Hacked Serial Cable Details and Bad Relay

A few people asked me about how I hacked together a serial port since AC kit people will need this in order to configure the controller correctly.


I basically took three 16 gauge wires (smaller would be fine) and soldered on crimp sockets at the end of each one. I also added heatshrink tubing so that adjacent signals wouldn't short out. The picture above shows the three wires plugged into the top three pins on the 8-pin connector on the controller. Yellow is Txd(controller to PC), blue is Rxd (PC to controller) and brown is ground.


Here's a view of the heat-shrunk ends with the sockets crimped and soldered on.


To connect to the PC, I got a female DB9 connector with solder cups. The solder cups were designed to handle 20 or 22 gauge wire, so I had to trim down the 16 gauge wire to fit into the cups. Txd to the PC goes on pin 2, Rxd goes on pin 3 and ground goes on pin 5. All connections were soldered to solder cups in the top row.

From there, I just used a long male-female 9-pin serial cable to connect to the male DB9 on the back of the PC. Again, if you use HyperTerm, the settings are 19200baud,N,8,1, no handshake.


Remember the flakey relay I found yesterday. Here it is, removed from the car. One set of contacts was highly resistive. I replaced this relay with the charger interlock relay from the front relay mounting board to get the car working. Afterwards, I pried off the clear plastic cover (off to the left in the picture) and used an extremely thin file to break through any corrosion on the bad contacts. The contacts on the common swing arm were actually slightly bent so only a tiny corner of the common contact touched the normally-open contact when the relay activated.

I'll keep this relay around as a spare since I replaced the front charger interlock relay with a normally-closed SPST relay from the auto parts store.

The car seems to start much more reliably now.

Next up: getting more performance and acceleration..... maybe.

Power calculations

After looking at the specs on the ElectroAuto website, I'm thinking that a maximum input power rating of 50000 watts is really too much. Here are the ElectroAuto specs:

AC24 Aircooled Motor

Length	Diameter	Weight	Controller	Efficiency
15.55"	9.45"	83.6 lbs.	DMOC445	83%

Specifications @ 156 V Input
	Ft.Lbs.	Amps	RPM	HP	KW
Peak/Maximum	54.57	280 rms	12,000	57.66 @ 4,500 rpm	43
Continuous	22.12	180 rms	12,000	18.77	14

55 Ft-Lbs peak is 75 Newton-meters. The controller is programmed for 100 Newton-Meters.
I'm guessing I should probably back off the peak wattage to 43,000 as listed in the chart unless I want to severely harm the life of the motor.

The original Porsche 914 2.0L engine had about 90 peak HP so this is definitely less. It looksl like I'll have to shift more often to balance the motor torque with my desired speed. The regenerative braking makes shifting really hard, so I'll probably have to utilize the regen-disable switch more often.

I also think I figured out what the high-pitched squeal/scraping noise was. The controller puts out a 10Khz PWM signal to modulate the three AC waveforms. I hear this squeal during acceleration and regeneration, but if I let the motor spin freely by putting the accelerator in the middle, there's no squealing. The squealing never changes frequency either. I didn't expect the motor to be that noisy... Live and learn.

The last big issue I probably have with the car is that the flywheel is probably out of balance. When the motor hits about 4500 rpm, the whole car starts vibrating rather nastily. This means I'll probably have to take the transmission off again and have the flywheel balanced, or re-turned by someone before general use. Urg.

I sure hope people don't have to put up with my mistakes on their own 914 AC conversions!

Good night.

Debugging, Debugging, Debugging...

Okay, things don't seem to be working too well. We have three issues:

1. The controller simply cuts out at high acceleration (bad)

2. Many times the controller doesn't even start up at all

3. There's very little power from the system, I can't go much above 30mph

After sending error logs to Azure Dynamics, they came back with the following:

"Vehicles with improper or substandard grounding and shielding sometimes exhibit nuisance errors flagged as EE3LastError = 16. Once every measure for improving the grounding and shielding has been taken, it is OK to disable this error if the problem persists. This can be achieved by setting EE2DisableChargedError = 1."

It's very true that I forgot to add the grounding strap to the DMOC controller that ElectroAuto provided. So I added the strap with anti-corrosion compound and made sure to scrape the metal clean on the bottom side of the bolt on the chassis to make a good contact.

Here's the grounding strap provided by ElectroAuto bolted in. Unfortunately, this didn't help much with the problem. I found that turning down IdsMax from 400 amps to 380 amps did help the problem. Also turning down the MaxAccelTorque from 100Nm to 85nM helped too.
Given that the car has not a lot of power to start with, I set the EE2DisableChargedError to 1 to get past the issue with all the original settings.


Okay, next up is the problem with things just not starting at all. I logged more variables and saw that the ISR2CarDirection status register was zero when the car failed to start and 1 when the car worked. This pointed to the "Forward" signal on pin 29 of the DMOC controller not getting properly grounded.

I double checked the connections on the neutral-start relay in the engine compartment and everything looked fine. I even looked at the contacts to make sure they were in the right place. It turns out when I wiggled the wires on pins 6 and 9 ("ground" and "forward"), the CarDirection bit randomly toggled between zero and one.

To debug further, I took two other wires with crimps and measured the resistance between the two contacts on the relay. The resistance was often infinite or around 5-10 ohms. This really caught me off guard since I put a lot of faith in relays, especially Potter and Brumsfeld's. I'm probably going to take the relay out tomorrow and see if I can open it up to see if something is damaged. I would have suspected my own wiring, but not the relay... (sigh).

I have to show off the car tomorrow to a bunch of friends and I can tap the neutral start relay now to get things running.


That leaves the problem of not having a lot of power. I could get up to about 30mph on residential streets in 2nd gear, but not much past that. I'm guessing I'll have to shift up and take the torque hit.

The power thing was really confusing to me because the current measurements as listed in the controller ccShell diagnostic tool said 400 amps. I wasn't seeing a huge voltage drop, so I didn't believe the controller, at least from a DC-current point of view. Sooooooo, I ran out to my favorite overpriced EV hardware store: WestMarine. They had a 150 amp shunt-based ammeter there for $90 (ouch).


This is the 150 amp ammeter shunt. It's in the place of the most-positive battery terminal in the fuel compartment. The shunt is remarkably small compared to the pictures I've seen of the ElectroAuto shunt. Also, placing it in the fuel compartment makes it much closer to the dashboard, so there will be less signal loss over the shorter wires to the dash.


Here's the ammeter dial itself (the camera flash whites out the background). It seemed to work quite well. At full acceleration, it pegs at 80 amps almost all the time. This is a lot less than the 400 that the ccShell window states. I suspect that the 400 amps is some internal calculated number of instantaneous current going through the stator instead of an actually measured value.

After messing around with several parameters, the only ones that affected the current draw were the EE?MinPowerAccel, EE?NormPowerAccel and EE?MaxPowerAccel. Since I haven't hooked up the dashboard switches and dials, the controller was operating in maximum power mode, so tweaking EE?MaxPowerAccel would limit the current to 40amps or raise it up to 95. I took a chance and bumped up the MaxPower from 31000 to 50000. I'll have to double check the power spec of the AC24 motor before using this too much.

Okay, enough for today. The kit requires the 12V accessory battery to run the exhaust fans while the car charges overnight, so I altered the circuit to use an external 12V laptop supply instead so I wouldn't drain the accessory battery.


Here's my temporary charging setup. The Zivan charger is in low-current mode (12 amps) and I have the 12V laptop supply also plugged in to run the exhaust fans.

Tomorrow: taking a break
Wednesday: dissecting the neutral-start relay and figure out why it doesn't work.
(I can replace it with the front charger interlock relay in the short term...)

Hoods Installed

Well, we're getting closer. My friend Rick and his friend Amy came over today to help install the front and rear lids. I was rather relieved when both lids closed without any interference. I installed the engine compartment cover this morning and realized that the rain gutter would have to be completely removed to not interfere with the rear battery box. With the rain gutter gone, perhaps it wasn't such a good idea to keep the two drain funnels and tubes in place...




I did a few more laps around the block this morning and played around with the parameters in the AC controller via the serial port. When I have the serial port plugged in, the controller fires up and things seem to work. If I power down and remove the serial port, nothing comes on. I'm trying to debug this further. Hopefully Azure Dynamics can get back to me by Monday to see if I've adjusted anything wrong.

I find that if I back off the maximum torque (EE?MaxAccelTorque), I can get get the car running without stalling, but I give up some power. I can also limit the stalls if I back off on the IsMax parameter from 400 amps to 380 amps. For some reason I find it very difficult to imagine that I'm pulling 400 amps from the batteries. The voltage doesn't seem to dip that low and I don't get much acceleration. I would think the car would have more pep pulling 400 amps.

With the serial port yanked, I had to push the car back into the garage for more analysis. This is all part of the learning process and I look forward to learning more...

Pictures from Randy

One of my fellow 914 AC kit EV'ers is Randy Pollock. He's been extremely helpful in my understanding of how this kit works. About three weeks ago, he sent me a few pictures on his own 914 AC EV project that uses the Electro Automotive kit. Here are his pictures and text (verbatim) from his e-mail: (Thanks Randy!)
---------------------------------------------------------------------------------
Hi all,

Attached are some pictures from my rear trunk now that I have the
Avcon receptacle wired to the Manzanita Micro charger. The junction
box next to the receptacle has two green idicator lights. If only
one is light, then 110V is present - 220V lights both. I have both
the Avcon charging station with will put out 220V and an extra cable
that I've added a 110V plug to the other end. So far I've only
tested the 110V cable and it starts up the charger as expected.


There is also a close up of the cooling fan I added. The small
component to the [left] (not completely wired yet) is a 105F on/90 F
off thermostat switch. When the trunk starts getting hot from either
the charger or the AC motor controller, the fan will kick on. It is
a very powerful side exhaust fan that should be able to turn the air
in the rear trunk over ever 30 seconds. It kicked up some dust under
the car when I tried it out. Note that the thermostat is mounted on
nylon screws so that it is sensing the air temperature, not the sheet
metal temperature.



The last picture shows the four 2" holes I cut behind my PORSCHE
reflector on the back of the car. You can't see anything from
outside, but since the reflector stands almost 1/2" off the sheet
metal, you can get reasonable air flow.


I do need to cut the mouse hole for the Avcon cable. It will be cut
out of the trunk lid. I have a spoiler that provides enough material
to make it work.

Just thought you would like to see.

- Randy

Closing the Boxes and Fixing the Suspension

I took a few minutes (just a few) to go out with friends to celebrate.


Here's my girlfriend Krista enjoying a very brief ride to the bottom of the driveway. The front tires still bottom out when I turn the wheels too hard, so I'm holding off major test drives.


Here are my friends (Krista, Ruth and Rick) just before we went walking to get some gelato on this fine day.


Okay, back to work after a good night's sleep. My first concern was the front of the car bottoming out. Fortunately one of the steps in the manual is to adjust the front torsion bars.
The Haynes manual covers this reasonably well.

The center of the torsion bars were supposed to be about 8.5 inches off the ground. Initially they were 5. No wonder I'm having issues.

Turning the torsion adjustment bolt was far too difficult with all the weight on the tires, so I jacked up each side of the front of the car and tightened both bolts until the center of the torsion bar was about 8 inches above the ground (after letting the front end back down).


Here's a closeup of the torsion adjustment nut. Its the nut on the very bottom that turns the vertical bolt that you can see the threads on. This picture was taken tooking toward the front of the car from just behind the front-right tire.


Next step was to finish the battery box covers. Here are the covers and hold-down bars in place for the front two battery boxes. For the rear bar on the front battery box (under the charger tray), the holes for the bolts line up exactly with the vertical walls of the cups on the bottom side of the cover (at least for the bar I was given). I had to re-drill these holes about an inch further out to the side to not interfere with the internal hold-down ups.

The hold-down cups on the bottom of the middle battery box interfered with the tabs on the speed-caps for the batteries. I took my cable cutters to one of the two tabs on each speed cap to fix this issue.


For the rear box, the lid was too big to fit between the passenger wall and the rear luggage wall, so I had to use vise grips to bend the rear luggage wall back about 1/8" so the lid would drop in.
I also had to knock off one of the hold-down cups on the bottom side of the lid because it interfered with the fusible link that I modified to fit around the speed-caps. With the other hold-down cups in place and the copper bars holding the batteries together, I didn't feel that this would be a huge safety issue.

The black wire going up over the roof of the car is the serial cable going to my laptop in the passenger seat.

After a few more test drives around the block, I've noticed that the controller tends to cut out suddenly under a heavy torque load. I can get the controller to die just by putting the car in reverse and flooring the pedal to leave the garage, so I don't think this is a reasonable limit. I'll be researching all the parameters again to see if there are some "unreasonable" limits I can increase without harming the system.

Next Up: Putting all the lids back on!

First Driving Test!

Well, I carefully fixed the black grounding wire to the motor encoders and the system seems to work fine now. I got the AC motor to rev up quite quickly in neutral. Both forward and reverse movements are fairly smooth.

For yucks, I drove the car around the block. It has very slow acceleration, probably due to all the battery weight. I drove it in second gear. Third gear seems to not want to go in, at least while the car is stopped. The regen braking seems to work fine. The front end is rather heavy with batteries and the tires scrape something in the wheel wells when I back out of the driveway down the small cement slope on the curb.

There is much to do, but I at least know it runs and that I'm probably not going to race it at Nedra...

Off to celebrate with a brownie and a very much needed nap. Yay!

Aha! A Broken Wire!

I collected a bunch of controller data over the serial port on my laptop and sent that off to Azure Dynamics for analysis. After looking at the data, the ISR2Hertz variable (i.e. RPM) was pegged at zero. This led me to believe that there was something wrong with the motor encoders.

I opened up the motor speed monitor box and probed around. All the encoder signals were up at 4.9 volts and the black ground wire was also up around 4.83 volts. After examining things some more, I found a broken wire on the AMP connector going into the controller.


Here is the black broken ground wire. I'm not great at fixing these things, but I'll definitely give it a shot. Worst case, I can get one of the technicians back at HP to help me fix it.

I let Azure Dynamics know so they don't spend too much time on the analysis.

Next Up: Try, try again...

Wow, This is Really Fast! NOT!

Just a quick update. I removed the jack-stands, cleaned out the garage and fired up the 914EV. It responds properly to the accelerator, but at full throttle, the car goes about six inches a second both forward and reverse. Looks like I've got more DMOC parameters to adjust. Fun, Fun.

Things still to do:
- Fix the right window
- Install the 12V transformer for the charger interlock and fans
- Add the battery box covers
- Put all hoods and lids back on the car
- Add the gauges and control switches to the dashboard

Onward!

9:12am July 27, 2007 - It's Alive!

This morning, I hacked together a serial cable to talk with the ccShell program provided by Azure Dynamics to communicate with the controller. You need to contact Azure Dynamics directly to get the .ccs file that works with ccShell; it's not available on their FTP site.


Here's the hacked up serial cable attached to the laptop. After setting up Hyperterm for 19,200 baud N,8,1,no handshake, I was able to turn the keyswitch and get a boot screen and binary data dumping out the serial port.


Here's a closeup screenshot of the "Edit" window in ccShell. While I haven't tried out many features, it looks like the tool is quite powerful and able to monitor and log a vast array of variables in the controller. The variables listed in the documentation don't quite match up to the variables shown in ccShell, but I could infer their meaning.

Okay, why the heck isn't my motor turning...

After looking at the wires attached to the controller, it seems that DMOC pin 30 isn't hooked up at all. Hmm, that's the drive enable signal! Why wouldn't we hook that up? It turns out that you can override this digital input by setting the EEXNoIgnSwitch variable in ccShell to "1". I had to do a reset on the controller after downloading the value to the controller's EEPROM.

Okay, after setting EEXNoIgnSwitch to 1, I lightly pressed on the accelerator and heard noises coming from the transmission! Yay, the motor spins! The car is up on jack-stands, so I put it in reverse (backup lights come on, good) and press the accelerator again. What??!!, the wheels turn in the FORWARD direction. Rats. Okay, back to the documentation. There's another variable named EE2ShaftDirection which allows the user to reverse the direction of the motor. After setting this variable, the wheels turn in the right direction! Yay! If you click on the ccShell screen above, you can see the EE2ShaftDirection variable set to -1.

One vaguely unsetting noise is that when the motor turns, I hear periodic light scraping sounds. I suspect that the flywheel might be rubbing against something. I really don't want to take apart the transmission again! I'm debating right now if I can let this slide for a bit (turn the radio up louder?). I'm excited but concerned that something might blow up at this point...

Next up: removing the jack stands and securing the battery box covers...

ADDENDUM (July 28th): In addition to setting the ShaftDirection variable to -1, you'll also have to set the EncoderDirection variable (some name like that) to -1, otherwise the motor will report negative ISR2Hertz values (bad!)

Close, but no Cigar...

I didnt' get a chance to do much tonight, but I did hook up the final fusible links in the battery system. Before hooking up the links, I jacked up the rear of the car and put in on jackstands just in case something started happening with the motor. I also put the transmission in neutral.


Here's the front fusible link in place. No sparks yet!


Here's the rear fusible link. Initially this failed the "spark" test. I touched the link to the two battery terminals and got a medium sized spark. I vaguely remembered getting a similar spark when plugging in the Zivan charger to the bank of batteries on the floor. Sooooo, I unplugged the Zivan charger from the system and tried touching the fusible link again. Voila! No spark!


Here is the voltage measured at the AC controller. Looks like we have about 8.4 volts per battery. Good.

Of course the next step was to get out the fire extinguisher and turn the key on. Guess what? Nothing happened. It looks like the controller is getting 12 volts, but there must be something holding back the controller from spinning the motor. Darn safety interlocks!

It's late so tomorrow I'll be running off to buy parts to build a serial port connector to the AC controller. My laptop is over three years old, so I ordered a new battery last week and it showed up today.

Hopefully, firing up the AC controller serial console will help me find out what's holding the controller back from turning the motor. I thought I heard something like a faint whine happen in the motor area for about a third of a second when I first turned on the key, but that could just be in my head.

Oh, one other thing that I think I figured out. A long time ago, when I hooked up the potbox, I thought that ElectroAuto provided the wrong instructions for hooking up the potbox microswitch. It turns out their instructions seem to be okay. The safety interlock inside the AC controller prevents the user from moving until the throttle is fully open and the "forward" signal is disabled. The neutral start interlock relay will only stay open if the user turns on the key with the relay open. After pressing the accelerator, this relay closes and puts the AC controller in "forward" mode.

Let's see what come up on the serial console tomorrow...

Wiring and Rewiring - Getting Close!

Ugh, I'm dehydrated, exhausted and mad at this inanimate object. I must love doing this conversion... (There's a fine line between a hobby and insanity)

Tonight was spent attaching all the copper bars to the battery terminals. I received an updated wiring diagram for the AC kit from ElectroAuto, and, much to my disappointment, many of the connections went between the battery caps. All the US Battery models tend to have "speed caps", so routing copper bars between caps on a single battery is impossible without breaking the speed caps. So, to use the bars provided, I bent them every which way I could to fit around the speed caps.


Here's the fusible link in the front battery box. Notice the large bulge in the copper bar on the right half.


Here's the same fusible link viewed from above. The bulge on the right half is needed to accommodate the opening of the speed-cap. I also had to hacksaw off about 3/32" of the bottom edge of the bar because it sits on the "wrong" side of the battery terminals and needs some clearance for the terminal heads.


Here's the long copper bar used in the rear battery box. To prevent routing it between the battery caps as shown in the ElectroAuto diagram, I used 2" stainless bolts to extend it beyond the speed caps on the top. I didn't like doing this because the stainless bolts would have a higher resistance than the copper and a much smaller surface area. Stay tuned for a better solution.


Here's the fusible link for the rear battery box. This is bent identically to the one in the front box and has the same curve on one side to accommodate the opening of the speed-caps.


Since the AC kit comes with 2 gauge wire instead of 2/0 gauge wire, I was able to use a short piece of welding cable with two lugs and route _under_ the speed caps to connect the terminals that formerly required the long copper bar.


The updated low-voltage wiring diagram shows different connections in the front compartment. I rewired the modification to the fuse block so that all the 12V accessories were connected to the key-switch directly again. I found the black wire going to the rear engine compartment and drove that wire individually from the interlock relay output in the front trunk. Hint: remember the two smaller wires you cut off the large black wire in step ???, the larger of these two smaller wires goes directly back to the rear engine compartment and was used in the original instructions to turn on the AC controller.

In short, we still route two black wires up to the front luggage compartment so that we can activate the keyswitch relay. The only difference is that in one case, the interlock relay turns off most of the keyswitched 12V system and this modification only switches off the AC controller when the charger interlock relay engages.

Electro Auto made the mistake of sending me two 12V-coil relays for the front luggage compartment. One of these was supposed to have a 120V coil so that plugging in the car would shut off the AC controller and turn on the fans. One of the problems with their updated wiring diagram is that when the charger interlock relay is on, all the venting fans are driven by the 12V accessory battery and nothing is keep that battery recharged. If the battery runs out, the fans stop, which is bad.

In short, I'm going to get a small 12V transformer that will drive both the interlock relay and drive the fans when the car is plugged in. This saves wear and tear on the accessory battery and let's me use the 12V-coil relay as the interlock relay.


Whew! After much playing around with the anti-corrosion goop, I finally have the front battery box all wired up (except the fusible link) and ready to fire up the system.

Note the thick welding cable coming into the box from the rear of the car. The smaller welding cable goes to the middle battery box and is small enough to fit under the speed caps to prevent clearance problems when closing the front-box lid.


Here's the middle battery box with the copper bars and welding cable installed.


And finally, the rear battery box with all copper bars and cables installed except the fusible link. It's much safer to wire things in when theres a break in the serial battery connections.

Next up: Getting some sleep and testing out the high-voltage system by measuring voltages and installing the fusible links. Not long now before we can try to spin the motor!

Hauling Lead and Confusing Connections

Tonight was an evening of heavy lifting. These high-capacity 8-volt golf-cart batteries are 70 pounds apiece. I'll definitely take some ibuprofen before tomorrow.

Here are the batteries in the front box.


The fuel compartment box...


And the rear box.

I pre-laid out these batteries on the floor to guestimate what the connections between the terminals were. I couldn't find a good solution with the copper bars supplied by ElectroAuto, so I just took my best guess and gave it a shot. I've got an e-mail into ElectroAuto for some connection diagrams, but haven't received the files yet.


Here is the battery strap designed for these kind of batteries. I got this battery strap at a Yamaha golf cart dealer. The advantage is that it attaches easily to the battery at the loading loops on the edge. The downside is that you can't use the strap for "edge" batteries. Note how close the loading loops are to the edges of the battery on either side of the filler caps. I was able to load most of the batteries with this strap away from an edge and then slide the battery into position.


For the edge batteries, the other battery strap I had contained two large loops which I could hook around some bolts threaded through the battery terminals. I didn't like to use this because I felt it put undue stress on the terminals.


A modification of the prior strap is basically what is suggested in the DC kit instructions. I used bolts, washers and nuts to create my own special battery strap which could quickly slide into a set of battery terminals and lift it. Again, I tried to use this strap on as few batteries as possible because I was concerned about applying too much tilt force to the "L" terminals.


Okay, onto the copper battery interconnects. It turns out that the only copper interconnect that fit right out of the kit bag was the completely flat bar with two holes. All other bars had to be re-bent in a vise to fit properly around the terminals.

Here's a picture of the front battery box with the short interconnects temporarily in place. I forgot to get 5/16" stainless steel flat washers to properly connect these copper bars (whoops, back to the hardware store). Note the large interconnect missing from the two battery terminals in the center of the box. These are for the front box fusible link, shown later.


Temporary links for middle box.


Temporary links for the rear box. Note the very far link in a reverse "S" shape. I found a funny shaped link in the kit, but could simply not get it to fit anywhere in the system. Out of impatience, I bent the link to fit the terminal spacing around the far corner of the battery box.

Also note the missing fusible link near the center of the pack and the long vertical link not really connecting the lower right two batteries. I might have to add long stainless bolts because this piece of copper just isn't long enough to get to the terminals and still fit around the filler caps.


Here are the supplied fusible links. I'm rather confused by them because they have 1/4" holes instead of 5/16" holes like the rest of the copper bars in the system. The bars also don't seem to fit anywhere in the whole battery system nicely, so something is awry with where these go. I'm guessing I'll end of bending them to fit the remaining terminals in the battery boxes, but I'd sure like to know what the designers intended.

We're getting closer. Time to go back to the hardware store for stainless washers and bolts to finish installing the interconnect. Goodnight.

Busy Day - Time to get your WooGah On

Whoosh! Despite being exhausted from yesterday, I got up early this morning and just cranked through a bunch of EV stuff on my day off.


Here is the board that the charger tray mounts to. There's a clear piece of acrylic providing a small gap so that the board can hinge forward and upwards without any edge interference. I'm holding this in place with clamps so I can drill the hinge holes without the board moving around.


After drilling the hinge holes, I went ahead and drilled the eight holes to hold the charger tray and filled them with bolts. I mounted the tray as far to the right as possible to open up space on the board to the left for one of my favorite pieces of equipment on the vehicle: the WooGah horn. Note: The AC kit instructions don't say what to install the charger tray with. I used one inch 1/4-2o bolts with washers and nylock nuts on the back.


Here's the mounting board on my kitchen table (er, workbench) with the washers and nuts installed on the back to hold the charger tray on. I've also bolted on the two hinges at the top edge as well.


Here is the bottom of the charger tray. I had to choose very shallow countersunk 1/4-20 bolts so that they wouldn't protrude beyond the black rubber feet on the top two corners. Alas, the rear two nuts were still too thick and I had to countersink the bottom and install the flathead bolts from below to get enough clearance.


Here's the Zivan NG3 charger sitting nicely in its tray with the AC power cord off to the right.


And here's the whole assembly in the vehicle. I still haven't bolted the hinges to the rear wall because I forgot to get enough 10-32 flathead bolts from the hardware store. The instructions call for 1-inch bolts, but I found that 3/4" worked just fine since the hinges are so thin.


Moving onto the middle battery box: Here are the fan wires coming off the exhaust fan. The brown wire tied to the black fan terminal goes to a stud that is hidden and not easy to see under the heater hose to the right.


Here's the front half of the rear battery box going in.


When installing the threaded hold-down rods, I found that there was so much gunk in the battery rack thread nut that I had to apply a rather large amount of torque just to make the rod go in the support nut. To get enough torque, I put two nuts on the top end of the rod and tightened them together so that I could put a wrench on the top nut and screw the rod in.


Here is the wiring for the rear box fan. I later changed the brown wire to point off to the left so there would be no interference with the tie-down bar. The instructions call for a red wire coming from the engine loom. I didn't find this and added my own red wire for the fan that goes back to the upper terminal block to the brown fan-power supply wire. Possibly a glitch in the instructions.


Here's the other half of the rear battery box installed. I was amazed at how tight a fit it is. The box didn't fit quite right (see far right corner poking up above the red wall), so I had to grind down some edges like I did a few days ago for the front battery box. Again, the fit is really tight. There's not more than one millimeter of space between the box edges and the front and rear walls. I feel rather fortunate to get this installed rather well. Hopefully the weight of the batteries will help it settle.


Here is the exhaust hose for the middle battery box. I think there's a problem with the instructions. They call for using 1/2" long bolts to hold down the exhaust port on the left, but due to the curvature of the wheel-well, this really requires more like 1-inch bolts for the nut to have enough threads to grab.


After running to the hardware store, I finally installed the hinges from the charger board on to the rear luggage compartment wall. Here is the whole setup installed.


Just to test out all the battery box fans, I shorted the positive terminal of the front fan to the battery positive terminal. All three battery box fans spun up without too much noise, so all the connections seem well.


Since I've finished all the work on the firewall, I installed the seats again to free up more room in the tiny garage.


Here's my favorite WooGah horn mounted to the left of the charger. I don't know if the connections to the battery are better, but it's really loud! Get your WooGah on!


With the majority of the wiring done, I added several tie wraps to the cables under the rear luggage compartment to keep things from moving around.


I also re-installed the rear tires since most of the undercarriage wiring is done.


Last but not least, I took off all the temporary charging cables from the batteries so they are free to be installed in the vehicle.

I still don't have any instrument gauges from ElecroAutomotive, but I can put together temporary switches to get things going.

Next up: installing the batteries in the boxes!

We are Green for 12V Electrical!

Whew! I spent the evening debugging the small sparking issue I ran into yesterday. The behavior was interesting in that the keyswitch relay closed for about a second and then released. In the process, the DC-DC converter turned on (indicated by red LED) and then slowly decayed to the off state.

It turns out that this behavior is explained by the rather large capacitive load between 12V and ground provided by the capacitors in the system, probably from the CD player and the VDO clock. To further explain, one side of the keyswitch relay is tied to the ignition switched 12V rail, now floating to the same potential as the unswitched 12V rail(i.e. 12V). Since the positive terminal of the auxiliary battery is tied to the unswitched 12V rail, the negative terminal of the battery is at zero volts.

When we attach the black wire in step XXV.R of the DC instructions, it drives the keyswitch relay coil instantaneously with 12 volts, energizing the coil. Current flows through the coil to charge down the capacitive load on the ignition switched 12V rail until it is 12V below the unswitched rail (down to zero volts). After the coil charges down the capacitive load, there isn't enough voltage to keep the coil energized and it turns off after a second. I suppose this is rather confusing, so send me a comment or e-mail if you'd like further details.


Here are the negative high-voltage connections. The 10 gauge black wire comes from the charger and the smaller yellow wire drives the voltmeter in the cockpit and drives the DC-DC converter.


Here is the wiring from the 9-wire bundle that was threaded through the driver-side heater duct. Most of the wires attach to the upper terminal block to interface with the DMOC AC controller. The dangling white and green wire go to the ammeter shunt and the dangling black wire I think is not used in the AC kit.


The moment of truth! After attaching all the wires and chassis ground in the front luggage rack, the green oil light comes on (and the annoying seat-belt buzzer) when I insert the key and turn it to the "on" position. I was also able to turn on the CD player and it started playing the CD I had left in there from when the car had a gasoline (yuck!) engine. Yay! This marks a rather huge milestone in getting most of the wiring hooked up correctly.

WARNING: Step XXVI in the DC instructions doesn't really apply to the AC system as many of the connections are much different. You can definitely test the green oil light, but don't short out any terminals as mentioned in step XXVI.G!!


Next step in the instructions is to add weatherstripping to the front battery box edges. The weatherstripping. The weatherstripping comes with two strips attached side-by-side. I found it most useful to measure all the horizontal edges and cut a piece to get both top and bottom horizontal edge before doing the same with all the vertical edges. Using this method, I was able to most efficiently utilize the dual-strip weather stripping.


Here's the battery box top sitting in place. We need this here to install the charger mount next.


We also need to add the flexible plastic pipe for the front battery box vent fan. Trust the instructions when they say that installing the upper hose clamp is easier.

Next up: Installing the mount for the charger.

Must.......Get.......Sleeeeeeeeeep.......

Forcing a Fit and Letting Sparks Fly

Well, after yesterday's letdown with the front battery box not fitting into the steel frame, I loaded up on caffeine and pulled out the grinding wheel.


Here is the front battery box not fitting into the front rack. If you click on the picture for a larger view, you can see the front-side edge not in the rack. I first tried a hand file, but made much more progress with a paint removal wheel attached to a drill.


Here we are, slowly grinding away 1/32" of plastic at a time to hopefully not reduce the structural integrity of the front battery box.


Yay! The front box now fits into the rack (albeit tightly) and we can move onward.


The next instruction calls for adding a threaded rod covered with heat-shrink tubing to prevent shorting out any of the wires on the relay mount board. The threaded holes in the battery rack for the vertical thread-bars had powdercote in them, so I used two nuts tightened together on the top of the threaded rod to get more leverage to twist the rod into the threaded hole.


Next up is installing the auxiliary battery. This is rather tricky since you can see that the front edge of the battery is resting on the front hood latch. Earlier directions for mounting the front battery rack say to move the rack at least 2 1/2" forward of the rear wall. What this really means is that you need to mount the rack EXACTLY 2 1/2" in front of the wall so components on the front of the rack don't hit other parts of the car. If this has clearance issues, I might have to re-drill some of the previous holes to move the rack. This will be a royal pain after adding all the wires.


Okay, we now have all the wires from the fuel compartment with connectors on them attached to the battery or components on the relay mounting board.

In the process of attaching cables to the auxiliary battery, I got a click from the key-switch relay on the right and the DC-DC converter turned on (red light). I also got minor sparks coming from the negative terminal of the auxiliary battery. I suspect I hooked up something wrong and will reverse engineer the connections next.

I was somewhat blindly following the instructions up to this point so I'm guessing there's a bug. Also, the instructions for the DC kit may not apply to the AC kit. Here's where the real fun begins since there are no wiring diagrams from Electro Automotive for the AC kit yet!

Off to sleep to prepare for another day... Cheers.

More Wiring and ACK, It Doesn't Fit!

Yesterday I ran out to Parkrose Hardware again to pick up the remaining wire I needed (hopefully) and all the bolts/nuts/washers for mounting the stuff in the front trunk.


Continuing with the wiring, here is the bundle of EV wires in the front luggage compartment, covered with the flexguard.


Again, the front luggage compartment with the vertical all-thread in the battery rack for the battery-box tie-down bars. I've added the black grounding strap to the front bumper mounting bracket. You can see the tiny yellow crimp collar on the closed crimp connector.


Now that I have more 10 gauge wire, I finished up the wiring on the battery box itself. Here's a front view with the DC-DC converter.

WARNING: The instructions provide direction for a different DC-DC converter with the "input" and "output" terminals swapped left-to-right from the DC-DC converter that comes with the AC kit.


Here is the local wiring completed on the relay mounting board.


The moment of truth for the front battery box. I lowered it into the front compartment and, Voila!, IT DOESN'T FIT! ARGHH! It looks like the battery rack is warped or there are some bulges sticking out on the box that prevent proper insertion. I'm going to look into this more this evening.

Wiring up the Front Compartment

I finally got to work on the electric car again today. The next major task is wiring up the front compartment.


Here is the 9-in-1 wire for the AC kit pulled through the grommet between the passenger compartment and the fuel compartment. The 9-in-1 wire (encased in flexwrap) is going back into the passenger compartment to the dials and controls. The yellow and brown wire need to come out of the flexwrap so that we can connect them to circuits in the front luggage compartment. The instructions call for a "Y" connector which ElectroAuto didn't supply. I hacked my own together by using wire and three insulated male quick-connect crimps.

The blue wire also goes from the front luggage compartment into the passenger compartment. I replaced the single-space connector by using one male and one female crimp connector on the blue wire.


This is looking straight down into the fuel compartment on the drivers side. Here is the bundle of added wires tie-wrapped to the main wiring harness going into the front luggage compartment. Note the thick battery cable going through the lower grommet on the left to connect the front batteries to the rear of the vehicle.


And the bundle of wires coming into the front luggage compartment ready to be attached to other components.


Here's the front relay mount plate with the relays, terminal strip and fuse block bolted on. ElectroAuto provided a six-space terminal strip instead of a five-space, so I had to add another hole on the bottom to hold it.


Here's the wiring specified in the DC instructions (supposedly the same for AC) on the relay block. Be careful as some wires are 16 gauge and some are 10 gauge.


Another look at the wiring from the side to better see the connections to the relays.


Here is the front battery box with the relay mount plate bolted on and the retaining hardware for the accessory battery.

WARNING: the DC kit instructions call for 1/4"-20 x 1/2" bolts to hold on the DC-DC converter; however, the holes actually take 10-32 x 3/8" bolts instead. Please update your instructions.

I was a bit non-plussed when I realized that the holes for the relay mount plate didn't line up with the holes on the battery box. I had to drill them out to get the bolts to go in the receiving holes. The holes for the accessory battery mount fit just fine.

I didn't yet purchase the accessory battery or the required 10-32 x 3/8" bolts, so I'll go get those tomorrow and continue.

With the NEDRA races on August 17, I've got a solid artificial deadline to beat now. Onwards!

Hanging out with NEDRA

Summer events have held me back from working on the 914EV, so I headed out to Portland International Raceway to get a boost of inspiration from NEDRA (National Electric Drag Racing Association) to continue the project. Here are some photos.


Here's the famous KillaCycle powered by just under 1000 A123 batteries, the same kind that go into the DeWalt cordless drills. The KillaCycle ended up posting a run on Friday of 152mph in the quarter mile. They will try again tonight to go faster. The purple box in the center of the cycle is a Zilla2K (2000 amp DC controller).


Here's Otmar's DC powered 914, controlled by his Zilla1K controller.


Here is Otmar Ebenhoech, designer of the popular Zilla DC controllers. He is standing in front of an all-electric Honda Insight which contains his prototype Tri-Zilla AC controller. You can see a bit more about Otmar on YouTube at: http://www.youtube.com/watch?v=Yl9uejKnMFQ

Here is John Wayland, creator of the fastest EV street-legal car in the world, the White Zombie.


And, of course, the White Zombie.


This time, White Zombie is running with A123 Lithium-Ion Batteries instead of lead-acid. The battery pack is tiny compared to the lead-acid version, saves about 700 pounds in weight and puts out so much power, that John needs to limit the current to prevent the car from skipping right off the road.


An older drag-racing cycle called FrankenDragon based on lead-acid technology.


Here is the White Zombie waiting in line for it's first warmup.


Thanks to my friends Ruth and Joe for coming out and hanging with me during the event.

I was amazed at how accessible these vehicles were to the general public. I was able to walk inside the "pit" area and talk with the designers directly and see all the vehicles, up close. The next NEDRA event at PIR is August 17-18. I hope to have my car ready for that event, not necessarily to race it, but just to share the technology.

Routing Thick Cables

My friend Rick came over last night to help me feed the thick cable bundle through the driver-side heater duct. I didn't get any action shots, but here's the result.

Here is the left side of the passenger compartment under the fuse box with the cables routed down into the heater duct. I've already added the 3-hole cap-plug provided in the kit.


Here are the same cables coming out into the fuel compartment through the large grommet behind the fuse box from the passenger compartment.


Here's the end of the cable lying on the floor that we pushed through the heater duct towards the engine compartment. The fishing wire and tape to keep everything together at the leading end has been removed.


And again, the same cable coming out of the heater duct. Note the dual wrap of masking tape and red electrical tape called for in the instructions. This tells us when to stop pulling the cables through.


After cutting all the tape that bound the engine compartment cables together, I slid on the three-hole cap-plug from the kit and bonded it in place with silicone sealant.


In addition to sealing the driver-side heater duct, there's also a cap-plug provided to seal the passenger side heater duct in the engine compartment. I suspect this will keep water and other outside elements from getting into the vehicle.

Today was a bit slow. The next task is to connect the wire ends of these two cables to the front and rear parts of the car. I did replace the 10-32 bolts that I used to hold down the PowerPost terminals so that the head wasn't so large that it cracked the post housing.

The DC version of this kit only has four instrument wires routed in the heater duct, two for the voltmeter and two for the ammeter. The AC kit has four more that allow the driver to control regenerative braking and rate of acceleration (like a valet switch).

Next up: More wiring.

Preparing the Front-to-Rear High-Current Cables

The next major step is to prepare the bundle of wires that connects the front batteries and controls with the rear batteries/controls.


I use my front hallway to measure, cut and line up all the specified wires in the instructions.


Here are all the wires with masking tape holding them together at 12" intervals so they feed through the heater duct more easily.


The instructions call for seven feet of mechanics wire to fish the cable bundle through the heater duct. Being an electrical engineer, I'm not sure what mechanics wire is, so I settled for this soft galvanized steel wire. Here's the loop in the end to prevent the wire from snagging in the duct as I fish it through.


After fishing the wire through, the tail end protrudes from the heater duct in the passenger compartment.


The looped end which I fed through the duct has come out the other end into the engine compartment. It took some patience and some well-placed bends, but the wire slid through reasonably well.

Next up: calling a friend to help me fish the high-current cable bundle through the heater duct.

Working with the Fusebox

I took this morning off from work to continue with hacking the fusebox wiring.


Here is the fusebox area with the left speaker grille removed. I also removed the remnants of the rotten heater duct from the heater opening at the bottom of the picture.


This is the fusebox. To lower it, take out the far left and far right screws in the black housing. Note: the blue press connector on the lower-right powers the after-market CD-player.


Here is the lowered fusebox. This looks slightly different than the picture in the DC Voltsporsche manual, probably because its a '75 model year. The instructions call for adding a red wire to the second terminal from the right (which is already taken). Fortunately, there are spare terminals behind the one we need to connect to.


Here is the added red 10-gauge wire in the foreground. It almost looks pink and goes from the fuseblock terminal along the loom up to the grommet towards the fuel compartment.


Here's looking straight down into the fuel compartment showing the red wire going from the passenger compartment along the factory loom to the front luggage compartment through grommets.


The next instructions call for adding two black wires, one with a piggyback-crimp and one with a regular crimp. The piggyback crimp goes on the wire with the tape. Note, I had to cut off the regular crimp and replace it with a non-insulated one later so that it fit inside the 1-space connector in the instructions.


Here are the black cables from the original harness with the two smaller of the three cables cut off and crimped with a blue female connector.


Here is the final wiring with the original thick black wire going to the added black wire with the female crimp through a 1-space connector. I had to crush both crimps flat so that they would fit inside the 1-space connector. Note the blue crimp attached to the piggyback connector from the other added black wire on the terminal block.


Here is the final wiring with yellow tie-wraps included to keep things clean. The upper-left tie-wrap holds the whole loom to the trunk release housing to keep the bundle way clear of the upper heater duct (see large black hole at top of photo).

After routing these black cables into the fuel compartment and then the front luggage compartment, I'm a bit skeptical that the wires are long enough, but we'll see when the DC/DC converter and charger get added.

Hacking Big Cables

Work was pretty quiet today with the July 4th holiday in the middle of the week, so I took the afternoon off to work on some of the high-current cables.


Here are two of the PowerPosts that I purchased yesterday from West Marine. The one on the right is the most-negative terminal and the one on the left is the placeholder for the high-current shunt that ElectroAuto hasn't sent yet. I used 10-32 bolts to hold these in, but the bolt heads were larger than the recess in the plastic, so I'll have to go out and get 10-32 allen-head screws with a smaller head to fit these without cracking the plastic.


Here is the mounting place for the motor speed control box that I re-wired yesterday. Putting it up on this panel gets it out of the way; however, I'll have to make sure that it doesn't interfere with the targa-top when it's in the rear trunk.


I've drilled two 1-inch holes in the rear trunk floor to route the high-current battery cables from the PowerPosts shown above to the motor controller. The rubber grommets are a bit larger than the cable, but that will work out fine since the cables have heat shrink tubing on them.


Since I purchased the 2/0 welding cable in a 20-foot length and a 25-foot length, I have to be careful to make sure I use them efficiently for all the necessary long cables in the instructions.
I don't have a long workbench, but the front hall and a long tape-measure works just fine.


As I mentioned before, I'm replacing the #2 gauge cable provided in the kit with a thicker 2/0 welding cable. I'm still a cheapskate and will still use the #2 gauge lugs with 5/16" holes provided in the kit. This requires me to use some small diagonal cutters to cut off several of the outer strands so that the inner cable strands fit inside the crimp connector. This shows my first crimp with the large crimping tool I borrowed from Gary. I forgot to squirt Noalox in this first connector, so I'll be careful to watch it. Fortunately, I used Noalox on all subsequent crimp connections.


Here's the same crimp above with black adhesive shrink tubing on it.


Here are the high current cables attached to the power posts in the engine compartment. I coded the most-positive terminal with red adhesive shrink-tubing.


Here are the cables again under the rear trunk going up through the grommets earlier. I plan to clamp all these cables up to support posts before actually running the car.


Here are the high-current cables (with crimp connectors) bolted onto the motor controller terminals with a heavy dose of Noalox gooping them up.


Here's the motor controller with the high-current wiring all attached and ready to go.


The instructions call for adding flexguard to the DMOC wiring harness to keep things clean. I unplugged the connector, fitted it through the 2" hole and added the flexguard.


Here's the wiring harness connector back through the 2" hole and plugged into the motor controller.


This is the most-positive power post terminal inside the fuel compartment on the driver's side ready for cable attachment from the front batteries.

That was quite a bit of work for today. I might continue work tomorrow morning and add the wires to the fuse box before going to work if I feel motivated. Cheers.

Motor Cables and High Current Posts

The instructions for the AC kit tell you to slide the motor speed control box through the two-inch hole that was cut in the wall between the engine compartment and the rear luggage compartment. In my haste, I added a computer grommet to the hole which made it just a bit too small to slide the motor control box through. I initially thought I could remove the base and cover of the box to reduce its cross-sectional area, but it still wasn't enough. Eventually, I decided that I would have to completely remove a cable from the box and just route the cable through the hole.


Here's the AC motor speed control box with its base and cover removed to see if it fit through the two-inch hole. It did not.


After carefully recording which color wire went to the terminals, I removed the cable from the motor end of the box.


Here's the cable going through the too-small two-inch hole.


Here's the motor control box all reassembled next to the controller, ready to be held in place by rivnuts or bolts and nylock nuts.


The next step was to attach the three-phase cable to the controller. This was quite a bit harder than I expected. A slight difference in the cable lengths made attaching the three lugs to the controller outputs difficult since the cables were rather thick and inflexible. I had to trim the copper webbing surrounding the cable. I used simple diagonal cutters with a small plastic bowl underneath the cable to prevent tiny webbing wires from splattering everywhere.


Here's the three conductor cable tied to the three internal lugs. The cable for the far right lug was just a bit shorter, forcing me to wrangle the bundle quite a bit. I'm hoping the strain relief nut on the left edge of the box will prevent more force from possibly cracking the terminal posts.


Electro Auto forgot to include the post terminals for the most-positive and most-negative connections in the kit. Since I didn't want to wait for EA to respond to e-mail, I went searching around on the internet to find these things. It turns out that a great source for high-current EV parts is the Marine store. Many people end up wiring up their own boats with high-current circuits, so I'm not too surprised.

I purchased these high-current post connectors from West Marine in Portland for about $9.00. As you might expect, the prices at the Marine Store were very high (about 2x the cable store), but they have a bunch of stuff and they're open during weekend hours when many specialty stores are closed.