Electric Vehicle Project

Novice Electric Vehicle Project

Less Ambition…More Results?

So I have come to the conclusion that a car may be too big a project for my first attempt at electrical engineering.  So I am taking a step back.  I am going to try and retrofit a gas riding lawnmower with an electric motor.

This is a project I may actually be able to make progress on.  You see, I can buy a cheep, used riding lawnmower for $150 (especially since “runs” isn’t one of my primary concerns).  Then I only need to find a motor, controller and battery pack and get to work.  Also, because I only have half an acre of land…I won’t need a large number of batteries (though I will try to figure out how many batteries I need before finalizing my design).

So, here are my goals and mission statement for this project

Mission Statement: Build an operational electric riding lawn mower.


  1. The mower must be able to cut my grass on a single charge.
  2. The mower must be rechargeable in one week
  3. When overloaded (if the blades get stuck), the mower must not cause harm to the operator or anyone nearby
  4. When overloaded, the mower must operate again when the overload is cleared without needing to replace parts.

That pretty much covers it.  Seems simple…now where do I start?


August 8, 2008 Posted by | Electric Mower, Mission Statement | 1 Comment


So, this isn’t about “my” EV.  But it is nice to see that some of the major auto makers and R & D firms are starting to look hard at Electric Vehicles as a future technology.

New EV

New EV

This guy can go 0 to 60 in 4 seconds and gets 200 miles/charge.  More importantly, it can recharge in as little as 10 minutes.  Check out the full article:


July 24, 2008 Posted by | Uncategorized | 1 Comment

Batteries are EVERYWHERE

Actually, I am having some trouble finding high-capacity batteries for sale locally, or on the Interwebs.  The closest I have found are these guys:



July 8, 2008 Posted by | Uncategorized | Leave a comment

EV Calculator

There are two EV calculators that I like.

First: http://www.geocities.com/CapeCanaveral/lab/8679/evcalc.html

This one has a bunch of information as well as a method for adding more information as needed.

Second: http://www.evconvert.com/tools/evcalc/

This one has a much better user interface.  I am in the process of developing one that relies on a database.  This will allow others to add data for retrofitting.

The following statistics for a Honda Prelude (taken from various sources) will come in handy:

  • Drag Coeeficient: 0.34 (2)
  • Frontal Area: 20.6 (1)
  • Curb Weight: 2866 (1)

I used the first site with the following selections:

  • Batteries/String: 9 (108 Volts)
  • Number of Strings: 2
  • Battery Type: 3M Lithium Polymer

Everything else I kept the same.  This gave me a top speed of 73 mpg and a range of 72 miles at 70 mph (in fifth gear).  That is a total of 18 batteries.  I tried to find the batteries on line, but could not.  The page was written back in 2004.  So the battery may not be available any more.  On the bright side, there may be something better.  Uve’s page had a unit cost of $177/battery. 

That means the bettery cost would be $3186.  That is almost half my budget.  But that is not surprising.

(1) http://92lude.com/prelude_dimension_capacities.htm

(2) http://en.wikipedia.org/wiki/Honda_Prelude

July 5, 2008 Posted by | Web Resources | 2 Comments

Initial Project Goals – Retrofit

This is something else I like to do with my projects.  Much broader than system requirements, but more specific than the mission statement.  These goals also tend to me “Nice to haves”.  Their importance and relative complexity will determine if they make it in to the final product.

  1. Travel 60 miles at 70 mph on a single charge
  2. Charge in less than 8 hours using a specially designed charger
  3. Charge in less than 16 hours using a standard 110 volt AC plug
  4. Cost less than $6,500
  5. Have an operational air conditioner that will still allow for travel for 45 miles at 70 mph
  6. Do the entire project in metric (exception: miles will be used where necessary instead of kilometers)
  7. Power Steering
  8. Power Windows
  9. Utilize Recouprative Braking
  10. Display the relative power remaining on the dash
  11. Display the distance that can be traveled at the current speed on the dash in miles

The nice thing about project goals is that I can add to them as necessary.  This will do for a start.

July 5, 2008 Posted by | Goals | Leave a comment

Mission Statement – Retrofit

I like to start all of my projects with a mission statement.  This helps to focus my efforts.  By specifying what I am trying to accomplish, it helps to prevent my own tendency to add to the project because “it will be cool”.  So, with no further ado:

Retrofit a Honda Prelude to operate off of portable electric power for daily commuting to and from work.

July 5, 2008 Posted by | Mission Statement, Web Resources | Leave a comment


I have been toying with the idea of building my own Electric Vehicle (EV).  This blog will outline my progress (or lack thereof).  I will also say that I have three EV projects in mind.  But I will be working on them one at a time.

  1. Retrofit a Honda Prelude
  2. Build from a kit car
  3. Build from scratch

The retrofit will be first on the list.  It will be a basic build.  I have not yet identified the mission statement or  project goals.  That will be a future post.

July 5, 2008 Posted by | Electric Car | Leave a comment