Sunday, July 27, 2008

Playing with Sketchup

I spent the evening playing with Google Sketchup, a free 3D "CAD-lite" program. It has a $450 professional edition as well, but I did not get that - just the free version. To learn it, I designed my rear battery rack. The whole thing will be made out of 1 1/2" angle iron, 3/16" thick. Here is the top view, with the top dimensions:

Here is the bottom view:

Here is from the right side:

Here is an iso view:

Here is a perspective iso render, with texture and shadows:

And here is a render with the 9 batteries installed:

Sketchup seems more than adequate for simple drawings like this. I would not design anything more major than these components with it, though.

One other detail - although this set of drawings shows just the rack, the entire box will be enclosed (since it fills a hole to be cut into the cargo area). I plan on using relatively thin steel and welding it to the outside of the rack. Proably 20 gauge or so.

Saturday, July 26, 2008

Motor Installed!

After a week of vacation, time to get back at it. Today, the task was to install the motor for real. The first step is to install the flywheel. The instructions call for 1.415" +/- 0.01" - with the modified hub / bushing, it was very straightforward to get the flywheel there:

A trick I figured out to make installing things easier was to push the bushing in as far as possible (with the flywheel installed and without using excessive force), and measure that distance. In this case, it was 1.275". This means that the hub has to come out 0.140" from its maximum "in" distance. That distance was 0.750", which means that the hub has to be 0.890" +/-1 0.01" - here is that distance shown:

It is *much* easier to measure this distance as you tighten the taperlock hub than it is to do as suggested in the "VoltsPorsche 914" manual - in that case, it suggests you tighten it *almost* all the way (so it is difficult to slide back and forth) and then adjust, remove the flywheel, and tighten for real. With the volt914, I kept moving the hub when I removed or reattached the flywheel. I like this "measure the bushing distance" method much more - I only had to remove / reattach the flywheel *once*.

With the flywheel mounted (and the bolts torqued to 50 foot pounds plus 60 degrees), time for the pilot bushing. A piece of cake, using a socket as a drift:

Here it is, installed:

Next, the clutch. You insert a pilot tool to keep the clutch properly centered when you install the pressure plate (side note - this is the last picture ever to be taken with my trusty garage digicam - it got dropped in an oil bucked right after this picture was taken):

Here is the pressure plate installed (the bolts are torqued to 23 foot pounds as per manufacturer's specs). You can also see one of the two brass bushings I bought to replace the transmission locator pins, which I cannot seem to remove from the original gas engine no matter how I try:

As part of the clutch kit, I also got a new throwout bearing. Here it is, on the throwout lever plate:

And here is the plate / bearing installed in the transmission, with the driveshaft greased up and ready to mate with the motor:

While the motor was out for this procedure, I took the opportunity to fix the interference problem with the motor mount:

Finally, with everything in place, I removed the lifting eye. This was trickier than expected. Basically, you are supposed to "tap it with a hammer" and it will slide out - this concept is well illustrated by the picture here:

However, there were complications. Either when it was installed, or during all the hoisting I've done over the past few months, a large burr developed on the heatsink fins. So, I had to take my angle grinder to them and widen the groove somewhat. And then I had to use my Big Friendly Hammer (a 6 pound sledge) with full-force "taps". The lifting eye was pretty banged up by all this, but I got it off:

Just for grins, with the lifting eye removed, I dropped my 3x1 battery box on top for a test fit:

Whew! Now, to weld the battery racks and boxes...

Saturday, July 12, 2008

Final Battery Layout?

With the motor in its final location, it's time to look at battery placement for real. After cutting the carpet from the cargo area, it became obvious where the limits would be (you can see the spot welds of the frame rails to the floor pan). It also became obvious that my original 3x3 layout will not fit in the area allocated, so it's time for an asymmetrical layout that matches the available space. In addition, looking more closely under the rear seat, it is clear that only two batteries will fit here. Four batteries are not possible without cutting the frame rail, which is an incredibly bad idea.

So, here is a test fit with actual batteries in the rear. The five batteries near the seat back are in their final position - a box will be built to contain them. The three batteries behind those five will join six others sunk into the floor of the cargo area. A box will be built to contain them as well:

In the front, the motor mounting provides a challenge for laying the batteries out as I had originally planned. Instead, I'll go with three groups of three, with the last battery replacing the large starter battery (a smaller aux battery will go on the driver's side, along with the DC-DC converter). Here is a test fit of the three groups of three - the box in the lower right corner is the same volume as three of my batteries.

Due to space constraints, there will not be a box completely enclosing the front batteries. Instead, there will just be racks supporting it, along with a plastic top / hold-down for each group of three (and the solo battery) to prevent the batteries from flying around and to prevent fingers from accidentally brushing up against 312-volt power.

The good news is, even with two-by-fours and 3/4 inch plywood in the way, the trunk still closes with the batteries in the above position, so I think that this design will work:

So, here is the new component layout. The controller still goes in the front, above a group of three batteries. Two more groups of three are in the front, along with a solo replacing the large starting battery. Two batteries are under the rear seat, and fourteen are in the rear cargo area (9 of which will be sunk below the floor level):

Business travel and vacation will interrupt progress for a couple of weeks; when I return, it will be time to start fabricating racks and boxes!

Motor Mount Fabrication

This week I fabricated the motor mount. I stuck fairly close to my original design, but tweaked it as I went along. It all started with 1 1/2 inch steel straps and angle stock - here is the first set, clamped and waiting to be welded (you can see where I wire-wheeled off the primer to make a clean weld):

This was my first attempt at flux-core welding (my previous welding experience was mig welding) so it is a little rough, but the penetration is good, and it is plenty strong:

I cut one side of the angle stock for the bend in the hanger - this leaves an unbroken strap all the way around. Here is the hanger cut, bent, and clamped in preparation for welding:

And here it is, all assembled. I decided not to add the forks from the original design - it would have made it so it did not rotate, and I think a slight rotation will be necessary.

After drilling the holes for attaching the motor, the next step is priming (here you can see the notch I had to cut in the hanger due to interference from the original Jeep motor mount):

Finally, it gets a coat of enamel. With all that done, here it is installed (on the left you can see how the notch fits against the mount):

And here is the motor, resting all happy in its new home:

That lifting eye has been handy so far, but the time is coming when it is just going to be in the way. Azure Dynamics' website says it is removable, but darned if I can figure out how. I'll send them email and see what they say.

Finally, after test placing 480 pounds of batteries in the front, I went under the Jeep to check lower interference. Unfortunately, there is some, with the front axle "pumpkin" (higlighted in red here):

When I remove the motor to do the final flywheel/clutch assembly, I'll take out the mount and grind a new radius on that corner, as outlined in green, to remove the interference.

Electro Automotive Delivers

Back in May, Electro Automotive shipped me the profile plate, motor ring, splined bushing, and taperlock hub. Unfortunately, the splined bushing was too long and prevented the flywheel from being properly placed. In this photo, you can see how far out the hub stuck with the too-long bushing:

EA said, "send it back and we'll fix it" so I did, but before I sent it back, I took some measurements. The bushing was 1.75" long, as shown here:

When inserted into the hub, the bushing stuck out about 1/8 inch:

I sent them the hub and bushing a few weeks ago, and it showed up this week, all better! Here you can see that the new bushing is 1.375" long (a full 3/8 inch shorter):

When inserted into the hub, it now is about 1/8 inch below the top of the hub:

Here is a test fit of the bushing and hub - you can see that the hub is much farther back inside the profile plate. This should be plenty of room to adjust the flywheel distance.

I have to say, I have been very happy with Electro Automotive's responsiveness here. They have changed their operations to try to do a better job at order fulfillment, and it shows. Thanks, EA!

Friday, July 11, 2008

Cam-Lok High Voltage Connectors

In this posting, intergalactic mentioned the following valuable advice:

Don't use Anderson connectors. The SB50 and SB350 styles don't seal and if wet will short out and burn up. The connectors used for long welding cables or outdoor power supplies with the tapered rubber boots work well. Cam-Lok, I think.

After some googling, I found an online retailer ( who carried Cam-Lock style connectors which would work with 4/0 welding cable. These are rated for 400A at 600VDC, so should work well for the 312V Jeep. They are waterproof, interlocking, and very large.

On the left are the components for the female connector; on the right, the male:

This picture shows how the components interconnect:

And this picture shows the female connector with the cam component inserted:

I got enough of the connectors to isolate each major battery group so that I can work on lower voltages than 312V. I found 144V to be dangerous enough; I don't want to work directly on higher voltages if it can be avoided. Which it can by making each battery pack independently connect into the series with these Cam-Lok connectors.

Saturday, July 5, 2008

Motor Mounting Design

The past couple of days have been spent getting the motor into its exact final position so I can design the mount. First step was to attach the motor to the tranny (using an adapter from Electro Automotive) - this is just a temporary attachment, since I don't have the clutch / flywheel / hub mounted yet. The center of gravity is just under the transmission bell housing, which makes a convenient place to put a transmission jack (out of the way of the rear mounting holes):

With the motor in place and the Jeep resting on its wheels, the interference I was worried about earlier is very obvious. The corner of the motor mounting "foot" just touches the steering / suspension system:

Here's another view from below. This, obviously, will not do. When the car is moving, this will be rubbing and grinding and banging against the motor, damaging or destroying both the motor and the suspension:

So, when the going gets tough, the tough get their angle grinder out. I marked the corner that I wanted to remove:

I then attacked it with a cutoff wheel on my angle grinder. This is an aluminum foot, so it cut like butter and did not get very warm at all (the corner that was removed, on the other hand, was hot as all getout - less thermal mass):

Finally, before designing the motor mount, I needed to make sure that the electric motor is mounted very close to where the gas motor went. I put threaded rods through the gas motor's mounting points and measured where that lined up against the bell housing mounting points:

I then hoisted the motor until it matched that offset. It's not 100% critical to be exactly aligned, but the closer to aligned, the better it will be for the U-joints and CV joints of the drive shafts.

I was originally just using the motor mounting points as convenient reference points for placing the motor. However, looking at it, it really is an ideal place to hang the motor from (since that is where the gas motor hung from). I've outlined the two motor mounting points with their integral rubber bushings in red here:

After taking lots and lots of measurements, here is what I designed. You can find a PDF file of all of it here.

Next step: prototyping the motor mount with cardboard and then cutting and welding the actual mount!