Ideas for a project

Hi there all this is my first post in these forums, I have always wanted to build an EV and having just finished a conversion project on a conventional petrol car I am now planning my next time and money hungry automotive experience, an EV or a hybrid vehicle.

I had an idea which I was wondering if I could get a little feedback on, they may be stupid, but I guess if you dont ask you wont find out.

So, it seems that two big problems of EV’s are weight and range.
My idea is for a hybrid vehicle that uses a small petrol motor (I have a great 7 kw motor which I have converted to run on ethanol) and run a driveshaft directly into a large altenator, and run the electric motor stright off this and use ony perhaps 6 batteries as backup thereby reducing the weight and alowing a weaker electric motor that will run off my altenator setup.

The questions I have are:
What rpm are the availaable motors generally used for these applications safe up until? I wanted to use a direc drive setup with only a differential and no gearbox, is this possible?

How feasible is the hybrid idea I have? I want the vehicle to be instantly refuelable and have good range, but do as little emissions and fossil fuel usage as possible (Id use hydrogen if it wasn’t so damn volatile)

Will the weight I save by not having battery packs allow me to use a smaller electric motor than normal but achieve similar performance to a regular EV conversion?

Thanks in advance guys!
All the best - Mick

Wow, lively lot you guys are…
Even a ‘thats a stupid idea’ would have been better than nothing.

Is it because my idea involves a petrol motor (allbeit a small one)?
I want to build a car that won’t impact as seriously on the environment, but in the line of work I am in, I drive long distances and cannot afford the luxury of stopping every 80 miles for a recharge.

If no-one is interested in passing on any advice I would greatly appreciate it if someone could recommend a site where I might get some answers?

Thanks in advance.
All the best - Mick

i’d give you advice…but i’m working on designing my first car right now too.

like you…i’m going with a ICE for generating capabilities, along with a couple of other charging sources.

like i said though, i’m incredibly new to this, and can’t help you with any of your other questions. Good Luck!

Mick, the answer you want are driven by the kind of Engine you have and the performance of the alternator and the kind of electric motor you want to use.
What is the power and torque curve of your wonderful 7kW engine? Is that a stationary engine or is it a former car/bike/lawn/sewer or wathever engine meant to run at variable speeds (revolutions)? If it were me, I’d set the engine to run at maximum torque setting (which is where the engine takes the most out of what it burns) and would look for a suitable alternator able to give the wanted output at that rpm. Or the other way round: you want to use a given alternator thus the engine must go at that rpm to have the wanted output. Then, I’d figure out how big the battery pack should be: the battery pack is the buffer which allows the generator to run always at constant thus optimal conditions, or to be shut off for longer periods of time. I don’t know if this can be of some help :o)