Well, we kinda/sorta have the Speedster Redux back on the road again. We’re a little ginger with the new motor/controller combination with the brush seating issue. But even at a 2000A/sec slew rate we got a 10 second 0-60 time. Hardly anything to brag about I’m afraid. I think we can improve it, but the much touted performance hoped for is probably not to be.
I’d guess because we’ve become a tad bit obese – probably a little blood pressure issue as well. I don’t know if that’s me or the car.
In any event, we are a portly 2385 lbs with the additional 21 cells in the car. Our front/rear distribution has moved a tad to 38/62 from 40/60 in Speedster Part Duh.
The heavier weight makes it a smooth ride and the center of gravity is sufficiently lower you can indeed feel it. The electric speedster never did “roll” in a turn nearly to the degree of the ICE version, but now it just doesn’t lean at all.
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The Chennic chargers we’ve used very successfully at lower voltages in the past didn’t last the week. They just crumbled in front of us with an audible and alarming snap crackle pop sound eminating from the rear engine compartment for 15 minutes. No smoke or fire. But no 12v either.
We’ve replaced the Chennic with a homebrew – three Vicor bricks obtained on eBay. Tom Alvary has pointed out that these come from Troy Gaud who in fact works for Azure Dynamics. The legend goes that they ordered a brazillion of these from Vicor for an Azure Dynamics DC-DC converter and are remaindering hundreds of them on eBay at $24.95 each. Such a brick direct from Vicor would be about $172.
The VI-251 series is supposed to be a 150v input 12v output module. It should handle 85 to 215 volts. But according to Tom, these are ‘special” made for Azure and indeed they are marked for 200v input. He tells me that he has it on authority that they are good from 130v to about 250v. They put out 200 watts each.
So we cobbled three of them together on a heat sink for a steady 12v output. Unfortunately, with the headlights on we’re doing about 11.4 volts and the EVnetics Soliton1 errors out and shuts down. Jeffrey Jenkins notes 11v is the trip point in actuality and indeed, our HID headlamps might kick it down that low when coming on. So we had a problem.
Fortunately, the Vicor bricks can be trimmed for different output voltages – all the way DOWN to about 2.5 v but up as well to about 13.2v maximum. We put a 470K resistor between the T terminal (trim) and S+ terminal (sense positive) on each of the three bricks. The result is 600 watts right at 13 volts.
We are further advised that anything we can do to stabilize that 12v rail would be a great boon to the Soliton1 and indeed some concern of DESTROYING the Soliton1 on noisy 12v spikes. I rather think that should be EVnetics problem, and point out that the automotive spec indeed is to operate down to 9.6v. But it gives me a good jumping off place next week to start talking about capacitors and ultracapacitors.
I’ve put this off for some time. And I’d like to put it off further. I fear my views on supercaps are going to seriously disappoint many of our viewers. And it appears its kind of like the regenerative braking thing. I’ve got Siemens and Maxwell and several universities all publishing reports of 30% gains in efficiency. Iv’e been playing around with it a bit, and I guess at this point I think it is ENTIRELY BULLSHIT. And i mean ENTIRELY. No such gains. And they leave clues in every report – mostly noting that even HIGHER gains can be obtained with regenerative braking and with the “proper algorithm” to predict regen periods and driving cycles.
We seem to paint ourselves into these corners with great regularity. I read all the typing I can. Get all excited. But if I can’t make the meter move, I can’t make the meter move. And all the kings horses, and all the kings men, cannot show me HOW to make the meter move, except to suggest longer and longer strings of tasks I can endure that somehow with JUST ONE MORE THING will get it there.
So I take on the dragon. And for months get screamed at by everyone who’s ever been in an online forum and just KNOWS how it is and how its supposed to be and cannot imagine WHY Siemens or Maxwell or whomever, with ALL their brilliant and educated engineers who ALL eat right and exercise regularlly and are much trimmer than me and have LOWER blood pressure to boot – people who clearly are NOT little and ugly and whose wife dresses them funny.
And I don’t know, my knees hurt and my elbows hurt and I just don’t know if I want to charge in on another fairy tale deflating confrontation with the entire population of the planet. So I’ve put this off and put it off. Maybe I can put it off some more.
But ultracaps DO make marvelous filters. And I think we have an astounding insensitivity to just how much electronic noise these cars make and how that impacts everything in the car. Worse, it is very difficult to deal with in that it goes to longevity – ie DC-DC converters for example. But also controllers and batteries in general. And so it’s hard to make a case for something that preserves the life of your components for 20 years when the car is two weeks old. How do I explain it and worse, how can I prove it and finally, how can I show THAT on video. We struggle to communicate the BMS issue with CARS bursting into FLAMES all around us.
So its not a topic I really relish.
We do hear from a lot of viewers about the Lee Hart Batt Bridge concept. It’s easier. I still kind of hosed up the explanation on the video, but close enough for government work. The issue here is we don’t use them. Actually we do. We just don’t do it that way.
Speedster Redux has an old version of Victor Tichonov’s EVision and it performs the batt-bridge function quite well actually – displaying an LED bar graph that comparies one half of the pack to the other. I myself am going a different way with a Roving Networks sensor and some Objective C software on a Macintosh that will give me the same dislpay.
But neither of those are really available. And the Lee Hart Batt-Bridge is both easy to implement, and costs about a dozen dollars. It accomplishes most of what the BMS crowd is trying to save us from – sudden infant cell syndrome where a cell mysteriously fails of its own volition. We haven’t had much of that, so we’re not quite as tuned into the need as they would like us to be. But the concept has bare merit. And for $12 you could implement this and it would probably work to accomplish that.
In any event, I’ve had so many requests for a detailed explanation that I finally did one. The original writeup and diagram has always been online and really covers it as well as it needs to be covered.
During our ride, we went out to the airport and happened to catch my daughter Jennifer in the act of committing aviation in our little MD-500C helicopter. This was another one of my little obsessions where I spent a million dollars on a $300,000 helicopter to wind up in the end with a very solid little $300,000 helicopter.
Probably spent that on the daughter as well. IN any event, after a VERY rough adolescence, she has emerged as a remarkable young lady on the Dean’s List here at Southeast University, majoring in anthropology and she’s been taking helicopter and scuba diving lessons. She likes the field work and presumes to displace Indiana Jones in the search for the Holy Grail and so needs to learn to scuba dive, fly helicopters and the rest of the James Bond repertoire to adequately compete. I’m actually very proud of her and might advise Harrison Ford to keep his grungy little deHavilland DHC-2 Beaver out of harms way if he knows what’s good for him. She’s already got a pretty heady reputation locally for bar brawling and sport fighting – but I’m hoping Southeast University can put a little polish on that. I do digress. My own fault. She really WAS cute at the Tai Kwon Do gig at age four. I just had no idea it would take….
Enjoy the show. 105 minutes as I recall…
I understand that the Jimerico dual 11 motor ships this morning… Hopefully we’ll have it in hand by the end of the week.