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!


Underside...


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. :-)

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!

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!

Battery Update

The batteries I ordered back in April have cleared customs! They should be shipped out of Oregon this week and arrive at my door shortly thereafter!

What's left:
Battery box.
Battery wiring.
Battery charger.
Controller heat sink.

I think my box is second from the left.

DC-DC Converter

I finally got around to wiring up the DC-DC converter. It's actually for 120V to 12V because I originally planned to have a 120V nominal Lead battery pack. I'm now only at 96V nominal with the Lithium cells, but I think there is enough overlap in the operating ranges of the batteries and the converter so I should be okay.

Two sets of wires from the converter. Red / black for input. Green / blue for output.


I wired the input to include my fuse and circuit breaker on the positive side so it will have a bit more protection. On the negative side, it is wired after the key contactor; so the 12V battery will not start charging until the ignition is turned on. I was debating on whether or not to have it connected at all times or just when the car is running. I finally convinced myself that I didn't want 96V constantly running through any of my circuitry (especially when I'm not there) if it wasn't necessary. (The length of the wire from the converter not being long enough to bypass both contactors may have influenced the decision.)


Here's a shot of the DC-DC output going to the primary positive and negative connections on the car.


Last I heard my batteries had arrived at port and were going through customs.

Stereo Sound

Back on February 16th I installed one speaker into the car. This past weekend I went ahead and built a mount to install a second.


The old mount worked great, so I cut a second one just like it.


The car had a flimsy piece of cardboard "covering" up the wires behind the dashboard. It looked terrible and was in my way so I ended up trashing it. I'll install something better to replace it later.


The new speaker installed!


Stereo sound is good stuff.

Seats and Horn

Our Australian Shepherd dog is not a pet, he's our child (as you could probably tell in the earlier photos). My wife bought new seat covers for the car to style up the interior a little bit.

The seats weren't too difficult to take out - just 4 fairly easy bolts.


Timber helped me put the new seat covers on.


One side complete. This also was a good opportunity to vacuum out the interior.


Finished!


The old horn sounded about as good as a frog near his last croak. I picked up one of those novelty aooga horns from the auto parts store to replace my old one. I actually received a new horn for Christmas that has a variety of sounds you can play (and record your own), but it turns out it can't be wired into the car's existing switch. I'm hoping to take the car to shows though so I'll definitely plug it in for temporary use then.


I removed the two old horns but left the bracket for my new one.


Nice!


The horn works great, but I'm a little disappointed in its "aooga". I was hoping to hear something a bit more ridiculous, but it's okay.

On a side note, my cordless drill battery charger was no longer charging its batteries. The spring style connectors wouldn't maintain contact with the battery terminals, and it refused to charge. Replacement used chargers on e-bay are like $30, new ones are impossible to find, and its constructed such that it's impossible to open up and repair. I do think companies purposely design their products to have a short shelf life. I however, refuse to buy an entire new drill set just because the charger is finiky.

So, wa-la, it's fixed!


One small victory for the consumer!