[GRLUG] OFF TOPIC Electric Car

[Collin Kidder]

Rick Vargo wrote:
> I did some research on this a while back and there are some companies
> out there that make conversion kits for older vehicles that allow you to
> bolt specific DC electric motors to your transmission (specifically I
> was looking at converting an S10). It was a relatively simple process
> but was cost prohibitive at the time (DC motor, charging station,
> converter, batteries, and plans = $$$). Basically you pulled your motor
> and replaced it with the DC motor with the converter, then a bit of
> wiring changes to the car (including adding electric heat) and filling
> up your truck bed with lead acid batteries. You can even add a solar
> panel to topper/tonneau cover to help charge the batteries while
> driving... The truck small pickup is a nice choice for this project
> because it can hold more lead acid batteries thus extending your range.
>
> Rick
>   
Part of the problem here is that lead acid batteries are very heavy and 
thus the more of them you add the bigger the motor you need to push the 
vehicle. Lithium or lithium ion batteries have much higher energy 
density but they can't be constructed very big (so you need a large # of 
small batteries) and they are more expensive. Ultra capacitors are good 
for better peak loading but they are expensive too. It's all around a 
real money pit.

As Adam said, for efficiency you really should have three phase AC 
motors (preferably running at about 440-600v) but the power inversion 
kills any efficiency. So it would take some real creativity to make a 
three phase motor work. I  wonder if it'd be possible to create the 
necessary input through selective switching of cells. I don't know how 
easy or cheap it would be to buy enough super high power transistors to 
do that though. Transistor switching through mosfet gates can be done 
very efficiently but there is an upper limit to the amount of current 
you can pass this way. It might work as you don't need so much current 
when running 600v three phase. It would require substantial electrical 
experience to pull off.