Friday, October 31, 2008

Sending Pieces off to Powder-Coat

Last night I disassembled all the battery racks and gathered the pieces in the living room to get ready for powder-coating.

Here are all the steel angle-iron and bar-stock pieces in their approximate battery rack groups (39 pieces in all). I put them in the plastic bin to the left and drove them over to Class Act Powder Coating for powder-coating. For $100 they're going to sandblast all the paint and oxidation off and coat the pieces with epoxy to prevent rust and acid damage.

While it may not seem like much, the above picture represents several months of trial-and-error design work to fit twleve group-31 batteries into the limited space of the Honda Civic. I'm looking forward to the mechanical design being finished so I can focus on the electrical design, which is much more up my alley.

Here's the rundown of pieces:

Rear Rack:
2 square tubes
2 angle irons (notches on outside)
2 angle hold-downs with notches
2 bar hold-downs

Front Rack:
2 short angle irons
2 long angle irons
2 bars
1 short wide angle iron
2 angle hold-downs
2 bar hold downs

Firewall Rack:
4 short bars (notches start at driver, clockwise)
2 side angle iron
4 horizontal angle iron
2 support angle iron
2 side hold-down bars
2 angle hold-downs
2 hold-down spacers

Motor Mount:
1 heavy short angle iron
1 end plate

Happy Halloween everyone!

Making the Battery Hold-Downs

I cut several pieces of metal for the battery hold-downs. The construction details are as follows:

All angle iron and barstock is 1/8" thick and 3/4" wide.

Front rack:
2 pieces of angle iron, 27 1/2" long with holes
2 pieces of iron bar, 7 1/16" long with holes

Trunk rack:
2 pieces of angle iron, 36" long , with notches described here
2 pieces of iron bar, 13 3/16" long with holes

Firewall rack:
2 pieces of angle iron, 27 1/2" long with holes
2 pieces of angle iron, 26" long (no holes)
2 pieces of iron bar, 14 1/16" long with holes

All items listed above "with holes" have a 11/64" hole drilled in each end, centered from side to side and 3/8" in from the end.

This description is terse as I'm trying to get the whole pile of steel out the door today for powder-coating. I'm an electrical engineer by training, so I'll be happy to get all this metalwork out of the way.

Saturday, October 25, 2008

Redesigning the Firewall Rack

After redesigning the firewall battery rack with rotated batteries, I wrote down some installation instructions. For the past two days, I've been following my own instructions to see how well they work out.

Here are the four 1" x 3/16" x 5.5" bars that will be mounted to the shock towers

With the bars mounted to the shock towers, I cut the left and right angle iron supports. I bolted the rear end through the 2 3/4" piece of 1" galvanized pipe and used a clamp to hold the front to the bars on the shock towers.

Here's a similar view of the supporting angle-iron, but on the driver-side. Note that I had to carve out a much larger notch out of the rear motor mount to accomodate the supporting angle iron. I also had to cut an angled piece off the back of the supporting angle iron to not interfere with the brake lines under the brake-fluid reservoir.

After measuring the distance between the two side pieces, I cut four horizontal pieces of angle iron, measured the proper distance between them to fit the Lifeline batteries and clamped them in place.

Same structure but on the passenger side. The rear-most horizontal bar has a curved piece cut out of it to avoid touching the brake lines. With all pieces clamped in place, I could now draw through the holes in the horizontal bars to the underlying metal to properly drill bolt holes.

After marking and the holes on the left and right supports as well as the bars mounted to the shock towers, I disassembled the structure, drilled the holes and bolted it back together. With the structure bolted together, I now added the two angle-iron pieces on the right that jut out towards you. These are just clamped in place so I can mark holes on the angle-iron pieces.

With the marked holes drilled on the rightmost angle-iron supports, I bolted the far right one on. These supports that jut out towards the front of the car will hold a platform for all the electronics.

Here's a final test to make sure the batteries fit in and I still have hood clearance. With the batteries in, I was able to close the hood easily without any interference. Yay! It took me awhile to get this solution to work.

Next up: making the hold-downs for the front and firewall battery racks.

Cutting the Battery Hold-downs for the Rear Rack

The upper edge of the LifeLine batteries has some protrusions that the battery hold downs must fit around. I'm using 3/4" angle iron to hold down the batteries in the rear trunk. To make the hold-downs work for the life-line batteries, I used the metal cutoff grinding blade to make several adjacent cuts, thereby making a much wider unified cut.

In order to notch out the 3/4" angle iron, I made one cut on the right and several vertical cuts (1/8" wide each) on the left side of the notch. I could then wiggle my sabre saw blad into the wider cut on the left and finish cutting out the notch.

Here's one of the rear hold-downs almost complete. I've used my sabre saw to cut the notches on the left and just have two left, including the unfinished one shown in the picture.

These pieces of angle iron seem fairly ridgid, so I think this scheme will work out reasonably well.

Swapping out the Front Springs

After unsuccessfully trying to use this tool to replace the springs on the front strut assemblies, I ended up going to Les Schwab Tire Center and they swapped out the springs for $30. Much less time and much less hassle than trying to do it myself.

One word of caution: Make sure to keep the correct orientation between the bottom of the strut and the bolts that go into the shock tower. After the spring comes out, the whole thing rotates easily. If you take your strut assemblies to a shop, make sure to mark the bottom of the strut relative to the orientation of the bolts on top.

Okay, back to the firewall rack...

Wednesday, October 22, 2008

Drafting the Firewall Rack

I drafted up a somewhat "exploded" model of the firewall rack. There were too many pieces to dimension everything, but I hope people get the idea of what I'm trying to accomplish.

(click on the image for a larger view)

All the Google Sketchup files for these racks can be downloaded from the Files area of the Civic-EV Google Group.

Let's hope this works...

Saturday, October 18, 2008

Drafting up the Front and Rear Racks

I spent this evening trying to use Sketchup to capture the design intent of the instructions. Click on the images below to get a larger version.

Here's the current design for the front rack just behind the radiator grille.

Here's the simpler battery rack for the rear trunk.

The firewall rack is a bit more complex; I'll try to draft that up tomorrow morning.

Good night.

Documenting the Racks

Last Saturday, my buddy Ian and I spent the day re-working the firewall battery rack. I wasn't sure on clearance to the hood with the LifeLine batteries and things just didn't seem to fit.

Ian and I re-attached the hood and put white masking tape on the underside to more easily see where the batteries would interfere. After much staring with a headlamp at the masking tape with the hood closed, Ian suggested that we rotate the firewall batteries 90 degrees. This would make them stick forward an extra half inch, but the terminals would be much more towards the rear of the car, giving much more space for the thick wiring.

I spent most of today re-engineering the firewall rack for this rotated orientation. I also spent most of the afternoon adding documentation to the Civic-EV Google Group with regards to installing the motor/transmission and constructing the battery racks. The instructions are far from finished and I still need to draw Sketchup pictures of the angle-iron, but things are moving forward.

You can see the latest documents at the following link:


Friday, October 10, 2008

Testing Clearance on the Front Battery Racks

With the motor and transmission in, I started to re-install the firewall battery rack to see if there were any clearance issues. The space between the passenger-side shock tower and the brake fluid reservoir is rather tight. There is also very little clearance between the top of the batteries and the underside of the hood. (see the dent I made in this post).

Since I need to slide all the firewall batteries as far left as possible without raising them over any bolt heads, I have to countersink the left-most bolt holes and use tapered allen-head bolts. These bolts are rather large, so I need a 3/4" wide countersink (typical 82 degrees).

Whoops! With the new motor mount in place, I have interference on the driver's side of the firewall rack. I supported the motor with a vertical 2x4, unbolted the mount and cut a reasonable notch in the angle iron to allow the firewall rack to fit again.

The rear of the firewall rack is held up by two pieces of galvanized pipe 2 3/4" long (remember this post). I purchased two long bolts with lock washers to hold the rack in. Tightening these bolts on the driver's side is rather tricky with all the brake lines and reservoir in the way. I had to use my longest socket extension to properly tighten the bolt.

Whew! With the firewall rack re-installed, I found out that the motor adapter plate interferes with it in the center, so I temporarily raised the driver-side part of the firewall rack with some spacers. I probably strained my back putting in all the 70 pound batteries, but they do seem to fit reasonably well.

While vertical clearance on the passenger side is tight, I have some extra vertical clearance on the driver side of the firewall rack, so I'll probably raise that end 3/4" to properly clear the adapter plate in the center of the rack. I also need to figure out how to better support the batteries and provide a platform for the motor controller and other electronics.

I spent some time figuring out where I could mount the vacuum pump and where the controller and charger might go. My cohort Ian Lomax is coming out on Sunday to help with the project. Perhaps we'll work on battery hold-downs or come up with a working design for the firewall rack.

Next up: taking off tomorrow to go hiking and going at it again on Sunday.

Bolting Together the Rear Motor Mount

Back in this post, I had cut a 1/4" steel plate for the rear motor mount and drilled appropriate bolt holes.

Here is that steel plate bolted to the rear of the Warp9 motor.

I'm planning on using a piece of 2" angle iron (1/4" thick) to attach the rear plate with the driver-side Civic engine mount. In order to get the angle-iron to fit, I had to hacksaw part of the driver-side engine mount flat to accommodate the angle-iron.

This is rather ad-hoc, but it worked rather well. With the motor jacked into place and held up by a vertical 2x4, I used small clamps to hold the 1/4" thick angle iron in place (5" long and 2" wide). With this setup held in place, I used a scratching awl to mark circles in the angle iron that matched the holes on the engine mount and the vertical plate.

I then unclamped the angle iron and drilled the holes that I had marked with the scratching awl. The holes for the motor mount are 1/2" in diameter and the holes for the vertical mounting plate are 25/64" (1/64" greater than 3/8"). Note that the rightmost 1/2" hole in the above picture is very close to the right-angle in the angle-iron, so you'll have to put the 1/2" bolt in the hole before mounting the angle iron to the vertical plate, otherwise, there isn't enough clearance to slide the 1/2" bolt in later.

With the holes drilled, I used 1/2" bolts and 3/8" bolts to clamp the whole thing together. The clearances are kind of weird for the horizontal 3/8" bolts. To get enought threads into the nylock nuts on the backside but not hit the chassis support, I had to add some washers to the rightmost bolt. The leftmost bolt had to be shorter. I'll try to get lengths on these later as part of the directions.

The vertical 1/2" bolts have regular nuts in the middle as spacers and nylock nuts on the top to hold things together.

Cutting the Tail Shaft

Back in this post, I discovered that the tail shaft on the Warp9 motor was interfering with the driver-side chassis. I had to decide whether to cut the tail shaft or cut the car chassis. Since I don't have welding skills and I prefer not to weaken the chassis, I decided to cut off the tail shaft of the motor.

Here's my cut line on the tail shaft of the Warp9. I'm leaving half an inch so I can attach an RPM sensor later.

I taped up the bearing to prevent metal shavings from getting in.

Agh! It's done! I've forever negated the ability to drive anything from the Warp9 tail shaft. After raising the motor back into the car, there are no more clearance issues.