Brakes, Car Shows and Solar Power

One of the readers of the blog emailed me a week ago and asked me if I was going to be updating the blog anytime soon.  He was wondering how things were going with the Z3 and if there was any new, interesting things to report.  There are a couple of small things that I thought I'd share, but really, there hasn't been much to report, so I haven't posted anything.  But then it occurred to me that not having much to report is itself, worth reporting.

Anyone who has read through this blog is keenly aware of the various issues and problems I've had with the car.  Usually brought on by a hardware/component issue of some sort, and occasionally brought on by my own ignorance or stupidity, I've tried to turn these episodes into some sort of learning experience, or at the very least, a good read.  These events have occurred frequently enough that I think people have become accustomed to regular posts.  But as luck would have it, nearly a year has passed with no serious issues or problems with the car.  I drive it, plug it in, charge it, and then drive it some more.  Not a particularly entertaining thing to read about on a daily basis.  But the fact that this has been going on for the last year, with no drama, is pretty damned cool.

Truth be told, it hasn't been completely trouble free; I have suffered a minor hiccup.  Sometime mid-summer, the MES-DEA vacuum pump I use for my brake booster stopped working.  It was a bit surprising, and a tad scary as I suddenly needed near Herculean strength to stop the car.  My overall impression at the time was "This is bad!"  I decided I should probably replace it. Apparently the MES-DEA pumps use a diaphragm which over time wears out and tears. As it happens, right around the same time that mine broke, EVTV started stocking a new, double piston vacuum pump.  The problem with the piston pumps is that they are notoriously loud.  But Jack demonstrated this on the show and I was pleasantly surprised at how quiet it was, so I decided I'd give it a go.  The only problem, it's a little bigger than the existing one, which means I'm going to have to do some re-design work to fit it in the car.  *Sigh*  I just haven't been able to muster the will to do it yet.  In the meantime, I've been driving the car carefully and found that the brake pedal has gotten easier every week.  A by-product I didn't expect is that my right leg has gotten much stronger and my pants don't seem to fit the same from one leg to the other.  I'm going to end up looking like Mr. Atlas on my right side.

Perhaps the biggest news, which isn't directly related to the car is that we had a 6.1 kW photo-voltaic solar array put on our house.  We contracted to do it through Solar City which has worked out tremendously well.  For a lease price of $70/month, it is off setting an average of $110 of electricity cost per month.  I call that a win in every respect.  When it comes down to it, it's producing roughly 1/2 to 2/5ths of the power we use.  In September it produced 963 kWhs, and in October 775 kWhs.  As Winter comes and the sun is lower in the sky and up for less time, that number will continue to drop.  But our consumption drops accordingly due to the fact that it's no longer 115 °F all the time.  Lately, I've taken to charging the car in the middle of the day.  So while I'm not powering the car exclusively on sunshine, it's very satisfying to know that a good portion of the electricity pushing the car was from the solar array.

As many of you are probably aware, Plug In America day occurred on Saturday last September 28th.  Every year the Phoenix chapter of the EVAA plans a gathering of electric cars for this event at a weekly car show that takes place here in Phoenix.  Usually I can't join their events scheduled for Saturdays, but in this instance my schedule cleared up and I decided to take the Z3 down to the show.  Now, to give you some perspective, I brought my car down to the same event two years ago.  There was a grand total of 8 EVs: 3 Leafs, a Smart EV, and 4 conversions.  This year was a bit different.

I showed up about an hour after the event was supposed to start.  I found the EV group and was shocked to see 50+ cars on display.  There were 25 or so Leafs, about 5 Volts, a few Ford Focus EVs, 3 Tesla Roadsters, 1 newer RAV4 EV, 8 or so conversions, and about 10 Tesla Model S's.  I was shocked.  I talked to Sam, one of the club's leaders and he welcomed me and told me to bring my car around to join the group.  Looking around I saw no parking spaces left but he said "Don't worry, we'll find a spot for you."  I walked away to go get the car and when I returned, it just so happened that one of the Model S's had pulled away in my absence, so Sam had me take that space.

So there I was, a little home built EV with 4 Tesla Model S's on either side of me.  It was an odd situation, kind of like seeing the cute high school girl you knew from your youth, surrounded by a bunch of super models.  Suddenly the little Z3 wasn't quite as impressive as she once had been.  But then a curious thing happened.  A crowd began to gather around the car.  Everyone started firing off questions.  "What kind of motor did you use?"  "How long did it take you to build it?"  "How many miles have you put on it?"  Suddenly, the super models next to me were largely being ignored, and people were mostly gathered around my car.  But then I realized that they weren't only around MY conversion, every one of the conversions had a crowd around it, were as very few of the manufactured EV's did.  It's easy to understand why that is.  Pretty as they are, once you've seen one Model S, you've pretty much seen them all.  Plus, there's no way to see the guts of the car, whereas the guts of my conversion, and indeed most any other conversion, are out on display in all their glory or horror (depending on your perspective and the car you're looking at).

Maybe I'm pushing it, but I see this as an indication that conversions are not likely to go the way of the dinosaur simply because you can buy an OEM EV.  Just like custom built hot rods haven't gone away even though you can go out and buy a really great muscle car for a fraction of the cost.  Nope, the appeal of custom cars, be it hot rods, or EVs will be with us as long as we use cars.  I spoke with one Tesla Model S owner that also has a Porsche 914 conversion in his garage.  After he got his Model S, he was bothered by the fact that it was faster than the 914.  So, the 914 was put back in the garage so he can upgrade it and fiddle with it until it's once again the fastest car he owns.

But, I digress.  The point of this story was just to illustrate that adoption of EVs really is starting to get some traction.  From 8 cars 2 years ago, and the few people who wondered by looking at them with idle curiosity, to 50 plus cars and dozens of people engaged and asking questions.  Things have changed quite a bit.

Finally, an entertaining story.  A month or so ago, my lovely wife and I were heading out for a shopping errand.  As the circumstances of our lives happen to be, she doesn't ride in the car very often, so it's kind of a treat for her.  Well OK, I define it as a treat, but I'm not entirely sure that she does.  At any rate, I stopped at a sign and for whatever reason, she looked over at the dashboard.  Apparently, she caught sight of the fuel gauge, which is still in the instrument cluster, and she said, with a certain amount of panic in her voice, and in all earnestness, "Oh my God, you're completely out of gas!"  I slowly turned to look at her and I saw the look of alarm on her face change suddenly to one of realization and then embarrassment.  I was doing my best to suppress the laughter as she was shouting various excuses "I just forgot!  I haven't been in the car for a while!  It was just habit!"  I just smiled and nodded, and we zoomed away in silence.

First Day Drive Report

The first day on the road was nice in many ways, but had a few drawbacks that I'll discuss in a moment.

The car is quieter than ever. The new vacuum pump seems to have two stages. The first stage, and loud one, seems to draw the vacuum down pretty quick, but then it switches to a different mode where it becomes much quieter and to finish the job. It's important to note that when I say "loud stage", that is relative. It is still 1/3 as loud as the old pump. The nice thing is that it never seems to go all the way back to the first stage in normal driving. It just kicks in with the second stage when I hit the brakes. It's so quiet, I can't hear it in the car. I can feel it in the floor, because it's mounted very near my feet, but I can't hear it at all. I couldn't be happier with the new pump.

The drive line is beautiful. There is no wobble, which I expected, but it's actually smoother than before. I'm not sure if this is due to the fact that the motor is better balanced than before, or because the flywheel is absolutely balanced now. My bet is on the flywheel. In either case, it's great!

On the very first drive, I pulled into a local shopping center, and a mother was waiting to cross the street with her little girl. They paused and waited for me to pass, and I parked near by. The mother then told me that her daughter thought my car was very pretty. I thanked her and told them that it was also electric. The mother stopped dead in her tracks and said "You're kidding." "Nope!" I replied. She simply said that it was cool and amazing. A nice little interaction.

Now for the rough bits. Driving in Phoenix, in the summer time, at 1:30 in the afternoon, with out AC sucks. There is no other way to put it and no way around it. It was 110°F in my back yard before I left, which meant it was easily 115°F on the black top. It takes almost no time at all for a person to get really sick of that.

Apparently, the Zilla does not like it either. Towards the end of the trip, I noticed the "Check Engine" light flashing slowly. While I can't say with certainty that it was caused by high temperatures, based on a number of factors at the time, it certainly seemed it. I didn't have a chance to get the error codes off the hairball before they'd been pushed away by different ones (I was doing a little experimenting). But I did put my hand on the controller to check and found that it was too hot to leave my hand on it. I measured it with an infra-red thermometer and found it was a 126°F. I verified the pump for the water cooler was working and the fans mounted to the small radiator were spinning. All is working, it's just too damned hot.

Sadly, adding AC to the system is only going to make things worse. I have no where to put the radiator for the Zilla except for behind the condenser for the AC system. So if that starts spewing out heated air from the AC system, the Zilla will over heat for sure.

The DC to DC converters continue to run their fans non-stop. The ambient air temperature, coupled with the heat they generate while operating must be above the temperature threshold. I'm not sure I can do anything about this. I'm going to prop a fan on a chair and point it straight into the back of the trunk. If they shut off, I know I simply need to find a better way of circulating air through there. If they don't, I'm not quite sure what I'll do. I let them run for 12 hours and found the fans and the DC to DC controllers sucked a full 500 W/hours from the main pack.

I'm still working on getting data on which will be the best way to go with the 12V system. Should I disconnect the DC to DC converters when the car is off, or the SLI battery? I have two pieces of data now. The one I mentioned in the last paragraph, though it's important to note that this was with the 12V SLI battery disconnected. If I shut down the DC to DC converters and let the battery handle the load, the car draws off only 44 W/hours. That tells me two things. One, at first glance relying on the SLI battery would seem to be the way to go; and second, these Iota DC to DC converters are energy hogs! I have more data to gather though before I make my final decision, and I'll share that later.

New Battery Racks

Loyal readers will remember that I've decided to take this opportunity to redo the battery trays in the front of the car. Since I had to disassemble the entire front of the car anyway, I figured now was the time to do it. Of course I should mention why. Two reasons really.

First, I've come to find out that these batteries really are supposed to be mounted vertically. Originally, I'd read it didn't matter, and you could install them in any orientation you wanted except upside down. But since then, I've seen in multiple places that if you don't mount them vertically, the electrolyte will pool to one side of the battery, shortening the batteries life. Well, I thought the electrolyte was a paste, but I turned one on it's side the other day and could hear a faint but distinct gurgling coming from the battery.

Second, when going through the pack with a wrench trying to tighten the lugs on the batteries, I found it extremely difficult to get a wrench on some of them, and in fact, I couldn't reach 7 or 8 of them at all! That meant over time the constant heating and cooling of the terminal would cause the lug to work it's way loose (I already saw this on the lugs I could reach) eventually creating enough of a gap that there would be arcing and eventually fire. So, vertical it is!

Here is a shot of the work I did today. there will be more horizontal pieces running between the sides. Three to be exact. They will support two rows of 9 batteries just over the motor. That means I need to find room for 12 more. As it happens, the space just behind the radiator, and in front of motor is wide enough (by 4 mm) for 12 batteries. So they should all fit pretty well, plus I got rid of some steel that weighed quite a bit more than the aluminum.

I'm also taking this opportunity to replace the vacuum pump that I've come to despise so much. It is by far the loudest, most annoying thing on the car. I'd bought the pump off of eBay about a year ago for the bargain price of $110. It was one of the few parts I thought I could save money on because a vacuum pump is a vacuum pump. Right? Well it turns out there are pumps that are a lot quieter.

Here you see the original one on the left. It measured in at a wopping 74 dBA. The new pump on the right puts out a relatively quiet 58 dBA. The dB scale is logarithmic, and every 10 dB increase means that the sound you perceive is twice as loud. So this new pump will be roughly 1.6 times quieter than the old one. Was that worth the $300 I laid out for it? Well, let me throw this little bone into the mix. The old pump drew 8 amps, the new one, 2.5 amps. Now are you impressed? I thought so.

The old one still works great, it's just loud. I'll probably put it back on eBay.

Vacuum Issues

While it's true that nature abhors a vacuum, nature has nothing on how much I abhor the vacuum brake system on the car. It turns an otherwise lovely quiet experience into a nerve shattering episode every time it kicks on. Part of that is my fault because I opted for pump I found on eBay for $90 instead of going for a quieter one from one of many EV component dealers. My efforts to deaden some of the noise it makes fell short.

But that's not what this post is about. I haven't posted much about this because I really haven't had a handle on what the issue was. Early on I noticed some erratic behavior from the system. It would refuse to come on, stay on too long, not turn off at all, turn off and I'd have no vacuum assist on the breaks or stay on and I'd lose vacuum assist with the brakes. I can tell you when that pump simply won't shut off, it sucks most all of the joy right out of my drive. As far as problems with that system are concerned, you name it and I've experienced it.

At first I thought that the vacuum pressure switch on the reservoir was bad, but ruled that out because I found a leak. I fixed the leak and the problem went away. Until one day the pump came on, pumped the system down and turned off and I found I had no vacuum assist. At that point, I was certain that the cause was a faulty check valve, so I ordered a couple replacements and some fittings to see if I could fix the problem. The check valve that came with the reservoir is kind of sloppy. It works, but you can suck a fair amount of air through it before it engages. As it turns out, that's really how it should work because a new one that allows for none of that play didn't work at all. It sealed off immediately and allowed no vacuum to the brake drum at all.

Well, after 4 more weeks and a number of episodes which I won't bore you with, I think I may have finally figured it out. I borrowed a hand held vacuum pump from a friend so that I could draw a vacuum on different parts of the system to see how things behave. I was hoping to find where the problem really is. I pulled into my driveway the other day and the pump was running non stop, and the brakes were working fine. I popped the hood thinking I'd pull the line out of the reservoir I installed that runs to the car's vacuum assist drum. I wanted to seal the canister with my finger to see if the pump drew a vacuum like it's supposed to and if the switch turned the pump off eventually. Well, I inadvertently flicked the vacuum pressure switch with my finger and the pump shut off.

Since then I've had the pump come on and refuse to come off on two occasions, only to find a quick tap on the switch causes it to trip and turn the pump on. After which it runs normally again. Now, I haven't ruled out a problem with car's brake assist drum, but this is certainly headway.

The switch has a screw that allows you to adjust the vacuum up or down depending your needs. I think I'll play with that a bit to see if it helps. If not, it looks like I'll be ordering a new switch. Eventually I want to replace the pump with a quieter one. They range in price from $250 to $400 for the real quiet ones. It's not the money at this point that's holding me back. It's the prospect of having to put the car back up on jack stands to incorporate the new pump into the existing system. It would require quite a bit of work. I guess I love driving it more than I hate the pump.

Sidelined

Loyal readers (both of you) may remember that when I first started the car up, I reported some odd behavior from the vacuum pump. It wouldn't come on regularly and the brake pedal had an odd feel to it. At the time, the car was still up on the jack stands, so I couldn't tell if the brakes actually worked or not.

A few days ago, my father was driving the car and I noticed that the vacuum pump came on and was staying on for what seemed like a very long time. I asked him to pump the brakes, and within 15 seconds or so, the pump shut off.

Well today, I headed out of the garage with the aim of giving my wife Mary the opportunity to drive the car for the first time. As I pulled out, I noticed the vacuum pump running non stop like it had when my dad drove it. I pumped the brakes but found that they were getting no vacuum assist at all, and the pump still wouldn't turn off, so we had to scratch this outing.

I pulled the car back in the garage and started looking, tinkering and thinking. In short order, I realized what was causing this repeated problem, and with a few simple tests proved my hunch correct. The vacuum canister came with a check valve, and that check valve was sticking open. What that meant is the pump couldn't draw down a vacuum (which is why it ran non stop), consequently the brakes had no assist.

I've ordered a replacement valve and some other fittings to make the whole assembly from the vacuum canister to the brake assist drum a little cleaner. Until they arrive, no EV driving. :-(

Vacuum Canister

Just finished mounting the vacuum canister this evening. Essentially it will store the vacuum created by the pump until the brakes are applied. (The thought of storing a vacuum is rather odd. How do you store nothing? I guess it's really a canister that keeps everything else out.) Once the vacuum drops below a certain threshold, the switch at the top of the canister will kick in and start the vacuum pump again.


You can see the orange line running from the newly installed canister on the right, to the brake's vacuum assist on the left.

More Work on the Tray Under the Motor

More work in the engine bay today.


Here is a shot of the engine bay at it's current state. The tray under the motor is mounted in place (although not permanently just yet). But it does give you an opportunity to see the tray under the motor, the duct work for the motor fan and the final position of the vacuum pump assembly.

Here's a detail of the passenger side. I believe I know what you're thinking. I can nearly hear it. "What on earth is that pink and yellow monstrosity next to the motor?" Well trust me when I say that the picture really doesn't do it justice. It's far, far uglier in person.

I mentioned earlier in the week that I need some way of keeping water from splashing on the motor fan and it's filter. Well, the space is tight and irregular, ruling out a tidy piece of aluminum. And by the way, for anyone who saw the work I did on the housing for the vacuum pump, you know I may not be capable of a tidy piece of aluminum.

Anyway, I constructed the shroud out of two flexible plastic cutting boards. I hot glued them together, and then ran some small screws along the seams just to hold them tight. It's not water tight, but it will keep all flying water off of the assembly. I'd show you a more complete picture of the whole assembly, but my fear of being mocked by all has gotten the better of me. Truthfully though, it works just great. It contains the assembly quite well and flexes around all the little things that stick out here and there.

I don't know that this picture is really all that different from the one I posted last week. But there is one important difference. The vacuum pump is actually in the housing now, and the housing is bolted down into place.

This whole tray assembly has taken a terrific amount of time, but it's all been necessary. It's a small car, with precious little space. Dropping a WarP 11 motor in that engine bay instead of a 9 hasn't helped matters as far as space is concerned. Everything that I need to fit in place I have fractions of an inch to spare at best. It makes for one challenge after another. But it's fun anyway.

Vacuum Pump Part II

I promised a picture, and here you go!



This is the vacuum pump nestled all nice and cozy in it's little home. It should keep it protected from the elements nicely. I'm not taking any bets on how it would do in a torrential downpour or hurricane, but then again, I do live in Arizona.

Vacuum Pump

I finished positioning and mounting the vacuum pump today. It was a tight fit, but there was really no where else to put it. It down below the steering column linkage, between the motor and the chassis. I had maybe a 1/4" in either direction to play with when fitting it in there. Sorry, no pictures today. By the time I was done, it was too dark to take a decent picture. I'll see if I can post some tomorrow.

Also tomorrow, I need to figure out how I'm going to shield the motor blower from water before I mount that to the other side of the tray under the motor. I've got a few ideas, but not one that strikes me as really good.

Engine Bay Pan and More

What a busy week! I got quite a lot done, and at the end of each day, I was just too tired to post anything about it. So I have some make up work to do.

Over the weekend, I decided that the big battery box in the front could really use some lateral cross bracing. So Tuesday I went about designing, cutting, drilling and painting some cross bracing that will mount to the steel we've welded in place, and the battery tray it's self. Only 1/2 lb of steel added, but it will add a lot of stability to the structure.

Wednesday I went about designing a pan to fit under the motor in the engine bay. It will do a couple things; 1, make the under side of the car a bit more aerodynamic, and 2, give me a place to mount a few of the components that I've yet to fit. I made a cardboard template, cutting, fitting, cutting, fitting, cutting some more... you get the picture. There is a "x" shaped cross brace that mounts to the chassis and the front sub-frame of the car. The idea is to shape the piece to sandwich between the brace and the car. Lots of trial and error and I got the cardboard just right, so I went and bought some aluminum plate.

Thursday was spent cutting the sheet of aluminum, shaping it and bending it to fit in the place I'd envisioned. I'd never given much thought to having a 10 ton press break in the garage, but I can tell you it would have been handy the last couple days. Instead, my work bench, some angle iron, clamps and a rubber mallet had to suffice. It took a while, but I got it to work out real nice!



In the top picture, you can see the passenger side of the motor and the aluminum plate underneath it. This space will hold the blower that will force air into the motor for cooling. In the bottom picture, you can see (although just barely discern) a box on top of the aluminum plate. This is located on the drivers side and that box will hold the vacuum pump. Which brings us to what I did today. I cut and shaped the aluminum for that box this morning. I have to do just a little adjusting to it before the vacuum pump is ready to be mounted into it, and then it to the plate.

Man, I can't wait to finish!