Monday, November 28, 2011

More Exposure

A few weeks ago I took the car to a couple of different events, and I'm finally getting the opportunity to share it.  The optimal word here is "different" as the experiences couldn't have been more different from one another.  The first, was a car show.

People who've been following this blog for a while may remember that last year I was invited to bring the car to General Dynamics for their employee car show.  It's worth noting that I don't work for General Dynamics, but I know someone that does, so really I'm not qualified to be there.  Last year he suggested to the organizers of the event that I come.  They were quite happy to have me there and I was available so I went.  The car was a big hit, and when I was driving out of the parking lot, they told me they'd like me back next year.  I agreed.

Well, mid-October rolled around and they did indeed contact me asking if I would bring the Z3 back for display.  So the first week of November, I drove down to their offices ready to answer all the questions I knew were coming.  Apparently I didn't warrant being placed with the "Premium cars" like last year.  They just lined me up in some random spot on the grid.  If they'd had some foresight, they would have put me next to the Nissan Leaf that showed up, but they didn't. 

It turns out, it really didn't matter where I was lined up.  Eventually, just like last time, there was a crowd around the car.  It's really the perfect venue to show the car.  This is a company full of technically oriented people, many of them engineers.  Each was curious to see the project and how it was done.  Several stepped forward to ask questions, many of them quite good, all picking my brain for details.  There was one guy who was telling me about the car he has and the conversion he's had planned for it for some time.  Hopefully, getting the chance to see a conversion first hand will inspire him to move the process along. 

This was the first chance I've had to show the car with all the new safety systems in place.  Of course by safety systems I mean sheets of Lexan strapped to the top of the batteries.  Still, like I'd said before, you could throw a bucket of wrenches in the engine compartment and there's no way for them to short on anything.  But best of all, there's no way for anyone to get their fingers on anything that could harm them.  They might cut them selves on something if they stick their hand somewhere too tight, but certainly no chance to electrocution.  It was very satisfying knowing that no one could hurt themselves by mistakenly touching something they shouldn't.

All in all it was a very successful event.  I believe several people walked away with a more positive view of EVs. 

The next day I was at an event sponsored by a local group called Gang Plank.  This was set up by another local EV enthusiast who also attended EVCCON in September, Kevin Larsen.  Gang Plank is what I would describe as a co-op for business start ups.  They have work space and meeting spaces available to people who are interested in starting a business but don't have office space available to them.  Once a week they have a brown bag session for a topic the administrators there think might interest their clients.  Kevin worked with them to arrange a brown bag session concerned with converting a car to an EV.  Understandably, Kevin thought it might be a good idea if I came along and gave a short presentation, show the car and answer some questions.

I thought our presentation was informative if not particularly polished.  What surprised me was how supremely uninterested the group seemed to be.  There were perhaps 6 people (out of 35 or so) who bothered to gather in front of the dais we used and most seemed only casually engaged in what we were saying; occasionally someone would look up. Apparently to see if we were still there.  When the question and answer session came up, there were a few good ones, but I found myself answering questions more about EVs in a broader sense rather than the merits or particulars of converting a car.  For instance someone asked me about the true carbon off set of an EV versus a gasoline powered car.  I did my best to answer these questions, but I'm no authority on such matters.  But more than anything the questions betrayed the fact that what we were presenting to them was really a few steps ahead of where they were as a group.  Just the wrong audience for our material.

After the presentation, a few people and I wandered back to where the Z3 was so that they could look it over.  It seemed more like something to pass their time rather than something that really interested them.  The whole time I found myself hoping that the entire endeavor wasn't simply a waste of time.  Everyone was very nice but no one seemed particularly interested.  There was an owner of a Leaf there who was quite engaged, and we chatted for a while, but he's one of the initiated (so to speak).  The whole day stood in such stark contrast to the events at the car show the day before.  I took solace in the fact that if nothing else these people saw a REAL EV that's being used on a daily basis by a REAL person.  Hopefully that will stick with them.

Friday, November 4, 2011

It's An Imperfect World, Screws Fall Out

One of the frustrating things that occurred during this summer's work on the car was that stuff seems to have broken all on it's own.  Through no intervention on my part, at least two items on the car stopped working.  Trust me when I tell you I've been responsible for breaking a number of things related to the car, but I think I'm innocent here.

After I hooked the batteries back up and turned on the new TBS Link-Pro meter, I had to run through a series of menus to set it up properly.  When it came to the prescaler menu, I selected the 1/10 prescaler because that's what I was using for the older Xantrex Link-10.  To my surprise the meter read that my pack voltage was 68.9 volts.  Well that's a bit off as my pack voltage is 160V.  I double checked the meter looking through all the settings and found everything was correct.  Eventually I pulled the meter out and measured the leads coming from the prescaler itself only to find that the leads which should have read 16V, instead read 6.89V.  Well that put the blame solidly on the prescaler, the meter itself is fine.

I checked and the prescaler was hooked up correctly, after all I hadn't changed any of that.  But there was no doubt about it, the prescaler was spitting out the wrong voltage.  I have no idea why it broke, how it broke or when it broke.  All I know is that when I unhooked the batteries in May, it worked, and when I put them back together in September it didn't. 

Not being an expert in electronic circuits, I have no idea how to fix the prescaler.  As far as I'm concerned, I put 160V on two wires that lead to a little box in which some magic happens, and then on the two wires coming out the other side, there's 16V.  Besides, the unit is sealed.  I was left with one option and that is to replace it. 

I got the replacement 1/10 prescaler and thought I'd measure it before I disassembled the dashboard to put it in.  I carefully hooked it up to the positive and negative leads to the 160V system, and to my amazement the other end read 48.3V.  What the hell!?  Now I had two different prescalers, each of which should be working fine, but both spit out completely different and incorrect voltages.  I sent the new one back at which point they evaluated it and said it was fine.  What!?

I'd ordered the part from Evolve Electrics and was working with Justin Dunn.  It turned out that both of us learned something about this prescaler and the TBS meters.  Both the 1/5 and the 1/10 prescalers will read 48V when hooked up to the pack.  It's only after you hook it to the meter does it somehow adjust the voltage and display it properly.  Like I said before, magic.  Neither of us expected that.  By the way, Justin was great to work with.  I feel quite comfortable recommending Evolve Electrics. 

The second thing that seems to have broken while the car was sitting still was the tachometer.  I drove the car around for a couple days after putting it back on the road, and all was well.  But one evening I left my destination to head home, turned on the lights and found that the tachometer's dial didn't light up.  A few moments later I realized it wasn't working at all!   It had been working when I arrived earlier when the lights weren't on.  When I came to a stop light, I turned off the lights and revved the motor.  Sure enough the tach sprang to life and worked perfectly.  It was hovering at about 2000 RPM and I turned the lights back on and the needle froze where it was. 

I have no idea what would cause such strange behavior, but I do know that I didn't touch any of those systems or their wires when I was performing the work this summer.  But then it just got worse.  A couple weeks ago I was accelerating from a light in second gear.  At about 35 MPH I went to shift to fourth and I noticed that the tach read 5000 RPM.  I thought that was odd because 35 MPH in second gear is about 4000 RPM.  I dropped it into fourth and watched the needle come down to about 3000 RPM, which I know is too high for that speed.  Suddenly the needle jerked up to 5000 RPM, then 6500 RPM.  By the time I finished my trip, the tach's needle had moved well beyond the 8000 RPM top of the dial, and was approaching a full lap coming around to 0 again.  Now the tach just jumps around all over the place providing no useful data.  It's just become a distraction.  I believe I'll be unhooking it.

So what the heck happened to these two pieces of equipment while they were sitting still and not being powered over the summer?  I really wish I knew.  The tach I can live without.  I'll probably replace it at some point, but for now, it stays.  Justin sent the prescaler back to me and I popped it in yesterday.  It works just fine and the meter is behaving like I expected.  If you ever end up with the TBS meter and prescaler combo, don't bother taking a voltage measurement from the prescaler itself, it won't be what you expect it should be.  It has to be hooked up to the meter. 

Monday, October 31, 2011

Safety Issues

While at EVCCON, I spent a good deal of time looking at and admiring all the conversion, and trying to get ideas for how I might improve the Z3.  Among the things that made an impression on me was the fact that the constructors of virtually all the EVs had made a great deal of effort to make the car's motor bays "touch safe."  The Illuminati team mentioned that during the X-Prize contest, they were required to shows that all the compartments that held batteries and electronics were also "wrench safe."  Meaning that you could throw a wrench into any compartment or area in the car and there was no danger of a short or explosion. 

It became clear to me that I'd fallen short in this area.  I never really considered putting much effort into making the z3 "touch safe" or "wrench safe" figuring I was the only one in that area, and I know what's safe and what isn't so why does it matter?  But as I watched all these people milling around my car, I found myself with an unusually high level of anxiety worrying about someone hurting them self.  Several times people leaned over the motor and battery compartment to get a close look at something, only to have their EVCCON lanyard drag across the top of the cells.  In fact a local boy came in to look at the neat cars.  I explained to him not to touch anything for safety reasons, but then watched him like a hawk to be sure he was safe. 

I realized at that time that not only would making the whole motor compartment touch safe be a good idea, it was essential.  Here's the thing...  I never anticipated that the car would draw as much attention as it does.  I never envisioned that I'd be taking it to car shows and there would be strange people so interested in it and getting so close to it to inspect it.  Imagine what the news media (especially Fox News) would say if some hapless person were accidentally injured, or worse, by an electric car at some car show.  In one fell swoop, I'd be responsible for not only injuring or perhaps killing some poor soul, but the EV movement as well! 

At the public car show the last day of the conference, one of the attendees, David Hrivnak, made a point of pulling me aside and asking me what I intended to do about the safety issues.  Not "are you thinking about doing something?", but "what are you going to do?"  David clearly recognized the risks I was exposed to and the implications, and had the courage to bring it to me.  By that time I had already got it.  I was absolutely on the same page as David.  I understood what was at stake and the imperative to resolve the safety concerns he, and by that time, I had.  Thanks again David, I'm very grateful.

I had been looking at the other cars to see which ideas of theirs I could steal.  What I saw was basically two ways of covering the batteries,  terminal and high voltage connections, if they were in an area where they were exposed.  Either they were sealed in a custom built box, or they were simply covered with plastic.  For anyone who's seen the Z3 or the pictures of it, you know there is no room to redo things in order to incorporate battery boxes.  That meant I was going to need to figure out how to simply cover the terminals of the batteries.  In addition, I needed to figure out how to cover the electrics bay where the controller and contactor are.  That bay is the only placed where the positive terminal is exposed that has full pack voltage. 

After a little research I learned that the best material was probably Lexan, so I purchased some from the local hardware store and started measuring and cutting.  Cutting Lexan is not too difficult.  There are special blades available to cut it, or you can cut it with a thin blade, fine toothed saw.  When you cut it with a blade, you simply score the same line 15 or 20 times and then bend the plastic to kind of tear it through the rest of the way. 

I knew the front batteries were going to be the most difficult to cover.  It looks easy enough, but the clearance between the front corner of the batteries and the hood is as little as 1/2".  So to place a piece of Lexan on top of the terminals and run it straight to the edge of the batteries would certainly be hit by the hood once it was shut.  It would require careful cutting and measuring to make it fit.  Since you can't actually see the space once the hood is closed, I used Play Dough to figure out the clearances.  I simply shaped a chunk of it to the size I needed and laid it on the area where I thought the battery cover and the hood touch. Then I shut and opened the hood and inspected the Play Dough.  You can easily see where it's been crushed too thin, or even pierced.  That's where I needed to trim and do some more fitting.

Ultimately I found I needed to bend the front edges of the cover to clear the hood.  I found a piece of scrap Lexan, and sicked my heat gun on it.  I used the low setting thinking that I didn't want to heat it too fast and potentially over melt or set the piece on fire.  It worked pretty well but I found that when I tried to bend a longer edge, the plastic started to show bubbles inside by the time it finally started to wilt.  I tried the higher temperature and that turned out to work much better.  First, it was faster, but second since the plastic was exposed to the heat for a much shorter period of time, so there was no time for those bubbles to appear.  So, higher heat yielded a much cleaner looking bend.

In the detail shot you can see what I mean about the plastic bubbling under the heat gun.  Structurally, it seems fine, but cosmetically it's kind of ugly.  You can also see the slots that I cut into the plastic and the clips I'm using to hold the piece in place.  These clips are an assembly of two channel clips used to hold a mirror up to a wall.  This works fine, but admittedly it's ugly.  I'd love to have come up with a better way to hold this cover down, but this was the best thing I could think of.  I also drilled little 3/32" holes in the Lexan next to each of the positive terminals.  This way I can stick the probe of my multi-meter through the plastic to measure any one or group of batteries I want.

On the larger set of batteries I used D-hooks mounted to the aluminum frame and Velcro straps to hold the piece down in place. Again, not the best looking solution.  You can see that the plastic follows the curve of the batteries nicely.  In the detail shot, you can see that I was able to shape the plastic to accommodate the 2/0 cable coming off the pack, and turn the corner down just a bit to make it less lethal.  I used high heat to make these bends; notice the difference in the plastic from the first bends I made.  It looks much better.

The cover over the electrics bay took a lot more fiddling and cutting to get it just right.  It rests nicely in the grove just below the cushy part of the rubber that seals the area from the elements when the hood is closed.  I made a template out of cardboard and then trimmed the plastic to shape.  As it happened, I'd run out of Lexan and the only sheets at the store were either too small or way too big (and expensive).  So I used an acrylic sheet instead.  I can see why people said that Lexan is better.  Acrylic is much more prone to snapping, cracking and chipping.  I was able to get it done, but it would have been way easier with Lexan. 

There is still one more safety concern I need to address, and that's an emergency cut off switch.  You may remember that I had the big red slap switch under the hood, but there were two problems with that.  One, I had no way of actually slapping it in the event of an emergency, that is if I were in the car driving it, and two, it melted.  At some point, enough current went through it that one of the internal contact points melted.  You can see pictures of that from a couple posts ago if you wish.  To replace it, I got this unit:

This needs to be mounted either in the cabin so that the driver can reach it while moving, or I need to rig up some way of actuating it from in the cabin.  I'm thinking that a push/pull cable mounted to the handle should work well.  The questions remaining are, where do I mount the switch and where and how do I mount the cable?  As of now, I have no idea about either.

Wednesday, September 28, 2011


I've finally arrived back in Arizona after having attended the first EVCCON (EV Conversion Conference) in Missouri.  I rented a car hauler from U-Haul, borrowed my sister's truck, loaded up the Z3 and then my father and I towed the car 1500 miles to Cape Girardeau.  For those of you unfamiliar with the convention, it was put on by the EVTV crew, Jack Rickard and Brian Noto.  The idea was to have the people that have adopted the use of, or are interested in EVs with LiFePo4 batteries, come together. 

To be honest, I simply had no idea what to expect.  My biggest hope was that there would be time to meet with the other attendees and exchange ideas and then see some of the cars up close.  The schedule that was printed up was pretty full and I was concerned there wouldn't be much of a chance for that.  The convention was scheduled to officially start around 10:00 AM Wednesday.  As it turned out, quite a people showed up on Tuesday and began descending on the EVTV shop.  We arrived at the hotel Tuesday around 4:00 PM and immediately ran into Mark Emon, one of the finalists for the EVTV $20,000 EV component give away contest.  Mark was getting ready to run down to the shop and said that we should come along and drop the car off.  We decided we'd follow along and do just that.

When we arrived, there were already 30 or so people gathered around looking at the E-Cobra that Jack and Brian have been working on.  Everyone encouraged me to unload the Z3 and then proceeded help.  I pulled the truck into the shop (a tight fit) and used one of the ramps inside to facilitate getting it off the trailer nice, quick and painless.  Once it was off the trailer, I opened it up so everyone could have a look.  There were certainly lots of favorable comments and questions, and it was fun answering them all.  Jack explained to me that people started showing up well before the appointed time (some as early as Monday morning) and took over his shop.  Though that clearly wasn't the plan, I think he was quite happy to have everyone there.  Around dinner time, someone showed up with several pizza's and we all sat around talking about EVs and sharing pizza and beer.   I don't know that it gets much better than that.  Before I left I asked Jack where he wanted me to put my car and he told me to just park it next to a couple of the others.

The Z3 has never been in better company, nor so thoroughly out classed.

Wednesday we arrived at the shop around 10:00 AM and found that it was already teaming with activity.  The previous day, they'd put the final pieces together in the E-Cobra and tried to drive it, but found it would not move under it's own power.  Motor spun, but in spite of the fact that the clutch was firmly engaged the car wouldn't move.  Six to eight guys were working on it and pulling the transmission to see if they could determine the problem with the clutch.  As the day went on, more and more cars arrived, each impressive and a joy to look over.  Sebastian Bourgeois' 911, Fred Behning's 1960 Austin Healey Sprite, Charlie and Tamera Rickman's 1973 Opel GT and Daniel Yohannes' Porsche Cayenne just to name a few. 

Fred Behning's Austin Healey Bugeye Sprite.  One of my favorites.

The back end of Sebastian Bourgeois' 911.  Yes, there are two motors in that space, one on top of the other. 

Eric Kriss' 356 Porsche replica.  An astonishingly beautiful build.

A peek into the back end of Duane Ball's Porsche 904 replica.  Another gorgeous conversion.

I can't express what a joy it was to talk to each and everyone of these great people.  Instead of the first two questions out of everyone's mouth being "How far will it go?" and "How long to charge it?", they were asking great questions like "How did you solve this problem?" or "Why did you choose that design?"  Starting off with a pool of people that already "get it" set the stage for some very substantial, entertaining and valuable conversations.  This was truly a fantastic day.

The next two days took place at Jack's hanger out at the Cape Girardeau airport and were comprised mostly of various speakers and eating (man, there was a lot of food).  The speakers lined up ranged from individuals that own and run conversion shops, suppliers of EV components (both sellers and manufacturers), industry analysts, with a couple of speakers on technical issues thrown in for good measure.  I had no expectations for most of the speakers and very high expectations for others.  As it turned out, each speaker was quite good.  A few stood out, having put together truly informative and interesting talks, but also delivering them quite well.  George Hamstra from Netgain motors gave two talks, both packed with information about where we, as a global community, are going in regards to oil usage.  Eric Kriss delivered a terrific analysis of why EVs make sense now and why and how that's come to pass.  Ryan Bohm of EVSource delivered a great talk about a variety of topics related to EVs including details of the new WarP-Drive controllers and safety concerns regarding EVs.  The latter made a big impression on everyone.  It was well stated and impassioned.

Thursday evening, Chris Paine, director of "Who Killed the Electric Car" and "Revenge of the Electric Car" gave a talk.  It was an interesting talk, but largely about the concerns and issues surrounding making movies.  He is, however, clearly passionate about EVs.  After speaking for an hour or so, and madly texting and emailing his producer to get permission to show us "Revenge of the Electric Car" he had still not received the OK.  Ultimately he took the decision into his own hands and rolled the film.  It's set to come out October/November in different cities, so it was a great opportunity to see it early.

The film was basically an overview of four different groups, or in one case a person, working to bring an EV to the market.  It featured, Bob Lutz and his efforts at shepherding the Volt into production at Chevy, Elon Musk and Tesla's saga, Carlos Ghosn and Nissan's preemptive dive into the EV world, and finally Rev. Gadget and his attempts to put together a 120 mile range Porsche 356 replica conversion that he can market.  It was basically a documentary on the difficulties, setbacks and successes of each.  It was well worth seeing and very entertaining.  When it comes to your city, I think it's worth your time.

Later in the day on Friday, we all went out to the runways behind the hanger for some festivities with the cars, including weighing each, a drag race, and an auto cross set up by the local SCCA.  The Z3 came in at 3285 lbs, which is rather portly compared to several others, being that so many of the cars there were built from light weight sports cars, or replicas.  (A side note, and I don't remember the source, but the stock Z3 actually weighed more than a standard 2 door E36, BMW 3 series chassis.)  What I thought was odd was the weight was dead on identical to when I had it weighed after it hit the road a year and a half ago, but the weight distribution went from 52% / 48% front to rear weight bias, to 50% / 50%.  Can't explain that.

I've never participated in any sort of drag race.  Not the official sort on a track, or the race off the line at the local street light.  It's just not my thing.  But I have to admit, it was great to find out just how well the Z3 would perform in an official, measured way.  As it turned out, my car was the first weighed and the first at the line to run the 1/4 mile.  It took some time for the next car to get weighed and staged.  When we were all set, the lights on the tree (that's drag racing talk for a pole with lights on it) gave us the green to go.  I started in 2nd gear and screeched the tires like mad, much to the crowd's approval, but I knew that meant I'd lost time.  At the end of the run, I left it in 4th, which meant my torque was dying off, and I lifted just before the end.  Like I said, I've never done this.  But I realized right away I could do better.  So the first run was 19.2 seconds at 61.8 MPH.

I lined up to try again.  This time I started in 3rd and hit the power with a bit more care to be sure not to spin the tires.  When 4th was losing torque I went to 5th, and I could feel a bit more torque kick in.  That run was better at 18.9 seconds, 66.4 MPH.  All in all, in a field of 22 cars, the Z3 came in a respectable 9th.  Aside from Ron Adamowicz's purpose built Camaro drag racer (which was awesome) the top runner was Dave Hrivnak's Tesla Roadster that ran it in 13.1 at 88.2 MPH.  Later, Dave gave me a ride in the Tesla, for which I will remain eternally grateful.  He took me down the 1/4 mile run.  I don't think I've ever experienced anything so blisteringly fast.  I'm not even sure the magnetically launched roller coasters I've ridden accelerate that fast.  It was simply astonishing.

Having run what I thought was likely the best 1/4 mile I could, I went over to the auto cross.  I picked out a helmet and was given an instructor.  He explained to me how to read the course and how to attack various corners.  We set off on the first lap and I did fairly well finishing in the mid 50 second range.  But the instructor said "This car has a lot more to give, so I know you can do better."  I knew he was right since I hadn't caused the tires to squeal once.  Within a couple more laps I was down in the upper 40's.  I ran several more times trimming off a little more each time.  The car performed great!  I was throwing it into corners and driving it like it was meant to be driven.  The last big corner you hit at pretty good speed and I was nearly drifting around it, the back end just barely hanging on.  When it was all said and done, it got down to 44.7 seconds.  Not the best time, but in the top of the pack.  It would likely come as no surprise, but the Tesla set the best time in the mid 41's.

Ultimately I had to stop because I was running low on charge.  That was the most fun I've ever had in a car, and that includes a few memorable nights in high school and college ;)

Saturday, we wrapped up at the hanger and then all of the cars drove down to a park in the middle of town for an EV car show.  Each of the cars was on display and each builder was available to answer all the normal questions posed by people just seeing EVs for the first time.  It was a great crowd and there were a number of people from the media there to film and photograph the cars as well as interview the drivers.  We left the park in a police escorted parade around Cape Girardeau.  Here is a fantastic video put together by one of the participants.  He highlights each car and puts some information up about each (though he did get a few facts wrong on mine, it has an 11 inch motor!).

At the end of the parade, all the cars were gathered in the parking lot of the hotel, parked and arranged ever so carefully for some photos.  First the cars by themselves, and then all the owners went and stood by the cars.  Sadly, I did not have may camera.  I'm hoping that one of the kind people that has a copy will send one to me.

It's difficult to put into words, but that was a profound and powerful moment.  I think everyone felt it and knew it was important.  There was something palpable in the air.  The sense that this was the beginning, the beginning of something big.  Sure manufacturers are going to begin producing EVs for the public.  But I, and I think everyone there feels that a big part of the future of EVs will be conversions.  We were there to bare witness to the beginning of a movement that will change the world. 

Wednesday, September 14, 2011

Cool Air

I took the Z3 down to the shop today to have the A/C lines evacuated and charged.  I had to explain to the technician that was going to drive the car into the service bay how to operate the car.  I wanted to make sure he was comfortable.  There really is no trick to starting and driving it, but the lack of noise can throw people off.

After an hour and a half or so, the service rep came out to ask me if the oil that ships in the compressor has any dye in it.  "Why, are you seeing dye?"  They weren't, but he explained that the system was not holding a vacuum and they couldn't pin point the location of the leak.  So they were thinking of putting some refrigerant in system to see if they could see the leak when it spit out colored stuff.  The thing is, it's the oil in the systems they use that contain the dye when they want to track a leak, but we can't contaminate the MasterFlux system with standard oil for A/C units because it uses a special type of oil.

I asked them to do what they could to find the leak and moped back to my seat dreading having to take the system apart again.  About 45 minutes later, the tech that drove the car into the service bay came back and asked me how much refrigerant they should put in the system.  He explained that they'd put just under 2 lbs. in and it wasn't quite as cold as they like to see.  Uh, what?  I thought it wasn't sealing properly?  He explained that it didn't under vacuum, but once they put refrigerant in the system, it seemed to be holding pressure just fine.

No one seemed to really know why this would be the case, or how something like this might happen.  But the service rep hazarded a guess.  He was thinking that the seals in the system may simply have been allowing air into the system when they were drawing the vacuum down because they'd dried out from the system being empty for so long, but once they turned the compressor on and the oil started flowing around the innards of the system, it may have lubricated the O-rings and helped them seat.  Since no one had a better idea than that, we decided that must be it.

They put a thermometer in the vent and let the system run for several minutes to get a temperature reading of the out put.  It read 60 °F.  That is on the high end of normal.  He noted that the high pressure side of the system had lower pressure than they're used to seeing.  While I don't know this to be the case, my suspicion is that this system, which is designed to run between 120 and 420 VDC is operating at the low end of the scale in my car at only 160 V.  So my guess is that it simply doesn't have the voltage behind it to drive it hard enough to get higher pressures.

In any event, the drive home was very pleasant.  The compressor is pretty quiet.  Standing over it while it's running, you hear a tick-tick-tick-tick sound, but its not particularly harsh or disturbing.  Inside the car, I can feel it more than I can hear it.  Well I can't really hear it from in the car, but I can feel it in my feet.  Without it being mounted on those rubber bushings, I'm sure it would be very shaky indeed.  All in all, I'm pleased.  I would have liked another 10 °F temperature drop, but this is so much better than no A/C, I'm not complaining.  I will be keeping an eye on it over the next few days, weeks, months to see if the output changes.  I'm not convinced there's no leak just yet.

I also had them align the front end so that it has 0° toe-in.  Normally cars are aligned with a slight 1 to 2° toe-in for tracking purposes.  Without that, cars will tend to wander about the road, potentially following cracks or grooves in the pavement.  Not a desirable trait really, but neither is an EV that uses more energy that in needs by scrubbing it off with the tires.  As it turns out, they didn't have to adjust it much, and like I said yesterday, I really don't know if it's had an impact yet.  On that note, I did receive the new 1/10 pre-scalar today, which will allow me to measure energy in and out again.  Now I get to begin the long, arduous task of disassembling the passenger side dashboard. 

Tuesday, September 13, 2011

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. 

Tuesday, August 30, 2011

The A/C Lines Are Installed

I confess, I expected that getting the A/C lines made to hook up to this compressor was going to be a challenge.  You could even say I was pessimistic about the whole affair.  I just couldn't envision how these lines could be made to fit in place, tie seamlessly into the car's existing system and hold pressure.  For a while it looked as if my doubts were justified. 

When I got the hoses back toward the end of last week, the technician handed them to me and began to explain how I should hook them up.  He said I should hook both ends up first, and then tighten the compression fitting in the middle.  I felt a wave of panic when he said "compression fitting."  You see, I hate compression fittings.  Despise them.  If there's a hell, it's occupied by the man that invented them and everyone else who is there is forever forced to try and make them work.  It's been my experience that compression fittings work absolutely fine, until you try to put anything in the hose they are on under pressure.  Then they proceed to leak everywhere, and nothing you do can makes them work. 

I hooked up the long, low pressure line that runs from the evaporator to the compressor, and began carefully tightening the compression fittings.  For those of you unfamiliar with how to tighten them, you are supposed to tighten them hand tight and then give the nut another 1/2 turn or so.  If you under tighten it, it leaks.  If you over tighten it, it leaks and you've ruined the ferrule inside and must replace it or the whole thing.  With that in mind, I followed the rules: hand tight, but then I did about a 1/4 turn.  I did a pressure test and it leaked like mad.  OK, 1/4 more of a turn and another pressure test.  More leaking.  *Sigh*  1/4 more of a turn and it's leaking worse than ever.  Undo the whole thing, check for dirt, debris or any other problems.  It all seems fine, so try it again. 

This went on for 3 hours or so.  It began to become difficult working through the tears of anger and frustration.  Eventually I had to resign myself to the fact that it simply wasn't going to work.  Oddly, the second hose, the high pressure side, seemed to work just fine.  Now I say that having not had the system charged.  I fully expect that when I take it down to have the shop draw a vacuum on it, and then charge it up, they're going to tell me it leaks from that joint.  I sure hope not, but if one of them is going to leak, that's the one that I can deal with.  I can reach it and remove it without dis-assembling the car.  The low pressure side requires I remove the larger battery rack under the hood to access it. 

I took it back to the shop today and explained my problem.  One of the guys, who's clearly been in this game for a while, looked at it and said, "Yeah, that will never seal.  It needs to be brazed."  That was music to my ears.  He said give us a few minutes and we'll take care of it.  They brazed a nut fitting on the aluminum tube and crimped it's male counter part on the existing hose.  I was a little irritated that I'd spent all that time on a fitting that clearly the expert felt was the wrong part for the job.  But I was so happy that it now had the right joint, I wasn't about to complain. 

I took the parts back home and began hooking them up.  It took a couple hours and I got the new dryer/receiver in place, both new hoses, the compressor mounted and the new lines attached to the compressor.  It looks terrific, but I have no way of pressure testing it apart from adding coolant to the system, which I'm not going to do until I know it won't leak.  Once the rest of the car is assembled, I'll drive it down to a local shop and they'll do all that for me.

I put together another quick (and very rough) video of what was accomplished today.  Take a look...

Another component to this is the controls for the A/C system.  They consist of an On/Off switch and a potentiometer that acts as the thermostat.  MasterFlux sells a little black box that incorporates both of those items, but I can't imagine using that in the car because it's simply hideous.  They say it's mostly for testing, and I can believe that.  I picked one up in case I needed it, but I don't think I will, so it's going back.  Instead, MasterFlux publish the specs on the device complete with part numbers and how to wire it.  I found the very same potentiometer online and bought it.  The great thing was they also had a variety of knobs to choose from to mount on the potentiometer's shaft, as well as the molex connector needed to plug all the wires into the controller board.  For the On/Off switch I'll be using the original A/C On/Off switch that came with the car.  Here's how the whole thing came out.

 Down low on the center console, just the right of the gear shift is the little silver knob that will be the temperature control for the system.  I really could think of no way to incorporate that functionality into the car's original thermostat dial above.  You see that dial just moves different baffles to control the direction of air flow, either over the A/C system's evaporator, or over the heating core.  There's no way to hook any electrical component up it.  At least no way I was willing to try.  I think that little knob will do just fine.  The On/Off switch is the top button in that two button module directly to the right of the new Link-Pro meter.

Lastly, you may recall that I was having problems keeping the Zilla controller cool in the desert heat.  I think part of the problem was the fact that I was using a radiator that was only 4"x8" in size.  Well in the video above, you saw that the new radiator is about 3 times that size.  Hopefully it will keep things a bit cooler.  But it also has a nice big fan to help suck air through it.  Well, I didn't see any point to having that fan run all the time.  After all, when I'm sitting idle in traffic, there's no heat generated in the Zilla, or when I'm cruising down the road at 40 MPH drawing only 60 amps, the air moving through the radiator is more than adequate to cool the controller. 

What I need is some way to monitor the temperature of the controller and turn the fan on when it starts to get too warm.  I started looking and found what I think would work.  It's a switch that will close a contact when it hits 122 °F.  It opens up again at around 115°.  That is well below the point the Zilla begins to complain about heat, but high enough that the fan won't run unnecessarily.  The switch itself is just a little button style switch that has to be in contact with the item you're monitoring.  The place I've noticed seems to get hottest on the Zilla is the top, right in the center.  It may get hotter else where, but I don't have access to where ever that might be.  So the question became, how do I mount a small dime-sized switch to the top of the Zilla without it moving around or looking too hideous.  Here's what I came up with, you be the judge...

That piece of aluminum is pressed and held down tight to the top of the controller.  The switch is held down tight to the aluminum strip.  I used some thermal paste left over from my last CPU purchase to help heat conduct into the switch.  The switch drives the relay you see at the bottom of the screen, which will then turn the fan for the radiator on.  OK, it might not be the sexiest of solutions, but I thought it was pretty clever and should do the trick nicely. 

Wednesday, August 17, 2011

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. 

Monday, August 1, 2011

The A/C System Has Arrived

Last week, the Masterflux A/C system arrived from Revolt Electric, a full 3 weeks ahead of the initial 6 week wait they said I was in for.  Fantastic news and time to get cracking on mounting it.  I opted for the Sierra Model 06-0982Y3, and the 025F0140-03 controller.  The controller can be driven with anything from 120V to 420V DC, and the compressor is capable of putting out over 15,000 BTU.  Of course, that's when it operates at over 300 V DC.  Since my pack voltage is 160, it will be putting out roughly 10,000 BTU.  Should be plenty adequate for a two-seater car that has slightly more cabin space than the inside of a microwave.  At full power, it will draw about 6 amps, just shy of 1 kW. 

First things first.  In order to mount the A/C compressor, I need to know how much room I have to work with.  It's going to fit right behind the condenser for the A/C system and the new radiator I'm installing for the Zilla.  But before I could measure how much space I needed to build the frame that will hold radiator and then mount it in place.  Here's a shot of the radiator in it's frame:

Essentially what I built is a frame made from various angle aluminum stock.  The radiator doesn't have any screws or brackets that you can use to mount it to anything.  All it has is three pegs meant to hold rubber bushings that would then be pushed into some mounting bracket.  Try as I might, I could not find any bushings that would fit the posts.  What I did find where rubber stoppers at the local hardware store.  I bought three of them and drilled a hole through each.  Then I constructed the frame, drilling holes to accept the "bushings" I made and then fastened the whole thing together.  It turned out pretty well.  The radiator is suspended in that frame via those bushings which provide a little shock absorption for the assembly.  It will be suspended from the front battery rack by those two tabs you see sticking out of the top of the rack.

Once that was complete, I put the assembly in place and just clamped it so that I could start figuring out how to position the compressor.  I was very worried that I'd have little to know extra room, but as it turns out, I have loads of space.  I think there may be as much as a full inch in either direction for me to play with.  That may not sound like much, but trust me, that is huge.  I've had a difficult time fitting very nearly every component since I started the build, running short by 1/16th of an inch here or there was way to common.  Very frustrating.

The A/C compressor will rest in a tray I've made, that will then be suspended from the front battery rack as well.  Here is a shot of the tray I made today:

Notice the three large holes in the middle.  They are for the rubber feet that hold the compressor, which cushion vibration while it's running.  The tray is 1/8" aluminum plate surrounded by 1x1 inch aluminum angle stock.  It is light yet remarkably stiff.  The compressor weighs about 20 lbs, so it needs to be sturdy. 

At this point, I'm very glad I made that rack out of steel.  It will end up supporting 12 batteries, the power steering pump, the Zilla's radiator and the A/C compressor.  Fortunately it's more than sturdy enough to support all that weight, as are the brackets it mounts to in the car. 

My recent experience working with steel and aluminum for all the different support structures that I'm adding is not too dissimilar than my past experience.  I've found that building an EV is an endeavor that requires a great deal of care and attention to detail.  You decide how and where you're going to mount something, and measure the space.  You measure even more carefully, and even build cardboard models.  Then you begin cutting the metal you need.  Once everything is cut, you start drilling and bolting and/or welding it into it's final shape.  You then go back to fit it in the car, and discover that it won't work for some completely unexpected reason.  So you scrap the whole thing and start over.  Maybe it's just me, but this seems to be an ongoing theme. 

Next I get to build the structure that this tray will be suspended from.

On a final note, I did finish installing the new Link-Pro meter in the car.  It fit perfectly, replacing the Link-10 effortlessly.  I still need to find a new place for that shunt, but I'm not too worried about that. 

Thursday, July 14, 2011

Now That's a Shunt!

There hasn't been a lot to report over the past few weeks.  I've been dealing with acquiring the hardware necessary for the Air Conditioning system. 

You may recall I'd ordered a Masterflux compressor and controller off a user on eBay for a bargain $200.  The unit was reported to be new but old stock.  In addition it required a 48 Volt DC supply.  I'd been looking for how I was going to supply the necessary current to the controller at the proper voltage.  Well the good news is that I've solved that problem, sort of.  It turns out the compressor was not new, old stock.  It was in fact used and not in good condition.  The compressor had been crammed into the box along with two poorly protected controllers.  Both had sustained damage while in shipment. Why the shipped two controllers, I have no idea.

Ultimately, I didn't trust either controller to work properly, and simply because of the circumstances, perhaps due to guilt by association, I didn't trust the compressor either.  Everything went back. 

Instead I have on order a brand new system that is designed to work directly off of my 160 volt DC system with no modifications required.  The upside is obvious; the downside is it was $1200 more than the other system.  Still, I'd rather spend the money and have a system that works.  I don't want to mess with it once it's up and running.

In the mean time, I've been working on the revised motor mount.  I cut and formed some steel and started dry fitting everything.  Sadly I ran into another road block on this front.  The problem I face is of course one of space.  I need to get adequate shock absorption material under the motor.  without any, it simply lays on the front steering rack with about 1/2" gap between the motor and the sub-frame right behind the steering rack.  I need to support the motor so it's at least 1/4" off the rack so that it doesn't hit it during any vibration.  More space would be better.  The problem is that if I push the motor up too far, I begin to ruin the alignment of the drive line. 

So, I need to find a way to support the motor in the proper position, with the proper attitude, provide shock absorption and tie it to the frame securely.  I could go back with the previous solution I had, but I'd really like to add more shock absorbing material.  The short story is that the pretty solution I drew up in the previous post simply won't work.  Back to the drawing board.

I also started working on a minor part of the A/C system, and that was how to turn it on and off.  The Z3 has a neat little button in the console with a picture of a snow flake on it.  When you depress the button, it glows orange and turns on the A/C.  I tried it out to make sure that it still sends a 12volt signal to the line that previously went to the compressor to turn it on, and no luck.  I don't know if the ECU needed other connections from the wiring harness that are no longer there, but there was no way I could get that to power up. 

Instead, I took the switch out, and started reverse engineering it.  That switch also has the button to turn on/off air recirculation within the cabin.  It has 8 points of connection.  In short order I figured out which blade had power to it when all the right conditions were met; the A/C button was depressed, and the HVAC system fan was on.  I simply spliced a new wire into that line so that I can draw 12V off it to power a new relay.  That relay will turn on power to a fuse box that will provide power to the Masterflux controller and the AC condenser fan and a cooling fan for the controller itself. 

I'm also taking this opportunity to swap out the Xantrex Link-10 meter I've been using, for a Xantrex Link-Pro.  OK, it's actually the e-Xpert Pro; same thing.  Why the change?  You can chalk this up to a rookie mistake.  In the beginning, when I was ordering all the parts for the car, I simply didn't understand how all of the component's specs needed to match up.  I ordered a Zilla capable of putting out 1000 amps, and the Link-10 capable of reading only 500 amps.  As long as I left the Zilla set to a 500 amp output or lower, then the Link-10 meter could measure the current accurately.  If I set the Zilla higher, it didn't hurt the meter, but it simply didn't read the current, which meant the usage it reflected in terms of the battery's state of charge would be wrong. 

Part of the package is a much bigger shunt, one that can handle 1000 amps vs. the 500 amp shunt for the old meter.  Check it out...
It reminds me of Crocodile Dundee, "that's not a knife..."  That thing is huge!  Which raises a concern as to where I'm going to put it.  I think I'll  be able to fit it where the old one was.  I hope.  Fortunately, the meter is exactly the same size and the leads I need to power it and provide data to it are identical, so it's a straight swap as far as that goes.  I did opt for one other thing when I bought the meter, and that is a temperature sensor that I'll be running to one of the batteries.  I'm going to pick one somewhere in the middle of the pack, one that is likely to get the warmest.  In this way I can keep an eye on the temperature of the pack during the summer heat. 

One other thing I've done was to remove the gaps between the batteries I have in the box under the trunk.  I'd put gaps between them so that I could force air between them if necessary.  I had installed a thermal switch that would turn on and force air over the batteries if they reached 125 °F.  It never came on.  Plus with the temperature monitoring I will now have on the meter, it's not really necessary.  But the biggest reason is that I intend to replace all the copper straps that connected the batteries with braided ones.  In order to do so, I need the batteries pushed together. 

So, I pushed all the batteries together and then carefully measured and cut some wood to push into the space created.  Mind you, this isn't to compress the cells, but merely to keep them from moving around. 
You can see it there over on the left hand side.  As I'd mentioned before, and as several people have discovered, the cells do not expand unless you over charge or over drain the, rendering clamping them together unnecessary. 

Tuesday, June 21, 2011

Motor Drama

I have refrained from posting about this for a variety of reasons, but mostly because I wanted to write it up in one story once I knew the whole story.  While there's no "happily ever after" quite yet, but I'm optimistic that there will be.

Sometime this last February I noticed a disturbing, but familiar feeling in the car's drive line; vibration.  It started small, and I kept telling myself it was my imagination.  But two weeks or so later, there was no denying it, the wobble that forced me to pull the motor a year ago was back.  I was, and remain absolutely perplexed as to how this happened.  I took the cooling shroud off the front and, sure enough, the balancing putty fell out the front.

I contacted George Hamstra and Netgain and told him what had happened.  He was more shocked than I was.  He explained that only one other motor had ever had the balancing putty come off, and that was because the owner had spun the motor up North of 9000 RPM.  He went on to say that they had never seen it happen twice!  Well, my motor has never seen anything over 5000 rpm, so that wasn't it.  I also have cooling air forced into it constantly, so heat shouldn't have been a factor.

George talked with the folks at Warfield electric, brainstorming on what the possible cause might be.  They were able to rule out the RPM and temperature possibility right away.  The wondered if perhaps they had a bad batch of putty, but reasoned if that were the case, then they would be seeing failures on multiple motors since a single batch will be used on several motors.  Well that wasn't happening.  They speculated that perhaps it had been applied poorly.  Who's to say, but it seems unlikely that it was applied poorly twice on the same motor.

George joked that "It's just you Tim!"  Truthfully, I don't know that he's wrong.  I explained how I had the motor mounted up in as much detail as I could.  The motor was tied down to the sub-frame of the chassis with a rubber pad under it to absorb shock as it moves down relative to the car.  He commented that what I described to him should be absolutely adequate.  In fact he's seen installs where the motor is tied directly to the chassis with no dampening material at all, so the motor feels every shock the chassis does to no ill effect.

We were all left scratching our heads.  I'm perfectly willing to accept the fact that it was something stupid that I did in the mount design or build, but I don't know what.  I'm also willing to believe that the putty just wasn't applied properly, but I have no evidence that's the case.  Presented with no clear cause to the problem, George stepped up and did what I think few manufacturers would do these days; he offered to fix it and cover the costs.  He and his crew arranged to have the motor picked up, shipped to Warfield Electric, fixed and shipped back at their expense.  I assure you this is not an inexpensive endeavor.

But then he went a full step further saying that if this doesn't fix the problem, he just wants to replace the motor.  I'm speechless really.  It's so reassuring to know that ultimately, I'm going to have a good motor.  On the other hand, I desperately don't want it to come to that.  At this point I'm certain that George has lost money on my motor, having to shipped and repaired it twice. He'd be better off never having heard of me.  This is a painful prospect to me.  The one way we have as consumers to vote for products we favor in the market and to support companies we believe in is to hand them our cash.  I don't know of too many causes, companies or products that I support more than EVs, Netgain, and the WarP motors.  So the fact that my "vote" has been nullified because of this pains me.  My hope is that this is the last time the motor is out of the car for repairs.  My hope is that the only time George hears from me again is when I tell him I'm buying another motor for another project.  Time will tell.

So, Netgain and Warfield have done their part to try and put a reliable motor in my hands.  The question now is what am I going to do?  As I mentioned before, I don't know if the way I had the motor secured to the car was the cause of my problems or not.  George may look at the car at the EV Converters Convention (EVCCON) in Missouri in September and say "Wait, you mounted it like this?!  You fool!!" and punch me in the face.  I don't believe there was a problem with the mount at this point, but I've decided there is an area where it could be improved.  Take a look at this crude drawing...

This is not too different from the old support with the exception that there is now some new rubber above the angle iron supporting the motor.  That additional rubber should offer additional cushion to the motor from movement.  In the previous mount, which does not have that upper rubber piece, if the chassis dropped down suddenly, the motor would be forced down, incurring a bit of a shock while it followed the chassis downward.  However, the new design will allow a little cushion to that shock providing some buffer to the motor when it moves both up and down.  What isn't represented there is the strap that goes around the motor to hold it down to the mount, and the bars mounted from the motor to the chassis for anti-torque support. 
Will this be sufficient to protect the motor?  I certainly hope so.  I've sent the design to George as well, looking for his input. 

At any rate, the motor arrived back from it's repairs yesterday and looks as beautiful as ever.  They even gave it a fresh coat of paint.  I'll be mounting it to the transmission over the next couple days and dropping it back in the car.  Once it's in place, I can start fabricating the new mount so it holds the motor in the right place.  I'm going to be building a whole new one from stronger materials rather than adapting the old one.  I think it will be easier to incorporate the change on a newer build. 

Tuesday, May 24, 2011

Some Over Due Updates

I mentioned a couple weeks back that I had some changes planned for the EV-Z3, and the time has come.  I'm not going to spell them all out now.  Rather I'll write about each as I tackle them, and go into detail as to why I decided the change was necessary.

Air Conditioning:

It doesn't take someone on a full ride scholarship to MIT to see why I'd want air conditioning in a car in Arizona.  Last summer, I thought I'd tough it out and put up with what I remembered to be "minor discomfort" when driving cars with no AC in my youth.  But I must be getting old, soft, or both because after a couple trips I'd had enough and the car started to see action only in the evenings when the temperature dropped to around 100 °F, or on rare occasions into the 90's.

You may remember that I had managed to install the original compressor into the car and planned to run it off a pulley mounted to the tail shaft of the motor.  I didn't have it hooked up because the compressor was in a different place in the engine bay, and the hoses didn't reach.  Well I'd just thought I'd have them remade once I was up and running.  With space being as tight as it is, there was no way to do that work without taking out the batteries.  It became clear I was going to have to remove the batteries in order to get AC.  So, into the garage the car went and up on jack-stands. 

There's an inherent problem running the AC off the tail shaft.  When the motor isn't spinning, you can't compress the refrigerant in the system.  I could sit with the clutch in and idle the motor, but I don't want to do that. I want a car that works normally, and not one where I hand the keys to someone and have to give them a talk about how to make the AC work properly.  That meant I need to run the compressor off a secondary motor.  I had bought a little 2.5 HP DC motor, originally used on a tread mill, back when I started the project, specifically for this purpose.  The problem is there simply isn't enough space to put that motor, the compressor, and the metal assembly needed to hold them together into the car.

Most people into EVs have heard of or seen the small DC powered compressors made by Masterflux.  Great product, and a perfect solution for me.  They are small enough they will fit in the space I have.  The only problem is the compressor and the controller needed to power it come in at over $1200.  In the scheme of things, that's not too much, but I'd rather avoid that expense if I can.  As it happens, someone is selling a number of older, new stock of these compressors on eBay at the moment.  The good news is that they are asking $200 for the compressor and controller.  The bad news is they require 48 volts input and can draw up to 18 amps.  So, I bought one.

Now, I have no way of delivering 48 volts to the system.  Especially at that level of current.  A friend of mine, who is quite savvy with electronics has offered to help me build a power supply for the compressor.  I know what you're thinking, and I can't really say your wrong.  I'm an idiot.  But I figured, the worse case scenario is that I can't build the power supply, and I simply re-list it on eBay.  But if I can get it to work, I've got a great little AC unit, at 1/5 th the cost after I figure in the cost of parts for the power supply.  I haven't convinced you have I?  I don't blame you, I'm not convinced yet myself.

Controller Cooling:

A second big issue I need to solve is better cooling for the Zilla.  The radiator I'd originally installed to cool the Zilla is 4x8 inches, or 32 square inches of area.  I installed two 120mm DC fans that continuously pull air through the radiator in an attempt to keep things cool.  It did just great 9 months out of the year!  I had enough room for a bigger radiator, and I found one that uses just about all that space.  Here it is right next to the old one.

It's 8x14 inches for a total of 112 square inches.  That's 3.5 times more surface area than the smaller one.  And the fan that came with it moves 331 cubic feet of air per minute, while drawing less than 5 amps.  The old set up had the fans running all the time.  During most of the year, and certainly when the cars moving through the air, this is a waste of energy.  What I intend to do with this set up is run the fan off a thermostatic switch.  I have a switch that will turn on at 122 °F, and turns off at 104.  The only thing is that it's a surface mount switch.  That means I'd have to find a way to physically press it and hold it to the Zilla, and preferably the area on the Zilla that gets the warmest.  That happens to be dead center on the top.  Hmmm...  Not sure how I'm going to accomplish that without venturing into the steam-punk genre of EVs.

What I'd really like is an inline thermostat I can splice somewhere in a hose.  The only problem is that all the ones I've found are for ICE cars so they come on at over 200 °F.  Not suitable for my needs.

Removing some junk from the trunk:

You may recall that to monitor the batteries, I'd originally installed some test lines which I ran to terminals in the trunk and in the front of the car.  The idea was that it would make it easier to test the batteries to find if they were different voltages to each other.  Well, I've found that's unnecessary.  Since bottom balancing the pack, I've learned which cells hit the top first when charging; and by top I mean 3.45 volts.  Of course the real top end of the batteries is 3.6 volts, but the difference in the actual energy stored in a battery that's 3.45 vs one that is 3.6 is so small that it's simply crazy to try to push that extra little into the cell.  Especially considering the crazy fast rate the voltage will rise above 3.6 at the end of the charge and the damage that can be done if it goes higher.

To safeguard those few batteries, and in turn all the rest of them, I have the charger shut itself off when those few cells get to 3.45 volts.  If I want readings off of other cells I just take them.  Having those extra wires in the car was not only ugly, but a fire hazard.  So out the came.

I had installed some relays in the trunk in an ill fated attempt to turn off the DC to DC converters when the car is not in use.  The problem is that those Iota converters have a large bank of capacitors in them that store energy quite nicely.  So when I would turn the car back on, there was a fair amount of arching inside those poor relays, and they welded themselves shut in 3 or 4 cycles.  The only reason I wanted the controllers off was that in the summer, the ambient air temperature is warm enough that their fans run constantly.  Slowly, but constantly.  I may address that at some point, but for now those relays and all that extra wiring was not needed.  So out it came.

I also decided that I would eliminated the spaces in between all the cells in the battery box in the trunk.  You are supposed to clamp all LiFePo4 batteries together between something that can keep them from swelling.  Apparently they have a tendency to bulge in the middle a bit after multiple charges.  Well, I'm not so sure about that.  I took off all the connecting straps that I'd made so that I could leave an 1/8" between each battery, removed all the hardware anchoring them down and shoved them together.  They nested up snugly, one to another just like when they were new.  Keep in mind that this is after one year's worth of driving and 287 charging cycles!

Giving some thought to this, I've come to believe one of two things is going on.  Either I simply haven't cycled the batteries enough to see this expansion they speak of, or my practice of not charging the cells to 100% full capacity has removed this danger.  While I have no conclusive proof, I'm leaning toward the second option.  Knowing what kinds of nasty things these cells can do above 3.6 V and how it affects them, it stands to reason that charging them to 3.6 V every time you charge them has got to put strain on them.  Regardless, I'm removing the gaps and re-securing them in the space.

Anyway, look how much cleaner the trunk looks without all those extra wires and components.

Many more enhancements to talk about, and of course I have to document the conclusion of each of these items.