I want to build an EV car, but Im not sure on what size motor to use. Im sure the motor should be able to generate a certain torque to be able to drive a car, but how much energy will it need to produce that torque? And what voltage , etc would that motor need from the battery?
These are fundamental issues you'll have to resolve before you can get your conversion done.
First off you're going to have to read everything you can get your hands on. Start going through all of the postings in the Wiki area for starters.
Im really confused on where to start so if anyone could give me step by step instructions, that would be awesome
The first step is coming up with realistic expectations. Then you need to work on design.
My answers to the following
- Your skill level with auto mechanics and fabrication
Barely to some simple do it yourself things like change oil filter, oil, replace light, change fuses.
You may need to have someone build it for you then. Generally doing it yourself requires close to the aptitude of a car mechanic.
- The range you are hoping to get (how many miles/charge)
I want to shoot for something like what an average day would be, about 80 miles.
That's actually in the realm of possibility. On of the first things that you need to understand is that an EV essentially is a car with a really tiny gas tank, something on the order of 1 to 2 gallons. So if 80 miles is possible on 1-2 gallons of gas, then you have a chance. Since it's possible, you have a chance.
- What level of performance you are hoping to get
the acceleration at this point is not that important, whats important is that the car run for a long time, like 5 hours
Now that's unrealistic. Considering that you're talking about an 80 mile range, if you have a 5 hour run time, then you're talking about a speed of 16 MPH. At normal street speeds you'd have a run time of less than 2 hours by any reasonable measure.
- How much money you are willing to put into your project
That's a big advantage, because that means that lithium batteries are on the table. That greatly expands you conversion possibilities.
- What parts you've already considered, if any.
I am planning to do a bigger car, sort of like an SUV, like say a ford excape, or a hyundai tuscon
Weight is your biggest enemy to range. The heavier the vehicle, the less range you'll generally get out of it. Escapes and Tucsons have a curb weight of 3200+ lbs. That's a lot of weight to be carrying around.
You'll want to work hard on trying to find a lighter vehicle to do your conversion on.
Given your specs here are some general parameters to start working with:
1) Donor vehicle: Try to locate something lighter. Simply google the name of the vehicle and the words curb-weight to get an idea of how much it weighs. I'm planning on a pickup conversion and they come in 600 lbs lighter than the two SUVs you suggested for example.
2) Batteries: You'll need to look at lithium. There are several threads floating around discussing the subject and the classified are talking about a group buy. You'll need to look to buy as many batteries as you can afford.
3) Motor: Stick to the tried and true. Motors such as the WarP-9 will satisfy all of your power needs.
As I stated above you'll probably need to have someone more well versed that you to do the conversion. If you want to see a sample of the process, go to youtube and search for n2confusion. This guy has a completely library of an EV conversion of a Geo Metro. It'll give you a great sense of how to go about the process.
Finally you're going to want to get a book or three. Brown's "Convert It" for example has step by step instructions of the process.
Good luck in your adventure.