Step One: How to Budget for Your EV Conversion

A lot of folks have asked me about step-by-step guides for building your own electric car. Since these vehicles are usually one of a kind and custom made, that kind of guide is nearly impossible to write. That being said, I’ll walk you through the processes that are common to all conversions and give you some technical guidance along the way. So, let’s begin!

How much does it cost, exactly?

Old-school hot rodders know that the question isn’t “how fast do you want to go,” as much as it is “how fast do you want to spend?” Performance costs money, so what are you willing to spend? You need a budget, and you need a performance goal. While your budget will determine what components you can afford, the performance goal will inform what components you actually prioritize with those funds. Plan on at least $5,000 for a bare bones conversion, excluding the cost of the vehicle itself. The sky is the limit.

Let me show you how fast I wanted to spend…

To start, let look at my design philosophy for the MG as an example. I wanted a vehicle which performed very well, but I didn’t care that much about having hundreds of miles of range. I wanted good acceleration, but I wasn’t terrible concerned with creature comforts like heat or air conditioning. I wanted power, and lots of it. I was willing to sacrifice in other areas of the build for that, and I would have to in order to keep the costs reasonable. I didn’t want to spend more than $5,000-6,000 on the whole thing. Let me give you an example of what that looked like in my case. These costs are approximate, but it will help you see how quickly these things add up.

Component	Cost
Electric Motor – Kostov 11″, used	$1,000
Batteries – 4x 48V Chevy Volt modules, used	$1,000
Charger – 3.3kW TC Charger, new	$450
DC-DC Converter – 1,000W generic Chinese unit, new	$180
Custom Driveshaft	$150
Controller – DIY P&S DC Controller	$500
Custom Motor Mounting Plate	$250
BMS – ZEVA EVMS System	$700
Miscellaneous – Heavy gauge wire, lights, switches, throttle, etc.	$500

The total cost there is $4,730, excluding the car which I got for a couple hundred bucks and fixed up, and that assumes a lot of DIY work. I designed my own mounting system for the electric motor. I figured out all of the components for the driveshaft and sourced them, but I only had a shop weld and balance it. I built the controller myself with a premade control board to save some funds in that area while still getting enough power. I skipped using the transmission to avoid the hassle and expense of adapting it. All of those things represent huge cost savings while allowing me to get to my primary goal: power. Power informed what I wanted, which is why I spent more for a very large and powerful motor, even though it was used.

I also needed batteries with a high enough C rating that I could get the amps for that power. More on that C rating thing when we talk about batteries. I completely skipped on any creature comforts because they would not contribute to the performance of the vehicle. I also chose a DC system because I’d get the most raw power out of it for what I could spend, even though it is less efficient and less refined than an AC system. My goals determined every component and my budget restricted which components were available for consideration. The MG only gets 50 miles of range, it has no heat, no AC, no cabin fans, and no actual radio. It has no modern conveniences, but it burns rubber on a budget.

So, what’s your budget…

Be realistic. This will probably cost at least $5,000-$6,000, assuming you do everything yourself. You will need a certain level of automotive skill, and you’ll need to be willing to pick up additional skills at that budget level. Are you okay with that? Again, be realistic.

If so, write down your number and multiply it by 1.25, since that’s what this thing will actually cost, and let’s get on to the performance.

…And what are your performance goals?

How many miles do you want to go, and at what speed? Will you be driving on the highway? What level of power would you be content with? Do you want a lot of advanced features? Those questions may come to mind naturally, but have you considered if you can you charge at work? What about how many people you want to move around, or do you need to move groceries or heavy loads? Do you need a usable back seat/trunk? Think of all the things you want to do with your vehicle, because they will all factor into the conversation at this point.

Once you’ve got these details figure out, then we can get on with actually picking some components to meet your goals while staying in budget.