Tuesday, February 24, 2009

Just plug it in

Somehow the electricity has to get from the outlet into the battery pack. This is accomplished with a charger/transformer that takes 110V AC from an electric outlet and converts it to DC current.



Most conversions try to use the old fuel door as the place for the hookup to the charger. Since that appears to be the general consensus I decided to do the same. And frankly it looks really cool this way :-)

Just plumbing

Now wait a minute. Plumbing? In an electric car? Let me explain...

Although electric motors are more efficient at energy conversion than gasoline engines they are not 100% efficient. Some of the energy is lost as heat within the controller.

The Zilla controller I am using is capable of drawing more than 300amps at 144+ volts. That's over 43,000 watts (think of lighting 4300 light bulbs at once). Now the controller is more efficient than a light bulb in terms of heat loss...but you get the point.

In order to keep the controller from overheating the Zilla is equipped with a liquid cooled heat sink. Coolant is constantly circulating through the controller to capture this heat. The coolant then flows through a small (book size) radiator to discard the heat before being pumped back through the Zilla.

Here is a picture of the pump (bronze, round thing at the bottom). The valve at the top is for adding coolant to the loop and purging air. You can see the green antifreeze in the tubing.


Here is the radiator.

Sunday, February 15, 2009

Just accoutrements

Battery accoutrements like cables, battery boxes, and fans. Where to start....

OK. Let's start with the box. After finishing the box I caulked all the joints and painted it with an epoxy paint to protect the box from acidic fumes.

During the charging process hydrogen gas is produced by the batteries. This gas needs to be vented out of the box. Most conversions use a small fan to vent the gas.

Here is a picture of the fan. The fan is connected to a relay that is activated when the old fuel door (the future charger plug in port) is open.

At one end of the box I have connected tubing that draws fresh air from outside the car. The inlet is the white tubing in the picture below. The end of the tubing you can't see runs to the battery box.


Here's a picture of the outlet tubing. The outlet is directly behind the fan. The top picture is where it vents from the box and the bottom picture where it vents out of the vehicle.




This is an overall picture of the box. Along the left you can see the white inlet vent tubing. The bottom right corner is where the fan is located. The wires in the box connect to the auxiliary 12volt car battery. The holes in the box are for wires and air to pass between the compartments of the box.


Next step was to make cables to connect all of the batteries together. Here is the layout for the batteries in the rear.


The final layout of the batteries had several goals to meet. The most obvious is that the batteries had to fit in the box. Goal number two was to minimize the lengths of the cables connecting the batteries.

A third an not so obvious goal is to minimize the voltage potential between neighboring batteries. For instance you don't want battery one next to battery seventeen. This would represent a 102V (6 x 17) potential. If you accidentally dropped a wrench across the neighboring terminals that would be one huge short. Although one and seventeen appear next to each other there is a divider between the last three batteries and the remainder of the batteries.

With the layout in hand I laid out the batteries on the garage floor. Then I started to make cables to connect the batteries.

First step in making the connecting cables was taking 2/0 welding cable and laying it in a path from the negative terminal of one battery to the positive terminal of the next battery. Because of vent caps and carrying brackets on the top of each battery this path was usually not a straight line.

After cutting the cable to length each end was stripped of insulation. A protective cover was slipped over the cable. Nolox was coated over the bare wire. A connector was then slipped over the wire. Since positive and negative terminals are different sizes it was important to make sure that I was not putting two positive or negative connectors on the same wire. The connector was then oriented to face the correct direction and secured to the cable with two crimps.

Here is the final result. Don't worry...they are all labeled for which batteries the connect.


Last but not least I put a few batteries in the box.

Just pedaling

Pedaling...the process of installing a pedal :-)

In a typical car you press on the gas pedal to go. The pedal is connected to the computer controlling the engine. The computer then controls the fuel injection, air flow, and combustion.

Since I no longer have a gas engine I don't need a gas pedal. Now I need an "electricity pedal".

The Zilla controls the "flow" of electricity to the electric motor. There is an input on the Zilla for connecting to an accelerator pedal. One option for connecting to the pedal is to use the original pedal, hook up a cable to the pedal, and have the pedal control a variable resistor (potentiometer). A second option is to use an electronic accelerator pedal. The movement of the pedal is directly translated to an electrical signal that is sent to the controller.

I chose to go with option two. The advantages include longer reliability and simpler connections to the Zilla (no mechanical cable to hook up). The disadvantage is that a new mounting bracket needs to be fabricated for the pedal.

This is a picture of the new pedal installed.


On closer inspection you can see the new mounting bracket. Not pretty, but functional. The bracket is attached to the old mounting points of the old pedal.

Friday, February 6, 2009

Just the instrument cluster...a.k.a. the dash

Well the instrument cluster is finished (as I say crossing my fingers in hope). The last picture I posted of the instrument cluster showed lots of wires coming from the back. After tidying up the wires I found some nice connector harnesses to tie everything together.




After connecting the harness to power I reinstalled the cluster. So far everything that is hooked up seems to power up. This includes left and right turn signal, high beam indicator, speedometer, tachometer, and a couple indicator lights.



There is one more gauge in the picture above that you can't see. It draws its power from the high voltage pack so I can't test it yet. Next step....start testing the high voltage components.

Sunday, February 1, 2009

Just batteries


The title says it all. Next step...just battery cables...lots of them.