Monday, March 29, 2010

A Video of the Car

For those of you who aren't familiar with Jack Rickard from earlier posts, Jack is the fellow that encouraged me to change my plans from lead acid batteries to the lithium batteries. And while Jack had very convincing arguments for doing so, one of the biggest factors in the switch was the tremendous drop in price since I'd first looked at the price. From $21,000 down to $7,400.

In addition to help with the batteries, Jack has offered other sage advice. Well he went and posted a video of the car on his website as part of the weekly Friday show he does. It's a long one, well worth watching, and the EV Z3 is embedded somewhere in the middle.

Check it out when you get a chance!

Thursday, March 25, 2010

Rolling Along

Well, I've managed to clock nearly 400 miles on the Z3 since it's debut. Aside for the faulty controller setting (my fault), the only problem has been a faulty check valve on the vacuum system. However, at this point I'm not sure it was faulty, and I'm really not sure what caused the problem.

I replaced it with a new one and found I had the same problem. Clearly I need to figure out what's going on here. I removed the check valve and the brakes work, but the vacuum pump runs longer. The more that pump runs, the more I'm annoyed with it. It's by far the loudest thing on the car.

I took the car on the freeway the other day for the first time since I got the controller setting issues resolved. It pulled up to 70 with no problems at all. At one point, traffic started moving quicker, so I decided to keep up and see how it did. I got to 80 and there was still room in the pedal and the car was still pulling. I'd love to find out what the top speed is, but I don't have a safe, legal place to do it.

One thing that freeway speeds do is suck power. The car averages around 300 Watt/hours per mile on surface streets. But take it on the freeway and that jumps to about 410. I certainly don't mind using the power, but it illustrates just how much energy it takes to push through the air.

Today I took the car over to a local auto shop that's right around the corner from my house; they specialize in BMWs. When I first bought the car and told them what I planned to do with it, one of the guys there was kind of skeptical. He didn't say he doubted that I could pull it off, but it was clear he felt that way. Well I wanted to show him it was done, but he's left the company. When I told the others why I'd stopped by, they all wanted to see the car. So we went out in the parking lot and I gave them all a quick tour. After 20 minutes, several questions and numerous complements I headed off to run some errands. The car never fails to impress.

Monday, March 22, 2010

An Interesting Interview

Shortly after I posted the car on the EV Album, I was contacted by one of the writers at Gearbox Magazine. They are interested in starting an EV portion to their online magazine and thought the Z3 would be a good car to start with. It seemed like a great idea to me, so I answered all the questions they had for me.

Here's a chance to read the article if you haven't already seen it. If the mood strikes you, post a comment. They're just starting this off and it would be good to leave them some feedback.

Wednesday, March 17, 2010

A Great Big Thanks!

Now that the car is out of the garage and running the way it should, there's some people I'd really like to thank. Some offered a little support, some where instrumental in getting the car built.

Tim Millward - Tim did all the welding. I was absolutely at a loss without his skills. He was kind enough to drive the 50+ miles across town to work with me on several occasions. What a champ. Thanks Tim!

Ryan Bohm - Ryan is the proprietor of EV Source. I got most of my components through him and he offered terrific support. He was patient enough to answer each question I had regardless of how stupid they were. Anyone considering a vendor for EV parts could not choose a better source. Period.

Jack Rickard - Last summer Jack encouraged me to take the plunge and go for lithium batteries instead of lead acid. Boy am I glad I listened. The painstaking research that he's done on this type of battery has provided the practical knowledge that everyone in the EV world desperately needed. Theory is nice, but there is not substitute for empirical data! Check out his website when you have the time. Thank you kindly Jack!

Leonard Ellul Bonici - Len is (as far as we know) the only other person in the world to have converted a Z3. In fact, we started our conversions the same week. He finished his mid summer 2009 and has been driving it ever since. Len and I shared quite a bit of information with each other and he developed the solution we both use for the power steering proximity switch. Thanks again Len!

Josh Hardison - Josh is a friend of mine that took the time to answer all the questions I had about the fundamentals of electricity. I knew next to nothing when I started this. Josh filled in all the blanks for me.

Bill Catellier - My father Bill is one of the most mechanically adept people you could ever meet. Plus he knows a tremendous amount about electricity. He helped me refine all the design work and is one of the reasons the car turned out as well as it did.

Emily Catellier - My daughter Emily patently assisted me when ever I needed a spare hand or a gopher.

Mary Catellier - Last, but not least, my wife Mary. She thought I was crazy doing this, and she may be right. But she patiently stood by supporting me through the entire endeavor. Thanks sweety!

There were plenty of others that contributed here and there and I'm grateful to you all. I'm also grateful to all the readers of the blog (both of you). I enjoyed the whole experience.

I'll continue posting data and updates about the car as time goes by, so stay tuned!

Tuesday, March 16, 2010

Acceleration Problem Sorted

Well, you can chalk this one up to a rookie mistake. There is a big difference between resting voltage in a battery pack and voltage under load. To keep the batteries safe, I want to keep them above 3.0 volts per cell. 3.0 x 48 = 144, so that's what I set the low voltage to. Well, they hit that when under load almost right away, which caused the Zilla to limit it's duty cycle to 25%.

Working with Ryan at EV Source, he recommended that I drop that to around 112 and see if that did it. Boy did it ever, I spun the tires quite easily.

I'll be posting more on the acceleration once I get the brakes working again. So stay tuned.

Saturday, March 13, 2010

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. :-(

Friday, March 12, 2010

Some Tests

Though I haven't heard back from the distributor of the batteries yet about the discharge capacity, I feel safe in saying that my original belief was true. These batteries are capable of putting out the current I'm asking them to dump. A kind reader of the blog pointed me to a great page at EV Works that detailed some tests they performed on the Sky Energy and Thunder Sky batteries. The tests reveal many things, but key among them is the discharge potential. So at this point, I feel safe saying the batteries are not the issue.

I took some measurements on the HEPI pedal yesterday. There are 6 wires coming from the pedal. One is a 5 volt power (Red), one is ground (Black), and the others are signal wires. The voltage on the signal wires changes as the pedal is depressed. Here's what I found.

In the up, or "not depressed" position
Red - 4.94 V
Green - 1.58 V
White - 4.94 V
Orange - .792 V

Fully depressed position
Red - 4.94 V
Green - 4.83 V
White - 4.94 V
Orange - 4.33 V

It would seem that the White wire is also just providing power. Truthfully, I don't know if the differences in these readings has any significance, but I find it interesting that neither the Green nor Orange wire come up to the full 4.94 Volts when depressed. But even more interesting is the fact that the Green and Orange wire don't match. My understanding is that the pedal has two sensors in it for redundancy. I would think that would mean the voltage they put out should match, but that's just an assumption. I'll be sending this data off to the distributor I bought the pedal from to ask for help and assistance.

The Zilla controller has the ability to put out a stream of data for diagnostic acquisition or DAQ. All the data is displayed in Hex format, at the rate of 10 lines per second. I connected my MacBook to the Zilla, set everything up and then captured some data during a full, pedal to the floor, acceleration. Once I had the data, I imported it into a spread sheet and converted all the Hex to decimal. What I found backed up what I was experiencing. Under full acceleration the current across the motor's armature peaked at 150 amps.

So, what did we learn from all this? I think all I really learned was that the Zilla is indeed sending a fraction of the current to the motor that it's capable of. And it re-enforces my previous beliefs that it's either the pedal, or the Zilla. Now that I have some data, it's time to get the manufacturers and distributors involved.

By the way, thanks to all that have been offering help and advice! It's truly appreciated.

Thursday, March 11, 2010

More Data

So far, I've put nearly 300 miles on the car. Everything has been working, more or less, perfectly. So lets have a look at the data.

I'm averaging about 330 Watt/Hours per mile. I've seen averages as high as 394 and as low as 288. That's leaving me a 50 mile range. What I can tell you from this is that the manner in which I drive makes a big difference. But there's a bit more too that story.

The meter shows that the car is drawing 0.2 amps when it's off. That seems pretty reasonable, after all the Zilla draws a small amount of current, as does the Link 10 meter, and the DC to DC converters are always pushing 13.2 volts to the 12 volt system. However, I've no idea if something on the original 12 side is leeching power from that. What I have found though is that if the car sits for 12 hours unattended, it will draw off something like 500 Watt/hours. Hmmm.... I need to find out what's happening there. So the higher numbers I'm seeing in the Watts/mile adventure above are a bit skewed because some of those have a power vampire worked in.

No improvement on the acceleration issue, but I do have some more information. I've noticed that under full acceleration the meter shows I'm drawing no more than 200 amps from the batteries. Well, that certainly lines up with what I'm seeing. 200 amps fed to a WarP 11 motor will produce about 40 ft/lbs of torque. The question is, why not the full 500 I've set? Again, I'm left with one of three things. The Zilla simply isn't drawing the higher current because of a fault in manufacturing or an incorrect setting. I don't think that's it. The hepa pedal isn't sending the proper signal to the Zilla, or the Zilla isn't interpreting that signal as a 100% "throttle on" signal. That seems just as unlikely. Last, the batteries can't release that kind of current. According to the manufacturer's spec, they should be able to release 480 amps for 20 seconds straight. And event higher discharge current for even shorter periods of time.

That leaves me sort of scratching my head. I need to test each independently. I've reached out to the various distributors that I worked with for assistance, so I'll keep you posted there.

I had the car weighed yesterday. I found that through all this, the car has gained a total of ... drum roll please.... 386 lbs. That's about 136 lbs more than I'd thought, but really not bad. So, the car weighs in at 3,285 lbs. The ride height at the back hasn't changed, but on the front of the car it's 1/2 inch lower than stock. Considering that new spring kits for the car, designed to lower the ride height will take 1 inch of the height, I don't think I'm going to worry too much about it. Still just to be safe, I intend to ask a few mechanics. The really cool thing is that I've managed to maintain the same weight distribution, front to back, that BMW had. I've got 52% front and 48% back. Not bad.

Here's a great story. I wanted to have the car reclassified as an EV because the registration fees are a fraction of a regular car. I called the ADOT, our DMV. When it was all said and done, I spoke with 5 people and got 5 different answers as to how I should do it. The one reliable one, as it turns out, was from the fellas down at the only state owned emissions testing place. He told me that ANY emissions testing place can certify it, but often won't because they don't know how. "Which is silly," he said "because all you have to do is look and see there's no engine or gas thank. Done!" He said if they wouldn't do it, I'd have to bring it to him which is about 15 miles away. No worries.

I went to the testing station 2 miles from my house and asked the guys there. They were completely dumbfounded. Completely! One guy said, "Well, we just check that the gas cap fits and plug the car into the computer." So I asked him "And when you find there's no gas cap or gas tank... And when you find the ECU says there's no engine?" Again, blank stares. I said "Look, you're supposed to have a form that you can certify and hand to me that says the car has no engine, and instead has a bunch of batteries." Blank stares.

So, when I pulled into the testing station 15 miles away, and told them what I needed, the guy laughed and said "They wouldn't do it huh?" He was the same guy I spoke to on the phone. He told me this wasn't the first time he's seen this by any means, or the most ridiculous case either. One of the stations in the west valley sent a Tesla owner down to their station to have it certified as an EV. "For-christ-sake!" he said, "That thing was manufactured as an EV. What's wrong with these guys!?" I'm sure I don't know. But I think it will all change soon with all the EVs that are supposed to hit the market soon.

Thursday, March 4, 2010

Real World Data: The Good, the Bad, and the Ugly...

The Good

I've been driving the car for three days now, trouble free. Everything works as designed. The vacuum pump for the brakes kicks on every second or third time I press the brake pedal. The speedometer and tachometer work properly. The heater works brilliantly, getting the cabin toasty warm in a very short time.

The car is very quiet. When sitting still, the only thing heard is the fan blowing air into the motor. As I mentioned above, the vacuum pump kicks on once in a while and it makes quite a racket, but nothing compared to the traffic noise around me. When I turn the car and the power steering pump comes on, there's a high pitched whirring sound, but it can only be heard when there's absolutely no traffic noise.

The power steering system is working quite well. It takes a bit of getting used to in that the first 3 inches I move the wheel, it's a bit stiff, but once the pump kicks on, it's easy as it was before I removed the engine. This can make for a bit of a jerky turn unless you're prepared for the sudden drop in resistance. It won't take long to get used to it. The good news is that I can change lanes at speed easily and the pump never comes on, which means I did a good job positioning the proximity switch.

So far I've put 62.5 miles on the car. With the local price of gas at $2.75 and figuring in cost of maintenance on an internal combustion engine, I've saved $6.10 so far. It costs just under $.03 per mile to drive.

The Bad

A couple days ago I mentioned a noise coming from the power steering rack on full turns. While it's still there, it seems to have diminished quite a bit. Not sure why, but I'll have to looked into that.

The Link10 meter is still a bit of a mystery to me. While it measures and displays the voltage quite nicely, the other measurements are either wrong or confusing. Because it's designed for battery packs under 50 Volts, I had to install a voltage pre-scaler. That means a voltage of 161.0 reads as 16.10. OK, that's no big deal. As expected, it's scaled everything else as well. Again, not a bad thing, but I need to learn how to read it. The kWh dial showed that I'd used 0.53 after my last trip. Based on the time it took to recharge the car, and the amount of current the charger draws, I'd think it took about 6.25 kWh to charge it up. If I'm dealing with the same decimal point error then that means the 0.53 translates to 5.3 kWh. That's about 15% higher than the 6.25, some of which undoubtedly is lost in efficiency converting AC to DC. Still it's impossible for me to know for sure because I don't have a meter that allows me to measure the current going in accurately. I may need to do something about that.

The most inaccurate thing the Link 10 displays is its "fuel gauge". If I really used 5.3 kWh (which I think is accurate), the "fuel gauge" showed that I was empty. I'd set it up to allow me to use about 16 kWh before it would display empty. So that aspect of the dial is worthless for now.

That brings us to range. Most everything I'd come across in my research lead me to believe I could expect to use between 225 and 275 Wh/mile. In reality, I'm using about 380 Wh/mile. That translates to a straight reduction in range. Now instead of the 60 to 65 I had calculated, I'm looking at more like 42. Not ideal, but I can certainly live with that. Now that's maintaining a 20% reserve in the batteries to protect their longevity, so the full range is closer to 53. Over time I may be able to increase that a bit here and there, but for now it looks like I'll be staying within 20 miles of home.

I haven't had the car weighed yet, but the front end is riding 1 inch lower than stock. Next week, I'll have it weighed so I can compare and decide what to do about the suspension.

The Ugly

Well, there's no getting around it. The car is slow. It accelerates like a 90 horse power economy car. I can't for the life of me figure out why that's the case. The controller is set to allow a full 1000 amps to the motor, which should produce enough torque to spin the tires! Instead, if I floor it from a stand still, it accelerates like a weighed down golf cart.

I've checked and I don't seem to be dragging an anchor, so I'm really not sure what's going on. I know it's not a friction problem. The car roles forever. If I simply let off the throttle pedal while doing 45, it will coast for over a quarter mile losing less than 5 miles an hour. It's like putting a regular car in neutral. I've gone over the Zilla's configuration again and again, but it's OK.

Now, I do have the controller set so that it can draw no more than 500 amps from the batteries. I did this for two reasons; first the Link 10 meter's shunt is a 500 amp shunt which means that if there's more than 500 amps going through it, the Link 10 can't read it leading to further inaccuracies in the meter's data. The second reason is the fuse I have on the battery pack is only good for 400 amps sustained. It will tolerate 1000, but not for more than something like 10 seconds. Still, throwing caution to the wind, I tried setting the battery current up to 1000 to see what would happen. I started the car gave it some juice and found that it was only slightly better than before. Not enough of a difference to warrant getting a bigger fuse and leaving it that way.

So there you have it, good news and bad. I'm going to continue looking into the problems I've encountered, and hopefully I'll find something. I think I'm going to have to ask a few experts some questions. Stay tuned.

Tuesday, March 2, 2010

The EV Z3 is on the Road!

I pulled the car out of the garage today, washed it down and started running it through the neighborhood for some tests.


video

The car isn't as quick as I'd hoped. In fact it's slower than it was with the original engine, which is quite strange. The motor should be putting out far more torque than the engine could. I'm not sure what's going on, but I'll be investigating it.

So far everything is working quite well, but later in the day I noticed some noise coming from the power steering rack when I made a hard left. I'm thinking that the seals in the rack may be going, so that's another thing to investigate.

While I was hoping to drive it out of the garage and be done with all the work, it's clear that I'm going to be fiddling with it a bit more over the next few weeks and months. I guess you had to know that was going to be the case :)

Monday, March 1, 2010

New Tachometer

The new tachometer arrived last Friday afternoon. I spent some time working to get it to fit into the space available in the instrument cluster. It turned out to fit quite nicely, although it was really tough getting it secured and sealing all the light leaks around the edges. Here's a rather dark shot of the instrument cluster installed in the car.



As you can see, the airbag still needs to be installed. Tomorrow, I'll remove all power from the car, and install the airbag and steering wheel. Next, I need to seal up a few gaps to be sure that the back battery box is water tight. After that's done, the car is coming off the jack stands and I'll be taking it for it's maiden voyage. I'm being encouraged to wash the car first, and I think I may do that. If I'm going to record the first drive, I want it looking good!