[RedDevil]

Why use a car at all?
We can use a small battery to power a motor to power a generator to power a bigger motor to power a bigger generator to power a really big motor, etc.
Free energy, we all are going to be rich!
Why hasn't anyone thought of this before?

Seriously, if you want to build an EV the wanting it part is not enough to make it happen.
You need to know at least:
- what your budget is,
- what range you need,
- what performance you need
- what batteries you'll use
- what battery management system
- which motor
- which motor controller you'll use
- how you are going to charge it
- what charge controller you'll use
- how to get your EV road legal
- how to insure your EV
- how to do the build and operation in a safe way
- how to deal with all the odds and ends that rear their ugly heads over a build.
- I probably missed a few essentials; you must keep track yourself.

And then you read, search, look, investigate, check, recalculate, plan, test and keep doing this over and over again.

Do not underestimate the size of the challenge!
I'm building a parallel booster pack for my hybrid.
Way easier than a complete EV build.
I do have a lot of experience with electrics and a solid physics background, still I am struggling hard!

If I had to build an EV I would avoid complexities with a vengeance.
I'd go with an existing design and parts off the shelf, maybe re-purposing an existing EV appliance.
MetroMPG has done a forklift conversion on his Metro. That is a nice example of how to build an EV cheap (provided you can get an electrically functional forklift on the cheap).
There are limitations, like reduced top speed and range.

You do have a 35 mile single commute.
A lead acid battery pack can barely make that one way. And wears out after a few hundred full charges.
A used Leaf pack would give you the range both ways, but needs a good BMS - and you'll never know how much life is left in the pack.

Heat is a problem with most battery technologies. You don't want your car bake in the Mexican sun all day and then drive off with batteries at 70°C / 158°F. You won't make it home after a few times that.

Whatever you do, focus on the essentials.
If your plans don't give you the range you need then make a new plan.
Don't lose your head on alternators; an EV does not need them.
If you want to harvest braking energy the motor can do that, working as an alternator on deceleration. Even so, that is hard enough to make many EV builders skip it altogether! And you need conventional brakes anyway.