Efficient EV Design

I am trying to build an energy efficient EV, for my senior project. I need it to be as efficient as possible. I want incorporate the following…
Lithium ion batteries
Carbon fiber body
A complimentary wired motor

I think I want it to go about 45-55 mph
I am looking for a complimentary wired motor, but I don’t know where to find one.

Any comments, advice, or criticism would be greatly appreciated
Thanks in advance

Edit: Spelling Fixed

AC motor Or DC motor? AC will be more efficent to my understanding.

Thanks for the tip, I was going to go with DC because I thought it would be more efficient (but if I’m wrong grate). But do you know how to run AC from DC batteries?

Thanks for your help

Edit: Fixed Spelling

Dude, spell check is your friend. Use it.

Sorry I’m using explorer and i can’t install a spell check program


use it

I don’t know what a “complimentary wired motor” is, nor can I find it anywhere.

AC is efficient, but whats your budget? are you building your own controller? AC is very complex, expensive and a PITA to program. DC is simple, easy to get into, easy to get setup and easy to get controllers/motors. All depends on your requirements.

I hope you’re talking LiFePo, there are several Lithium ION technologies. LiFePo will be spendy. Carbon fiber is spendy too.

Ask yourself what the absolute manditory specs are, and go from there.

You need to know:
Acceleration desired
top speed
nominal speed
approximate weight

I am making a design and a conversion only if I have time, and if I do; I will use a junk car, lead acid batteries, you know the cheap stuff. Just to show how an EV works. So this is only a design for efficiency I’ll worry about expenses later (but what you said is a good point).

As for the complimentary wired motor, I read in a book about different types of motors; series wound, parallel wound, and compound. From what I read the series and parallel parts can help or hinder each other. But I haven’t found anything on the web like that (the book was “how to build your own electric vehicle” and I can’t remember the authors name now).

Thanks for your input (I am going to check out your link now)

Wow, there is a lot there It will take me a while to ketch all this

Thanks greatly appreciated

[QUOTE=U4edot;4669]As for the complimentary wired motor, I read in a book about different types of motors; series wound, parallel wound, and compound. [/QUOTE]

ahh, compound… makes sense.

full AC is easier to get a motor for, an the most efficient of what you’ll find in an EV. Anything else is totally custom, and spendy.

I’ve been reading about AC motors, but I don’t know which one I should use.

From what I read (from the site you gave me) it seems like a 3 phased motor would be the most efficient. But I haven’t read much so I don’t know.

Thanks for your help
PS: sorry my post was confusing

I just read about universal motors. What I read clamed that universal motors have the “Highest horsepower-per-pound ratio of any AC motor,” but it did not say anything about energy efficiancy.

well, you’re basically limited to an AC Induction motor for a conversion, because there’s just not that many controllers/motor combos for small vehicles out there.

If you’re doing AC on a car, plan on spending at least 15 grand on the conversion with bats.

I’d stick with a series wound motor, simple series motor and some lead bats to do what you need. You’ll run fairly efficient. have some good power too.

cost could be under 9 grand.

A series wound motor is limited to DC, right? I think a AC motor will be more efficiant. And this project is centered around energy efficiancy, not cost.

So I am trying to find the most energy efficant mode of transportation (for 1-5 people)

I was also thinking about using a variable voltage transformer to regulate rpms, insted of a potenchiometer. However I can’t find a diagram of how one works, and I don’t know how efficiant it would be. Does anyone know anything about them, or anything about AC motors (i’m having trouble finding info on those too, particuly 3 phase AC motors).

Thanks for your time

you don’t vary voltage with AC, you vary frequency. Plus, by that theory, you’d need a 3 phase variable transformer (very expensive). frequency on AC determines RPM’s, in DC, you vary the voltage. Keep reading up on motor science on that link I sent. You NEED an inverter for a 3 phase AC system. This is NOT the same type of inverter you use for a laptop in a car. This type of inverter is variable, programmable and made for AC motors.

series wound motors work regardless of polarity, so you COULD use a single phase AC source, but would be inefficient.

Try looking at EValbum and see what others have in their 3 phase AC cars… and look up the controller/motor model numbers to do some reverse research… thats what I did with my DC series motor.

If you want efficiency and power to weight ratio, you need to look at the Ev White zombie. The guy who built this car is probably way ahead of the curve. Not only can he drive the car day to day, but he can also race it and beat out 450 horsepower ICEs’. I think looking at his developments will show you the path you are looking for and give you a basis on how to design what you are looking to do. He has a great concept to work from. Not to mention videos to prove what he can do.

Not to forget the chevrolet VOLT. This is more towards a hybrid but it is very efficient. I would read up on that too.

sorry Im late. I don’t expect you guys to hand feed me everything, but thanks for all the time you’ve given me. I’ll try to ask what I can’t find out for my self.

I still don’t usderstand why a variable voltage transformer wouldn’t work. Of corse I still don’t under stand how AC works ether (next on my list).

Thanks for the refferinces, I’ll look into the EV album and the chevrolet VOLT.

Thanks for all your help

I still don’t usderstand why a variable voltage transformer wouldn’t work. Of corse I still don’t under stand how AC works ether (next on my list).

Transformers only work if there is a change in the flow of current. DC is constant current, so it won’t work.

I think you really need to research some on that site some more and read up on how DC and AC is different.

I think I need to do more research too.