Sunday, August 30, 2009

Battery Box Pt. 1

I found a local metal supplier and drove by to pick up a couple steel plates...

And then while I was there I asked if they could cut them...

And then I asked if they had a couple angle strips...

And then I asked them advice on my design...

And then they basically built the entire thing for me while I waited!


The smaller battery box for the trunk...

Sure looks good in the car!

I 'would' have pictures of me drilling the mounting holes for the battery box, but alas my drill was out of power (see my battle with the charger on post July 2, 2009).

On a side note, the larger box was a bit too tight so I had to dremel down the corners to get the batteries to fit. When the battery finally squeezed (rather quickly) into place it did so with my toe in the way. Luckily it only ripped off a chunk of skin instead of a chunk of toe. I'll refrain from posting any bloody pictures though. :-)

Monday, August 10, 2009

Batteries Arrived!

It's Christmas in August! My batteries have arrived!

My plan to fit them all under the hood isn't going to work. If I had just 1 more inch I think all 30 cells would fit, but as you can see in the picture, just 20 cells fill up the space quite well. I'll throw the remaining 10 in the trunk.

On the bright side the split pack will help distribute the weight, down side is I have to run cables down the length of the car.

Picture of the car without batteries...

With batteries, the dog, and me in the car (Timber left his toy by the camera)...

I measured the sizes of my mounting plates for the batteries and the cable lengths. I'll order those soon so I can get these batteries mounted permanently!

Sunday, August 9, 2009

Heat Sink Pt. 1

Electric vehicle controllers produce a lot of heat, and their performance is greatly affected by how hot they become. The Electrocraft controller is mounted to a thick U-shaped piece of Aluminum to help distribute the heat, but it didn't have any fins or fans to help air flow pull the heat away.

From reviewing other converters build pages, it seemed most of them added additional cooling to their controllers (regardless of the manufacturer). The top of my controller is really just a thin aluminum cover to keep the internals protected from the elements. It's not used by the controller to distribute heat, so there isn't much purpose in cooling it. Ideally I would have mounted the controller upside down so I could mount the heat sink / fans on top, but hind sight is 20/20 and I can't change my copper connectors.

The long sides of the controller are part of the U-shaped aluminum plate the controller's electronics are mounted to, so it is beneficial to pull the heat from those. I picked up a couple CPU heat sinks/fans and removed their stock mounting hardware. I then fabricated metal end tabs and cut an aluminum rod to length.

After applying a thick layer of thermal paste, I mounted the heat sinks against the controller and screwed the tabs into place. Not perfect, but it seems to hold pretty well. I'll come back another day and hook the fans to the car's 12V system. I'm feeling a lot better about my controller's cooling with this relatively minor addition.

Batteries are scheduled to arrive tomorrow afternoon via FedEx!