Sunday, April 24, 2011

New Web Site

The big news this week is actually a new web site design. Count Domagni has finally gotten things to a pretty good state with our video interface. The entire website now resides on an server with the videos remaining in the Amazon cloud.

This is all a bit of a technical issue and much of it is not particularly visual.

But for those with any interest, I'll spray a few words of wisdom for those wishing to delve into video distribution.

Basically we have had the gathering of a perfect storm for some 20 years that is just now coming to fruition. This involves both the expense and capabilities of the video cameras, is heavily a function of the available non-linear editing suites and the computers that run them, advanced video compression techniques, and the Internet - primarily a bandwidth function.

Canon's Vixia line of video cameras will give you 1920x1080 high definition video that is "good enough" for government work and in fact at this point a bit of overkill for our purposes. The uncompressed 1920x1080 version of our show this week is 96GB in size for example. That requires a couple hundred GB (uncompressed) of source video. Way to much for the Internet.

We edit down the video of course, and then compress it with h.264. H.264 is an international standard for video compression that kind of rolls up a lot of different compression techniques into one almighty mess. The heart of it is that we transmit a full video frame only about once per second. The intervening 29 video frames are much smaller, just a fraction, providing "difference data" of the image from one frame to the next. This video compression technique, along with dropping the resolution to 1280x720, drops us from the aforementioned 96GB to about 2.5GB. It is a phenomenal amount of compression.

We use an editing suite called Final Cut Pro on a MacPro computer that features 12 processors actually. These 12 processors allow us to render the video, a process that until just recently required about 18 hours, in about 2 hours.

And then there is the distribution. A couple of things happening there that aren't quite finished. One is the iPhone/iPad Apple vs Adobe flash war and HTML5. Basically we have warring parties over what format our video should be in to properly display on a browser. Apple eschews "flash" because it's from Adobe. This little battle hasn't sorted itself out. Eventually, HTML5 will accomplish all, but the implementation of HTML5 is far from accomplished.

As to bandwidth, some of you have faster and some slower. We are focused on high end delivery of HD video. And we have to forfeit some of the late adopters as viewers frankly. Google is actually experimenting with home delivery of INternet in Nashville and now Kansas City at GIGABIT rates.

Meanwhile, we have to have servers to host these large videos and make them available. Anything I would build would be the wrong size on any given day, and worse, it would be in the wrong place. Enter Amazon has been building a global network since 1996 to host their retail book store and now their retail anything store. This has grown to about 30 servers spotted worldwide and connected with hundreds of MB of bandwidth. They have an enormous IT department to maintain all of that and it is really quite separate from the retail operation. They kind of make tools the retail side can use to operate on this network.

A year or so ago, they decided to develop another revenue stream by making the same tools available to large corporations to use to outsource storage and other server intensive operations. They called it Amazon Web Services or AWS and it is really quite good. They priced it based on usage but I would call it "realistically" priced. The charges are on par with what you would pay to build and run your own service. And so in a buy or build decision, they come off very well. For corporations needing additional computer power between additions to their own network, it is a great way to "fill in."

This really very open and inexpensive approach has worked well for Amazon. So well, that many corporations simply don't have a server farm anymore or are simply running a legacy system from inertia, and doing all new development on the Amazon side.

The reason has MOSTLY to do with scale. The Amazon service is not as powerful or easy to develop on as a local server. But it has this huge advantage. It's already BIG. We need a tiny bit of bandwidth in the great scheme of things to serve our viewers even largish videos, but it is hosted on this huge global network. If we suddenly "went viral" for a day, and had a million visitors, I would get a largish bill from Amazon, but otherwise our videos would serve as normal.

And it has reach. The servers are placed around the world. They just added one in Paris for example. If you are in France, you get your EVTV video actually from a server in Paris. This greatly reduces delays and network obstructions from the viewing process.

Our videos have been hosted on Amazon's "Cloudnet" for some time. The actually web page was just on an Apple server. Frankly it doesn't do much. It just has links to our blog (on Google) and the videos (on Amazon) and so it doesn't actually do much and in fact the pages held on Apple are really quite small, simple, plain vanilla HTML that just barely glues all this mashup in place.

It was a little gawky looking admittedly. But it never really was what we are about. We see the web as almost collapsing into a video black hole that sucks up cable television, broadcast televsion, most of what you know of as the web, and parking lots on both coasts, into one massive video network. Within a few years, we'll have hyperlinks IN the videos, text overlays, and the world will be one big video experience.

This is why we didn't just start a print magazine for electric vehicles. Or try to get something on the Discover Channel. Or be MythBusters. Or Senior/Junior. Most of that is all going to be irrelevant as a communications medium. It's going to be the net, and the net is going to be video. HD video and beyond. Picture 4000x4000 pixel video. That's right Buzz... to infnity and BEYOND.

For any of my previous Boardwatch readers from the net, enormo opportunity here. This is the killer app of the Internet. IT will dwarf the web as you know it by an order of magnitude. YouTube will no longer be on the web. The web will actually subsume and become YouTube.

The ones who will struggle with this the most are what I call the Walking Dead. That is the mega industry that relies on video already. The "professionals". They've been so busy shutting out the "indies" for so long, they have missed the beat change in the music. It will be all about "indies" and the distribution advantages that large video production houses and cable networks now have will evaporate like mists in the morning. What cable did to broadcast, is about to happen to cable.

Fortunately or unfortunately, this continues the trend to decentralization. And so as the enormous budgets for CBS and ABC and NBC news got reduced to a relative pittance in the move to cable, so the enormous cable budgets will evaporate as well. The good news is that there will be MILLIONS of jobs in video production. The bad news is that they will all pay $8 per hour. The entire economic model gets dispersed, instead of concentrated, and everybody is a video producer.

This is what we have been demonstrating with EVTV. Yes, I'm fascinated with electric cars. First love was networking and not likely to be supplanted easily. We are a demonstration of how to produce, develop, distribute, and monetize a video production on HUNDREDS of dollars per day, not tens of thousands. Kind of like the shift in magazine production in the 1980's. And on a GLOBAL scale. in HD.

Next year there will be 1000 EVTV's. And the year after that, 10,000. And then of course millions. Mostly bad. But some good. And some excellent. We hope by then we are excellent.

Meanwhile, we've moved our little HTML page to Amazon as well. Count Domagni has developed a bit of a new look. It is going to take some getting used to both for us and you. We'll try to duplicate the features we had, but we are no longer going to fight the HTML5, iPhone, etc. battle on our pages. We'll try to make an iphone version available somehow. For now, you can display the flash, or download the Apple .MOV movie.

In this weeks show we show a new build of a hot water heater for the Escalade. How's that for a comedown. From infinity and beyond down to a hot water bottle. But this is a 24kw unit to produce a LOT of heat to heat both the car and the batteries. We won't need all of it very often, or any of it that often. But we basically put a hot water box together with pump, individual control relays and two 12kw heating elements, for under $800. By using a relatively high end system ($589 on eBay) we get a nice metal enclosure that can old all of that in one box.

We'll most likely add external components anyway. We'll put an ordinary block heater and 120vac aux pump in the line elsewhere so that we can "plug in" our heater on cold nights and maintain a bit of a temperature in the system so it won't need so much heat on startup in the morning. A little 1500 watt AC unit should be overkill.

We also talk in this episode about documentation for our Speedsters. We've named the Duh model Grunflachen (new fresh green areas) and the more powerful Redux model Geshwind (fast as the wind). We are working on an owners manual for Geschwind and you might find our acceleration performance page instructive. In this, we compare the acceleration performance of the original 1957 356 Speedster with the popular 1600cc S engine with both the Grunflachen and the Geschwind models we have constructed with electric drive.

As you can see Geschwind is a huge increase in performance. That's not quite the entire story. The original 356 did not become an iconic classic based on its acceleration. It was a combination of an Erwin Komenda body design, and a very pleasant driving "feel" that put you in touch with the road.

The body design I continue to marvel at. Here in Cape Girardeau, very young children and adolescents marvel at this replica of the 1957 Porsche Speedster. There is no nostalgia here. They were not around in 1957. In fact, they don't know it's a Porsche, and don't know anything about early Porsche's. They haven't seen it before. In fact, they think it is a NEW model car. But it looks "cool" to them just as it did to me as a young sprout. That's a classic or iconic design. You could introduce that exact same shape in a new car in 2057, and people would think it looked very strange and very cool. You could do it again in 2157.

As to the feel, well frankly Grunflachen mimics it best. It has the same peaky 3500-5000 rpm band of performance as the original Speedster. It is lighter. We did extremely well with this design and I much prefer its driving characteristics. Putting the 9 inch Netgain and Soliton1 in Geschwind upped the performance dramatically, kind of like dropping a small block V8 into a 1957 Porsche Speedster and it makes about as much sense.

The trick is that the extra batteries in Geschwind give it a 150 mile range. And the HPEVS AC-50/Curtis controller can't cope with the resulting 192volt pack voltage.

To tell the truth, I don't need the range either. It's kind of a bragging right. Yes, we can make a small sports car go 150 miles on a charge. And it will not be stupid looking or ungainly. But this car works best on the winding country two lane blacktops we have in such abundance hereabouts, through some beautiful country. It was the nature of roads when the 356 was born. ANd you wind along at 45-55 miles per hour mostly. I can do that for an hour and a half or two hours in Grunflachen, and that is usually more than enough for me.

Actually using it as a car here in Cape, 50 miles would be overkill. But that's ok. This will preserve the batteries very nicely.

We do also feature an update from Duane Ball and Scott Smith with their Porsche Carrera GTS build - the Porsche 904. This car is coming along nicely and we think is going to be a stellar example of an electric sports car. By doing it themselves, they wind up with another inconic piece of history, fantastic performance, and instead of the $150K for a Tesla Roadster, they'll probably have $75K in the vehicle. With a Soliton1 and an 11 inch Netgain, this thing will just fly. I think they'll see something in the range of 5.5-5.9 second 0-60mph. And 120 mile range.

Jack Rickard

Sunday, April 17, 2011

This week we return to Slingblade's Dynomometer for another test. I'm a little weary of test graphs this week as I've been making a number of them. But this is probably more interesting to you.

High Performance Electric Vehicle Systems has kind of cracked the AC drive market with the only system we're aware of for less than $5000. They produce a sturdy little 50kw motor with a face mount matching the popular Netgain Warp 9 which it makes it very easy to install with available adapter plates.

They don't do the controller at all. They use a Curtis model 1238 3-phase AC controller. Curtis controllers are widely dismissed by the cognicetti in EV land in favor of more exotic offerings such as our just reviewed EVnetics Soliton1 and the Cafe Electric Zilla.

But if we use EVALBUM's 3218 conversions as a representative sample, we find over 50 different controllers in use but 27% of ALL listings are Curtis powered - 878 vehicles. Since probably a third of the vehicles are bicycles, motor cycles, and lawn mowers, this is probably more like 50% of the market. Number two would be Alltrax at 276 and the long time darling of EVland, the Cafe Electric is a distant third with 155 installations. Our recent find, the Soliton1 has 22 vehicles listed.

Curtis makes controllers for industrial electric vehicles, floor washers, fork lifts, etc. We've talked to them and they profess to be oblivious to the Electric Car end of the world and claim to want nothing to do with it. But their products are migrating in that direction with brake light signals, regenerative braking (on a fork lift?) and more.

HPEVS has done an outstanding job of integrating the Curtis with their AC line of motors. The 50 kw AC-50 is the most powerful and most popular of these. And they've quickly gained a foothold. We used the HPEVS system in Speedster Duh to considerable effect and Duane Ball used it on his Spyder 550 as well.

Just this past month, Curtis began shipments of a new model 1238-7601 controller which is a bit of an upgrade from the 1238-7501 we had been using. The 7501 was nominally a 96 volt controller with a current limit of 550 amperes. We routinely run this controller at 120v and understand that it can withstand voltages up to 130 before shutting down to protect itself.

The new 7601 ups the current limitation by a full 100 amps, to 650 amps total. If you could put 120v in at 650 amps, that would render 78 kw. If we are low enough to get it to start, we actually sag to a little over 100 volts at those current levels and ergo, perhaps 65-70kw are truly available. That's potentially 94 eHP input to the motor.

ALL the other AC systems available that we are aware of START at about $5000 or $6000 for the controller and perhaps the same or slightly less for the motor - typically with a 30kw motor rating and 100-125kw on the controller. To get to 150-200kw in the Tesla/AC Propulsion range, you are in the $15,000-$35,000 range buying a really untested undeveloped one off prototype dream of some crackpot and it just makes no economic sense in an electric vehicle.

The advantages of AC are widely touted as regenerative braking, efficiency, and durability.

We have tested regenerative braking on both HPEVS and the MES-DEA products and were heroically underwhelmed. The oft cited 10% or 15% gains are simply nonsense - entirely myth based on observations of output and input. Real world tests of routes in the same car with it ON or OFF provide results of 5-7% AT BEST and this is very much a function of the driver and terrain. I actually generally get negative numbers when I'm driving.

As we see in this set of tests, the efficiency theory seems to be blown as well. If you take the motor and controller as a unit, they appear no more efficient than our series-DC and chopper PWM controllers - indeed the numbers would indicate LESS efficiency.

As to durability, it again makes sense. But we have no data. There are no brushes to change. Certainly.

But a funny thing happens in AC induction land. ALmost all the high end systems from Siemens and MES-DEA and UQM etc seem to be high voltage, comparatively low current devices. You rarely see anything beyond 300 or 350 amps through the windings of these motors. Instead, voltages are normally used to achieve higher powers- usually STARTING at 300v and going as high as 1000v in some systems.

This poses some problems for an electric car. To get such high voltages, you wind up with an extremely large number of cells. Our Mini Cooper has 112 cells in series, each of 100Ah. Further, all the peripheral equipment has to work at that 375 volts as well, our air conditioning compressor, our DC-DC converter, our water heater, and the list goes on.

HPEVS has carved out a niche as the ONLY sub $5000 AC system out there and it does it at LOW voltages and HIGH currents. Very unusual and a characteristic of their motor. If they can get a controller to do 650 amps and a BIT higher voltage, say 200v, we could in fact see 130kw.

Rumors exist noting that Curtis is CONSIDERING (not really working on) a 144 v model of this controller. That would be very useful.

In the interim, this 96v 650amp model tests out very well as you'll see in the accompanying graphs. We did a full 650 amps and upped our HP on the rollers to 74 from about 63 just by doing the controller swap.

As you can see, the -7501 model offers improvements of 15 to 25% depending on what you're looking at but torque jumps as much as 25%. If nothing else, this considerably widens the size of vehicle this system would work on - probably very effective at up to 3000 lbs. It's relatively low price under $5000 (we don't actually have pricing yet on the new model), relatively easy connection and configuration, make this drive system a contender for most electric car conversions we've seen. You will not get the torque or horsepower of an 11 inch series DC out of this package, but it is very sturdy and offers the advantages of AC if driveability is your thing instead of racing. It would still be under a little strain in our 3500 lb mini cooper. But at 3000 lb and below, with a transmission for leverage, this is a good package that got better.


Jack Rickard

Friday, April 15, 2011

Now This is interesting...

It fits the profile. Charging at 4:15 AM. Total destruction of both cars and the garage, melted the doorknob off the door to the garage it was so hot.

What is interesting is that Storm Connors Suzuki Samarai uses flood lead acid batteries. I have never gotten a lead acid to burn. Blew the end off a few, but the electrolyte is 90% water and they just don't burn.

The other car was a new Chevy Volt. LG Chem batteries. Our first VOLT fire?

More news:

UPDATE: Apparently, days AFTER the fire was put out, the charred Chevrolet Volt AGAIN reignited in the already burned out garage. Here on AUTOBLOG

Chevrolet spokesmen have been howling that it is NOT the volt that caused it and urging everyone to NOT jump to conclusions. I wonder what the latest hasty conclusions might be....

Tuesday, April 12, 2011

The Graphs is Always Greener....

This week we return to our 1957 Porsche Speedster Replica, the electric rebuild we call REDUX as it is the second version of the same car USING the same car. Recall we had upgraded this vehicle to 57 CALB 180 Ah prismatic LiFePo4 cells, a new version of Netgain's Warp 9 series DC drive motor, and a new to the market Soliton1 Controller by EVnetics.

After a broad misadventure with our first Soliton1 installation, Sebastien Bourgouis came to examine the problem and replaced the controller with a new one. It indeed seemed stronger, first blowing a Stage II Kennedy clutch and on replacement of that, blowing a 400A fuse we had forgotten entirely.

To find out just how much was gained in a numeric sense, we returned to Slingblade Performance in Anna Illinois for another round of dynomometer testing on their Dynojet dynomometer.

The results were interesting from a number of angles. Though young, the Soliton1 proves notably easy to configure, and now confirms a muscular presentation in the arena of the spinning of the tires. We hit about 156 peak horsepower at around 3200 rpm, and a clutch tearing 277 lbs of torque in the lower regions of the rpm band.

We had developed a bit of mistrust of the Soliton1's data log. It was clearly reading 150 rpm off on our test bench, and as it turns out, it's initial difficulties spreading the mustard were also entirely a measurement issue - not ours - but rather internally. It thought it WAS doing 1000 amps when our other best indicators were showing something in the 720 to 750 amp range. That's a noticeable variance that needed to be investigated and adressed.

As it turns out, the measurement itself WAS the problem. But the new Soliton1 that Mr. Bourgois so graciously not only provided, but personally delivered, measured amperes with good attention to detail. All comparisons with the other test equipment we had available looked essentially identical.

Surprisingly, the RPM problem went away as well. We assume the same calibration procedural issues had caused the RPM variance as well. And at that point, the Soliton1 log file function became seriously more interesting. Once we had some confidence the values recorded were real world, the value of this data logging capability quickly became apparent.

Essentially, the major gain was the ability to correlate voltage and current information with the Dynojet data files's horsepower information using RPM as the link as both machines record RPM.

This allows us a heroically finer level of graphing detail, as we can graph each mph of the run instead of every 10 miles per hour, and better we can correlate motor amps, battery volts, and more at this order of magnitude more frequent rate.

The leftmost column of the Soliton1 log is simply a timestamp and it indicates that the Soliton1 confesses its' secrets each 20 milliseconds. This is a useful thing, we actually then have a clock on our car runs.

The first column to the right, let's call it column two, is somewhat less useful. It features the percentage of available CPU cycles that are being used by the program. We have to assume the EVnetics software guru cares.

Column three indicates current in amperes. But it is't real. This is actually the level of current, after your throttle calibration, deadzone, and mapping are all taken into account, that the Soliton1 thinks is commanded by the accelerator input. Picture this as a request for power.

Column four provides a readout of actual motor current in amperes. This value, an important measure of the power in the system, is not nearly as controversial as many of our viewers believe. And I guess I'll have to explain that in more detail below.

Column five lists the duty cycle as a percentage. If you assume the entire period of time for one cycle at 8 khz, performance mode, or 14khz in quiet mode, is 100%, then duty cycle is that portion where the output waveform is positive.

Column six is the voltage of the battery pack. This will vary somewhat with load and indeed we saw the pack voltage sag as much as 22% during our runs.

Column seven is the internal temperature of the Soliton1 in degrees Centigrade. Almost all controllers monitor their internal temperature and when it reaches some higher value, the controller normally LIMITS the output current in an effort to reduce temperature.

Column eight is Revolutions Per Minute or RPM. This requires an external input from a magnetic or optical pickup reading the motor shaft rotation. This is important for our purposes because it allows us to correlate these Soliton1 values with the Dynojet values by finding the same RPM.

Columns 9-11 show the input voltage to IN1 through IN3, the general inputs to the Soliton1 that you can use for various things such as connecting the motor temp switch, etc.

Column 12 is the voltage of your 12v auxiliary system.

And finally the Soliton1 records a STATUS message indicating if it is running normally, is limited by slew rate, is limited by temperature, etc.

This wealth and granularity of information allowed us to graph in a resolution we've not been able to achieve before. We can take the horsepower output at each MPH increment and then use the RPM recorded by the Dynojet to lookup the same moment in time in the Soliton1 log. At that point, we can note battery voltage, motor amperes, temperature, and much more.

We published the graphs and put them on camera. The video wasn't up a couple of hours before we received a note from Steve West of New Zealand that we had it all hosed up.

Indeed, we had used motor amps and battery pack voltage to calculate kilowatts - kind of mixing apples and oranges. And of course we used kilowatts to calculate eHP by dividing by 746. And we used eHP to calculate efficiency by comparing it to the HP output on the Dynojet. In this way, we can compare how much power we are putting into the system from the battery pack, to how much power we are getting OUT on they Dynojet to see our losses.

And this brings us right back to the motor current vs battery current that many of you believe is so very important. For the purposes of determining peak power output of the controller OR the entire drive train, it really really isn't. But for this last calculation I threw in, the difference is significant.

The relationship between the two currents is largely a function of duty cycle. And it is quite proportional.

So to put out 500 motor amps with a 20% duty cycle, we need but 100 battery amps. Battery amperes will never exceed motor amps, as at 100% duty cycle the battery is basically connected to the motor. But motor amps can quite exceed battery amps.

The corrected graphs are depicted below. This grandly changes the calculation of KW. More importantly, if perhaps less grandly, it also changes our efficiency curves.

But while doing it, I might as well graph duty cycle and motor and battery amps separately. This leads to a bit of a busy graph at this point, probably beyond the level of useful. But it does show the relationship between battery and motor amperes.

We originally simply wanted to measure battery current to find our peak power output. A whole little army of people jumped up to try to "splain me" the relationship. I was quite familiar with it. The point was it doesn't matter. If you stomp on the accelerator pedal, they are one and the same very quickly, and we will certainly see full power, and full current, out of any controller very soon. And we were not getting it originally. We were getting something like 720 amps.

You will note that the motor and battery current are quite different right up to the point of peak power, where the duty cycle first reaches 100%. From there on, they are precisely the same. That point is also our peak power point as RPM also builds with duty cycle and current. From that point on, we are starting to be reduced in current and power by the counter electromotive force generated by the motor itself. Notably, you can move this point further right along the RPM scale by INCREASING your pack voltage. And of course, you move it left and down by REDUCING your pack voltage.

There are a couple of things that jump out here. Most of you do NOT have a dynomometer and I would find it astounding if anyone went to the trouble we did to manually extract several hundred data point values out of the Soliton log and type them into an excel graph. Assuming your controller is working properly ITSELF, you really can accelerate your car at maximum speed, and read battery amps and voltage to get a pretty good idea of how much power you are applying. Volts x Amps = kilowatts/746 eq eHP. Multiply that by 85% and that will be pretty close to what you will get on a dynomometer.

Without having a "go by" it is VERY difficult to tell if you are getting full power seat of the pants without such calculation. One of the reasons we have spent so much effort on this is that we have found NUMEROUS instances of people with perfectly operational electric vehicles, that ran WELL. But they were experiencing a FRACTION of the power available in their system - which was artificially limiting their power output.

This one even got US as it was an unusual situation where the controller itself was at fault. The most common problems in achieving full power, in our experience:

1. Battery voltage limits. Note that our pack voltage sags as much as 22% during a full acceleration. Most controllers have a well intended and largely useless function to limit current to protect a low battery pack voltage situation. This is intended as a poor man's "limp mode" and it almost never performs any useful function. But assume we had set this value to 160v. With a 192v pack this would seem logical. The controller would increase power until the pack sagged to 160v and at that point it would limit current. It is microprocessor controlled and can do this at a very fast rate. The result is such a smooth limitation of current, that it will hold your pack voltage at almost EXACTLY 160v, and vary the output current to do so. The result would have been MUCH less power than we see here in sagging to 147.

2. Temperature Limits. This is another very tricky one. First, again the controller can limit current in a very timely fashion to maintain it's temperature limit. You will notice that temperature rises to the limit, but never really exceeds it. This is because the controller is making constant adjustments to output current to maintain this temperature. Again, you won't really know you are current limited. Further, temperature in a controller is really quite a tricky thing. At these high current levels, it can change DRAMATICALLY and INSTANTLY. And so you will see a temperature spike ONLY when requiring maximum power. Let off the accelerator and temperature falls quickly. You won't even know this is happening.

Indeed, in our fourth gear run we can see that late in the run we WERE actually temp limited. Fortunately, it was so late in the run that we were not making much current anyway so it had little effect. But understand, we have a Toyota Prius pump squirting 20 liters per minute of glycol through the Soliton1 and thence through a pretty good sized heat exchanger. True, the car wasn't actually moving and so there was little air flow, but the point is that we intentionally OVERBUILD our cooling systems.

One of the myths of EV's is that they do not have the failures of components like ICE cars. Unfortunately, they have regular component failures and the most common is the controller. You can not only achieve maximum power, but GROSSLY extend the life of your controller if you keep it cool. There is no heat sink to large. We have developed a profound preference for liquid cooling of all controllers. And in the event of a controller such as the Curtis 1238, we actually manufactured a liquid chill plate to mount it to so we could have liquid cooling. And we entirely avoid the cheesy little kits most of the controller guys suggest. We use automotive pumps of at least 20 liters per minute, expansion tank fillers, high efficiency exchangers and quality hoses and fittings. It is always a thousand dollar expense. But it avoids power limitations and more importantly extends the life of the controller.

Finally, temperature is local. There is rarely a lot of heat energy to deal with, but it is very localized. The "case" temperature of your controller isn't the issue. It is at the IGBT itself. It drops about a volt and a half and at 1000 amps that's 1500 watts. Good internal design is important, but you cannot overcool this device. In fact, we suspect if you could cool it to about -400F, the volt and a half might go away.

3. Throttle input. The controller's primary job is to convert your throttle input to motor control. If you have the maximum throttle input set at 5v, but your throttle really can only provide 2.8v full pedal, you're going to be disappointed in your car. The car is fine. The configuration of throttle input is not fine. The controller basically maps the available power across this throttle input range. And 2.8 v is a little past half power. If you set the throttle max value in the controller to 2.7, then you will get full power BEFORE reaching the end of the pedal. Some controllers have byzantine configurations for this with different throttle TYPES and a MAP to alter the curve of applied power across the throttle input. You must become familiar with those configuration items.

Those appear to be the three most common power limiting mistakes. This has been the only event we've ever had where the controller itself was a problem. But if you have one of the Soliton1's, you might want to check. If they do not have now, they will undoubtedly have soon a procedure for you to follow to determine if you have a calibration issue I'm sure. But you might check with EVnetics to see what it is and check it. Ours sure got better when it was replaced. But again, the pernicious thing about this problem was the controller operated PERFECTLY in all respects and the car drove VERY NICELY and without actually measuring the current, we would have NEVER known how much power we were missing, if we had not measured.

Jack Rickard

Monday, April 4, 2011

Sebastien Bourgois and the Soliton1 that thought it was a Junior

This was a good week. Kind of strange, but very good.

The good part was that Sebastien Bourgois, the head of EVnetics, travelled at his own expense from St. Petersburg Florida to our location in Cape Girardeau Missouri to address our Soilton1 weeney power problem. I would guess he had it fixed in about 20 minutes.

The problem, from what I understand, is that the Soliton1 was reading it's output current at 1000 amps and of course dutifully limiting it to that.

It is safe to assume that the Soliton1 uses a Hall-effect current sensor, and since we use those for many, but not all current sensing in electric cars, it might bear some examination.

Edwin Herbert Hall discovered the phenomenon while he was working on his doctoral degree at Johns Hopkins University in Baltimore, Maryland in 1879. Hall noticed that if he applied a small magnetic field to a section of conductor that was carrying current, an electrostatic field would be caused traversing the conductor. Essentially, the magnetic field caused all the free flowing electrons to move to one side of the conductor and the positively charged "holes" to the other. This voltage was both measurable and proportional to the level of current in the conductor.

And so a hall effect current sensor has a small loop enclosing the conductor and a small magnetic field is generated by the loop. Then the voltage from one side of the loop to the other is measured and output as a signal.

Typically, this signal is very low level. The LEM HAS sensors we use, for example, are bidirectional. The power we provide to it is 5v and ground and the resulting output signal is 2.5v with no current through the conductor. Current in one direction will cause this to rise to as high as 5v, and current in the other direction will cause it to fall to as little as a bit over 0v.

Normally, we would take that signal and apply it to an analog to digital converter to convert this value to a digital value that we can use for intelligent purposes. A 10 bit A/D converter would then output 1024 possible values with 512 representing the 2.5v and 1024 representing 5 volts for example. In the case of a 16 bit A/D, you would have a better resolution with 65535 possible values with 32767 representing zero current and 65535 representing 5 volts for example.

There are two problems with this. The digital output is quite precise, but the analog output of the sensor is somewhat less so. The 2.5 volts wanders around a bit with temperature, and so your 32767 value for zero amps is a little squishy. Normally, you would temperature compensate this numeric value by having another A/D input for temperature. You might also give it a little room and declare a plus or minus 25 count as still representing zero amps, in software.

From there, you get to scaling. If the sensor is a 200 amp sensor for example, 5 volts might represent 200 amps. Unfortunately, the inexact nature of the sensors means they might build ti for 200 amps and it actually indicates 186 amps or 214 amps.

And so the device has to be calibrated. Fortunately, this is quite easy. Let's say 1000 amps is nominally 5v and we have a very nice zero point at 32767. If we divide the remaining 32762 value by 1000 we see we have 32.762, or very nearly 33 as the value of ONE amp. We can calibrate this by actually measuring a known current value, and changing the 33 to 32 or 31 or maybe 34 or 35 to get a digital output corresponding with our known current level.

The astute among you will immediately see the problem here. Where do we get an exact 1000 amp current? Ok, we can calibrate it at 200 amps. That moves the problem to the still difficult, where do we get a precise 200 amp current to use to calibrate.

The problem in our Soliton1 was that its calibration was off, and at about 700 real amperes, it read 1000 amps. The iGBT's in the Soliton1 are undoubtedly good for a higher current level - you would typically do this to provide a little "headroom" from the spec so you don't easily blow up the component. I'm guessing 1400A IGBT's. But then in software you "limit" the current. In this case, the current limit is of course set to 1000. We can in fact, in the configuration screen, limit it to a lesser value. But we cannot limit it to a greater value.

The fix is simply to recalibrate the Soliton1. IN our case, it was easier for Seb to swap it out.

Since we already had three other Soliton1's sitting around, why didn't we just swap one out. Well, duh, because I thought it was working. It operated fully and smoothly, and 722 amps at 160 volts is not an irrationally minute amount of power in itself. That the Soliton1 was reporting 1000 amps while I can't measure 1000 amps made me somewhat skeptical of their advertised claims. If they claim 1000 amps, and report a 1000 amps on the log, if you never measured you would of course believe you were getting 1000 amps. Not that any vendor would do such a thing.........

As it turns out, I do not believe they were doing it on purpose. When he swapped the Soliton1, it immediately made 1000 amps that we COULD measure externally as 1000 amps. There's no purpose in rigging such a thing if you really can do 1000 amps. ANd indeed, as Yogi notes, "It aint' braggin if you can do it.'

So I'm persuaded they simply have a calibration issue and further that it's probably just procedural - going back to where do you get a good 1000 amp calibration "signal" and a lab certified ampmeter as well. Or even a 200 amp source. Well, you see the problem. I have no idea what the calibration procedure is and Seb didn't share, but he did state in a clearly annoyed fashion that they were going to revisit the issue.

Meanwhile, he and Brian took a test drive and immediately burned up a Stage II Kennedy clutch. Brian had CB Performance overnight a stage iV Kennedy clutch and 3000 lb pressure plate. Man are THOSE guys good. It was hear the next AM. He and Matt pulled the motor, swapped the clutch and pressure plate, and had it all back in by noon. THEN we blew the 400amp fuse on the system. We had simply forgot to upgrade it when we rebuilt Redux.

As George Hamstra notes in his ongoing redesign of the Warp series of motors - "If you beef up one thing that fails under extreme load, you simply move the problem. Next time then something ELSE will blow."

But by Friday afternoon, Brain had done a test run with a zero to sixty time of 6.96 seconds. He relates that at 6.98 in the video.

As our shift points will have shifted given the higher power, we expect to improve that very slightly on the dynomometer this week. And it will be interesting to graph the results there. I'll work on improving the graphs. Now that the reported amps and the measured amps are pretty close, I can probably use the log file to back up our video technique of matching amps/volts to the dynomometers output hp/torque. I'll work on it.

Motor amps vs Battery Amps.

This is entirely forum speak. And I've avoided it. Enraging both the forumites and forumicators. From my perspective, everyone who raised their hand and brought this up is a moron in public. I understand that that IS the minority view.

If we treat the controller, motor, and transmission as a black box, we don't need any test equipment really. Many of our viewers have EV's, and many of them do NOT have $20,000 in test equipment laying around on the off chance that they MIGHT want to measure something like that someday. I not only show what we do on the video, I am very careful to TRY to do it in such a way that YOU can do it yourself and either get the same result, or get a different one. In this way, you can determine if what we say is real, or if we have made an error. And you do not have to depend on the overabundance of self appointed experts on the forums to "interpret it" for you.

Almost all EV's have instrumentation to show battery amps and pack voltage.

A dynomometer is a heady investment. Fortunately, so heady that almost every town (except Cape Girardeau) has one where you can rent some time for a hundred bucks or so. They will give you precisely what your output horsepower is and what your output torque is by RPM.

IF you have the ability to note the current and voltage at those RPM, you can correlate this very nicely. You will put IN an mount of power calculated by multiplying the voltage times the current and expressed as watts. You can even calculate this as horsepower by dividing the watt value by 746.

You will note a disparity between what you put in and what you take out - that is the efficiency of your drive train. You will typically get OUT 80 to 85% of what you put in.

And all that is related to the limits of your controller, motor, and in this case clutch, but primarily your controller.

The difference between battery amps and motor amps doesn't matter because they are going to be the same. When you get on the dynomometer, you're going to mash that accelerator and it will accelerate as best it can right up through your maximum RPM. And at all those values, you are going to match on both sides of the controller the same amp rating to within less than 1%.

The ENTIRE purpose of this PWM waveform is to provide LESSER amounts of power for lesser throttle positions, and you're not doing any of those on the dynomometer. BACK EMF, power peaks, etc etc ad nauseum do NOT have any effect on this. Your efficiency actually varies a little across the RPM band. And both the current and voltage can vary, but the relationship between battery and motor amps won't and that is why I have said they are the same and they do not matter. And they do not.

Dragging it off into discussions of PWM waveform analysis was not where I wanted to go and I refused to do so. It had NOTHING to do with whether or not the Soliton could put out 1000 amps ever.

Ensued a big discussion of what Jack knows and what Jack doesn't know. It isn't, and never was about Jack. I don't even know how to address all the things I know and don't know to this group. It would astound you in both directions. I've lived a very large life on a very wide front and to a very deep depth. And at 55 years old, I'm just really really comfortable with it. In almost all cases, I attune my output to what I think is useful to the person I'm talking to. In thiis case, it's a rather wide group with doctorate level viewers in materials science and battery research, and guys who can't put batteries in a flashlight and get it right before the first try.

HERE is a huge line of distinction. MOST of what I have read and you might read on the forums has little do to with anything beyond the personal self aggrandizement of the posters. They are very insecure in their lives and what they know and will seize any opportunity to demonstrate any knowledge they think they have, and in most cases have part of and have that part misunderstood, in an effort to have YOU believe they are an expert in the field. 90% are outright poseurs, but even those that are doing it I would observe are MOSTLY doing it for the personal satisfaction of personal self aggrandizement.

I don't live in that world. I don't need to. That's not why we have an EVTV. I already thought I was a thorough genius and fabulously wealthy and successful person on such a wide array of fronts you don't even know about that I have ZERO interest in it at all. Actually probably negative numbers. Here in Cape Girardeau I live very quietly in very modest digs and spend most of my time trying NOT to call attention to myself.

EVTV is not about me and what I know or don't know. I just can't share all that with you.

I see a "perfect storm" of issues and problems that encompass our air, our money, our kids, our troops, our relationships with other countries, our idiot politicians, and a very real potential for total economic collapse that will effect us all. It has a lot of aspects, but an UNUSUALLY NEAT little Nexis centered on about 1/3 of our energy use for personal transportation purposes. And we don't need the whole hog to win. if we translated 20% of just that 1/3, using a readily available efficiency multiplier of about 8 that we get by using electric motors instead of internal combustion engines to drive our personal cars, MOST of it all moves out 50 years. That's plenty of time to convert everything ELSE to electric and make the whole thing eight times more efficient.

And to do THAT, I am absolutely certain of what I need and it would surprise you no end. It's not 300 milliion people, nor General Motors, nor Barrack Obama.

If we could get 10,000 guys to build an electric car, and use it to each persuade 10 other guys to do likewise, we have 100,000 people intimately familiar with electric drive automobiles. The advantages are more persuasive than having a global Internet. And I watched just that happen in those numbers on my watch.

And it will happen here as well. I get up at 5 AM and go at it till midnight and I do that seven days a week until it is done or the big heart attack removes the problem for me. It's not the 100,000 that's hard, it's the first 1000. Once it hits critical mass, I'm sipping whiskey and looking at the river.

AND YOU'RE A LONG WAY FROM THERE YET. You don't have probably 300 LiFePo4 builds worldwide.

In the meantime, I'll do whatever I can to persuade you, to enable you, and to goad you into action. But it never was about me. And I have no need to be politically correct, give up smoking, give up whiskey, flex my muscles, do my hair, wear a necktie, hide my microphone, or demonstrate any particular knowledge or expertise so anyone thinks well of me. We seek advertisers and sponsors and we don't need ANY of them. THEY will be better off for getting on the train and they can enable YOU. If I want to call you all Nappy Headed Whores, you'll hear it and CBS hasn't got shit to say about it. If you try to put me in a box like CNN or Mythbusters or Senior/Junior or whatever, there's a REASON we're not on cable. It would be a mismatch from the get go. The cable networks would never do precisely what I told them to do 12 minutes before I thought of it and they would be immediately dismissed from my own little insular world for even thinking of such irrational insubordination.

So EVTV is never going to look like television you are accustomed to watching. And I'm not a forum guru. And there are reasons for all of that. But I am single mindedly devoted to the notion of persuading YOU to CEASE being a VICTIM of oil companies, governments, global economics and the uncertain future. I happen to know it really IS what you make of it. You have no CONCEPT of how powerful you already are. Go to your garage NOW and sweep out a space about the size of a car. That's the first step..... Now picture a car in your mind.... that's the second step. The rest of the steps are so easy we can do a video while we're doing it.

Rant off.

Boy, rainy morning has me all smokey.

Jack RIckard