On the Road Again

All Willie Nelson references aside, the Z3 is back on the road.  There's a lot to tell, and I'm sorry I haven't posted more as I was working, but as most of you know, I have a deadline that I had to make.  This made for some very long days and nights in the garage.  I'll touch on some of the highlights, good and bad.

The controller for the MasterFlux compressor comes as a circuit board with an aluminum heat sink anchored to one side and all the components open to the world on the other side.  You don't have to be a computer expert to know that probably ought to be protected from the elements.  I started looking for a project box big enough to put it in and would fit in the space I had picked out for it, but found none.  It wasn't long before I realized I was going to have to build my own.  Well, I figured that would be fun.  My material of choice would be thin sheets of aluminum, but I don't have a press break, or access to one.  There was no way I was going to be able to build a nice box out of metal with neat edges.

OK, that meant plastic was the material of choice.  I found someone on eBay selling sheets of PVC plastic, so I ordered a 2'x4' sheet.  I was able to cut it quite easily with a utility knife and a metal straight edge.  It was clearly formed with a PVC foam-like material rather than the type used to cast PVC joints for plumbing.  But on thing was certain, it would glue the same.  I very carefully cut sheets the proper size, planning on two sheets per side, sandwiched together, with staggered edges so I would have more surface area to make sturdier lap joints at the corners.

My plan to build a box around the controller was going well.  But then my dad had a great suggestion.  He noticed that the heat sink is a bit larger with the edges sticking out beyond the edges of the circuit board, so he suggested making that one side of the box and simply enclose the circuit board.  Brilliant!  I was able to do just that and build a secure mounting system and put it exactly where I had hoped I would be able to.  This had the added benefit of leaving the heat sink open to the outside air for cooling

Notice the fins of the heat sink facing the front of the car between the two battery packs.  Right next to that, to the left, is a little project box that holds a large diode and two relays.  The diode is to prevent current from the capacitors on the controller board from flowing back into the car's traction system should the voltage in traction system drop below the voltage stored in those capacitors.  Apparently this was a common problem with the MasterFlux units that they've decided to overcome by recommending you buy an extra $25 part.  The relays work like this: the on/off switch on the car's dashboard for the A/C system triggers one relay, which provides power to the fan mounted on the condenser at the front of the car, and to the second relay.  That second relay simply makes a contact that will allow the 5V signal back to the controller turning it on.

(By the way, notice the nice new braided connectors between the batteries.  Nice huh? )

All of this should work flawlessly.  In theory.  You see, I tested what I could before hooking everything up, but there was no way to test all of it as one system after it was hooked up, until all the batteries were in.  Plus, I have no idea if it's even safe to run the compressor before the system has been evacuated of air and charged.  In fact, I've been trying to reach Revolt Electric (the resellers of MasterFlux products) to ask them about this and a few other things but they have been, how shall I say, less than diligent about returning emails or phone calls.  Part of being a reseller is living up to the responsibility of offering end user support, and they're falling short at the moment.

Tomorrow morning, I'm taking the car into a local BMW shop to have them evacuate the system and charge it.  First, they'll put a vacuum on the hoses and pump all the air out.  They'll leave it like that for a couple hours to be sure it holds the vacuum.  If it does it's good to charge.  At this point I have no idea if it will.  I can't express how much I hope it does, but there's no telling.  Since one of the new joints in the system had a brazed fitting, I think that one will be fine.  The other one was still an accursed compression fitting.  I give it a 50% chance of holding a vacuum.

If it holds up they'll charge it and I get to turn it on for the first time.  I'm not worried about incorrect wiring and/or damage to the system, but there is the distinct possibility that it simply won't work for some reason which I can't conceive of at the moment.  I'm about 90% sure that will go well.   Whether I drive out of the shop with A/C tomorrow, only time will tell.

They are also going to align the front end to take out all the toe-in.  I never had it re-aligned, so it will be interesting to see how much of an impact this has on energy consumption.  Sadly I won't know right away because the new meter I put in isn't working.

Actually, the meter is not the problem, it's the original pre-scalar I was using with the Link-10 meter.  When I put power to the system yesterday, I turned on the meter and started running through the various menu setting to set it up for the car.  When it was done, it read that the system voltage was 68.8V.  Wha...  I double checked that I'd selected the 1/10 pre-scalar knowing full well that I'd never seen a 1/4.3 setting that would be necessary to see 68.8 Volts.  Eventually I pulled the meter out of the console and actually measured the voltage on the wires coming from the pre-scalar.  I found that it read 6.88 volts.  Well how about that.  Apparently while the car sat doing nothing over the past 4 months, the pre-scalar developed some sort of problem that renders it useless.  I have no idea how, or why, but a replacement unit is $54.  *Sigh*  A new one is on the way. 

Astute readers will have noticed in the picture of the motor bay that the big red slap switch I had in the prior builds is gone.  "Where did it go" you ask?  Well after I pulled it out to start the work in the area, I noticed something peculiar about one of the contacts on the positive terminal side.  Take a look:

You can see in the top right side what the contact pads should look like.  They are little silver pads soldered on the copper bar.  However in the bottom frames, you can see that one of them has completely melted away.  The bottom left picture is the bottom bar in the contact, and the bottom right picture is it's mate above.  At some point, there was some serious arcing in there that, for all intents and purposes, destroyed this switch.  Well there was no way I was going to put it back like that, and I see no reason in replacing it with a like one as there will now be the possibility of sending even more current through it.  Nope, I need to find some other safety disconnect.  But, that will have to wait for later. 

I finally added an expansion tank for the coolant used to keep the Zilla cool.  Finding a location for it was a challenge. The fact is, it's on the opposite side of the car from where the pump is.  As a result, there are coolant hoses running all over the place.  The underside of the car is, quite frankly, a bit embarrassing now.  It's just too crowded with stuff and it all looks a bit thrown together.  Such is life.  The cooling system does seem to work great though.

Yesterday after putting everything back in and together, I was working near one of the batteries while touching the chassis of the car, and I grazed a battery and felt an unmistakable shock.  What the!  My mind raced.  I got out my meter to check and sure enough, there was continuity between the chassis and the battery pack.  I stood there cursing, wondering how the hell that had happened.  I disconnected the positive most terminal and started looking to see what had happened.  Eventually I isolated the problem to the motor.  My first though was that as I'd lowered the battery pack on top of the motor, I must have crushed one of the lugs and it shorted out to the motor's housing.

There was no way around it, that pack was going to have to come out.  Mind you, this is coming less than an hour after I'd put the final bolt in holding everything together.  What a bitter pill that was.  Rather than take the pack out as a whole, I decided the best thing would be to dis-assemble the first row of batteries and remove them so that I could see the terminals which are under them and if I'd crushed a lug.

What I found was no crushed lugs, but one was clearly wedged in there and under pressure.  I as able to get to it and get it out.  I found that the plastic boot on the terminal had what amounts to a pressure wound on top of it and was actually pierced, ever so slightly.  The heat shrink tube underneath it looked intact, but I cut if off and could clearly see a hole you could fit a pencil lead through when I held it up to the light.  There it was, that was what had been touching the chassis.  I found a less risky path for that wire and bolted all the wires back in place.  I checked and there was no continuity.  Problem fixed.  Whew!

This morning, I re-assembled the rest of the system, put power to the system, dropped the car to the ground and carefully drove out of the garage.  I took off down the road cautiously and found that the car was driving perfectly.  Furthermore, the wobble that was in the drive line before it went up on blocks was now completely gone.  The Warp 11 motor was perfect again.  Finally, on the road again.

Tomorrow is my appointment with the shop, which I'll report on.  The rest of the week will be spent replacing that pre-scalar, and getting ready to trailer the car and tow it to Missouri for EVCCON.  I am genuinely looking forward to that. 

Mounting the Compressor

The last two weeks have been exceedingly busy and it's only been these last two days that I've actually had the opportunity to begin working on the car again.  Very frustrating!  But I've made some progress, and I thought I'd share what's been done. 

I finished building and installing the motor mount, which meant that I could finish making all the connections to the transmission; drive shaft, clutch slave cylinder, gear shift linkage, and reverse light connection.  Incidentally, I was able to find the proper Bosch female connector to go with the male connector used for the reverse light switch mounted to the transmission.  That was not an easy item to locate.  To make it worse, apparently Bosch only manufactures them in lots once every so often because they were unavailable at every place that carried them for months, and then in a weeks time everyone had them. 

At any rate, the drive line is complete, and the motor is safely tied down.  It is resting on and held down to a solid piece of hard rubber designed for motor mounts.  The original cross members that prevent the motor from spinning while under torque are still there, but I've added some rubber cushioning that will absorb shocks from upward travel as well.  So to recap, I have hard rubber pads set to absorb any vertical bumps or vibration, and braces to keep the motor from spinning.  It's not going anywhere, and it should be nicely isolated from any sharp bumps the chassis receives.

The last couple days I finished building the tray and the supports that will hold the MasterFlux A/C compressor.  It's a tricky fit, just like everything else in the car.  It will be suspended from the front battery tray as mentioned in previous posts, but it can't be directly under, or there would be no room to hook the pressurized coolant lines up.  So it has to hang below and slightly behind the rack.  Maybe a video will demonstrate it a bit better.  Take a look.

I'm not sure that the shaky camera and rambling dialogue help clear things up, but hopefully you get an idea of what's involved.  Afterward, I took some careful measurements of where the new hoses needed to run, and disconnected the existing hoses.  I took them down to a local shop and explained what I need.  I was worried that they'd want to finish the hoses on the first visit, and I'd run into problems when tying to put them in the car.  Not only do the hoses need to be the correct length, but the new fittings that I need for the new compressor have to be crimped on at the proper angle so there's no twist in the lines.  Apparently this is not an uncommon problem. 

What they intend to do is cut the old hoses off the fitting end that I need to keep and crimp new hoses on that are a bit longer than I need.  Then they'll call me in and hand me the half completed hoses and the new fittings.  I can then bring the whole lot home and mount it up, cut the hose to length and mark the proper angle to crimp the new fittings on and return it to them for the final crimp.  Of course I still need to find a place to mount the compressor's controller and all the supporting electronics.  Truthfully, that has me worried.  I have an idea of where it might go, but I won't know for certain if it will fit in that space until both battery racks are mounted back in the car. 


With the addition of the new meter, and it's larger shunt, I thought I'd take this opportunity to hook things up in a cleaner way.  The old set up had all of the negative lines from the high voltage side running to one side of the shunt.  There was the 2/0 cable from the controller, the 6 AWG from the charger, a 10 AWG from the heater core, a 12 AWG for the DC to DC converter and a small 18 AWG for the negative lead to the meter.  That's a lot so squeeze onto one terminal.  So instead, I'm adding a bus bar.  The bus bar I got has 4 leads, three of which will hold all those cables and wires mentioned above, and the last remaining one will be reserved for a new cable that will run to the new shunt. 

The only problem is that the bus is only rated for 400 amps.  As we all know, I'm looking to put 1000 amps through it.  Well the reason it's rated at 400 is that there is only one 1/8" thick piece of copper tying all the connectors together.  To over come this, I've made 3 new strips of copper totaling 3/16" to stack on top of the existing one, for a total of 5/16" of copper.  That is more than enough for 1000 amps.  That's nearly twice the thickness of the battery straps. 

Speaking of battery straps, I'm taking out the original copper straps that came with the Sky Energy (CALB) cells and replacing them with the braided copper straps from EV Works.  While I'm at it, I've gotten rid of all the old washers and split ring washers in favor of Nord-Lock washers.  These changes will allow for two things.  First, as the chassis moves around and the batteries jostle about, those braided connections will flex the tiny amount needed and not put any strain on the connection point at each battery.  This will help to ensure that there is always a good connection at each terminal.  To further ensure a good connection, I'm using the Nord-Lock washers.  Once you've tightened down a bolt with one of those washers on it, it does not back off.  Vibration or the usual expansion and contraction due to temperature changes simply won't affect them.  Consequently, no loose connections, no fires. 

The Home Stretch

I took care of a few more odds and ends today. Installed the new radio.

There's the new radio. Just above the gear shift is the Link 10 I've mentioned in other posts. It's reading 160 Volts at the moment. I can cycle it through the current Amps being drawn off the pack, the total number of kWh's drawn since the last charge, and the percentage of charge left. The little green lights across the top are the "fuel gauge". The switch just to the left of the Link 10 is the new switch for the heater.

I also ran all the wires that go from the back of the car to the front, or vice-versa, in a wire loom. Those wires all go under the car in the transmission/drive shaft tunnel. I then anchored it, as well as the battery cables that run up front, to the chassis. That was long tedious work that I'm glad I only had to do once.

To protect all that wire, and to help make the car a bit more slippery through the air, I covered up the tunnel as best I could with some left over sheets of aluminum.

That first seam there looks crooked, but it's not really. The front piece was slightly longer on one side. To get each plate to stand off from the chassis evenly, I used a 1 inch nylon dowel, cut into the proper lengths as stand offs. There were several screws and bolts sticking down from the chassis that had been used to hold either heat shielding for the exhaust or the fuel system. I simply cut a proper length of dowel, drilled a hole in it on one end and then screwed it onto the existing bolt or screw. Once they were all event I screwed the aluminum to them for a nice flush surface. I don't know if it will make any difference in the drag coefficient of the car, but it protects the motor and the wires.

I also finished cutting the carpet and the plastic trim pieces that had been in the trunk and refit them as best I could.

I need to get some Velcro to hold down the back corners of the flooring, but it turned out pretty good. The floor of the trunk is about 1/2" higher than it was and it's a bit wobbly. I'll see if I can't shim it later on sometime. Eventually I'm going to have to figure out some way to keep groceries from falling into the equipment in the back. For now, I'll probably just get a plastic crate or two.

Well, that's just about it. The only thing left is to install the new tachometer when it arrives, and then re-assemble the dashboard. I desperately want to drive it around, but it will be easier to do all that while it's still up on the jack stands. So, for now, it stays put.

Odds & Ends Part XI

Let's start with a list of things I did today...

• Installed high voltage (HV) fuse
• Ran +HV line from trunk to fuse
• Ran +HV line from fuse to breaker
• Ran -HV line from trunk to forward batteries
• Ran -HV line from shunt to controller
  
• Ran +HV line from breaker to contactor
• Re-routed signal wires away from HV cables
  
• Attached all signal wires for the Link10 monitor
• Attached throttle control wires to the Zilla controller
• Attached the RPM sensor wires to the Zilla
• Connected the hairball (Zilla's brain) to the Zilla controller
• Attached wires for heater to the battery
• Attached charger to the battery

Here's a shot of the breaker and the shunt to the right and above it. As I was running all the wires to those two, I realized that there was no safe way to get all those wires in place while the batteries on the right side of the picture were in place. So, I had to disassemble the pack in that box to get that work done.

Here's a shot of the fuse I installed today. That fuse can easily handle the 1000 amps I could draw from the battery pack. But it would blow quickly in the event of a dead short.


Here's the zilla controller at the bottom of the frame, and the hairball at the top. I think I've got all the components wired to it at this point. In fact, I think I'm ready to test the system and see if I can spin the wheels. But before I do, I think I'll go over the wiring of each item, just to make sure I haven't made any bone-headed mistakes.

Time to Make the Cables

Measure, cut, strip, crimp; repeat. Though I can't make the cables that will be the inter-connects between different battery boxes yet, I can make several others. It's a slow process. Actually, you can do it quickly, but I read what seemed like good advice on the subject. It said something like "treat every crimp like it's the most important thing you'll do today." One of the most common points of failure in EVs is bad crimps on the cables, or crimps that seem good at first but with the repeated thermal expansion and contraction, eventually go bad. I sure hope to avoid that. Anyway, so far, so good.

Odds & Ends Part IV

1. Finished the duct work for the forced air cooling on the motor. You can see the gray striped tubing heading toward the firewall. The fan itself will sit back in that area.

2. My first attempt at building a cable with 2/0 copper. It wasn't too bad really, but you can see that it takes a bit of a strange route. Why didn't I go in a straight line from one terminal to the other? Well, to do that, the lug under the rubber boot stuck up from the motor a full 1/4" more than routing it the way I did. Believe it or not, I need that 1/4" to help the batteries that will be sitting on top of that to clear the hood above.


3. On both sides of the motor, you can see the brace I made running down from the motor to the motor mounts. Those are strictly to hold the motor in place when it tries to spin from the torque it generates when accelerating. I still need to drill the hole at the top to allow the 1/2" diameter bolt to go through it, but I don't have a drill bit that size yet.

Odds & Ends Part II

This last week has been spent doing a variety of things.

1. I've been working on removing the remnants of the gas tank, as promised. Loathsome, horrible work. Still, it's coming along.

2. Spent time measuring out and calculating how much 2/0 cable I'm going to be needing. I need to measure it out carefully because the stuff is $4.50/ft on a good day.

3. Worked on fitting the big battery box under the trunk. I have to work out how I'm going to suspend it from the frame and keep everything secure. This frame has to support just over 250 lbs of lead, so it better be up to the task.

4. While out looking for some steel to do #3, I happened to park near an automotive paint store. Though I knew I'd have to paint all the bare steel, I really hadn't given it much thought beyond picking up some spray paint at Lowes and going at it. I thought it would be nice if I could make most of the visible parts the same color as the car, but figured that would be too costly. On a whim, I stopped in and asked if there was anyway to paint some bits to match the car and not pay for a 1/2 gallon of paint, spray gun, etc. He said well I could put it in a standard "rattle can" for you. Apparently if you're in the biz, that's the lingo. I walked out with 2 cans of BMW Hellrot (Bright Red, for those of us who don't do German) for $14 a pop! I did get some primer and clear coat as well, but what a deal! This will help make things look real nice.

5. Look at the pretty sparks! Started measuring and cutting steel. I was hoping that the 10" abrasive wheel I got for my miter saw would do the trick, but no such luck. It cut through a couple of pieces then just stopped cutting. It would seem their claims that it cuts metal are a bit over stated. Looks like I'm going to have to buy a real steel cutting blade.