Friday, January 30, 2009

My First Week of Commuting

This has definitely been an interesting week. With the front suspension coil-overs installed, I felt much more confident in driving the car around without bottoming out. The link-10 is pretty good at measuring state-of-charge with Peukert compensation, so I felt good about knowing how much juice I had left.

I commuted to work three days this week (Monday, Tuesday and Thursday). It's 17 miles one-way with charging at work. I lose about 40% of my battery charge (DOD) in one direction which is what I was hoping for. Warmer weather might make this even better.

Things seemed to go fine on Monday. I left the charger on float-mode to make sure I didn't cook the batteries.

Tuesday was interesting. I woke up and found that the 1 amp fuse had blown on the 7watt DC-DC converter for the link-10. I replaced the fuse and the system worked again. Must be a glitch. I had some errands to run after work and the link-10 showed that I had 55% battery remaining when I started the errands, so I thought I was okay.

Around 48% remaining, the LVP protection on the Belktronix system kicked in and the car slowed to a crawl of 15-20 mph. I did what many EVers do: I pulled over, waited 15 minutes and then drove the remaining mile home. After waiting the 15 minutes, the car felt a bit better, but after 1/2 mile, it slowed to a crawl again, so I put on my hazard lights and got home. Trying to signal to change lanes with your hazards on is interesting.

I let the battery sit for 1/2 hour and measured the standing voltage on all the batteries. All showed 50% charge remaining except for one (tied to the IsoBatMon) showing %45 remaining. I'm guessing this one battery tripped the LVP (low-voltage-protection) signal and slowed the car down. To more quickly balance the pack, I put a 12V charger on the low battery at 30A for 25 minutes and then charged the car. I didn't want to get stuck like this again, so I installed an override switch for the LVP circuit going to the main controller.

Here's the override switch (top center). It's attached between the IsoBatMon unit and the motor controller. This enables me to see the LVP indicator on the dash if I need to put the system into override mode. Hopefully, I'll only have to use this for limping home.

Tuesday evening, I also started swapping out the rear suspension and found the chewed up strut (see previous post), so Wednesday, I commuted with the 914 EV and went out to purchase the new strut. Wednesday evening I finished the installation and made sure the Civic was charged for the Thursday commute after going for a run ride with my friend Andrew.

Thursday morning, I noticed that the 1A fuse for the Link-10 DC-DC was blown again. I replaced with a 2A fuse. I also noticed that the car was filled with a burning smell. I didn't figure out what this was until I was on my commute to work. It was the smell of overheated resistors, specifically the bypass shunt resistors for the batteries.

After arriving at work, I plugged in, knowing that the charger was in float mode and went to work. I drove home without a problem, did some errands (and opportunity charged with an extension cord to prevent the LVP "crawling along" problem) and went home.

This morning (Friday), I noticed the burning smell again and did some closer inspection under the hood. It turns out that the charge detector malfuntioned again (perhaps by the 30A battery charger?) and I've been dumping 8 amps of current into the batteries, even when full (argh!). All the bypass resistors had become discolored from over-heating.

I'm taking the Civic to the line-up shop this morning to fix the right-side CV joint (i.e. replace the axle) and do an alignment. I'll ponder what to do next at the shop...


Rear Coil-Overs

To finish up the suspension, I installed the rear coil-overs. The procedure is much the same as the front coil-overs.

When the guys at Les Schwab swapped out the rear springs for the cut-down front ones awhile back (see this post), it looks like they chewed up the shock end pretty bad. I had to go to Auto-Adventure and buy a used shock. The whole assembly was only $30 and they have tons of used Honda and Subaru parts.

After following a similar procedure to the front coil-overs, the rear ones were in. For the rear height adjustment, I left six threads *above* the top edge of the gold ring instead of six threads below. The car is still sitting about 1/2" high, so I'll probably lower it a bit later.

Next up: reports for the first week of commuting.

Sunday, January 25, 2009

Installing the Front Coil-Over Suspension

Here's the process I used to remove the existing Civic springs and install the front coil-overs.

The first step is to jack up the front of the car and put it on jack-stands for stability.

Since I don't have a spring compressor, I'm going to use the entire car as my spring compressor instead. I rolled a floor jack under the swing arm and raised it until the car just came off the jack stand.

I then used an allen-socket wrench and a 14mm box wrench to loosen and remove the nut at the top of the shock strut. The allen-socket wrench prevents the strut from spinning while I loosen the lock nut.

This is the top of the strut with the nut and underlying washer removed.

I can now slooooowly lower the floor jack to release the tension in the spring. Even with all the tension released, there's still a bit of the strut top sticking out, as shown here.

Now to remove the bottom of the strut. The first step is to remove the two bolts holding on the brake line. After pushing the brake line aside, I put the bolts back in the nuts to prevent losing them.

Here I'm using a ratcheted socket wrench to loosen the top of the suspension fork.

I also had to completely remove the bolt at the bottom of the suspension fork. Once the nut is off this bolt, you might have to "finesse" it out with a hammer. I had to use a smaller bolt and hammer to slowly push it out. Sometimes you can just twist it with a socket wrench and the threads on the end of the bolt will force it out.

Okay, I removed the strut assembly and, in the process, released the coil spring pressure without a spring compressor.

If you remove the spring and slide off the strut cover, you can see the bump-stop (orange) attached to the strut.

The coil-over instructions say to remove the bottom half of the bump-stop. This seems to be made of a light rubber, so I was able to cut off the bottom half with a sharp utility knife.

The instructions also say to remove all but the top 1 1/2 inches of the strut cover. Here is the strut cover with the top 1 1/2" inches cut off. I used a file to remove the sharp edges.

After washing all the mud off the suspension parts, I'm now ready to put things together. The kit comes with a rubber sleeve to protect the inside of the coil-over thread cylinders.

With the rubber sleeve on, I now can slide on the coil-over threads.

Next is to slide on the custom spring that should handle the extra 400 pounds from the batteries. While this picture doesn't show it, it's best to rotate the gold ring so that there are 5-6 threads showing to the left of it before moving on. The assembly in this picture is at its lowest setting and needs to be raised to give a good ride height.

Next comes the large black "top hat" and the original washer that was above the strut cover.

Next comes the rubber flexible mount that sat on top of the washer. This picture should have the large black "top hat" in it, but doesn't (I had to try this a few times).

Now comes the upper spring perch that bolts to the chassis.

And finally the perch washer and lock-nut. If you rotated the gold ring to expose six threads, you'll have to press down somewhat hard on this perch to get the lock nut on. Ideally, you'd be able to adjust the assembly later, but it's easier to put the spring under slight compression now with the proper height dialed in.

Here's the finished assembly. As I mentioned before, you should really have about six threads showing to the left of the gold ring so that you can start with a good ride height. This picture was one of my first tries before learning about the proper height setting.

Install the assembly back in the car, following the directions in the Helms manual. Don't forget to put a floor jack under the swing arm and put the whole assembly at its normal height before tightening the suspension fork bolts. This will prevent the rubber fittings in the suspension from getting torn when you put the wheels back on the ground.

The above diagrams show the driver side. Repeat for the passenger side.

After I finished this and made sure there were six threads exposed below the gold ring, the front of the car sat at its original ride height of 24.5" from the ground to the fender. With this height, the car seems much less likely to bottom out when hitting speed bumps. There's plenty of adjustment room on the coil-overs to lower my ride in the future, if I so desire.

Have a great weekend,

Frustrations with Springs

Okay, I admit it. I'm an obsessed control freak. That said, let's move on...

The drooping front suspension on the Civic is really getting me down (no pun intended) and I'm getting anxious with the coil-over kit sitting in my living room. So, I spent an hour and a half watching you-tube videos last night to see if I could install the coil-overs myself.

My biggest frustration is that I can't find a spring compressor that will work with the springs on the Civic. The space between the coils is just too small to fit a standard spring compressor in.

Remember this beast from several months ago? The hooks are too thick to fit between the coils, so it's been sitting in my garage.

I even ran out to Sears and spent $54 on a smaller pair of compressors. These are still too thick, so I returned them for a (fortunately) full refund.

In the end, I'm going to take a calculated risk and end up possibly damaging a bunch of stuff. Sounds like fun, huh? In short, I'm going to remove the springs and install the coil-overs without a spring compressor.

Here goes...

Saturday, January 24, 2009

Over-Rev Protection, MTF and Labelling

Today involved a bunch of miscellaneous items.

Bryan at Belktronix sent me a little circuit that plugs into the back of the tachometer that triggers the LVP protection and shuts down the controller when the shift light goes on. I basically routed a two-conductor cable through the grommet next to the throttle cable (where the cruise control cable would go) and connected the system.

This picture is crummy because it's difficult to see active LEDs when the flash goes off. I had to wedge the camera between the headrest and the seat to hold it steady enough for a flash-free photo. In short, you can see the bright red LED on the tachometer on, which is also activating the LVP circuit and turning on the battery idiot light on the dashboard (just above the "H" on the steering wheel).

After driving around a bit, I realized that I never really got over 4000 RPM, so I set the shift point at 4000 RPM, put the car in neutral and slowly pressed the accelerator. Surprise, surprise, the shift indicator came on at 4000 RPM, the LVP circuit went active and the controller shut down, preventing an over-rev condition. I pushed the circuit a bit more by pressing down a bit harder on the accelerator from zero RPM and it jumped up to about 4800 RPM before shutting down.

If you choose to implement this circuit in your own vehicle, make sure you set the brightness on the tach for the LED for its brightest setting. You'll have to set this brightness with the headlights on AND off since the tachometer saves two different brightness settings. If you choose a lower brightness, the LEDs gets pulsed and the controller won't fully shut off.

Thanks to Bryan for providing this circuit. I guess I have to fork over some $$$ to him now :)

As part of tying up loose ends, I also drove about 15 1/2 miles round trip to the Honda dealer to pick up two quarts of special manual transmission fluid (MTF). Honda recommends 10W-30 motor oil (which is in there now) or this MTF, which is much thinner. Since I have an electric vehicle, I'd like to remove as much friction as possible in the transmission.

This is the first drive that I took with the Link-10 E-meter hooked up. I appreciated the amp readings and the percentage of battery left over. It took me down to 45% depth-of-discharge to go 15 1/2 miles, so I'm guessing the full range of the car is really 30 miles or so. This will be fine for my 17 mile commute to work, one-way.

Since I'll probaby be showing off this car at a few electric vehicle shows, I wanted to label all the major components to help people understand what the parts are. I still have to mount all the BatMon boards inside plastic boxes, but I have to figure out a heatsink strategy first.

I feel much better now that the tach, over-rev, and link-10 E-meter are installed. This will give me more confidence is knowing how far I can go and how hard I can push the motor before shifting.


Friday, January 23, 2009

Suspension Toys

Since I've been having difficulty finding springs that actually fit the car and handle the extra battery weight, I broke down and called Ground Control to see what they had to offer. They were very responsive and their technician recommended a coil-over set with custom springs for the project.

Delivery was remarkably fast. I ordered these Tuesday and they arrived today. The two thicker springs on the left are for the rear and the two on the right are for the front suspension. Ground Control offered to replace the springs for free if they didn't allow for a proper ride adjustment and I didn't drive on them.

Here are the installation diagrams that came with the kit.

Just so others can see the spring numbers they sent me, here's a copy of the invoice. A full suspension set for $350 isn't too bad, although it just eeks over my $10,000 goal for parts cost.

I'll be calling around to see who can install this set. My friendly local EV group ( suggested a place about ten blocks down the street. They open again on Monday, so we'll see how it goes.

I still have to paint three metal pieces with POR-15 to prevent them from rusting, but the temperatures around here are still in the 30s (yes, I know that's balmy for some of you). POR-15 doesn't really stick until it gets above 50 and I don't want to use that stuff inside where I might get woozy from the fumes.

Finishing the Guages, Link-10

I worked all day to get the tach sensor fixed and the link-1o installed.

Here's my solution to fixing the tach sensor. I'm using a stainless steel bolt to hold it in (which is just barely magnetic). I'm also using a salvaged plastic gear as a non-magnetic spacer to put the spinning magnet disk inside the sensor housing.

At first the gear was too thick and the head of the bolt rubbed against the inside of the sensor housing. After filing the gear down to 1/4 inch, it seems to work well, even under acceleration.

In hooking up the system, I cheated a bit and pulled the positive 144V tap needed for the Belktronix system off of the other side of the main circuit breaker. This saved a bit of wiring, but (as always) ended up biting me when I wired up the Link-10. This is a picture of the Airpax circuit breaker under the car. The 144V tap is coming from the rear battery pack is on the left post. I added a 16 gauge wire to this post and ran it into the engine compartment to attach to the Belktronix system and the link-10 connections. This allows the breaker to blow and also let me disable the system without losing power to the link-10.

Here's installing the 500 amp shunt for the link-1o meter. I have just a little space left on the driver side chassis. Just above the shunt are two silver-looking indentations aligned vertically. Those are the marks I made with a 3/16" drill through the mounting holes in the shunt. I used those to drill some holes and insert two 8-32 threaded rivnuts.

Here's the shunt mounted into place with the 8-32 bolts in the installed rivnuts.

When I had the car running before this, I simply had a negative battery cable from the Belktronix controller running directly to the negative terminal on the battery. With the shunt, I now break this path and use two cables, with the shunt in between. While your mileage may vary, I cut welding cable 9 1/2" long for the battery post to the shunt and 13 1/2" long from the shunt to the controller negative terminal.

Just under the 2/0 cable bolted to the shunt, you'll see a piece of four-twisted-pair cat5 cable. The link-10 requires a twisted pair of wires from the shunt to the display to reduce noise. Since there are only three other connections going to the display besides the one twisted pair, I decided to combine the other three twisted pairs into single wires to carry more current. The combined brown pair goes to link-10 pin 1 (negative terminal). The green twisted pair takes the differential signal from the shunt (link-10 pins 2,3). The blue combined blue pair goes to link-10 pin 4 (high voltage prescaler output) and the orange combined pair goes to pin 5 (7watt DC-DC output).

Here's everything wired up. The shunt is wired and I found some space for the Belktronix DC-DC and Link-10 prescaler beside the engine mount. Note the filler cap for the washer fluid. I'll have to be careful filling this since the washer fluid is somewhat conductive.

Yay, the link-10 works and tach above it as well. After reading the manual and setting some parameters, it seems to work fine. I used the following for my system:

  • charging end voltage: 172V
  • Peukert Constant: 1.11
  • amp-hour capacity: 100

I still have to configure the tach shift light to stop the motor from over-revving. I'll get to that tomorrow.

Tuesday, January 20, 2009

Debugging the Tachometer Signal

I spent this evening, trying to figure out why the tachometer was flat-lining under acceleration. After talking with some EMI suppression engineers at work, they suggested covering the sensor with a steel shield to prevent magnetic fields from interacting with the sensor.

So, I headed out to the grocery store and got a nice steel can of organic tomato soup. After dinner, I washed out the can and cut the bottom two inches off with some tin-snips. After covering the sensor with this and revving up the motor, I still had the same problem. Rats!

The next experiment was to purchase a piece of 24 gauge steel plate from Parkrose Hardware and cover the face of the motor behind the sensor to see if I could prevent magnetic fields from interfering. I drilled a 1" hole to fit over the spinning magnetic disk and drilled two holes to match the mounting holes.

Result: After installing this under the plastic spacer ring, the tachometer failed to work at all. Rats again!

However, this did provide a clue to what was going on. The steel plate (along with some wiggle room) added about 1/16" spacing to the sensor. After taking some more measurements, I found that the spinning disk was only just inside the bottom edge of the Zolox sensor.

As a third experiment, I added 1/4" of spacer washers under the spinning magnetic disk to push it deeper inside the sensor housing. This actually worked fine, at least for mild acceleration. The spacer was loosely added, so I'll make something more permanent tomorrow after I get some decent spacer hardware.

In short, make sure the spinning magnetic disk is deep inside the Zolox sensor housing to make it work.

Good Night,

Sunday, January 18, 2009

Making a Charging Timer

I wanted to make a timer so that I could charge the car for a specific amount of time to prevent over-charging the AGM batteries with the Belktronix charger. The only timer I could easily find that would charge for several hours was a wall-socket mount like the one shown above. I found a weatherproof box with weatherproof cover and mounted the timer in the box. There were also special cord protectors that screwed into the holes in the box. I simply cut a 25 foot 14-gauge extension cord in the middle and wired in this contraption to limit the time on my charges.

Mounting the Link-10 E-meter

I decided to start mounting the Link-10 Battery Monitor (E-meter) this weekend. As many of you know the Link-10 is very deep and doesn't fit too well in typical pillar pod holes.

To solve this problem, I purchased a piece of 2" (inside-diameter) ABS plastic tube from Home Depot for $3. This is very common stuff and should be in the plumbing tube section.

I basically cut a 1 1/2" piece of this tubing and filed the end to make it smooth and flat. I then used black industrial plastic adhesive to glue it to the pillar pod hole as shown here.

After the adhesive dried, I was able to slide the link-10 in quite easily and use a tie-wrap to hold it in place. I have to rewire some of the engine compartment and add the shunt before I can wire this up.

Saturday, January 17, 2009

Real World Driving Tests

I had a chance to take the Civic out for about 25 miles yesterday (two charges) and see how it handles in traffic and on the freeway. Here are some first impressions.

The potbox, being directly under the accelerator pedal, is very sensitive, especially at slow speeds. Since the Warp9 is rather powerful, trying slow moves in reverse gear are tricky. This can be problematic for parallel parking where a sudden lurch might send you into another car. There's a positive feedback loop where if you press just a little too hard while in reverse, the car lurches backward, which makes your body/leg move towards the front of the car and press the accelerator even more, causing an even bigger lurch. Be careful in lower gears!

Given the power the Warp9 and sensitivity of the potbox, starting in second gear seems to be just fine, even on hills. Even starting in third gear works well if you don't need jackrabbit starts at stoplights. Higher gears take the jolt out of moving the car so you get much smoother, albeit a bit slower acceleration. I plan on using third in stop-and-go traffic due to its smoothness.

If I didn't pay attention, very light acceleration in second gear gave me oscillations in car movement. This again was caused by negative feedback between my body/leg mass and the accleration of the motor. If I'm not careful in second gear, light acceleration will cause the car to lurch forward, pulling my body/leg towards the back of the car, releasing the pressure on the acclerator and slowing the car down. This slowing returns my body/leg to a neutral position where I'm accelerating again and... well, you get the point. This is only my first major day driving so I'm sure I'll get trained to the dynamics of the car.

As with many DC motor powered cars, accelerating from zero to 30 mph is great and getting up to 60mph is a bit slower. I can get on the freeway no problem, but it does take a few extra seconds over the original stock Civic. With the Belktronix system, the batteries tend to sag to their low-cutoff point of 10.8V under heavy acceleration. I'm tempted to add an "emergency power" momentary-push button that disconnects the LVP protection to the controller in case I need an extra boost (Think "Turbo" button in Knight Rider) to save my ass when I don't care about drooping down the batteries lower than 10.8V. I'm guessing that Bryan at Belktronix is cringing at this statement, but, hey, they're my batteries and can kill them if I want to.

I'm very thankful that I chose to keep the clutch for this implementation. Shifting is a breeze, both up and down without any delays whatsoever. It just feels so much like a regular ICE car but without the noise and pollution.

Overall, I've been pretty happy and nothing has blown up yet, so we'll see how things go as I break in the batteries and start commuting.


Wednesday, January 14, 2009

Tachometer Problems and Insurance

As with any project, things rarely go as you hope they do. The Zolox speed sensor, which has been used in countless EVs is flat-lining (i.e. being pulled down) whenever I accelerate, which gives me a tach RPM of (drum roll....) zero. The Zolox sensor works using a magnetic sensor that detects four small magnets in a spinning disk. It turns out that having a 9" DC motor that puts out large magnetic fields interferes with this (go figure).

After getting some advice from Bryan at Belktronix and some EMI suppression engineers from work, I plan to add some steel shielding around the Zolox sensor to break up the magnetic flux lines that may be interfering with the sensor. Stay tuned...

Since this vehicle is now road-worthy, I thought it might be a good idea to get it fully insured before I take too many long drives. Getting insurance for an EV conversion is somewhat tricky. There's a local insurance agent who promotes electric vehicles but was rather embarrassed when her underwriter refused to insure my vehicle because I wanted to use it as a daily driver. Apparently having an EV conversion that's just a weekend fun vehicle isn't a problem. I ended up going with Progressive auto insurance and was able to get what I wanted.

Installing the Tachometer

Happy Belated New Year everyone! Things have been quiet on the blog recently as I've been taking a break for awhile.

Last week, I installed the tachometer in its pillar pod.

Here is the pillar pod next to the driver's side A-pillar that I pulled off. I originally marked a line (see left end) where the two-gauge pillar pod should rest. I marked where I could drill two holes to route wires through. The circle with the X through it would have been ideal for the tachometer, but... can see the hole would have interfered with the metal clip on the bottom of the A-pillar, so I moved it an inch higher.

The instructions call for drilling four 3/16" holes in both the pillar pod and A-pillar to install bolts through. I clamped the two together (without the tach installed) so that it wouldn't shift around.

Here are the two parts ready to install with the 1" holes drilled for the wiring.

The tachometer has six wires coming out of it. Two of them attach to the ground and +12V for the face lighting. To save wiring and utilize the existing wire harness, I simply spliced the face lighting wires into the ground and pointer-light wires from the main connector. To keep things a bit cleaner, I zip-tied the whole thing together.

Okay, now for the hard part. The tach wiring harness simply four dangling wires attached to a connector. I placed electrical tape every 9" along the harness to make a single thick snake. I then taped the ends together and fished it down where the bottom of the A-pillar was to underneath the dashboard.

I received a special circuit from Bryan at Belktronix that plugs into the shift-light output on the tach. In order to thread this back up to where the A-pillar is, I taped it to the cable that I threaded downward and then pulled everything through to fish it upward.

Here is the tach wiring harness with white connector and the 1/8" stereo plug that I fished up towards the base of the A-pillar.

Here are those same two cables, now plugged into the back of the tachometer, which is installed in the two-guage pillar pod.

With the tachometer/shift-light wires routed underneath the dash, I now had to get the Zolox speed sensor signals from the engine compartment to underneath the dash too. Here you can see the Zolox speed sensor wire (finger touching it at left edge of picture) going through the rubber harness grommet. I just punched a small hole with an icepick and fished it in.

Here's my wiring scheme to connect the tach to the Zolox sensor and the car wiring.

  • Red from the tach goes to the keyswitched +12V and the red wire that powers the Zolox
  • White from the tach goes to the headlight switched terminal in the car to power the tach pointer and face lighting
  • Black from the tach goes to the car ground and the black ground out to the Zolox sensor
  • Yellow from the tach goes to the white signal line from the Zolox which also ties to a 2.2K pullup resistor through to the +12V red wire above
If you enlarge the picture, you can see the small 2.2K resistor between the red and white wires just to the right of the fast-on connectors.

Since my Civic didn't have any options installed, getting access to the keyswitched +12V and headlight switch power was fairly easy. There are some fast-on terminals on the fuse block just above the fuses. The second from the right (white wire) gets +12V when the headlights are on. The third from the right gets +12V when you turn on the keyswitch (but goes off when you turn the key to "start").

With things installed, I revved the motor and measured the pulses coming from the Zolox (4 pulses per revolution) with an oscilloscope. The picture is bad because I couldn't use the flash on my digital camera and the camera sampled multiple times. I verified that I had programmed the tachometer correctly because I was able to get 6000 pulses per minute and have the tach register 1500 RPM.