[Ziggythewiz]

So I'm putting together an EV Conversion presentation to share at DEF CON later this month and one thing I want to touch on is some of the common pitfalls that people often ask about/want to try.

The ones at the top of my 1:30 AM brain are:
Perpetual Motion: wind generator, alternators, etc
Hybrid: you want the best of both, but get the worst instead
Solar: looks great, charges little
Supercapacitors: energy density on par with Capitol Hill
Hub motors: How would you feel hitting potholes on a 1000 RPM merry-go-round?

What other things are there that people burn lots of grey matter plotting/discussing without accomplishing much?

[Woodsmith]

I would add over estimating personal skills where someone attempts to make or recondition parts that are beyond their skills base in an attempt to save money on professional engineering.
It is important to recognise where it is just more sensible to put money towards professional services.

[Salty9]

Swiss army vehicles - people wanting one vehicle for all their transportation needs which ends up being ideal for none and wasteful for all. Start with a vehicle that fulfills most of their transportation needs.

[Ivansgarage]

Here is three questions every body seems to keep asking..
Batteries Lead or Lithium
Motors AC or DC
Trans or direct drive

[Ziggythewiz]

Thanks for the inputs. Most of those are already covered in other areas, but a couple things I can add/expand on