Fixing up the Rear Suspension

Whew! I finally got my internet connection back up at home. This is the first of ten entries that will attempt to show many of the tasks I performed over the four-day Thanksgiving weekend.

First up, we need to beef up the rear suspension to handle the extra 420 pounds of batteries in the trunk. As you may remember, I swapped out the front springs with beefier ones. Since the old front springs were much stronger than the existing rear ones and had the proper taper to them, I opted to take the same route as Rob Connelly and cut them to handle the appropriate rear load.

Rob used six Optima Yellow Top group-31 batteries in his trunk. Since I'm using Concorde Lifeline batteries which are 9 pounds heavier each, I needed to support 54 additional pounds on the rear suspension.

Using Rob's spreadsheet, I was able to calculate the proper spring length from the old front springs that would handle the load. Many thanks to Rob C. for explaining spring physics to me and providing the spreadsheet. You can see a discussion and the spreadsheet in the Google discussion at this link.

After modifying the spreadsheet, I realized that I needed to cut the old front springs to 13.3" long.


Here is one of the old front springs in my cutoff wheel saw. There were quite a bit of sparks, but the wheel did an excellent job of making a nice flat top to the spring coil. Since the cutting process is very hot, I added an extra 1/10" to the cut length just in case the heat softened the top of the spring.


Here are both springs cut off to 13.4" length (13.3" plus the .1" for heat sag).
After cutting the springs, I removed the two rear shock strut assemblies and took them to Les Schwab to swap out the springs with the cut ones above. Several months ago, I had purchased a spring compressor to do this myself, but found it really scary given all the pressure. I found that just having the guys at Les Schwab do it with the proper equipment was $30 well spent.


Here is the spring assembly on the ground with the newly cut spring inserted.

Note: when you replace the springs, make sure you mark the orientation of the shock tower mounting bolts (left end of the assembly in the picture above) and the swing arm mounting bolts. Shock assemblies rotate and if you get the top and bottom bolts back with a different alignment, it's really hard with the spring under tension to rotate the top into the proper orientation.


Here's the spring mounted in position. Follow the instructions in the Helm shop manual to properly remove and install these. You need to raise the rear support with a floor jack to put the car's weight on the spring before tightening all the bolts, otherwise it doesn't sit right.


Since I had all the wheels off, I felt it was a good idea to check the front brake pad thickness. This is a close-up of the passenger side front wheel hub. I still have 9mm of brake pad left, which ought to be plenty for awhile. I will have to watch this since the extra 840 pounds of batteries will put an extra load on the brakes.

Movies of the First Test Run

Well, my home internet connection is still down, so I uploaded a few videos here for your viewing pleasure and to prove that I'm not just blowing smoke :)

Thanks to my friend Rick for capturing these on my small camera. These are unedited and Rick tended to rotate the camera a bit. I'll probably make something more refined later...


Here is a quick tour of the major components under the hood.


Here is the Civic backing out of my driveway and taking off. It's nice and peppy!


Here is the Civic coming back down the block with some comments about its abilities. The loud buzzing is the vacuum pump for the braking system (hmm, rather loud).

I should be posting several pictures of my work over the next few days.

Cheers,
Tim

It's Alive! Updates coming...

Okay, the cat is out of the bag. I've been working many hours a day over this four-day weekend to try and get the Civic running. As luck would have it, my internet connection went down Thursday morning and is still not back up (I'm typing this from work). I'll post all the progress and pictures when my connection comes back.

Suffice it to say, I'm exhausted, but the wheels are spinning as of 12:15pm yesterday(Saturday). I still have some charger connections to finish, but things look good at this point. If I'm lucky, I'll take it for a spin around the block this afternoon.

Cheers,
Tim

Arranging the Electronics

The next step was to figure out where to put all the control electronics under the front hood to minimize wiring.


The Belktronix system comes with velcro attached to the underside of most of its components. I was able to fit the Integrator and Charge Controller in the passenger-side nook, next to the main charging unit. I attached the IsoBatMon circuit to the top of the closest AGM battery (right side of photo) to minimize cable runs.

Also, notice that I kept the thick wire that came from the alternator (thick white wire in lower-left of photo). I plan to re-use this to take current from the DC-DC converter (hmm... just like the alternator...)



Several of the fast-on connections on the Belktronix components are really tight (like the double blade connectors). After feeling uneasy about forcing the existing crimp connectors into these tight holes, I took the advice of another Civic EV converter (Bob Kaiser) and replaced the plastic enclosed crimp connectors (on the left) with bare ones (on the right).


To keep all conductive surfaces unexposed, I added heat-shrink tubing to the bare crimp connectors (sorry for the blurry picture). These slid right into the double blade receptacles without any undue force.

Next up: more wiring!

Buying Heavy Battery Cable

I spent last night visualizing how I could most effectively connect all the traction batteries with the least amount of welding cable and the shortest distance to the controller and motor.

This morning I took some thick rope to serve as a fake battery cable and used it to measure the long cable lengths needed to connect the front and rear batteries. Measuring this is important because welding cable is expensive and you need to get enough but not too much. Here are the measurements I came up with:


Rear battery rack:

• battery 1 to 2: 6"
• battery 2 to 3: 12"
• battery 3 to 4: 6"
• battery 4 to 5: 12"
• battery 5 to side battery: 14"
• battery 5 underneath car, through the circuit breaker to the contactor: 16 1/2 feet

Front batteries:

• front battery 1 to 2: 6"
• front battery 2 to firewall battery 1: 34"
• firewall battery 2 to 3: 6"
• firewall battery 3 to 4: 6"
• firewall battery 4 underneath car to rear battery 1: 13 1/2 feet

Controller connections

• controller to motor: 19"
• controller to front battery 1: 14"
• controller to contactor: 8"
• contactor to motor: 15"

All in all, I calculated about 44 feet of welding cable. I already have 13 feet, so I purchased 33 more feet to have a little extra. For those in the Portland, OR area, I highly recommend United Welding Supply up on MLK for 2/0 cable. The price is based on the commodity price of copper and was $2.90 a foot today. This compares to $4.75/ft from Electro Automotive, $6.00/ft at Parkrose Hardware and $8.85/ft at evparts.com.

I also dropped by Napa Auto parts to pick up all the fuse holders required for the BatMon battery monitors. I'm thinking this is going to end up like wiring spaghetti, but we'll see.

Have a great weekend, everyone.
Tim

Hacking the Final Hold-downs

I installed the remaining hold-downs for the 12V auxiliary battery and the extra battery in the rear trunk this evening. I hadn't designed these hold-downs before I sent all the pieces off to powder-coat, so I'll have to paint them with POR-15 protectant before I finish.


Here's a picture of the 12V aux battery hold-down. The battery is a smaller motorcycle battery. The bar across the top is held down by a 3" piece of 5/16" all-thread with 1 5/16" spacing between the bar and the hold-down for the traction battery next to it. It turns out this is five nuts and a 1/16" thick washer.


Looking the other direction, the other end of the hold-down bar is simply held down with a piece of 5/16" all-thread going down to a hole we drilled in the last post (see third picture down in the last post).


This is a view underneath the passenger side of the car looking up at the 12V aux battery (which looks scratched up alrady). The nylock nut in the center right caps off the 5/16" all-thread above and holds it in place.


Here's where the extra battery in the trunk sits on the passenger side. I cut a 15" long piece of 1" wide steel bar (1/8" thick) and drilled a 5/16" hole in each end 1/2" from the end. I laid this piece down where the battery sits and marked through the 5/16" holes. The rear-most hole sits right on top of rear-most structural bulge. The front hole sits just in front of the forward-most bulge.


After marking the holes, I drilled them with a 11/32" bit so the holes would be a bit larger to allow a bit of inaccurate drilling.


Here are two pieces of 11 3/4" long 5/16" all-thread. I used regular nuts with washers on the top side.


Here is the underside of the car with the two pieces of all-thread through the holes in the 1" bar we laid out earlier and capped off with nylock nuts.


With the all-thread in, I added a piece of 3/4" angle iron with 11/32" holes drilled in it through the angle-iron corner at each end. It's held down with a washer and wing-nut. Drilling the holes in the corner of the angle-iron was rather tricky; I had to use four progressively larger drills to get the final hole size without the drill corner binding on the inside faces of the angle-iron.

I think I'm finally done with the vast majority of the mechanical design. I'm tired of designing mechanical things and just want to wire this puppy together. Let's see what we can do tomorrow.

Charger, Controller and Contactor Mounting

Today involved trying to mount the major electrical components to the car.


Before covering up the transmission, I thought it would be a good idea to fill it with transmission fluid. The Honda Civic specifies 10w-30 oil for the transmission. Since the fill hole is really hard to access, I used a funnel attached to a plastic hose to get the oil in.


Before mounting the plastic panel to mount the EV components on, I drilled two 3/16" holes, 6 3/4" apart on the passenger side battery support. This will be used to mount the large 3-ohm resistor used by the charging system.


I still haven't figured out the hold-downs for the cars 12V auxiliary battery or the extra battery in the rear trunk. Since access will be more difficult after I install the EV components, I drilled a 5/16" hole (top center in picture) in the passenger side front battery support iron. I think I can use 5/16" all-thread with some angle iron to get this hold-down working.


Okay, on to mounting the control board plastic. As we stated before, this plastic is 1/2" thick, 28" long and 8 1/2" wide. I clamped it in place with a plastic clamp to prevent marring the surface. I placed the main contactor near the right edge, approximately centered front-to-back.
With the the plastic and contactor in place, I scratched circles in the plastic for the two 3/16" contactor mounting holes and underneath the plastic in all the 1/4" mounting holes from the angle-iron that juts out.

Afterwards, I removed the plastic, and drilled out all the holes (3/16" for the contactor, 1/4" for the board mounts). I used a countersink bit to taper the bottom of the contactor holes so the bolt-heads would be flush with the bottom side of the plastic. I also countersunk the top-side of all the 1/4" holes so that the main mounting bolt heads would be flush with the top-side of the plastic. By making all these bolt heads flush, I don't interfere with any components or support angle-iron.



Here's the plastic installed on the angle-iron supports and the contactor in place. I used six 1/4" flathead bolts 1" long for the main supports and two 10-24 x 1" long flat-head bolts to mount the contactor. All bolts were held in place with nylock nuts.

With the plastic mounted, I placed the charging unit and controller unit on the plastic. The front edge of each component was 3/4" from the front edge of the plastic. The charger was on the passenger side and its heat-sink fins aligned with the inside vertical wall of the passenger-side angle-iron support. The controller unit sat between the charger and the contactor with 1/4" of clearance between the heatsinks. With the two units in place, I dropped a 1/4" bolt down through the mounting holes and marked the plastic.

After removing the units, I drilled out the 1/4" holes. The hole closest to the passenger seat had to go through the plastic and the metal support. After drilling these holes, I bolted the components to the plastic using 1/4"-20 x 4" long bolts with washers and nylock nuts underneath. The rear bolt on the motor controller was very close to the transmission housing, so I added some spacer washers to raise up the bolt a bit to prevent interference.


Whoops! I accidentally mounted the contactor with the activation terminals on the high-voltage side, so I had to disassemble the whole thing, flip the contactor around, and re-install it (shown correctly here).


Here's the final installation with the two main EV components and the contactor on the right.


The last item of the day involved installing the large 3-ohm (90 watt!) power resistor on the passenger side angle-iron support. This simply used two 10-24 round-head bolts 1" long and nylock nuts. I thought it would be easier to wire with the terminals up, so we'll see.

Next up: mounting all the small EV control boxes