but this is a start i guess.

I also made a mis-calculation on vehicle weight. The range weighs 3000 dry but i never removed the motor-trans before adding EV weight. The actual EV ranger that was produced weighs 2000 lbs in lead-acid configuration so i figured about 3000 would be accurate(ish) but i won't be able to tell until I get my generator head picked out. The AC50 motors seem around 150lbs or so plus 640 for the kubota. Now just to find a generator head.

that's one thing I've not had any suggestions on....gen head and motor combinations?


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## charliehorse55 (Sep 23, 2011)

jlangholzj said:


> I've got a LOOONNGGG ways to go before i get there but I wouldn't mind trying out a similar system. As of now i was planning on doing a direct drive with the vehicle but there's obvious benefits in having a transmission added to it. You're basically doing with an EV what we do with the ICE's in FSAE. Our shifting is pure electrical thats driven by a dual throw linear actuator. I've got it set up for ignition kill on the shifts, which sounds about like what you're doing.
> 
> out of curiosity what platform are you using for the transmission? gearing? etc.
> I'm looking at getting most of the legwork done over the next semester and summer as far as budget and jumping through hoops and then fall '12 the actual "design" phase of the project will start. (just to give you an idea)


Funnily enough, on the U of T FSAE team we are doing the exact same thing! Using an ATV gearbox with a dual throw solenoid. I just finished the PCB for it yesterday. It has an ATTiny85 to receive the signal from the driver, which then executes code to tell the engine to shut off, waits a bit for the gears to unload and then performs the shift.


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## jlangholzj (Nov 7, 2011)

charliehorse55 said:


> Funnily enough, on the U of T FSAE team we are doing the exact same thing! Using an ATV gearbox with a dual throw solenoid. I just finished the PCB for it yesterday. It has an ATTiny85 to receive the signal from the driver, which then executes code to tell the engine to shut off, waits a bit for the gears to unload and then performs the shift.



this sprouted a rather interesting conversation so I'm going to send you a Pm to keep this from getting too derailed


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## charliehorse55 (Sep 23, 2011)

Why not use an AC-50 as a generator? 3-phase AC motors are just as efficient as generators as they are motors. 

Another option is the Yasa-750. I don't know what your budget is, but Yasa motors may be willing to part with their Yasa-750 for a reduced price on a sponsorship deal. Normally they are about $9k/piece, but they are known to sponsor university projects. They are AMAZING little motors. Their RPM band is also perfectly suited for diesel engines as their peak efficiency is around 2500 RPM. 

100kW peak/60 continuous
750NM torque
*25kg*


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