Monday, March 18, 2013
Three Years On the Road
It was three years ago that the Z3 rolled out of the garage as a fully operational electric car. It seems like an appropriate time to run through some statistics, as well as some of the hi-lights and some of the low points that the car and I have experienced in the last 1096 days (there was a leap year in there).
Number of miles driven: 14032
Number of charge cycles: 742
Average depth of discharge: 34.6%
Greatest depth of discharge*: 93%
Total kWh's used: 4948
Total cost of charging the car at $0.075/kWh: $371.10
Total $ saved on not buying gas: $2001.62
Some of you may have noticed the new widget toward the bottom of the right hand column. You may have even noticed that my numbers don't seem to match it. I recently enrolled the car in the EVClub website, which is a nifty site whose intention is to track how many electric miles have been driven by it's members. They also provide this nifty widget you can place on your website to keep everyone up to date on your EV miles. Well when you enter the data for your car the first time, it asks for the number of electric miles you've driven so far and the price of gas. I entered the current price, but really what it needed was the average price. Thus the discrepancy. I assure you, the total above is correct, but the one in the widget is close enough for government work.
The saga begins...
Two months after it's launch I noticed a vibration in the drive line After disassembling the drive line I was able to isolate it to the motor and discovered that the balancing putty had fallen off the armature. After the manufacturers finish winding the armature, there is bound to be a slight imbalance in it. To correct this, and save the motor's bearings, they bake some putty on one side to even things up. Well mine fell off. Netgain had it shipped back and repaired all at their expense.
By the time the car was back on the road, it was mid summer, and I realized that I've grown soft in my middle aged years. A car with no AC was fine when I was 16 or 19. Not when I was 45. It sucked. But I wasn't the only one suffering. The Zilla controller was flashing warning lights at me, constantly warning me that it was in thermal cut back mode, dropping me down to 50% power. Clearly I was going to have to get some cooling for me and the controller. I couldn't address it then, and frankly stopped driving the car for the remainder of the summer. A trip here or there at night, but that was it.
That following September, I blew up my charger. A completely self inflicted wound, but this blog is all about honesty. While charging the car, I was measuring one of the batteries. The probe slipped and managed to touch part of the chassis and the battery terminal at the same time. The Manzanita charger is not an isolated charger, meaning that it is grounded to the chassis. Why, I have no idea. But the consequence of this is if you do what I did, your charger blows up. Fortunately, or unfortunately depending how you look at it, this is not an uncommon problem for people with Manzanita chargers, and Manzanita Micro has gotten rather good at fixing them with a quick turn-around time, and for a very reasonable cost.
The sharp minded among you will be saying to yourselves "Clearly he had something, probably a mounting bracket, too close to the terminal. What a poor design. What an idiot!!" And you'd be right. To address this, I could either spend a lot of time, effort and money to redesign the battery rack. That, of course, would be the right thing to do. OR, I could simply wrap all of those metal bits in rubber. Which is what I did. Only one degree up from "idiot" status, but it was a step in the right direction.
Nine months after the motor went back in, I notice the drive line wobbling again. You guessed it, the putty fell off. Again! Netgain to the rescue one more time.
This time, since the car was apart, I decided I was going to fix the cooling issues. I added a Masterflux AC system to the car, and a much larger radiator for the Zilla. But as the car went back on the road in early September after that work, I didn't get the opportunity to really put the new cooling systems to the test. That would have to wait for summer 2012.
Five months later (January 2012) I turn the charger on and hear a pop at the front of the car and the charger turns itself off. To make a long story short, the car had a frame leak, meaning that you could measure the high voltage system on the chassis. That is bad. I was shocked and sickened to discover that the motor was once again the problem. A build up of carbon dust from the degradation of the brushes resulted in a frame leak that I could not clear no matter how much air I pushed through the motor. Plus, I found one of the brushes had been drilled by Warfield (the people that build the motor) and it had started to crumble. Who knows where that crumbling carbon went and lodged itself! Netgain to the rescue once again. George decided he'd had enough of this motor and sent me a brand new one. I still can't sing his praises enough. But I'm certain he curses when ever he hears my name. George told me that he has my old motor in his garage and plans to put it in a Bricklin that he's been planning to build. I really hope it treats him better than it did me.
The summer of 2012 came and went and the cooling systems I'd installed the previous year worked great. I was cool, the Zilla was cool, we were both happy.
In July however, while checking to see if the batteries were still balanced at the bottom of the state of charge, I blew up my e-Xpert Pro meter. Another self inflicted wound. I didn't just blow it up, once I pulled it out of the dash, I realized it nearly caught fire. For the price of one brand new meter, the car was whole again.
September rolled along, I went to charge the car one morning and the charger emitted a series of loud pops, a couple bright flashes, and then some smoke. The charger made another trip back to the repair shop. Talking to Rich Rudman, the owner of Manzanita Micro, he said he believed it was due to a faulty set of mosfets they had received some time back. I got the charger back only to find that it wouldn't charge the car consistently. The current output would jump all over the place. So another trip back to Manzanita.
The last post I put up, from January, detailed a problem with more carbon build up in the motor. That was easily resolved by re-positioning the inlet for the motors cooling fan, and with the aid of a leaf blower hooked up the cooling duct. It blew every bit of carbon out of that motor.
There you have it. Three years worth of EV adventures summed up in a few paragraphs. I guess I focused primarily on the bad stuff. But the fact is that the good stuff wasn't one or two events. It was all the times between those problems. Really, it's any time I get to drive the car. I simply love it. The 14,000+ miles of driving bliss far and away, out weigh the troubles I've had.
I've kept close track of the costs associated with building the car, and I can tell you that it cost me as much, if not a bit more than a new Nissan Leaf would have cost me. Of course the Leaf wasn't available when I started building the car. Nissan hadn't even announced it. So would I swap the Z3 for a Leaf or another OEM electric car. I have to say, there is something very appealing to off-loading maintenance and repairs to a warranty claim. But missing the satisfaction of having built my own is too steep a price to pay. Truth be told, I want one of each. But that will have to wait.
Last week, I ordered some long over due parts for the car. I'm going to be upgrading the suspension. I will be able to bring the ride height back up to BMW's spec, and put on some slightly heavier springs to handle the extra 385 lbs the car gained. Should be fun.
*That excludes the two times I took the cells down to 0% state of charge. Once to bottom balance, and the second time to check if the cells were still balanced at the bottom after a year's use. They were.