Electric Car

I have not started constructing my EV yet. I have selected most of the hardware and will begin construction after I complete my speed controller. I expect the controller design to be the most difficult part of the process.

For additional information on electric vehicle conversions, visit the web site diyelectriccar.com



Home Contacts Links Tommy's Big Single 93 Rx7 Mike's Turbo Convertible Rx7 View More Images Electric Car Forums	The car on the right is the donor vehicle for my electric vehicle project. It's an '89 Honda Civic. It has lots of miles on it which is something that I wanted to avoid, but the price was right and this was exactly the model that I was looking for, so I decided to pick it up. The car's paint is terrible. The previous owner painted the whole car with black rattle can primer. He even shot the door jams. None of it was prepped properly though, so the paint is already flaking off. That means that removing the paint will be that much easier for me. I plan on shooting a custom paint job on this car. Something with lightning bolts would be nice. The seats and carpet inside the car are also poor. I will be upgrading the seats to later model Civic seats and I will probably buy a carpet kit. The seller claimed that the car's starter was bad. I don't know if this is true or not, and I don't really care. The motor has enough miles on it that it's not really worth much. If it is blown, I will probably part it out. If not, I'll sell it whole for a rather small sum.
			To the left is a picture of the motor that I acquired from an old electric vehicle (EV) project. I got a really good deal on this motor as it came with a huge pile (some of which is shown below) of supporting hardware for only $200. The motor is a 9" diameter three-phase unit that weighs in at about 102lbs. In its previous application, it was propelling a student-raced Escort wagon with a 32KWh battery pack. I expect that it will propel my 11 KWh '89 Honda Civic without any trouble. The label on the motor states that the motor is designed to turn at 3500 rpm, but that is at 60Hz. I should be able to run the motor at 69 Hz or 86 Hz for 4,000 rpm or 5,000 rpm respectively without any trouble.
	This AC circuit breaker is a pretty sweet score. It also came from an older EV conversion. The breaker is adjustable, so its sensitivity to magnetic field can be tuned and thus different current limits set. It is a three-phase AC breaker too which means that it actually has three circuits running through it. This way, if any one of the phases shorts to the chassis, the motor will lose power completely. This should be safer than using three individual breakers.
			The device on the left is a contactor. It has a solenoid built into it so that it can be operated remotely. This way a person does not need to route heavy gauge wires through the passenger compartment which would be very dangerous. This contactor could be used on the motor's three-phase signal, but it is currently setup to run on the DC side of the motor controller.
		The trio of IGBTs at the left are fast recovery, high current transistors. They basically act like an extremely fast switch. In this case, extremely fast means about 30 KHz. That's 30x10^3 or 30,000 cycles per second. That's fast enough that the motor doesn't notice. Also important, the human ear is incapable of hearing that frequency. In their current configuration, each IGBT will be able to switch either a positive or negative current. By doing so, each IGBT can create its own sine wave. The sine waves created by each IGBT will be 120 degrees out of phase of one another which makes a complete 3-phase AC signal.
	From what I can tell, the board on the right was used as a driver for the IGBTs. The board contains 12 MOSFET transistors, so I believe that each group of four transistors was used as a driver for a single IGBT. The heat sinks on the board look pretty handy. This type of heat sink design eliminates the need for an external heat sink. This means that the board's enclosure can be cooled via a typical computer cooling fan. Whether or not I will be able to use this driver board is debatable. Many of the components on the board require voltages that I will not be using. I may end up simply using this board as a general guide.
		The battery at right is a 12 V 17 Ah absorbed glass mat (agm) battery. I will be using 52 of these batteries in series for a total of 650 V at 17 KWh. My conversion is a 3-phase conversion, so the equivalent voltage that the motor will see is only 460 V RMS. As mentioned above, the actual energy storage capacity of the batteries is about 11 KWh. I have not started constructing my EV yet. I have selected most of the hardware and will begin construction after I complete my speed controller. I expect the controller design to be the most difficult part of the process. For additional information on electric vehicle conversions, visit the web site diyelectriccar.com