Topic on my electric car

[The Toecutter]

I couldn't find the MATLAB simulations on my university's computer(I think it purged them since they went unused for so long), so I made a new one in OpenOffice Calc(Similar to Excel. It will probably work with Excel, but just in case it doesn't, go to www.openoffice.org and download the stable version). I've been busy this weekend working on school-related things, but still found time to get this simulation mostly finished. It can calculate the forces acting on the car versus speed, graph these things, simulate the electric motor's dynamics(torque vs. amps, efficiency vs. amps, ect.), and calculate range per charge at various speeds depending upon the gear you select.


I still have to add in the constants to simulate inertial losses versus selected gear and wheel diameter, have to add in the components that allow rolling resistance losses to change depending on the gradient input, and still need to add in top speed with gear and acceleration(depends on your shift points) calculators.

I'm now sending it to those who requested it.

Under this simulation, my car is given the following inputs:

Curb Weight(lbs): 2300
Drag Coefficient: .25
Frontal Area(square feet): 14.7
Coefficient Wind: 1.2
Toe In/ Toe Out(inches): 0
Tire Tread Width(mm): 185
Tire Aspect Ratio: 80
Rim Size(inches): 14
Coefficient of Rolling Resistance: .0085
Total Drivetrain efficiency(%): 87
1st Gear Ratio: 3.14
2nd Gear Ratio: 2.01
3rd Gear Ratio: 1.33
4th Gear Ratio: 1
Differential Ratio: 3.7
Battery 20 hour Capacity(Amp Hours): 65
Battery Reserve Capacity(Minutes): 125
Internal Impedance per battery(Ohms): .004
Nominal Voltage: 12
Number of batteries: 25
Shift Point from Gear 1 to 2(RPM): (not used at the moment)
Shift Point from Gear 2 to 3(RPM): (not used at the moment)
Shift Point from Gear 3 to 4(RPM): (not used at the moment)
Max Motor Volts: 216
Max Motor Amps: 1000

The environmental conditions were as follows:

Wind Speed(MPH): 5
Incline(%): 0
Coefficient Friction of Road: .5
Air Density(slugs/cubic ft.): .0023

Under this simulation, my car would achieve the following:

235 lb-ft of peak torque from 0 RPM to around 3900 RPM, about 170 peak horsepower at around 3900 RPM, and about 80 miles per charge at 60 MPH speeds. Energy consumption from battery pack to wheels, counting peukert's effect of battery at 60 MPH is about 240 wh/mile, or if it were burning gas and getting this efficiency, 141 miles per gallon(33.8 kWh of energy in a gallon of gasoline).

From other simulations, range has consistently been projected between 80 and 100 miles per charge at 80 MPH. In simulations I've made that could time acceleration, with a 1000 motor amp limit, 0-60 acceleration has consistently been about 6 seconds(about as fast a Porsche Boxter) and top speed consistently over 135 MPH, some simulations I've previously done showing up to 160 MPH(With different tire size and lower outside air pressure with no outside wind speed).

Further, in previous simulations, with a 2000 amp controller as opposed to a 1000 amp one(controller limits motor amps), torque increases nearly 60% and 0-60 acceleration drops into the 4 second range(about as fast as a Dodge Viper),

Up the maximum motor volts more, and top speed also increases, provided the batteries can deliver that sort of power.


Whoever wants the simulation I just did to replace the one I lost, say so. I'm sending it to those who have already requested it.

It will have an acceleration calculator and top speed calculator later added to it, along with supporting the condition of an incline and accounting for battery voltage sag versus battery amperes(Battery's will be a limiting factor if they cannot put out enough power to meet motor demands, causing motor power to drop). Unlike other simulations, this one will be able to simulate other cars besides my own(Since on the others you could not have the user input their own values). So anyone that's going to make an EV? You'll probably find it very useful if you're concerned about performance, and you'll find it useful enough as it is if you're not and just need to know range.


Sometime soon, I'll also be posting pictures of my car as it is now, with some body work done and a gas engine placed back in it. Eventually, it will be an engineless car again, like it was, but I just had to toy with it since money for EV parts is low right now. Also, when I get the time, I'll be posting wiring schematics and other stuff.

[Czechs Mex]

Re: Topic on my electric car

This is interesting stuff. Do you have any projections for how much this whole thing is gonna cost you?

If I had the know-how, I'd really be interested in building my own EV someday. How would you recommend getting started?

Edit: By the way, are you an electrical engineering student or mechanical? Or something else?

[Valkysas]

Re: Topic on my electric car

what are you accomplishing with an electric car? instead of giving your money to the oil companies, you'll be giving it to the electric companies. and instead of your car polluting, the electric companies would have to increase output, thus increasing THEIR pollution.

[Ryner]

Re: Topic on my electric car

Shhh, he might explode.

[The Toecutter]

Re: Topic on my electric car

This is interesting stuff. Do you have any projections for how much this whole thing is gonna cost you?

Depends on what motor-controller I decide to use. It will either be a Zilla 1k or zilla 2k. If I go with a Zilla 1k, it will cost me $10-12k total(dumped a few grand into it already over the last 2 years. Progress on it is a function of how much money I pull in. No jobs or too few working hours = no money), and a Zilla 2k will produce so much torque I'd need a complete replacement of the transmission and drive axel with stronger components, which would then necessitate getting rid of the rotoflex suspension, boosting the cost to $14k-$18k.

With a Zilla1k, performance will be like a Porsche Boxter, and with a Zilla 2k, like a Corvette or Dodge Viper.

If I had the know-how, I'd really be interested in building my own EV someday.

Just takes patience. High school kids have done it. So can you.

http://www.austinev.org/evalbum/589.html
http://www.austinev.org/evalbum/387.html

How would you recommend getting started?

1) What are your requirements? What range do you need, and if you care about it, what performance do you want?

2) How much are you willing to spend? Expect $5,000 for a highway capable conversion with golf cart batteries that routinely need watering and cleaning, and which accelerates like a slug. For 80+ mile range high performance sports car like what I'm building, $10,000 or so, WITH the selection of a lightweight and aerodynamic body, OR for the same money, 30-50 mile range high performance sports car with a non-aerodynamic and somewhat heavy body(Like a Toyota MR2, Porsche 914, Fiat X 1/9, ect.).

3) Research. Few good places to look for pricing EV parts or conversions:

www.go-ev.com
www.metricmind.com
www.fastevs.com
www.electroauto.com
www.cloudelectric.com
www.grassrootsev.com

Also, look at the conversions people have done to get an idea of what can be done as far as range and performance and for what price:

http://www.austinev.org/evalbum/

4) Join the EV discussion list. Hundreds of experts there that have built EVs and can guide you through the process:

www.evdl.org

5) Simulations. Figure out the components you want, and model a simulation.

From there, decide what you're going to do.

Edit: By the way, are you an electrical engineering student or mechanical? Or something else?

Electrical engineering, with ane mphasis on mathematics(definate minor), and depending on future course load(influencing additional courses I'll take), maybe minors in both mechanical engineering and physics as well.

what are you accomplishing with an electric car?

a) building a VERY fast car for cheap
b) building a car that is extremely inexpensive to operate(Savings will be enough to pay for itself with 10 years driving)
c) ecologically sustainable
d) as gas prices rise, I'll be able to fly by the gas station at 100+ MPH, flipping the rest of the stupid ****ers off for paying out the ass (Will be over $3 a gallon this summer, and if the world's economists are correct, peak oil will make gas prices $10+/gallon in a timespan of years, *if* you'll be able to get gas at all)
e) it's something different. Not many people have one. Given that the car is very tiny and very fast, seats only two, and resembles a 60s Ferrari, it will be an attention getting after it's fully detailed. As it is, gas car with cracked windshield and peeling paint, it already draws crowds because it's an exotic. As an EV, I'll get a lot of "what the **** is that!?" when I pop the hood open..

instead of giving your money to the oil companies, you'll be giving it to the electric companies.

But I'll be giving away MUCH less of it. Not only that, but once I get a set of solar panels, I'll get to keep my money.

and instead of your car polluting, the electric companies would have to increase output, thus increasing THEIR pollution.

They wouldn't have to increase output. Anyone that understands how electricity is generated will realize this. The car will be charging mostly at night time, when it's not used. This is when power usage is off peak, and powerplants end up wasting a huge amount of their electricity due to there being less demand than what's generated. That's power that would otherwise be wasted, being used to charge an EV.

PLUS, even when you do count in pollution from a coal fired plant, emissions are much less than even today's 'hybrids'.

[Valkysas]

Re: Topic on my electric car

and if everyone had electric cars and charged at night, it would be at peak consumption all day, possibly causing blackouts.

[The Toecutter]

Re: Topic on my electric car

and if everyone had electric cars and charged at night, it would be at peak consumption all day, possibly causing blackouts.

Our current grid capacity is enough to handle about 20 million or so EVs in the road in the United States driving an average of 12,000 miles per year, depending on the study you choose to look at.

Easy to see still doing just a little bit of math. America generates about 3.7 trillion kWh of electricity per year, and grid runs at about 90% capacity. Assume the average EV consumes about 300wh/mile of travel and travels 12,000 miles per year, charger efficiency is 75% and battery efficiency is 75% and a 40% power plant efficiency. This is 3,600 kWh consumed per EV per year, or 16000 kWh from the powerplant. Or enough leftover capacity for about 20 million EVs using this crude figure.

Fun little fact: In California during their Enron-induced power shortages, hair dryers were consuming more energy than all electric cars in that state.

EVs are hardly a threat to our electricity supply. It's simply the lack of electricity supply that's the problem. EVs or not, we'll need more power, and with EVs, they'd hardly be a factor. We can have 20+ million of them right now.


Not included is the power that would be saved from processing crude into gasoline, among other things.

[Czechs Mex]

Re: Topic on my electric car

Yeah, that simulation doesn't work with Excel, and I'm pretty much out of disk space. I'll check it out sometime this week when I'm at school.

But thanks a lot for all the good info! It's kind of impractical for me to do this immediately, because my car is parked in a lot, so I'd have nowhere to build or charge the thing. But if something doesn't start happening here with the auto industry, I think that'd be sweet to build my own if I have the chance.

Edit: I don't know how difficult it would be to find, but it might be worthwhile to try and get the simulation input specs on an EV that's already been completed. Enter it all in and see what results it gives, and then compare that with the actual performance of the given EV.

[The Toecutter]

Re: Topic on my electric car

Tried it with John Wayland's Blue Meanie. It's an electric Datsun 1200 and gets about 25-30 miles per charge at 60 MPH to 80% discharge when driven carefully.

Simulation showed results within 10% of that.



I still have some refinements to make though, so you'll be able to figure out how your car would accelerate and what not.


Anyway, here is what my car looks like simulated:



That's how it should look when you open it up.

[The_Real_Crunk]

Re: Topic on my electric car

Its funny because here in B.C., like 95% of our power comes from hydro electric dams.

[The Toecutter]

Re: Topic on my electric car

Wow. It would be zero emissions from hydro power.


In America, % of our power comes from the following sources:

Coal - 52%
Natural Gas - 20%
Nuclear - 13%
Hydro - 11%
Oil - 3%
Other - 1%

These are off the top of my head, so they could be off a small amount.

[The Toecutter]

Re: Topic on my electric car

I earlier edited this post, but since that didn't bump it up, I had to double post to get this update visible. Added some more info to those interested.

Here's a breakdown of the parts cost for my car:

-WarP 9'' series DC motor x1 $1,395
-Optima D750 YT battery x25 $2,500
-Godzilla Controller(72-300V DC, 1,000 amp max) x1 $2,495
-PFC 20 Charger x1 $1,500
-Todd DC-DC converter x1 $400
-Steel for battery racks $50
-Battery Cable $50
-EV200AAANA contactors x2 $150
-Feraz Shawmut A50QS600-4 fuse x2 $220
-Curtis Potbox(To control acceleration) x1 $75
-E-Meter x1 $235
-Solid-State Ceramic Heater Core x1 $75
-Adaptor Plate x1 $1000(I will be machining myself, so don't count cost)
-Miscallaneous components(Heat shrink tubing, tools, ect.) $500
-Leaf springs from Renegade Hybrids $300 (increase GVWR)
-Rudman Powercheq Battery Regulators x25(Unassembled) $250
-x1 1969 Triumph GT6 Sports Car = $1,200

- restoration costs, including what I spent so far and what will be spent later: $1,000

Total = $12,395.


I have some of the parts bought from this list, not all. I'll need a few grand to finish it. Does not include price of all tools used.

Here's a simulated torque curve of the car's performance from that little spreadsheet I made, which coincides with other calculations and estimates I made by hand and with other programs:



Perfectly flat torque up to about 4,000 rpm. What a beautiful power curve. So much of an advantage that this little 160 horsepower setup will perform like Nissan's 287 horsepower 350Z. Just compare torque curves:



I'd kill a 350Z off the line for sure, and even though I'd have only 160 horsepower, the guy driving the far more powerful car would have to really work to catch up.

[Kanick]

Re: Topic on my electric car

I should get back into electrical engineering...*sigh*

Are you doing the body work yourself? Im assuming you are since your cost aren't very high. Also where did you get your car at for that price? And is anyone helping you put it together... the motor and other parts have to be pretty heavy to be doing by yourself.

[The Toecutter]

Re: Topic on my electric car

Are you doing the body work yourself?

Indeed. No way could I afford for someone else to do it.

Also where did you get your car at for that price?

Internet. Look around. Generally, Spitfires/GT6s in the condition I got mine in, non-running, some minor rust, no functioning electrical system for heating, lights, ect. will go for $2,000 to $3,000. Sometiems you will find some bargains that someone needs to get rid of, because they may be moving, may be having a child on the way and no time to work on the car, ect. Sometimes you will find Spitfires and GT6s in perfect running condition with little/no rust for $2,000 in these rare cases, but in really good working condition with little/no rust the cars tend to fetch $7,000+.

To make an EV of one, you'll need to repair the body of all rust, then figure out where you'll put the batteries and other components, then how you'll gut the engine, then strip the horrible Lucas electronical system and figure out what will take its place, and if you got a stock Spitfire or GT6 transmission/drive axel, you'll want to replace with TR6 parts of same type to handle massive electric motor torque, figure out how you're going to do the acceleration and tach sensing, and so on.

A reasonable 30-40 mile range 0-60 MPH in 9 second 100 MPH top speed EV could be made of one for about $6,000-$7,000. Much less with used parts. Mine is a few grand more expensive as you can see, which comes with larger battery pack, more range, higher voltage controller, more expensive fuses/contractors, larger motor, and more power. Should I ind my controller and some other parts used, I will have some significant savings on this car.

One thing to be weary of: These cars are TINY. I'm 5'11'', 140 pounds and I can hardly fit in my GT6. My legs crunch against the steering wheel when I try to get in, and it takes about 30 seconds for me to get adjusted properly. But I love this car. The stock seatbelts will get you killed, so take them out and do what I'm doing. Replace them with a 5-point safety harness like what is used in racecars and fighter airplanes. You'll probably want a roll bar too. All that costs time and/or money added. The stock seatbelts are only two-point, and in a wreck where your car is stopped or slowed abruptly, your face will end up smacking the dashboard. Great way to loose all your teeth! Get broadsided and you're a garunteed goner in a car like this. Adds to the appeal I say. My head is right where all the bumpers of other cars and trucks/SUVs are at as far as height is concerned. This car is nice and low, just the way I like it.

I have about the only road-legal go kart in my city. And it will soon be electric to boot.

And is anyone helping you put it together... the motor and other parts have to be pretty heavy to be doing by yourself.

Yes. Help is rarely needed, but when the time comes, I do have help on hoisting the 160 pound electric motor into the car, along with help already for whenever I need to take the body off the car.

[The Toecutter]

Re: Topic on my electric car

I finally have gotten pictures of it. I borrowed a camera from the aeronautical engineering department at my university. Enjoy.


The exterior is in pretty good shape. Mostly rust free, the bodyis the item I was worried about most. I checked this car with a magnet very closely and the body was great, although ever since it's been in my garage, the floorboards have gone from adequate to almost non-existant. The parking brake recently broke, so I hold the car in place with rocks, one in the front and one in the rear. Also, it has no plates, but that hasn't kept me from driving it on occassion! I love how it can smoke its tires and make a savage growl not too different from a Harley Davidson motorcycle. Nothing beats sneaking up on SUV and minivan drivers who cannot see it because it's too low to the ground, then suddenly slamming the pedal to the floor right next to them! I'll miss that noise when I have an electric motor in her.







Interior is crap. Doesn't matter: I'm stripping the hell out of it anyway. Make note of all the room in the back. The back is going to be filled with batteries. This will be an electric car.





Now under the hood. You can see all 2.5 Liters and 210 horsepower of this bored TR6 beauty. In an 1800 pound car. This will be taken out, to make way for the electric motor and the controller, along with a few batteries.







I'm going to paint her dark British Racing Green after I take that baby **** yellow off. It needed that paint on it though, otherwise rust would have seeped in killed the poor thing.