Batteries and Sparks!

Well it's over a year since I started the project and today I put the batteries into the car!  I just want this to be over so I drive the car...

I loaded them one by one and they're very heavy!  I bought a rubber loading strap from the battery place which hooked into the two plastic brackets molded into the top of each battery.  I had to be careful not to bang them into the body or drop them, and everything turned out OK.  Here are the saddlebag batteries.

And this is the former engine bay.

This is the former gas tank area.

This is the former front trunk / spare tire area.

Here's the full front area with the charger in place.

 I then started hooking up the battery bus bars.

I put all of the battery bus bars in place as a mockup and found that there was one missing!  Another final insult from EA!  I had to buy some copper stock but the best I could find was too thin, so I had to double-up.  I had to get some 1" shrinkwrap too.

Measuring and bending the double-thickness was difficult to get right.  I had to put the shrinkwrap on before I started bending the second end.

And it's complete, short of a little fine tuning.

Here it is installed, looks almost factory-stock.

The last missing piece was a copper bus bar going between the two bottom terminals on the motor.  I thought about making it out of a small piece of leftover 2/0 battery cable and two lugs, but since this is going to be exposed to the road, I decided to build it the way EA would have, if they had shipped it to me...  And here it is.

Here it is bolted to the bottom of the motor, just like it should have looked.

Next I bolted up the bus bars in place to all of the battery posts.  I then followed the directions in the EA manual and checked the voltage of each battery bank, and everything looked good.  The last connection to make was the most-negative battery's negative terminal to the most-negative post.  This is where it got exciting...  I touched the lug to the terminal and it made a big spark!  The manual didn't say anything about that and I was worried I had a short somewhere.  I started unbolting the cables between the battery racks and checking voltages and grounds.  I couldn't find the problem and it was getting dark so I figured it was smarter to sleep on it.

I decided to check in with the accumulated knowledge of the 914 electric conversion world on the 914EV newsgroup.  Here's my post:

As I mentioned in the previous message, today I was going to make the
motor turn for the first time.  I had all of the battery bus bars and
cables attached, except the final connection from Battery 14's Neg
terminal to the most-ground post.  All of the partial-pack voltage
readings matched the manual's checklist.  When I went to put the final
lug on the mount-ground post I got a big spark, which I assume is a
short somewhere.

I started trying to narrow down the problem by isolating the battery
boxes, removing cables from battery terminals, the controller, the
motor, the contactor.  I couldn't get rid of the spark.

In frustration, I put my meter between the battery and the most-ground
post and found I had a current draw of 0.3A.  Not really much, but
enough to make a spark and make me think twice about proceeding.  This
is with the aux battery disconnected, the DC-DC disconnected, the
motor disconnected, key off and breaker off.  None of the car's 12V
features are on.

The only thing out of the ordinary is a PakTrakr system, with a
voltage sensor wire on each of the 20 batteries.  I disconnected each
PakTrakr unit's power supply wire and the LEDs all went dark.  Even
when powered up, the PakTrakr should pull no more than 32 mA, and I'm
seeing about than 10x that.

I got several great suggestions back almost immediately.  The gist of the problem is the spark was from the current draw on the big capacitors in the motor controller.  The next morning I was convinced it was the source of the problem by holding a heavy-gauge jumper wire between the cable and the battery terminal.  I held it there for 1 minute, took it off and touched it again and there was no spark!  I bolted the terminal in place and everything was good!

Next up, wiring up the PakTrakrs and the first attempt at spinning the motor!

Energizing the 12V circuits

After the ignition switch was wired in, there was nothing stopping me from hooking up the battery and turning the key.  This should help me test the 12V circuits.

I had my son standing next to the battery with a fire extinguisher as I turned the key.  BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEP!  I nearly jumped out of my pants.  I had tucked the horn wire into a space in the steering column, completing the circuit.  As soon as I turned the key, the horns went off at full volume.  I switched off the key and pulled the horn wire out.  I turned the key again and heard a click in the relay box.  I followed the diagnostic tests in the EA manual and immediately found a problem.  The green oil pressure indicator light is supposed to light up when the key is turned, indicating that the 12V circuit is on.  But the light didn't go on.  After tracing the wiring and checking with a meter, I found that the light bulb was bad!  I bought a box of replacement lights for the instruments, but that particular one still had its old bulb.  Lesson learned...  The rest of the EA tests with the batter and DC/DC converter were successful.

Next I tried pushing the electron pedal and heard the contactor engage with a loud clunk.  Success!

I don't have any of the original 12V devices in place like lights, blinkers, etc. so there was nothing else to test.  As I rebuild those parts of the car, I'll test them.

DC Power Harness

The next major step is to build the high-voltage DC harness that brings power from the front batteries, through the circuit breaker and then to the contactor and on to the controller.

ElectroAuto has you measure two 2/0 welding cable, plus a 10 ga ground wire and a 4-conductor signal cable, then tape everything together at the proper offsets.

The instructions provided a convoluted set of steps using "mechanic's wire" to prep for pulling the cabling through the heater duct, and you need an assistant to do the cable pull.  I decided to use my fishtape, and it was easy to do by myself.  Here you see the fishtape running into the heater duct from the rear of the car to the front.

The tip of the fishtape sticks up out of the hole just below the fuse block.

I put the end of the fishtape through the lug hold, then strapped it into place with a ziptie.

I then wrapped it in tape to make for a smooth pull.

At the end of the pull, you want a tape marker to just be coming out of the heater tube in the engine compartment.

And this is the other end, with the cable waiting to be bolted to the circuit breaker.  I'll have to do some minor pull adjustments to get enough cable.

After finishing the prep, I put the "CA Plug" in place, and used the same silicon as for the saddlebag battery rack.  The CA Plug is slightly angled so it didn't want to stay in place.  I helped it by sticking a screwdriver in as a wedge.

One small complication due to my use of the weatherproof enclosure.  The end of this cable bolts to the contactor but the lug is about 1/16" too wide to get through the weatherproof gland nut.  My solution was to grind just enough off to get it to fit through.  Unfortunately I forgot to do the grinding before I pulled the cable, so the grinding occurred on the ground under the back of the car.

Final connections on each end happen in later steps.

Building weatherproof boxes for the electronics

The standard design from EA involves mounting some sensitive electronic parts and terminal blocks out in the open in the engine compartment, subject to to water, dust and other nasty things.  Working for a solar power company, I've learned to protect this kind of equipment as best as possible to give the car the longest possible life without having to worry about electrical failure, rust and ongoing repairs.

I started with the relay board.  EA supplies a thick plastic board, predrilled for mounting the components.  I bought a NEMA4 rated enclosure sized to fit the board inside.  You can see I had to do a bit of machining to make it fit.

I mounted the relays and the terminal blocks to the supplied board.

I then followed the instructions and wired everything up.

Here's how it looks with the clear cover on the box.  I bought the clear cover option so people can see the internal workings of the system and I can keep an eye on things for moisture intrusion, discolored wires, etc.

Next I moved onto the contactor.  The contactor, a small relay and two terminal blocks are supposed to be bolted to the side wall of the engine compartment.  I wasn't comfortable with that, so I proceeded the same way as the relay board above.  Here's the contactor - it's essentially a very large and powerful relay that is wired between the motor controller and the motor.  It needs to handle 600A of current flow.

The boxes I bought did not have internal mounting plates available, so I found these pieces of plastic sheet at Lowes, and machined one to size to fit into the box.

I spent a lot of time figuring out the best position for each part inside the box, making sure there was enough space for wire bends and clearance for inserting and removing wire connectors.  Here's a picture of the final assembly.  You can't see the clear mounting plate with the protective film removed.

Then I moved on to the potbox.  Alert readers will remember that the potbox assembly wouldn't fit into the space defined by EA because the brake proportioning valve was removed before I got the car, so I had to do something.  I decided to disassemble what EA had me build, and stick it into a weatherproof box.

Here's how the potbox fits insde the box.  Just right.

Another change I had to make was to reverse the mounting of the accelerator cable pivot post.  It sticks up too high, so I'll just flip it around.

I figured the plastic sheet wouldn't stand up to the stress of the moving parts, so I made a metal plate that the potbox will mount to, which will then be mounted to some embedded nuts in the box.

I drilled mounting holes in the box and then into the firewall.  I installed rivnuts into the firewall and bolted the box into place.  I sealed around the bolts and washers with silicon sealant.

Here is the potbox in place, with the accelerator cable coming through from the left side and attached to the pivot arm of the potbox.  When I continue the build and figure out where the potbox cable needs to go, I'll drill a hole and install what we at REC Solar call a pongi - a weatherproof fitting that compresses down on a cable as you tighten it down.  I don't want anything coming into the box.

I'll do the same for the relay board and the contactor box when I mount them.  Well I'm off for a 2-week solar monitoring road trip, so the car gets to sit and wait for me to return.

Final Parts Dribbling In

When I got back from my trip to Infineon, I had a small box from ElectroAuto waiting.  Inside I found:

The lug crimper.  I'm not going to use this because the hydraulic one I borrowed from Kelly is far superior.

The contactor diode.  I can't find anything in the instructions that says which terminals to attach this to on the contactor, so I'll have to do some research later.

Positive and negative terminal posts.  The electrical system design uses these posts to be the main mounting points of the positive and ground parts of the circuit.

Battery box weather stripping.  This sticks onto the top edge of the battery boxes and seals out the elements.

Wiring harness.  This is a pre-built harness to accelerate the process of hooking up various electric bits.

This means the very last parts I'm still waiting for are the hood pins!  I also realize now that I'm at the point of wiring up the high-current DC cables, that I'm missing a copper piece that goes between two posts of the electric motor.  It's a flat copper bar with heatshrink tubing shrunk onto it, with a hole drilled in each end.  I emailed Shari that I didn't realize I was missing this part because it's not explicitly listed on the shipping list.  Of course I didn't get a reply, but I'm hoping it will just show up some day.  Worst case I can fabricate it myself.

Finally Some Electrical Bits!

Now that I've got my remaining electrical parts, I can get started.  I can't do the whole job yet because I'm searching for some "affordable" plastic boxes to hold the contactor, potbox and terminal blocks.  I'm not leaving those out to the elements as the EA manual says.

Anyway, I was able do get started.  This is the supplied DC high-voltage, high-current cable.  It's called welding cable or locomotive cable, and is made up of hundreds of hair-sized wires, so it's very flexible.

EA is supposed to supply a cable lug crimper, but it hasn't shown up yet...  I checked around at work with the electricians I know and found that Kelly Minton has a great hydraulic crimper.  You can see the steps to make a solid crimp below.

You can see the crimper crimps from 4 sides for an extremely good connection.  The final step is to put some shrinkwrap tubing and shrink it down.

I mounted the controller to the backing plate.  This was heavy and messy due to the white heatsink compound.  I built cables and mounted to the controller and the motor.  The rest will come in when I mount the contactor in the box.