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Getting Started

The Donor Car

Removing the ICE

Electric Motor

Coupler
Adapter Plates
Installing the Motor
Batteries
Controller
Brake Vacuum

12 volt Circuit

Testing
Driving

Driving an Electric Car

Now that I have a working electric car, I have to figure out how to drive and maintain it without breaking it. How fast can the motor turn? When should I shift gears? How hot is too hot for the controller and motor? How do I efficiently charge the batteries? How far can I go before I must recharge? How do I maintain the batteries? How efficient is this car? How do I know it is running right? There are many answers to these questions in books and on line, but how do they apply specifically to my car?

May 12. I got permission to plug in at work:

 

May 16. I have driven 520 electric miles. Here is what I have learned.

Driving

The car accelerates about like it did when it was a gas car full of people. At first, I used first gear just to get going, but I found it is better in terms of acceleration and current draw to get up to about 20 mph in first. The shift into second is fairly easy at that speed also. I stay in second between 20 mph and 52 mph. If I find myself at 55 mph, I shift into third gear, but only if there are no significant hills to climb ahead of me. There is a formula in Brown's book that calculates motor rpm based on tire radius and gear ratio. This tells me that the motor speed is 5000 rpm at 26 mph in first gear and at 52 mph in second gear. The only annoying problem is the heavy rear end, as you can see in the photo above. There are certain dips in the road that I try to avoid or I will hear a bump in the back, shocks bottoming out?

Overheating

I have not had any problems with overheating. The heavy copper cables are all at ambient temperature after a long drive, as are the battery terminals. The motor is only warm to the touch. The hottest component is the speed controller. I checked its temperature after a long run using an infrared digital thermometer. The hottest part of the controller body was 138 degrees F. This is well below the over temperature cutback point of 185 degrees F. This week was a relatively cool week. I may not see such favorable results on a hot day in June.

Range

I can easily make it 23 miles to work with little performance degradation at the end of the trip. Then I plug in and charge all day. It takes about 6 hours to get back to full. I can go 30 continuous miles under normal commuting conditions, no lights or wipers on. "Normal" means I accelerate to keep up with traffic, I cruise at 50 miles per hour for most of the commute. EV America suggested 20 pounds of battery will give 1 mile of range. My batteries weigh about 960 pounds, so I was hoping for a 48 mile range. I'm not getting that yet. Range is reported to increase as the batteries wear in. I will believe that when I see it.

Charging

According to US Battery, the batteries should be charged to 2.583 volts per cell at a rate not greater than C/10 amps, where "C" is the 20 amp hour rating of the battery. I have 15 8-volt batteries with 4 cells per battery, so my digital voltmeter should read 155 volts when the pack is fully charged. My batteries are US8VGC batteries with a 20 amp hour rate of 170. So my maximum charging rate should be 17 amps. My Russco charger can push 10 DC amps, but I run it at about 8 amps, or about C/20 amps. I get a full charge in less than 12 hours from "empty." I get a full charge in about 6 hours after my one way commute of 23 miles.

When is my battery pack "empty?" For practical purposes, I want to recharge when my dash voltmeter drops below 105 volts under full load. I did a couple of range tests where the voltage dropped below 100 volts. Not a good feeling as I had to slow to 30 miles per hour or less to keep voltage above 100 volts. Here is a battery charging web page:

http://www.solarnavigator.net/battery_charging.htm

It includes a table of resting voltages showing state of charge for a 12 volt battery and per cell.

Here is a more practical table sent to me by a fellow EV converter (Thanks, Michael) showing pack voltage under load for a 120 volt system:

Battery Voltage vs State of Charge at 75Amps
Hold at 75 Amp and Read Volts

Loaded (volts)
%DOD
Cell Voltage
126
0
2.1
123.6
10
2.06
120.9
20
2.015
118.2
30
1.97
115.5
40
1.925
112.8
50
1.88
110.4
60
1.84
108
70
1.8
105
80
1.75
101.7
90
1.695


Efficiency

I got a Kill-a-Watt monitor so I could see how much energy I use to charge the battery pack. I monitored energy use for three trips to work this week, found that I use an average of 0.41 kwh/mile. Not as efficient as GM's EV-1 at 0.26 kwh/mile but I made my car in my garage using a 22-year-old Honda Civic. I will hopefully see some improvement as I make a few more modifications.

This Department of Energy article on electric vehicle research shows how to calculate the petroleum fuel equivalent of a pure electric car charged by home electric service. To get the miles-per-gallon equivalent of an electric car, divide the petroleum equivalency factor (PEF) 82,049 by energy usage in watt-hours per mile. For my car, I get 200 miles per gallon. This makes me feel good. The next paragraph makes me feel bad, until the end of the paragraph, where the sun comes to the rescue.

According to a 1999 Department of Energy report on CO2 emission by electric power plants, the generation of a kwh in the Middle Atlantic Division (New Jersey, New York, Pennsylvania) produces 1.05 pounds of CO2. A gallon of gas produces 20.3 pounds of CO2. If I compare my electric car to my previous commuter car, a 1994 Honda del Sol that gets 40 mpg, I produce 2.5 pounds less CO2 per gallon of gas, based on 1999 figures. My electric car produces the pollution of a car that gets 46 mpg. If power plants progressively produce more power from renewable resources, my commute will produce progressively less CO2. I will not wait for that to happen, though. I will put solar panels on the roof of my house as soon as possible. If the car gets, say, 60% of its energy from the sun, it will produce about 7 pounds of CO2 per 40 miles. A gas car would have to get 114 mpg to achieve that.

Both paragraphs above are accurate, based on real numbers. It is said that big power plants are cleaner and more efficient than little power plants in gas powered cars. I think I have done the right thing, making an electric car. I will no doubt revisit this topic.

Maintenance

None yet. I have checked several of the battery cells. Still plenty of electrolyte in each cell. I have pulled on each battery cable to check for tightness. All good. I will have to periodically add distilled water to the battery cells. I plan to do that once a month, when I equalized the batteries by overcharging, as per US Battery instructions.

June 7. I checked the battery voltages today, and inspected each cell to see if any needed water. Here is the equipment I used to do battery maintenance. The plastic box came with the motorcycle battery, to add sulfuric acid, but it is handy for adding distilled water to the cells.

I recorded my findings on paper, then made a spreadsheet:

Battery Log
date:
7-Jun
temp,F:
75
charge:
full
rest:
about 1 hour
Battery
voltage
cell 1
cell 2
cell 3
cell 4
1
8.75
add
add
ok
ok
2
8.81
ok
ok
ok
ok
3
8.78
ok
add
ok
ok
4
8.77
ok
ok
ok
ok
5
8.83
add
ok
ok
ok
6
8.79
add
add
add
ok
7
8.81
ok
ok
ok
ok
8
8.8
add
ok
ok
add
9
8.77
ok
add
add
add
10
8.76
ok
add+
add
add
11
8.78
add+
add+
add+
add+
12
8.8
add
add
ok
add
13
8.77
add+
add+
add+
add+
14
8.77
ok
ok
ok
ok
15
8.79
add
add
add
ok
total
131.8

I had to add many mL of distilled water to several cells (add+), but all levels were well above the plates. The battery below needed water in each cell. Since many cells had water up to where the red plastic starts, I added water to that point.

At this point, I know that all cells have the same amount of electrolyte. My next check will show if all cells behave the same way.

A Wish List

As time allows, I would like to address the following:

* paint the car

* get higher pressure tires, possibly with low rolling resistance

* raise the rear end by an inch or two (see details below)

* replace the front brakes with "heavy duty" rotors and pads

* change the transaxle oil to lighter grade, possibly synthetic

* install some kind of heating system, at least to defrost the windshield

May 2009

Updates to follow.

August 2009

I painted the car. Click on the picture below to see details:

I drove at night for the first time on August 16. When the pack voltage was up there was no dimming of the lights on acceleration. The pack voltage was getting a bit low when I was nearing home, however, and when I accelerated in second gear, the lights dimmed noticeably. I don't consider this a problem since I shouldn't run the pack low!

I received heavy duty springs on 8/17, hope to install them soon.

August 19. New springs installed. Here is a picture of a new spring next to an old spring. Same spring dimensions, but thicker spring wire:

Installation was easy because I didn't have to remove the lower strut bolts this time:

The rear sits at the right height now, as seen in this view of the freshly painted car:

I drove 30 miles with the new springs. It's a smoother ride now: no bumping or bottoming out!

September 11. I drove in the pouring rain through big puddles. No problems: