This page covers research that went into selecting the 1st generation scion xB for my EV conversion, and research into design and component selection to achieve my goals.
The main steps of decision making when converting a gasoline powered car to an EV as I see it are as seen in the following sections. First though you may want to make sure you are familiar with EV Terminology and EV History.
Here are some Useful Links for further EV conversion research.
Define Goals and Budget
You need to define what you want to build, and how much you have to spend. Commuter, Dragster, Show car, etc. Spend a lot of time looking at what others have done with a similar budget and goals to what you are considering. Your goals will be heavily influenced by your budget. Prioritize. Decide if time, cost, range, performance, looks, or something else is most important. If you want to succeed, you will need to be realistic, and likely you will have to make compromises somewhere.
As part of your planning you should take stock of your own skill set and tools. Building an EV conversion is a tour de force of garage engineering skills. You can learn as you go and buy tools as you need them, but if you are not at a reasonable starting point already the project will not get far.
My 1985 Toyota MR2 EV conversion was totally successful and I drove it for almost 6 years. However my needs were changing and my budget is more now that it was when I built the MR2. My basic goals with a new conversion were:
- 4 doors, retain seating for 4
- Maintain useful interior cargo space
- Ability to tow small (1000lbs) trailer
- 100 mile useful range at 60mph
- Utilize Solectria AC55 motor and UMOC inverter
- Capable of using L2 public charging network.
- Modern body
- Not a sedan
It is critical to select the best chassis you can that fits your budget and goals. Chassis Selection should be on the basis of utility (meeting your needs), efficiency (best weight, aerodynamic drag), ease of conversion, and of course cost.
Given my goals, the chassis research I did, and my own personal taste I looked at smaller modern MPV class vehicles and settled on the first generation scion xB as the best conversion candidate.
In approximate order of overall impact: Battery type and size, Inverter/Controller, Motor, Charger, DC/DC. Each of these must be selected and those selections considered against the others to ensure goals and budget are met.
In my case, I had purchased my Solectria AC55 Motor and UMOC445TF Inverter prior to purchasing my xB so I already had these on hand and intended to use them. This meant the only major variable would be the battery type and size, which I was able to narrow down given my range goal and performance analysis.
Given your chassis, components, and goals, you can perform some performance analysis. This can be heavy on the math, or can be largely seat of the pants. In both cases the goal is to ensure that the range and performance are adequate to meet your goals.