Electric car

Introduction

So you may wonder why you would want an electric vehicle.  Here are some reasons why I want one.

Cost to drive – I can charge my car at night using off peak power which is currently about $0.04 per KWh.  Looking at the specs on a Nissan leaf, it has a range of 85 miles on a 24kwh battery.  This translates to $0.96 per fill, or $0.011 per mile (note, that is just over 1 cent per mile).  At current gasoline prices of $3.30 per gallon, this converts to 300 miles per gallon.  Now don't let this confuse you, when you look at Nissans website.  I know they list the leaf at 126/101 city/hwy MPGe.  This is because they don't calculate it based of charging at night on time of day power, and they use the average peak power price.  These numbers are based off me and current gas and electric prices in my location.  However I would like to see a gas vehicle break 100 MPG!!

I can charge my car from my solar panels – Since I have solar panels, I can use them to pay for my electricity using my grid tie inverter, so no matter what happens with electric prices, I have my fuel paid for (See my solar panel section, but $4,000 for 30 year (or more) of fuel is not bad.  Also if you don't have a grid, or if the grid goes out, you can charge your car directly from your solar panels.

I can use my car as a battery backup for my house –  If the grid goes out, I have a nice storage of power that can run my house (an can be charged by my solar panels).  This is a great emergency backup, however I should mention, if you use your car as a battery backup, you won't be able to drive it.

It is clean – I don't know about where you live, but where I live we have inversions during the winter, and the air quality gets really bad.  With an electric car I will not be adding to the pollution (especially since the electricity used will be generated with my solar panels).  Also you have no oil, and mess to worry about.

Convenience – There are so many advantages with an electric car, such as turning on climate control from your cell phone, so when you get to your car it is the prefect temperature, to not needing to worry about your engine not starting.


You can view my progress on my conversion here 

Converting considerations

There are several things to consider when converting a car to electric.

You may want to consider purchasing an OEM vehicle.  Recently Car manufacturers have started making them, and they are quite affordable.  It will save you some time, effort, and you will have a warranty.  However if for one reason or another you decide to convert your own like I am doing, then here are some things to consider.

1- You will want to choose the smallest lightest vehicle that will suite your use.  As you increase the size of your vehicle it will increase the cost of the conversion exponentially.   So keep that in mind.  (See number 4 on how this works)

2- Choose the Motor and controller you are going to use.  This is more complicated than you may think.  Not only are you going to need to determine the size, but also if you are going to use a DC or AC motor.  For the cost, DC is the cheapest, however DC motors require maintenance because the brushes will wear out.  They also produce dust from the brushes, and you will not be able to use regenerative breaking with a DC motor.  As a note, all the car manufacturers use AC Motors, and I choose To use an AC motor on my conversion.  Also if you choose to use an AC motor, you need a controller that is designed for that motor (most AC motors come with the controller).  With DC motors you can choose any controller that can handle the voltage and power of the motor.

3- Determine the minimum range you will need between charges.  Again your cost will go up exponentially with how far your range needs to be, but at the same time, your car will not be very useful if you can only go 5 miles before you need to take it home and charge it.  Someday hopefully there will be quick charge stations everywhere so it will be easier to charge without taking your car home, but for now there are not many.  For me, I need to commute 60 miles round trip, so I am planning on a 75 mile range to keep it safe.

4- Now that you know the range you need, and the weight of the vehicle, you can calculate the size of battery bank you are going to need.  You can use the following http://www.evsource.com/battery_calculator.php

Just click the Ah Rating to calculate to.  Put in the vehicle Weight, and the desired range, the pack voltage will be determined by the Motor/controller you choose.  For my vehicle I put in 4,000 lbs., 75 miles, and 200v (my motor/controller runs off of 160-300 volts, but is designed for about 200 volts).  This lets me know I need Batteries with 187.5 Amp hours (I used 200 Ah batteries), and that I will need 37.5 KWH.  As you can see, If I used a smaller vehicle (1500 lbs. = only 70 AH batteries or 14 KWH).  As you can see, the cost difference is $17,000 for the 3,000 lb. vehicle and $6,000 for the 1,500 lb. vehicle, keeping the same range (using CALB LiFePO4 batteries).

5- Now as you can see from the above, Batteries are a big cost to this conversion.  There are a few options, such as golf cart batteries.  However if you go with flooded led acid batteries, you are going to greatly increase the weight of your vehicle (which will cause you to use even more batteries).  They may look like you will save money, but in the long run you will be better off using some high quality LiFePO4 batteries.

6- Currently there is a fairly hot topic on BMS (Battery Management System).  This is not really a concern with led acid batteries, but if you use LiFePO4 batteries, many people say you need to have a BMS in order to not destroy your batteries.  Rather than me repeat what I have read, you can go here:  www.electric-cars-are-for-girls.com/lithium-battery-management-systems.html

I choose to not use a BMS, and am going to set my charger to stop charging at a voltage slightly under its maximum capacity, due to these articles making a lot of sense to me:  http://evtv.me/category/bms/  But the choice is up to you.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

7 + 1 =