Showing posts with label Performance. Show all posts
Showing posts with label Performance. Show all posts

Wednesday, September 28, 2011

EVCCON 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. 


Thursday, April 1, 2010

So How Fast is This Thing?

Most of you are aware of the difficulties I had with the car regarding acceleration early on, and how it was my own dang fault. And most of you are aware that problem has been sorted. Which probably means most of you are wondering when I'm going to post some 0 to 60 times and what not. Here's the full story.

Right now I have the Zilla set to only draw no more than 500 amps from the batteries. The batteries voltage is 160, so that works out to 80,000 Watts. Netgain recommends that you push no more than 170 volts to the motor, and as you probably know, the Zilla can put out a maximum of 1000 amps. That means that the most power I can theoretically send to the motor is 170,000 Watts. So, as the system is configured right now, I'm allowing just under half the power possible to go to the motor.

"Why" you ask? That's a good question for which I have a couple of lame reasons. First, the Link 10 meter I have can accurately read only 500 amps. If I pull more than that, it won't hurt the meter, it just won't read it accurately. So that's not really a problem as long as I don't put myself in a situation where I need to rely on the meter to determine how much energy I've drawn from the pack. I don't want to run the pack dead and destroy the batteries. Second is that I just want to spend some time breaking the batteries in under less than full stress conditions. I don't know if this is completely necessary, but I seem to remember reading somewhere that treating them kindly the first 75 cycles can add to their longevity.

The bottom line is that I do intend to ramp it up at some point in the future, just not yet. I likely wont' leave it there, but I'll do it just long enough to get some readings and have some fun. I was thinking mid April.

Right now the car does 0-40 faster than stock. It really sets you back in your seat. Above 40 though, the acceleration begins to fall off. It reaches 60 in about 10 to 12 seconds which is higher than the stock 7 seconds, but certainly acceptable for everyday use. I've reached 80 on the freeway, and the car was still pulling. I can easily spin the tires in first gear, and the tires chirp in a hard start from second. There's no question that there's a beast under the hood, it's just leashed at the moment.

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.

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.