Duane Ball's Spyder 550

This week is a fairly short show. We mostly feature Duane Ball's Electric Beck Spyder 550 build. Built by Scott Smith in New York state, this car features many of the components in our own Speedster Part Duh prototype. It is an excellent example of craftmanship in an EV build.

Here are some further detailed photos.

This is the slotted heat sink for the Curtis 1238. This should provide excellent cooling for this controller.

The Spyder filler cap is most interesting. In this case, it allows external connection of the power cord.

This is a shot of the front compartment



This shot shows the rear compartment. Click on any of these for a larger view.



We continue to work on Speedster Part duh. Truth to tell, we did our first test drive this week. It will be featured in next weeks show.

We put some further thought and experimentation into the daughter box and valet function. Essentially, we eliminated the box entirely. We're down to a couple of resistors and a switch wired to the Xantrex LinkPro. Here's the Linkpro connections:

It simply applies a current limit resistor of 100 ohms and a 5k 10-turn pot across the 0-5v throttle output to throttle return lines. Either the valet switch or the Xantrex can do this. We measured throttle inputs TO the controller using teh Curtis 1311 Programmer and it works fine.

We also found that the Curtis would NOT drive our two series Gigavacs. These comprise a 24 volt coil together, but the Curtis did not agree. So we replaced them with a Kilovac LEV200A5NAA contactor and the Curtis is now quite happy.

Jack Rickard

Life in LiFePo4 - Cycle Life and Attenuation Data

Kind of a late blog entry. Busy week with Rickard Electric Speedster design. The May 28th show rounded up a lot of little parts such as the accelerator - with a little valet function box I refer to as "daughter mode."

The basic concept is that we can use the TBS E-Xpro instrument to monitor state of charge by AH. And we can kind of flexibly define a percentage SOC based on any AH value we like. The unit will close a relay when a defined value is reached. But a relay to what?

I have a bevy of daughters. Not to denigrate them, but they are not precisely EV enthusiasts, although they like cars and like the feel of an electric. But when out and about, if they did start to "run out of gas", I'm trying to visualize something that would convey to them that it is time to go home, and if they don't go home, it will cost Dad about $9000 in batteries.

An LED probably won't cut it. I can picture a daughter saying "Hmmm, a light. I wonder what that's about. I better ask Dad when I get home." She would then continue her travels until it suited her.

With a buzzer or audio alarm - "Hmm, that's certainly annoying. I better ask Dad to fix that next time I see him. "

So what can I do to get her to have a sense of urgency that there is something wrong with the car that needs attention NOW.

Well of course we could easily wire this up to a controller input to disable the controller. But this is a little extreme. What if she is in traffic and needs to get off the road?

The concept we've settled on is in no ways original. It is commonly referred to as limp mode and indeed there are some ways to do it in the controller. Our Curtis determines state of charge by voltage and I'm none too enamored of that. I want to use the AH counter.

So we devised a very simple little box, it has not enough circuitry to even be considered a circuit. Indeed there is no circuit board. It's a couple of resistors wired across the terminals of a relay.

In normal operation, it simply passes the 0-5v throttle signal from the throttle through the normally closed contacts of a 12v automotive relay to the controlller.

We can use a small dash mounted switch OR the TBS amp hour counter relay to pass 12v to the valet box to activate it.

This simply divides down the voltage to about 1/4 of its normal value before connecting it to the controller. I've added a 5K pot to trim this from the 1/4 value down to zero basically.

We also made kind of a discovery with our Vantage Vehicles GreenVan. This miniature van is a very el cheapo little Chinese cargo van that is SO small and SO basic and so ugly it actually starts to look cute. The company is based in Corona California (http://www.vantagevehicle.com).

But we were surprised to learn they used some pretty high quality components in the "conversion" they do to these vehicles. The system is 72v but use some unidentified but physically enormous AGM cells of 198Ah. The charger is a DeltaQ. These are really pretty nice chargers though not adjustable. The only reason we don't talk more about them is they are just focused on the low voltage market. I think the highest voltage they will do in their product line is 96volts. And just about no one is doing 96v in EVland. It's kind of a Neighborhood ELectric Vehicle thing.

The motor is also a little mysterious, but seems to be a 10HP three phase AC induction system with a 35 HP peak rating.

To drive that, we were a little astounded to find a Curtis 1238-6501 three phase controller. This is the 80V version of the controller we are using in the Speedster (Curtis 1238-7501).

The system appears to do regenerative braking only on applying the brakes. I'm increasingly leaning toward this on the Speedster and the Mini is now dialed down to very low values when you take your foot of the accelerator, but quite a bit when applying brakes.

The GreenVan does this a little differently. Instead of simply keying on the brake light signal, they employ a pressure transducer in the brake line to convert brake pressure to a 0-5v signal into the controller. The transducer gets 5v and ground from the controller, and puts out a voltage varying across its 500 psi range.

I thought this transducer might be hard to find. We located the company that makes it, MEAS Specialties, and contacted them. Never even got a reply to an e-mail. Before calling, I looked around a bit on the net and worked out their part number scheme. Turns out, it is VERY commonly available on Digikey at $104 each - Digikey part number MSP3501P2-ND. And you can get them at various pressures, 250 psi, 500 psi, 1000 psi etc. This might be important. I don't know how well our Speedster pressures will match the GreenVan's.

Anyway, this will take some experimentation to get the feel right, and may not be enough improvement to justify the effort. But I like the feel of the GreenVan's brakes.

May 15th marked the 1 year anniversary of our first video post. As many of you know I was in publishing before (print magazine) and just love the business. I've tried other businesses, but after publishing, nothing really makes any sense to me. I've seen them and they didn't make sense. So I would try them myself, and was surprised to learn I had nothing to learn there. Most of them just don't make much sense. It's hard to move heavy objects around for a 30% markup.

One of the things about publishing that I understand viscerally is about the flow of information. You give it away. To anybody who will listen. And you can't give it away FAST enough to avoid becoming successful at it. The only way to fail at publishiing really is through a lack of generosity of spirit. If you start viewing information as proprietary and valuable, you generally sell off the office furniture at auction a few months later. If you strive to pick up information gems and IMMEDIATELY give them way, it seems it rains money and other good things.

This is a bit counterintuitive. But one of the keys is that the information is not one way, and you are not really the producer. If people find the info useful, and gradually come to trust that it isn't a trick, they start to add to it. It's kind of a stone soup process. You of course have to initiiate it with the stone. But soon people are showing up with cartots, vegetables, onions, potatoes, etc.

Basically, you become a goto focal point where people can usefully promulgate useful information. As these contacts improve in quantity and quality, your information flow improves dramatically, and becomes something quite beyond what you are actually capapable of. Your role kind of devolves to sorting and categorizing, trying to filter through to find the gems that your readership, in this can viewership, might find useful. The more useful, the more people tune in, and the information sources grow and improve.

The good news is that you wind up with a lot of information. The bad news is, there are some real world problems publishing all of it. This gets a little hard to explain. But what made us very successful at Boardwatch was we got very good at sorting out the bullshit from the infogems - initially through hard work and experimentation. But over time we just developed a feel for it. But the other skill that is kind of hard define, goes hand in hand with the generosity of spirit.

It's actually hard to describe. If I use the word "tact" the people that know me in the forums I've just left are going to laugh outloud. Simillarly "appropriate judgement" rather fails. How about a "sensitivity to info issues."

Most everyone loves secrets. And the greatest joy is in telling them. Even greater is seeing them told widely. And often the value of the infornation is kind of tied to how secret it is. Scarcity being a key element in the value of anything.

Unfortunately, in the real world, we face certain ethical dilemmas. We may not quite approve of what our employer is doing and have a need to get some information out, but on the other hand, you don't want to lose your job in today's economy - with a couple of young children to feed and an upside down house payment.

So the GM Volt engineer loves to call and chat about some very interesting things. But if her employer knew she was putting this info out, there would be a rather immediate career change. And often, just the nature of the information points to the likely source.

So one of the frustrations is that I wind up with some inflows that are terribly interesting, but I don't know precisely how to deal with them without wrecking lives and careers. At one time, I was pretty brutal with this. "If you have a secret that needs to be a secret, why in the hell are you calling a magazine editor?"

Unfortunately, our actions have consequences, and often the consequences are someone ELSE's consequence. And if you see this go down a couple of times, you just can't help but become a bit more discrete. Time heals all. Often a month or so in the "aging cellar" changes the whole situation and no harm no foul then.

Sometimes, I can just generate this info out of thin air without attributing a source. That makes me look very smart. That's not precisely the goal. If it came to me in a dream or I'm a little vague about it, occasionally there is a reason. But it appears it would damage someone or something if I get too detailed on where it came from.

That's all a rather long winded tour of the joys of journalism. I really like the position and I'm frightfully good at it. But like Chess or Bridge, you never really master it. Actually, I always assume some portion of our viewership/readership is actually a lot more knowledgeable and a lot more intelligent than I am. It's not ALWAYS the case, but it's a good assumption to start from and particularly appropos in technical fields. Everyone is a specialist. And by definition I have to be a generalist. So, it's pretty real. Those in that ca
tegory will hopefully pick up from this why some elements of EVTV are always going to look a little odd.

For the rest, here's a little example. You may or may not know that I'm particularly enamored of these Chinese prismatic cells. Of course the reason is obviously weight and volume to power - they make electric cars viable in a way that lead acid, NiMH, etc simply cannot in a very ratiometric fashion. The particulars of the lead acid battery are immaterial. At that size and that weight and that power, it just doesn't work except for toy demonstrators.

But for now, the price is high. So high, that the only way this works is if the cells last a very very long time compared to the other battery technologies. If you have to replace them every three or four years, you have simply moved the operating expense from the gas pump to the battery store.

But at some point in longevity, rather keyed to the life of the car, the expense moves out of the recurring operating category and into the capital expense of the vehicle itself. We no longer talk about miles per engine. In fact, miles per tire used to be an EXTREMELY important factor in tire sales. It just isn't anymore. True, we go through a few sets in the life of the car. But somewhere past 50,000 miles, we ceased caring very much.

The heart of all this is that a good Trojan lead acid cell is rated at 350 cycles. The LiFePo4 cells are spec'd at 2000 cycles if we limit discharge to 80%, and 3000 cycles at 70%. Thundersky recently went to 3000 and 5000.

Those deeply experienced in the lead acid pool, have pooh-poohed this forever as being hopelessly optimistic. I feel their pain, but I've known for some time that it is off base. Part of this is cultural and part technical. The good news is that your LiFePo4 cells will last a VERY long time unless you actually destroy them, and of course a BMS is a quick way to accomplish this.

The cultural part is pretty broad. You have to understand the Chinese a little bit. "Managers and Scientists" are very highly regarded there. "Salesmen" are almost viewed in the same light as street hawkers selling roast peanuts. And it is not seemly to brag on your children. Indeed there are some serious karmic issues with mentioning your children in a positive light. And finally, if you ask a question of a superior in China, you are basically challenging him. If it is something for you to know, he would have already told you.

This all sets us up for some serious disconnects with America. First, in the good ol' USA, if you will do 180AH sometimes, even for a second, label it 180AH. Better, let's call it 190AH. Who measures? If it's a problem, we can always add a four point disclaimer at the bottom of the back page.

In most American corporations, the sales and marketing guys not only pretty much rule the game, that's almost always where the CEO's come from.

What you will find in dealing with the Chinese is that if they tout it as a feature or specific value, it will ALWAYS exceed that value - or at least they really did believe it would. They actually pad things the OTHER way. We're right around 190AH, - label it 180AH and we will not appear unseemly.

Second, the sales person you might be dealing with is essentially POWERLESS in the organization. They have to get permission to use the restrooms. And if you press them for technical information necessary to make the sale, you put them in a very awkward position. They either have to go appear to challenge their boss, a very painful prospect, or risk losing the sale. They do NOT work on commission as is common here, but failure is its own reward in China and you do NOT want to fail as a salesmen. There is no lower place to fall to. So you might note a little stress from a simple question about how they come up with cycle life data.

In China QUALITY is the golden horizon. The executives there actually do not understand why we want all this info. Don't we know they are claiming to have the HIGHEST QUALITY - GUARANTEED. Who would want more than that?

Finally, they're just a bit secretive about everything germane. I myself don't quite undetstand this, but all Chinese drama centers on a secret. The companies who make these batteries are not scientific in nature. They discover nothing and they invent nothing. They do develop manufacturing processes to ensure quality and output. The cathode material in the China Avaition Lithium Battery Company cell comes from a company titled ALEES in Taiwan. They buy it by the barrel. Similarly, you can buy aluminum foil and copper foil in China in a wondrous array of widths, lengths, and weights and some if it even perforated in various ways.

What you know of as a battery company in China develops clean rooms and workshops with some automation and they order these materials and produce a lot of cells - 1000 cells per day say. They know about as much about the chemistry as my daughter does.

They DO do testing, for quality purposes. And of course to develop better batteries with higher outputs etc. But the data is for internal use only and indeed, the salesmen aren't normally very privy to it.

I did stumble upon a pretty bright sales guy with Sky Energy. And he was pretty good at hunting down information although this was a painful process taking weeks and dozens of e-mails to get even the most basic info. He appears to have not made the cut in the transition to CALB - probably too inquiring and uppity.

One of the most fascinting things I got from him was an actual .XLS spreadsheet listing the AH values from 500 cycles of testing for what they term "attenuation" or the decrease in capacity over time from cycling the cells. I got one of these for the 180AH cells and one for the 100AH cells, with two cells tested and the actual values. I've prepared a couple of simple graphs from this data.

There are a couple if interesting things about this test. First, the 500 cycle length is impressive. This is 500 actual cycles, in a world where lead acid cells are ESTIMATED to have a 350 cycle life. They show a pretty uniform 5% degrade from their initial value - and it appears to be quite linear. That implies 2000 cycles easily to 80% of initial capacity.

More encouraging, the initial value is ABOVE the rated capacity. And indeed we are just starting to break below advertised specs AT 500 CYCLES.

The tests are of course at a very moderate 0.3C. But the thing that just blows me away is that all 500 cycles are to 100% discharge - not 80% or 70%. They run until the voltage at 0.3C breaks 2.0v which is their definition on the spec sheets of 100% discharge.

So what the data appears to show is a minimum 2000 cycle life at 100% discharge. They are fudging this to 2000 cycles limited to 80% and 3000 cycles limited to 70%.

In America, we would test at 50% DOD, claim the 3000 cycles, and not mention this silly depth of discharge thing at all. Or else it would appear at the bottom of the back cover of the report with a tiny little cross and in 2 point type.

So I am very taken with the prospects for long life from these cells. They just appear to be bullet proof to me.

Another interesting aspect that explains some of my own observations. These cells appear to INCREASE in capacity over the first 50-75 cycles. Further, the curve made looks just a little bit like the discharge curve. It appears steeper on the left than it does on thte right where i appears to flatten. This might imply even LONGER lifetimes if it si flatter at 1500 cycles than at 400 for example.



Jack Rickard

Online Forums - signing off

My experience with online forums goes back to the early 1980s, and indeed I wrote one of the very few 8080 assembly language software programs to manage large numbers of Usenet Newsgroups - PIMP.

But the experience has always been mixed. The written word in the forums or newsgroups leaves many more able than others, depending on their ability to express themselves using the written word. And the instant nature of the technology leads to some rather interesting interactions.

One of the things we're trying to do with EVTV is of course promote the evolution of electric vehicles as a personal indiidual effort that many can take to demonstrate or lead us to an energy policy and practice that reduces our dependence on foreign oil and the existing oil based unholy alliance between government, extremely large oil corporations, and equally large automotive manufacturers.

And we've been somewhat successful. Despite lower gasoline prices, there has been renewed and indeed increased interest in electric cars and doing conversions, and the chatter from the large manufacturers has changed subtly from "maybe someday" and "hybrid, hybrid, hybrid" to "me too, we've got plans" and "battery, battery, battery."

The latest of course is Toyota CEO's joy ride in a Tesla Roadster and subsequent announcement that he had "felt the winds of the future."

For individuals converting cars to electric drive, information is at a premium. The obvious attempt to get it involves Google, and that subsequently leads to forums such as Electric Vehicle Discussion List (EVDL) and Do It Yourself Electric (DIYElectric).

Like all forums, these lists attract a set of "regulars" who simply post more than anyone else. And any information, repeated often enough,, becomes "the word" simply because everyone has read it, passed it on, and read it again.

Unfortunately, there is no check on technical accuracy.

Combine this with a certain level of anonymity, most of the "regulars" have pseudonyms and do NOT post their real names. And you have pretty much a formula for misinformation.

I call this "online engineers typing themselves smart."

In most cases, despite screens full of text proclaiming their expertise, these are self taught diletanttes, whose education and engineering practice again comes primarily via Google, Wikipedia, DigiKey, and most of all, by typing in the forumes themselves furiously.

As an engineer and technical writer for 30 years, this all smells like opportunity. I don't mind wading into technical confusion at all, it's probably what I do best. Misinformation in bulk is a little harder to deal with. DISinformation is just beyond the pale.

With the rise in interest and the search for ever better components, there has been some economic opportunity. We were deeply disappointed when one of our suppliers, James Morrison of EVComponents, came under some internal strife and economic issues and made a startling move to simply disavow responsibility for some $400,000 in prepaid orders from potentially 75 customers who had paid in advance for batteries and components. Apparently Morrison has deecided to stiff these people of their products, and sell the already sold stock AGAIN at bargain basement prices to raise further money and so deal with his economic difficulties.

Like all new frontier industries, this one has attracted its own bevy of snake oil and patent medicine sales force.

The EASIEST target is Battery Management Systems or BMS. After spending $10,000-$15,000 on the most necessary component, batteries, most innovators are struggling to get maximum life from these cells. The problem is the manufaturers provide very little information, and some of that not terribly accurate.

Enter our hero, BMS designer. They throw together some ill thought through designs using inexpensive components, rush it off to Sundstone to make PCBoards, and immediately start selling them to any hapless yuck that they can find. NO testing of any kind in most cases and in the thoroughly tested cadre we are talking about thoroughly tested by running it on the designers car for two weeks. These are available at ALL prices, ranging from $12 per cell to several thousand dollars. The tout is essentially always the same:

If you don't have a BMS, YOU'LL BE SORRY WHEN YOUR $15,000 BATTERY PACK BLOWS UP HORRIBLY. DON'T SAY WE DIDN'T WARN YOU.

I have spent some time and effort on a particular forum DIYelectric over the past year trying to sort all this out and counter the disinformation provided. The result has been a very understandable attack from those who more or less huant these forums, using them as barely concealed fronts for sales operations. If I come along and mention that their design won't do what they claim, they go berserk. And if I offer real data information from real cell tests that indicate that the BASIC premises they are using in BMS design are fatally flawed from the beginning, they go into rage.

They are quite accustomed to simply shutting up this talk by gathering the herd, jumping on the heretic, and giving him a good thrashing. Of course, as I said, I was in a VERY rough and tumble world of online forums before many of these people were born. And as a technical writer, I sometimes feel like a child molester picking apart their wholly unsupportable technical nonsense in writing. So the gang up and abuse stunt neither awes or dissuades me. Rather, I find it entertaining and indeed can stoop as low as they want to go in the ad hominum attacks. It's just not a problem.

We've been effective. The sales of useless blue elephant gun BMS systems has plunged. The top balance shunt systems are virtually dead. And generally we have shifted the goal toward Battery MONITORING Systems and informational instrumentation.

But many of the regulars have at least side-business type income from these activities and some are trying to make a living at it. It's hurt. Since the usual bullying and attempts to simply "vote" me off the island haven't had their usual result -- most people don't want the abuse and simply quit the forums, the new tactic is to appeal to the forum operator to have me removed or edited.

This came up on EVDL some months back. Administrator David Rhoden contacted me with some very paternalistic advice on how not to stiur up controversy or anger any of his participants. I pointed out to him that I WANTED to stir up controversy and did not MIND angering his participants if it helped anyone sort through the dreck of disinformation and bullshit. But if he intended to delete messages I posted or "edit" them to a tone he felt more comfortable with, I would simply leave the list. And I did so.

Over the past year I've posted a lot on DIYElectric and indeed paid for advertising on thise widely used service. This week, I was attacked wholesale by a 14 year old who only identifies himself as METHODS and posts photos of his BMS systems, which are particularly inept. We actually weren't even in a discussion. He just launched a bomb of ad hominen attacks likening me to "cake and dogshit in a blender."

My response was quite muted, as the entire thing reallyhad no context. I simply asked if this anonymous person might be another 14 year old boy blunder forum engineer who just might have a BMS product on the table.

Incredibly, I heard from Robert Green, forum administrator, cautioning that several people had complained about my posts. I pointed out that if he cared to check he would find ALL of them were in some way involved in BMS design and sales. I quoted the message I had responded to and he seemed at the time to agree it was a very provoked attack and a measured response.

I got on the service later, and found the attack slightly reworded (edited) and my response deleted entirely.

I pointed out to him that he had apparently decided to edit the stream and essentially disable my ability to respond in a public forum. If we're going to manage the debate by falsifying the text, what the hell are you doing? He simply explained he was trying to reduce the anger.

I asked him to delete me from the group and remove the ad and incredibly, he initially REFUSED to do so. I then asked him what he thought he was doing. DId he intend to have me "appear to be" active on the forums and condoning the site despite my leaving? Who was going to fake my posts? Was he aware of the legal implications of this?

He finally agreed to delete the account and the ad.

This attempt at editorial "control" which essentially borders on onlien identity theft and fraud. What if someone, with the access of an administrator, starts editing your posts to change their meaning? Or worse, starts posting under your login things you were not even aware you had posted? Where would this end? Online identity theft out of control....

In any event, we are going to continue publishing a video series online with the best information we can determine at the time. Its likely imperfect. But it isn't dishonest. And having learned now twice how insidious these little relationships are between the forums and the "engineers" that are trying to sell product (most of the ads on Mr. Greens service are BMS ads with the exception of the EVCOMPONENTS ad and ours).

Basically the information on these sites is no longer to be trusted at all. They are willing participants in a scam to milk ducats from people who are interested in electric cars. It is done quite cynically, and quite by design. That is not to say everyone on these forums are part of the conspiracy. Most are simply unaware of the level or purpose of the manipulation. That it would extend to actually editing posts by subscribers, to subtly alter their meaning, by the administrators, is beyond the pale.

We're probably going to avoid the forums in the future entirely. It takes a lot of time and effort, and I cannot correct every technical idiot theory on perpetual motion in any event. I'll try to post here to the blog more regularly, and let the forums do what forums do, lead to a lot more heat than light.

I would urge you all to view what you read online with a skeptical eye and exercise critical thinking. The level of misinformation/noise is always horrendous. But at this point there are actually unholy alliances between the forum administrators and their friends, the BMS designers, that are quite deliberate DISinformation.

Jack Rickard

May 7th Show Now Online

We've made some recent progress on the Speedster Part Duh, and rather gotten ahead of ourselves on the video thing. We were trying some things, they came together, and we're not too much wanting to remove them at this point. So in this video we kind of do a walkaround to show the week's progress.

Brian installs our Chennic charger in the front of the car. Very neat assembly.

We decided to mount the charge receptacle, a Marinco NEMA 5-15 recessed male, where the torsion bar access port is on the drivers side. This looks good and is very easy to access, though down low. If you are going to get in the car and drive it, you pretty much have to stumble over the power cord to do so, which should prevent the situation of driving away with the cord connected.

Brian installed the AC-50 motor in about 15 minutes. He simply put it on a jack, jacked it into position, and it slide into the transmission. Four bolts and it was over. Looks great. Not much to report.

I've been working on some secret sauce. I've been fascinated with carbon fiber and kevlar hybrid resin materials. I love these little carbon fiber body parts you can get. They look great and they seem quite strong but very very light. I wish we could get the Speedster fiberglass body in carbon fiber of course.

In any event, we had a huge problem with Speedster part UNO. It was supposed to use 160Ah cells. We wound up with two strings of 90AH which actually gave us more range in some ways. But the reason was that we got beat by about a 3/2nd of an inch on our battery box in the engine compartment. The motor winds up being a little over an inch off center from the frame. And on the right side, we couldn't get our box in after building it.

In Speedster part DUH, we have a little thing going on. The AC-50 just isn't quite as big in diameter as a Netgain Warp 9. That gives us some room. As you saw in the April 30 show, we did some things different with the adapter plate as well to gain some more room.

I've been playing with carbon fiber/kevlar hybrid cloth and some very slow cure 2:1 epoxy resin. Basically, we built a smooth aluminum box to the precise dimensions I wanted to hold 10 Sky Energy 180AH cells. This includes a cutout around the engine adapter and transmission brace.

We then waxed the box with form release wax three times, and then painted it with PVA - a liquid form release agent.

I then gave it a good thick coat of this remarkably thin slow set epoxy. We let it dry until it was more sticky than wet, and layered a layer of 5 oz carbon fiber square weave over it.

We then started layering kevlar/fiberglass hybrid cloth. This stuff is so stuff we couldn't cut it. Finally bought a pricey set of dress designers shears and it cut it VERY nicely. We would layer on a layer of fabric, and then "stipple it" with the thin epoxy using a cheap paint brush. We added about 3 layers of that, and wove in a couple of flat aluminum pieces in between layers. We'll use those to screw into the car frame.

When we got done, we disassembled the aluminum box underneath, and we were left with a carbon fiber/kevlar eggshell of a battery box.

The result is incredibly light - about 3 pounds. It holds 126 pounds of batteries very nicely. It's chemical resistant. It's non-conductive. It has some fascinating thermal characteristics. And it is THIN.

We're going to do one for the left side. But I think I'm going to try styrofoam block for the form. Acetone dissolves it, and it should be easier to remove than the aluminum box.


We also started installing parts of the Curtis 1238 controller cooling system. We mounted a fill bottle, the heat sink, and the pump.

Enjoy

Jack Rickard

April 23 Friday Show

I've posted the April 23rd Friday Show. We had a lot of wind noise I had to filter out so forgive Brain and I in the opening segments. We hadn't been breathing helium or anything, I just had to lose the low frequencies to make the wind more or less go away. We're still learning this video game, and most of it seems to be audio actually.

We did do a walk around of the newly reassembled Mini Cooper. We talk quite a bit about the Speedster Part Duh heater assembly. This is actually a kit from Canadian EV that we used and Brain and Trace did a marvelous job of installing it. It is just factory in operation and fit.

We ground off the fiberglass around the frame in the engine compartment. And I did a bit more in-depth review of the Xantrex LinkPro/TBS E-Xpert Pro instrumentation. It is cheesy looking. But it actually works quite well. It is quite accurate. And it is much more flexible than I realized when I dismissed it out of hand initially. At $250 it appears to be THE extant solution in EVland for the very necessary counting of AH to determine state of charge.

I've since done a bit of testing on the 2009 Mini Cooper Clubman. Yesterday I drove it to Perryville and back at as constant a 60 mph on the Interstate Highway as I could manage. It was 78 miles roundtrip with a consumption of 75.1 AH. It took 42.9AH to get there and a little over 32 to get back, indicating Perryville is mostly uphill from here.

At 60 mph, in the Getrag's 6th gear, I'm loafing along at about 1400 rpm. We did NOT get the Tach on the Mini working yet, but we did install a Summit Racing tach temporarily and the output of the TIMS600 controller seems to drive it admirably using the TIMS default and the 4 cyclinder setting on the tach.

We average about 60 amps at 60 mph on the straight and level, not even breaking a sweat for the 100AH SE cells. I DID mash the accelerator a couple of times - ZOOMING over 85 almost immediately. This drew a maximum of 372 amperes and dropped the cell voltage to a saggy 2.79volts for a total power of about 116kva (nearly enough kilowatts). I took this as a VERY good sign. It's hard to zoom anywhere with such an overdrive gear. The TIMS 600 is SUPPOSED to have a 300 amp limit.

I stopped in Perryville to do a Marine Corp temperature check of the motor and controller. They were at about skin temperature. In fact, the transmission was hotter than the motor. Our AN-8 sized cooling system, using the MIni radiator and fan, do indeed seem to be doing a superb job of keeping things cool and allowing MAX POWER out of the TIMS600 without stress. Probably a combination of the high flow rate and huge heat sink relative to what is normally used with this.

Finished the drive at ostensibly 75% Depth of DIscharge (DOD). However, the average cell voltage was 3.278. This is a bit of a puzzle. The SE discharge curve is quite flat. But I can't imagine it being THAT flat. We did do one measurement when the cells were first installed at 111 amp hours out of these 100 AH cells. It is quite likely, we have much more capacity than it appears. That would somewhat explain such a high resting voltage after the drive.

In any event, though I'm always looking for a bugger in the potato salad, the EV grin is starting to widen. The weight and coilover springs make the ride almost stately - like an Escalade. The performance is quite beyond the ICE engine which was already perky as you recall. The steering is stiff in local quarters but actually pretty good on the road. And with NO regen really on the highway we seem to be doing about 0,96 amp hours per mile. This indicates a "no regen" range of about 80 miles at 80%DOD.

The drive shaft issue (fingers crossed, eyes skyward) seems to be solved for the moment. I'm growing more confident in shifting and driving without fear of throwing a drive shaft. And the EV grin is starting to come on. This is a marvelous car. We have plenty left to do, but it is shaping up as an all weather all season ride with bluetooth and IPOD. Good performance. Good economy. Good creature comforts. And the Getrag transmission verifies our selection of this car. We take off in 3rd and road cruise in 6th for a good solid 4 speed experience.

Jack RIckard

April 16 Friday Show

This week we digress a bit from vehicle issues and take a look at the progression of LiFePo4 cell offerings over the past two years.  We also do some full 1C discharge and charge tests on the cells.

The first cell in this series is a Thundersky TS-LFP160AH cell we purchased about 18 months ago.  This cell is a Lithium Ion Iron Phosphate cathode cell.  The spec sheet for this cell is available here.  Note that the cell measures 182 x 276.4 x 71 mm in volume and weighs 5.6kg.  It would contain 3.4v x 160AH = 544 watt hours of energy.  With shipping, this cell cost almost exactly $244.

Second cell was a Sky Energy SE-180AHA cell. You can download the spec sheet here. It is only slightly taller at 279.5 mm but is also 182x71 mm and 5.6kg, but offers 180 amp hours at the same voltage - essentially 612 watt-hours of energy. It was purchased at $241 with shipping 9 months ago.

The third cell is a brand new Thundersky TS-LFP-200AH cell. Spec sheet here. This cell features the addition of Yttrium to the cathode material and offers longer cell life cycles - 3000 cycles vice 2000 at 80% DOD and 5000 cycles vice 3000 at 70% DOD. This is a pretty significant extension of life cycle claims. It's dimensions are actually 183 x 276 x 101 mm  or 362 x 256 x 55.5 and quite a bit heavier at 7.3kg. It is also about $240 once delivered to Cape Girardeau MO.

The latest Thundersky cells are quite interesting. Most significantly, they manufacture an unadvertised  variant of this cell at the original 183 x 276 x 71 mm size and 5.6kg weight. But they can sell enough of these without advertising it that there is NO MENTION OF IT on the Thundersky web site.


Because of the quantities of these cells they are now selling, EVCOMPONENTS can get these 276x183x71 mm cells. They do test out to 200AH, though not any more than that. That's 680 watt-hours per cell. http://www.evcomponents.com.  You do have to know to ask

This is rather an amazing occurrence.  In the space of 18 months, we've gone from 160AH to 200AH in the same form factor and at the same price.  That's a 25% increase in energy density, and at least a 50% gain in cycle life.

We developed an Arduino based circuit with some LEM-HASS hall effect current sensors to measure current and AH into and out of the cells. We used our GIgavac contactor box, described in last weeks show, to switch the batteries in and out.

We used a pair of ACME 1500 watt constant current loads to load the cells to a 1C rate, 200AH, 180AH, and 160AH respectively for an hour and recorded the voltages and temperatures at each 2.5% increment by counting 5, 4.5 or 4 AH between each notation.

And then we reversed the process and used a Lambda 10v/200A power supply to do the charge curves the same way.

The result is a series of graphs.  Here is the discharge/charge curve for the original TS 160AH cell.  Click on the image for a larger version.

Here is the results of the Sky Energy 180AH cell.

Here is the results of the new Thundersky 200AH cell.

Because we measured these cells at the same percentage of their total AH capacity, we can compare them. Here is the charge curve comparison of the three cells.

We can do the same thing with the discharge curves.

The interesting area of this test is of course the temperature gain during charge and discharge. The discharge process caused the greatest temperature gain.

But there were some additional temperature gain during the recharge process.

Finally, we're making the entire Microsoft XLS spreadsheet file with all the collected data available for download here.

March 26, 2010 EVTV News

We were recently featured in a story in our local paper, the Southeast Missourian.  Nice story.  Thank you guys.

We've been in quite a struggle with our MES-DEA 200-250 Motor.  On assembly, we found a vibration in the drive train.  When we removed the drivetrain from the vehicle, we found a huge crack almost all the way around the end plate.

We appealed to our supplier, Victor Tichonov of Metric Mind and the manufacturer, MES-DEA for relief.  They threw us under the bus but big time.  No support at all.

We opened the motor and found the end plate was 6.22mm thick of CAST ALUMINUM.  An eggshell.  Hopelessly underweight to mount this motor with.

Our Friday, March 26 video describes the fix.  We had to have an entirely new endplate machined for this motor.  Cape Precision Machine came to our rescue with a superb job on this end plate and we finally got the wheels spinning on the 2009 Mini Cooper.  Hopefully, we'll have it out for a first drive this week.

We also include in this week's news show a walk through of Tim Catellier's 2000 BMW Z3 conversion. Tim did a great conversion of this car with a Zilla controller and Netgain 11 motor.

Jack RIckard