Tell me if I”m correct. And tell me if I’m not. I rather see the future of EVTV as moving somewhat away from our various builds, though we undoubtedly will always have some project going. And more toward viewer contributed videos of their builds.
This video kind of qualifies. We have Richard Rodriguez with a report on a build he really finished in 2010. But 20,000 miles later, living one day at a time BMS free, he HAS made some changes. Instrumentation – some great looking new rims, two more cells, a larger charger.
Jeff Southern being on the other end – still wrestling with the dust and dirt of finding his car underneath all that rust, but starting to work on mounting a motor with an adapter.
And star of this week’s show – John Hardy. John’s got a kind of wry British understatement I find enormously appealing. But because he’s not ranting and raving quite the way I do, do not miss the point. Five hundred cycles on some Headway LiFePo4 cells with a comically egregious NO on the concept of cell drift. That is the END of the cell drift debate as far as I’m concerned.
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I originally started Boardwatch Magazine and wrote every word in it for several years. By the time I sold it to Mecklermedia, we had 22 regular contributors and I pretty much did the letters to the editor and an editorial. The 22 scoured the ISP space digging up pretty much everything that as happening there and we became more or less a mirror of the industry. You couldn’t hook up your grandmother without it showing up in our rag someplace. I kind of see this developing at EVTV only more on a build by build basis. Everybody does things slightly differently. Some work out. Some not so well.
We had a visitor this week. Ed Cochrane is trying to get off the ground selling Sinopoly Cells and we promised we’d take a look at them if they ever appeared in real time. From my interaction with Patrick Wong and Sinopoly, I would say Ed’s biggest challenge is dealing with Sinopoly. These were money people who backed Winston Chung and NOT battery people. They are curiously inept at either building batteries or marketing them. ANd their arrogance and vanity are just beyond belief.
Ed’s a returning veteran from Afghanistan. He has an oddly honest demeanor that is going to hurt him in some ways but I found engaging. He had two direct criticisms that I was fascinated to hear.
The first was that we were long and boring and over the head of many of our potential viewers. The second was that our sales of components had enraged some of the existing component sales web sites. I was kind of delighted with both criticisms.
We ARE long and boring, and quite over the head of those new to the EV world. Not quite so long and boring to those deeply involved in it. In any event, that’s what fast forward is for.
We went through this at Boardwatch. We have to either be the intro for newbies, or do things in depth. We choose B. I’m sorry what was A again. First, I just can’t DO an article on how XMODEM works over and over again. IT is boring for me. Second, it is easier for the new among us to GET up to speed, than it is for all the rest of us to review why a generator and motor won’t drive each other forever, over and over and over. And unlike the magazine, which becomes unobtainable after a few months, video is forever. WE have our FIRST video still online and in fact it is in the number one position on our home page. It of course remains the most watched video we’ve ever done. Party like rock stars. We still have a convenient response to an inconvenient truth and when I go back and view that video, I’m struck by how LITTLE we have varied in tone or message over the hundred and some odd videos since. I stated very clearly then that our mission was to get 100,000 guys about my age to take responsibility for their world, and CHANGE it, by building their own electric car. I truly believe that is the TIPPING point. And while I live and breathe that is where we are headed without variation, apology, or redirection.
But we are just NOT for the Plug-In America crowd or even the Electric Vehicles of America membership. People who advocate electric drive simply aren’t sufficiently interesting to me personally. If you’re not building, you’re watching. That’s great. But its not what we are about. People who have great ideas about what SOMEBODY should do about a problem are not interesting people in my experience. But people who do things and make things happen ARE. So being an ADVOCATE for alternate fuels means little to me. One of the presenters at a very large EV conference recently asked the audience how many people actually DROVE electric cars. The response from the crowd was shocking to everyone there. Maybe 5%.
If you DRIVE electric. More interesting. If you BUILD electric, much more interesting yet. If you ENABLE building, more interesting yet. If you think electric cars are cool, and have some great ideas for perpetual motion – go away. There are other web sites just crying for your presence. They get BIG numbers of people. We have just a few. They’re the few I want.
So we very consciously design our show to drive copper foil helmet freaks away as fast as we can get them to move. We pay about 30 cents every time somebody downloads a video. These guys are NOT what we are after. Even the NPR spot at last year’s convention, which I’m told was the most listened to segment that day and had the highest listener response, caused 11,000 downloads. It made our attendees feel great and our vendors at EVCCON 2011 feel even greater. It cost me $3400. Small price to pay, but we did have to write the check.
And that’s the game. Out of the 11,000, we probably did pick up 80 or 90 regular viewers and 20 builds current and more of the 80-90 to come as they get comfortable with the idea that they can do it – with families and lives and no time for building a bird house much less a car. Face it, this game takes ducats and commitment. I never meant to imply otherwise. Complaining, even loudly, does NOT really change the world. It just increases the background noise for those who drive change.
As to the online retailers of the wares of EVdumb. I have to laugh. I try to be sympathetic. It IS early in the game and the industry is really entirely in its infancy. I understand their struggle just to survive. But you’ve got to be kidding me. We personally contacted every major and most minor players in that space and tried to sell them a commercial at historically trivial rates – truly trivial even in their budgets. To a man they told us we were little and ugly and our mother dressed us funny and would never grow up to amount to anything and weren’t worth advertising on if it were free. We got a little encouragement from the developers, such as EVNetics and Masterflux, and NEtgain and Winston Battery. But NO ONE from the retailer side. Imagine my surprise to learn that their margins are in many cases higher than the developers?
As I think the developers should sell directly, lower their prices and up THEIR margins, cutting out the middle man, none of this makes any sense to me. But that’s where it is at at them moment.
So now we’re trying to find cool stuff for our viewers to enable their builds, and kind of sidled into the online component sales without master plan or mission beyond originally improving their cell connections. And the online resellers are enraged? How can that be? if we are not effective as an advertising medium, then how could we possibly affect their sales? And if we are, why weren’t they advertising?
The answer is a little bitter, and does not match my insistence that everyone is a gentleman and scholar and that the world is really a great place, because there really are a LOT of GREAT people in it. The answer is they LIKE it that we were drumming up business for them, and they would graciously take advantage of that as long as it was A FREE RIDE. So as long as I was paying to promote their business, we were ok. But if WE made the sale instead of them, that was another kettle of fish. Indeed they are ENTITLED to the results of our efforts in some way…
Let me offer you all a little hard won advice from someone who has been extraordinarily blessed with the resources of our world, including hard cash, and has the scars to prove it – Obama’s view that the government actually did it notwithstanding. THere are takers in this world and their are givers. NOT ONE of the players who thrive in our economy is a taker. Takers never make it. They ALWAYS wind up selling off the office furniture at 10 cents on the dollar. And they ALWAYS have a million excuses why the forces of the universe conspired against them and the failure wasn’t really theres. Givers actually have to struggle to avoid success. It comes at them from all directions and can be a bit overwhelming.
Givers find ways to leverage every breath to have maximum impact on minimum effort to do something worthwhile they believe in that will make their world a better place. People just naturally send them money in the mail. They are never sure why.
Train yourself for success. If someone OFFERS you a free ride – don’t take it. Run, don’t’ walk away from it, or find a way to double down where you pay more than its worth. While counterintuitive, it’s how it works. Never take anything for free. Pay it back double or pay it foreword double. Just do not allow yourself to GET without GIVING. It’s like painting LOSER on your forehead with lipstick. Pay the price. And truly, as Bob Mahoney told me years ago, if your mission is to make money, you don’t have a sufficiently complex set of goals to build a life, much less make any money. If i recall all the details, he sold EXEC-PC for $21 million. I think he has his own island now off the coast of Florida. Interesting guy. But can’t stand to deal with the public. Very private.
I personally know dozens, if not hundredsn of multimillionaires many times over from the Internet bubble. And despite the common myths, this holds true in 100% of the cases. I cannot think of a “gimmee” guy that made it from that era. Not a single one. ANd there were plenty of them. They just ALL failed ultimately. They thought they were winning for awhile. But one by one, the universe eliminated them from the pool somehow. I know one particularly loud and high roller from that period who’s now a night watchman at a dairy. It’s as much a part of the rhythm and pace of the universe as sunlight and rain.
No doubt when they fail, these guys will blame us for it. They always have to reconcile failure to an outside force. They MUST rationalize it to live with themselves. But it is pathetic to watch.
If it helps any, we price a bit above the market on everything, specifically to avoid damaging the industry or starving out developers. We pay whatever they charge. And we pay promptly. ANd then we try to value add on everything we sell. If the world were perfectly priced, we’d sell nothing because everything is available somewhere else for less money. We’re probably the only online store even attempting to sell at MSRP. And our mission if you do buy from us is to make sure you get MORE than you paid for. How can that work? I don’t know. It just always does. People are pretty cunning with their ducats. And they see right through our scam….
Actually they see through YOURS as well which is the problem….
As soon as it moves from an adversarial “him vs me” battle for the final farthing to fall to the carpet, it becomes a collaborative transaction to meet needs and accomplish goals. Very different relationship. The former is so normal in the “zero sum game” view of our society, some don’t know how to play at a higher level. Oh well… That’s why there are more night watchmen than there are millionaires. As my daughter says, “circle of life, circle of life, move on…”
And the bubbling cauldron of innovation continues. Eric Kriss devised a simple billet aluminum frame for a Marinco NEMA 5-15 three prong male recessed plug. It allows you to mount it on the outside of your car easily and securely. We do J1772 now. And he wanted too much money for the device I thought. But following the principle, we ordered 10 and paid promptly – like 10 minutes later.
I received the frames. Also ordered 10 of the Marincos. As soon as I fit a pair of them together, I got it. Just freakin gorgeous. And are we EVER going to be where we don’t want to take advantage of an opportunity charge someplace that doesn’t have J1772? Like grandmas house? OR daughters house?
In twelve seconds with this thing in my hand I got it. Brilliant Eric. It’s just gorgeous. We’ll never build another car without one. Again. People just send me stuff in the mail… I could probably make a living just selling these for Eric. Boats. Big trucks. It goes way beyond EVs.
Within a year Marinco will rip it off themselves.
Let’s talk a little bit about Lithium ion batteries and John Hardy’s results. Like chess, bridge, and hand grenades, battery discussions theory and discussions can be played on many levels. I have a bias toward useful clarity of communication at the expense of deep technical accuracy and precision of word choice. But I’ll go a little deeper here.
We do not use battery management systems as they are discussed online by EV enthusiasts. But at the same time we strongly advise you to not overcharge and not over discharge the battery cells. This is because that is how you can
1. REduce cycle life
2. Destroy them.
Overcharging does a couple of things. BUt in extremis, you have basically extracted all available lithium ions from the LiFePo4 cathode, and moved them to the carbon anode and intercalated them there. If you continue to apply a voltage, SOMETHING is going to move from the cathode to the anode. The first thing the cathode gives up is LITHIUM. This does a couple of things. First, it deposits lithium metal on the surface of the anode. This appears as lithium metal plating. And that restricts the capacity of the battery to intercalate and deintercalate true lithium ions from the anode.
It also leaves the cathode as a strongly oxidative compound. Our electrolytic solvents are mostly carbonate, ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DC). When oxidized, this results in CO2. CO2 is of course a gas and this is what causes the swelling of the cell. At some point the cell vents and despite the mysteries described by the experts, it is really almost entirely CO2. But it can be explosive enough to vaporize and carry some small amount of volatile and
indeed flammable compounds of the electrolytes. In this vaporized form, they can cause a flash fire. As they are mostly essentially ethanol, it is not a high temperature situation really.
If we continue to charge the cell, we cause a rise in temperature. At some conduction level, the cathode begins to release oxygen, which reacts with the electrolytes leading to thermal runaway. This process really cannot be stopped until you run out of cathode material.
Let’s talk about THAT a little.
CATHODE RUNAWAY TEMPERATURE
Lithium Cobalt Oxide LiCo 266-302F
Lithium Nickel Manganese Cobalt Oxide – LMC – 338-356F
Lithium Manganese Oxide LiMo – 482F
Lithium Iron Phosphate LiFePo4 – >500F
And now you know why I am very leery of LiCo cells and a big fan of LiFePo4 with regards to safety.
There is no actual fully charged charge voltage. The CC/CV thing is a recipe. In theory, the open circuit fully charged voltage of a LiFePo4 cathode is 3.45volts. Because of certain conductivity additives such as carbon it is actually 3.40v.
But when charging, we see a higher voltage. To GET there is a function of voltage and current. We could charge to a lower voltage, but leave the low level current on longer. Or a higher voltage with less holding current. These are RECIPES to charge the cell. Not actual cell values.
But it is ALL we have that we can measure. And so we see a voltage. When these cells first came out, the magic voltage was 4.2v. THis was because above 4.3v you started to get into some overcharging issues. The manufacturers have steadily revised this value DOWNWARDS, in almost precisely the manner I did four years ago. And for the same reasons.
Believe it or not, there are no absolutes in cycle life either. I can give you a longer cycle life for the same battery simply by giving you a lower charge voltage. Approximately thusly:
4.3 volts – 150-250 cycles
4.2 volts – 300-500 cycles
4.1 volts – 600-1000 cycles
4.0 volts – 1200-2400 cycles
3.9 volts – 2400-4000 cycles
Now let me say something that will REALLY raise some ire. What John is showing you is CHARGE voltages which have LITTLE to do with voltage of the cell. When we are charging, we are FORCING the lithium ions to deintercalate from the cathode material, migrate through the electrolyte, and intercalate into the carbon anode. This process is a little mystical, and further delayed by the SEI layer on the anode. But basically it is not a covalent chemical combination. The ions literally migrate to points in an orthorhombic crystalline structure where they can attach or disattach to the crystalline structure at the corners. Think of this as “tunneling” through a maze. We talk about this as a diffusion constant or diffusion delay.
In John’s charge curves, you see the cells diverge as they become fully charged. When charging in the flat part of the curve, the lithium ions have no difficulty finding places to lodge in the crystalline structure. But toward the end of the charge they do – depending on the thickness, porosity, and olivine structure of the crystalline material. This varies as part of the construction of each cell. I suppose it has SOME relationship to capacity, but not what you think. It is a diffusion DELAY. And so these voltages are NOT REAL. They are manifestations of diffusion delay at the end part of the charge.
If you idiotically try to BALANCE those voltages with a BMS, you have NO IDEA what you are doing but you are certainly NOT bringing them to the “same state of charge”. Indeed your efforts to balance the pack may have just the opposite effect.
In ANY event, if we don’t charge them that far, we do not have to worry about diffusion delays at the end of the charge cycle because we never GET to the end of the charge cycle. The lithium ions that we intercalate ALL have handy places to quickly reside.
You will notice that most of the cells fall to something LESS than 3.4volts within an our or two and we talk about this as “relaxing” or bleeding off the “surface charge”. Not a bad description. The cloud of ions trying to intercalate and having to tunnel a bit to find a place do eventually find a place. Occasionally you will see a cell that “sticks” or doesn’t actually fall below 3.4v. Don’t worry about this. It will sort itself out after a few charge and discharge cycles. If it is persistent, you have overcharged the cell and damage has been done.
Charging cells in series becomes more complex. Some cells have smaller capacities than others and would reach state at different times. The solution is more of the same. Let’s drop the charge voltage from the manufactures recommended 3.65v down to 3.50 or even 3.45 volts. We indeed have less stored energy and give up range. But we get out of the diffusion confusion, and FURTHER extend the cycle life of the cells.
For most of us, the THREE TIMES ADVANTAGE of LiFePo4 cells over lead acid cells leaves us with plenty to play with with regards to range. But it came at a price – $10,000. So we think CYCLE LIFE is the most important determinant and
we’ll give up a mile or two of our now 100 mile range to extend the life of our cells. Richard Rodriguez believes that by charging to a lower value and not over discharging that he will REALIZE the 3000 cycle claim of the manufacturer.
Indeed, should he live long enough, and not want to upgrade his cells, he may well be looking at 10,000 cycles or 15,000 cycles before they reach 80% capacity. He just drove his car 140 miles.
And so we continue to advocate that top balancing with a BMS is the most idiotic concept since aluminum foil inside hubcaps to fool police radar guns. ANd that undercharging is just like putting money in the bank.
That leads us to over discharging.
What happens when we over discharge our cells? Well, we are moving lithium ions from their cozy location in the graphite on the anode, through the electrolyte and into the cathode. If we continue past a certain level, a couple of things happen AGAIN. First, we again go into oxidation and produce CO2 and our batteries swell. Second, we start to emerge copper from the copper foil the anode rests on through the carbon in a streamer we will refer to as a shunt. It penetrates the separator and connects to the next “cell” that is, between two foils inside the cell. ANd it shorts them out. The more of them that are shorted, the less cell you have active. And they cause heat. The most common cause of death is over discharge. You cannot make the shunts go away. A little swelling is telling. But the shunts are death.
Because of the dynamic nature of our cell voltages under various current loads, it is devilish to produce an automated system to cut off our cells based on voltage. We use coulomb counting. We sum up the amp hours and at some level, we shut off the car. If you built the car, and paid for the batteries, you can do this yourself by watching the numbers or even watching your odometer. But if you have a wife or daughter or son who drives your car, understand they may not be similarly motivated and when weighing $10,000 against arriving at a hair appointment on time, you all may not share the same values.
Enter daughter mode. In the Speedster, we describe a simple circuit using the JLD404 amp hour counter to count amp hours and dramatically cut back the throttle if you reach a certain level. We also talk about how you could entirely disable the car at a second level preventing its use.
Neither is fool proof. We assume if she knows little about the car, that she will not realize that by pressing the down arrow key for three seconds this resets the JLD404 to zero amp hours. You may know this and it might be pertinent to keep the information to yourself.
Even that’s a bit problematical. The round trip charge and discharge is not 100% efficient. And so a small error in your amp hour counting will be incorporated with each charge. For absolute accuracy, after fully charging your car you should Synchronize your JLD404 with the charge state by pressing that down arrow for three seconds and zeroing out the accumulated errors. This really isn’t necessary EVERY time you charge. But most of the time. I glance at the value to make sure the charge occurred and I am indeed fully charged. If it’s within an amp hour or two, I assume the charger has fully charged the battery, and zero it out. If a larger number is displayed, I assume the charger did NOT fully charge and terminate and some investigation is in order. Never reset after a partial charge.
But it mostly works to avert disaster on over discharge.
The leaves the final case, that what do you do if a cell just fails at the end of its life. Won’t that take out all the other cells?
Well yes and no. We have experienced few cell failures. But if it does fail, it is unlikely to do much damage to your pack before it tells you. Most likely, your car won’t’ work vey well. If it starts to behave strangely, like say, not moving forward, some further investigation might be in order. Do it manually in a garage. Not while driving.
49 thoughts on “A BIT OF THIS, A DASH OF THAT”
Glad to see the VW Thing running and anxious to see what fun things you have planned for it. Jeff Southern had to deal with a bit of rust in the pans on his, and I feel his pain. The pans on my evTD were disgusting. Check here for the remedy: http://evtd.blogspot.com/2012/06/new-floor-pans.html. Pretty drastic, but the replacement pans are readily available and surprisingly inexpensive. If you have the body off anyway, what could be better?
I haven’t gotten any photos to update the blog recently, but the body has been painted and it looks magnificent! I came close to choosing the VW Harvest Moon Beige, but went with Chrysler Cool Vanilla because it was a little more yellow. The disk brakes and coil-over shocks are installed and we are just waiting for the transaxle to get back to install the motor and assemble the body. Then it gets home to my garage for batteries and wiring. We’re on track to finish in time for EVCCON.
Thanks for a great show this week. It was neat to see what Rich Rodriguez is up to and I hear you on contributor video. I’ll get you an update in the next couple of weeks.
I truly appreciate your sobering explanation of what goes on during the charge – discharge cycle. I have a few cycles down on my headway pack and noted two different discharge slopes on my cba. Despite similar capacity, the voltage slopes did vary on the way down. What was interesting was inconsistent slopes on the same cell across cycles. Mind you, I got too bored continuing the single cell testing and have just thrown them all in a pack and will put many cycles on before running another per cell testing campaign. We’ll then see if those variations were just part of break in or not.
One piece of experience I’ll share is that there is another condition where cells will swell. I’ve had an SE 40ah cell in my back seat for show and tell purposes. On a particularly warm day my oven on 4 wheels induced a swelling in the blue case of my cell. After cooling, it has situated itself back to shape nicely. I have not tested it for any ill effects. I doubt there will be any. No aroma was noticed; I know what it would smell like. I mention this to help illustrate that not all effects are from the same cause. There was no charging or discharging causing this swell. Just volatile compounds being rather warm. I do intend to encase all batteries to provide support in such circumstances.
Harm to an SE cell is conceivable at 60C and becomes pretty likely at 80C. I’m struggling with solar gain in a parked car here.
Interesting show. I too think a lottery system for our congress is a great idea. People always think I am crazy for suggesting it. I never consider something to be a good idea unless I can get at least ten people to tell me it is a bad idea…. The EV Thing should be great. Everyone thinks I am crazy for building it…
Great to see some real battery data… John Hardy is doing a great job of debunking most of the so called info on the web about Li batteries… It really is some great info.
I got most of the rust repaired today. Still have thee small holes about the size of a half dollar to fix. I could have finished it today but was getting tired and started making mistakes. In fact, the grinder with a wire wheel got away from me today and gave be a nice road rash like wound on my leg. It should make a nice scar. My wife measures the complexity of my projects by the number of scars I get. She predicts three for this project. I really want this Thing running for EVCCON but it is really fighting me…
Great show this week Jack. Sorry to hear about angry vendors: they might want to reflect on the thought that there are people who have been encouraged to start a build (and buy stuff from a number of suppliers) as a result of watching your show. I’d be surprised if you don’t make more business for them than you take in a handful of sales
Well of course that was my point John. As long as we’re a rainmaker out inspiring people to begin builds, it was indeed causing them business. In the spirit of “gimmee” rather than getting behind that and supporting it to cause more of it, they preferred the free ride.
At this point we’re doing some significant sales and I would indeed look to that to grow.
And so they are hoisted on their own petard of petty greed, and of course lose again. Circle of life…circle of life…
Jack maybe you could do tutorial, introductory video giving viewers a foundation of knowledge that would be useful in understanding some of the more technical aspects of your show. Or even a nudge in the right direction with a reading list of books. They needn’t be specifically technical books about EVs, but textbooks on electronics, or mechanics or whatever.
There’s a lot of information that you probably take for granted. For example: How to read a schematic, what a relay, or a diode is, the difference between AC and DC, normally open, normally closed, grounded (why ground?) etc, etc. And explain simply, but no more, to paraphrase a famous 20th century scientist. Maybe viewers could contribute to this video once we identify the key subject list. I know you have explained some concepts yourself, but they are scattered through 100s of hour of video, and like you say you can’t go over basics again and again.
Yes, I could stop the video stuff entirely and write an opus magnus on the topic. Of course much of it would be dated by the time it got printed.
Trust that I am well aware that I’m a much better writer than I am an onscreen personality (cough, hack, cough) and I have faced a HUGE and often painful learning curve in adopting this new medium learning how to shoot, edit, and host videos in the most effective manner. Indeed, we still struggle.
But I think this is the most effective way to do this. We’ll have to have help from authors such as John Hardy on the book end of it and indeed there is now a magazine as well – CHARGED.
We have to pick a hill and make our stand there. For us, it’s video. It’s weekly. And it does get a bit technical. This effectively filters out the Plug-In America activists. I want them filtered out…
Jack, I didn’t mention anything about writing anything. I don’t know what you think I wrote but I suspect you misread my post. Which, I have to admit, is common and something I do regularly. I am not talking about tutorials in the current technology that will undoughtly change in the very near future, but the chemistry, physics and laws that do not change. The basic fundamental knowhow doesn’t change. If I learn how to read a schematic today, I don’t have to relearn it in a year because how a schematic is drawn is completely different, a volt is always a volt the terminology doesn’t change. Your video presence if you watch your present performance with your first ever “performance” is far more natural. You are more than capable explain concepts on camera.
Reading alone as a tool used to learn is COMPLETELY outmoded. I find having something written down in summary form is an excellent way to revise, but a poor way to learn. An in-depth chapter in a textbook is often too long and impenetrable for a learner on his or her own without assistance through lectures thought by an expert. Lecturers that often use multiple ways of explaining how something works, as opposed to a paragraph and a stupid diagram that isn’t even on the same fucking page. A two minute video would remove reams of text and pictures and often times animation is the only way a person can understand how an electric motor work for example. Imagine reading about that, compared to watching an equally detailed animation for feck sake. I wouldn’t throw away the book, it’s useful for recapping, but I’d watch the video first to learn.
Do you understand what I am talking about? Possible this is a failure on my part, but I would be more than happy to keep going until your patience runs out.
I am passionate about the idea of technology and learning. My kids, I hope, will never have to carry a schoolbag with books but a tablet. And they will read, but also watch video animation, interact with and access notes quickly. I believe more difficult concepts could be thought thanks to video, imagine learning about calculus and the orbit of planets and the connection visually step by step. Anyways, I’m gone a bit off topic. My main point is READ MY POST AGAIN!
I wrote this with a flare of whimsy but I bet is comes across as vitriolic…..not if I made a video though. That because it would be more textures as a form of information. Get my point?
Surely Jack has already stated what you want is not his market.
You know more than anyone exactly what you mean. Could you help Jack by doing it yourself. And submit your work to him? – you could make this handy “ready reckoner” for anyone who might be a late-comer and a future contributor to the cause?
I can see the reason for a complimentary counterpoise for Jacks work.
On that score,
Not many people realize how differing manufacturers of cars, aerospace companies etc. work together.
It’s the right idea to let the smaller ev businesses know they should all work together or surely die alone. Not all traders are directly in opposition either. EvWest could help out far better for the performance guys. Others work in differing Continents. Our young man in Holland has gained much knowledge with EvBoats. Others are big on bikes or big on stock. others are big on trust but not many know who they are.
If you have a business. The only way to makes sales is to become known as a person, be trusted and have the time for people. Got business. Who are you?
EVCONN should be surely, for the traders, the manufacturers the movers and shakers. I think Jack is right on the nail and will be a great springboard where hopefully lone trader/enthusiasts can springboard themselves forward, get their name out then in turn hopefully have their own open days to build public interest.
In my youth, a friend was going nowhere with his DJ business until he started to splash out money advertising. He was the one with the quarter column in the local telephone book. snatched all the business and sold off extra work to needy start-ups.
It’s not what I want, I wrote it in response it to Ed Cochranes’ critiscism that Jack’s videos are too boring, and Jack’s response in which he say’s he would rather keep the videos tecnical. I agree that the videos should be tecnical, all I was talking about was an intruductory video seperate to the video series. I think if your an undergrad, or a technically minded person that doesn’t have the specific knowlegde needed the intro tutorial video may be usful.
Quoting: “Tell me if I”m correct. And tell me if I’m not. I rather see the future of EVTV as moving somewhat away from our various builds, though we undoubtedly will always have some project going. And more toward viewer contributed videos of their builds.”
My twopennorth: my hope is that your builds/projects will push the boundaries and try out new technologies. Most of us on a limited budget and with limited time will tend to take the safe well trodden route of Warp 9/11 or AC50 + CALBs. I wouldn’t go for Lithium Sulphur or Lithium Air unless someone else had been there and done that. Another option would be to set yourself a goal – e.g. Nashville via Memphis in a usable car
One thing I feel is lacking in the build community is a succinct knowledge base of component system designs. I have toyed with the idea of starting a site to address this for a few months but keep coming to the conclusion that just building another unqualified EV enthusiast site is not the best way of disseminating this type of information. Your blog post this week really hit home about enabling others to build cars and it’s high time I get in the game and try to make more of a contribution myself.
The idea I had was for a blog or wiki site that is simply a collection of road-proven systems and some component reviews that actual people have running in their vehicles. The type yourself smart crowd pontificating about systems they’ve never even built or designs that don’t have at least 1000 (or 10K for that matter) road miles on them need not apply. Your daughter mode circuit design from this week’s show is a perfect example of this. There are dozens of design gems in your videos which would be of great benefit if they were broken out on their own page with a description, schematic, component list, sources of supply, link to a video, etc. That is just the tip of the iceberg though. There are hundreds of other good design elements your viewers and other EV builders have toiled over for their builds that would be an equally rich resource for new and experienced builders alike.
Designing an EV for the first time is a daunting prospect. Your site is the only thing close to a comprehensive resource to building your own EV but it could be better. What I propose is that EVTV add a new knowledge base section similar what I’ve described. Ideally there could be a small group of volunteer editors responsible for reviewing submissions and following through with creating and formatting into publishable pages. Your involvement would only have to be for final editorial review as I know the last thing you need is more work. Establishing good criteria for article submission (I am fond of the idea that there needs to be video included with each submission) should keep the quality high and reduce the inflow of crap.
Does this sound at all interesting?
A sort of crowd-sourced but moderated EV-pedia?
Of course it is interesting. Christopher Fisher proposed an INDEX a year or so ago. And he did one. But in the end, he found it was a LOT of work for a handful of users.
Perhaps something a bit more organized would be more popular. But what I’ve seen of most Wikis and so forth is not encouraging. They almost all suffer from lack of a full time editorial commitment.
I’ve made one. But to a weekly video. I’m pedaling as fast as I can. If you see an area where you can make a difference, by all means jump in.
I don’t really see it as something to connect to EVTV in any particular way. The geographic distance between two points on the global Internet is approximately one click. That’s what Tim Berners-Lee basically set out in a white paper in 1989.
What I WOULD like to do eventually, and could certainly use some help with, is an EVALBUM type database of all our viewer builds that you could search by component type or vehicle type or location or whatever. That gave the basic stats of the vehicle and what you did and why you did that.
I like EVALbum, but it is mostly riddled with bicycles, lawn mowers, and lead acid cars so that it makes it a little tough for me to deal with. But that’s the idea.
Basically CHristopher just did his own index on his own host and we linked to it. He became more and more involved in things for our web site. A few months ago we put him on the payroll and had him actually migrate his stuff to our Amazon account. The latest improvement is this blog. It has made Dan Friedricksen go away and is more visual in some ways – wider and easier to read.
As you may notice, more and more of the main page of EVTV has migrated to the WordPress blog. Eventually they will be one and the same.
Future developments? The irony of starting an online forum for people to type themselves smart in and have flame wars is not lost on me.
And a viewer build database would actually be more useful to my way of thinking.
In its most base form, you are advocating STICKIES for newbies. I’m onboard, just unable to organize or edit. What IS the definitive guide to Basic Electronics and Electricity you found useful? You see. Since you’re not a newbie you cannot really even recall.
I myself use WIkipedia. There are descriptions of almost any circuit you can imagine there by name. If you want to know about opamps, they have em. If you want to read about IGBT’s – they’re there. Electric motors. Ditto.
It’s FREE. But don’t be caught in the trap. I’ve contributed $1000 to Wikipedia every year since 1999. Pay it BACK or pay it FORWARD. THe karmic forces of the universe don’t care about the direction. Just don’t let ANYBODY paint a big red L on your forehead with lipstick.
Sure we should have stickies, like a list of PC components and little howto’s.
People have vehicles on EValbum that simply do not exist any more, are sold, died and dumped, never got built in the first place. Also as Jack says, lawnmowers and bicycles…. Including vehicles bought from a shop! I know peoples efforts that fit in any of these categories.
However, if Bikes and lawnmowers are going to figure in some parts of EVTV, will all serious road vehicles be honoured and reported about if relevant enthusiasts wish to turn up at the EVCONN? motorcycles, various trike’s etc?
It’s a thought I had and decided to write (after the smoke cleared from between my ears after thinking) by the serious enthusiasm of other sectors in the EV world that open up new avenues.. I’ll explain:
Some guys make road going motorcycles for economy at highway speeds and recently there has been a growing number of electric bikes taking part. One guy who has “Enertrac” I shamelessly quote:
“The thing I love about electric bikes that are built “right” is that they don’t ride like gas bikes. I think people who ride my bikes agree they have a character all their own and ride better in their own way. The 100% torque from almost a standstill and the smooth ride; you just have to go for a test ride to understand.
I never understand why almost everyone tries to build electric cars to be just like gas cars. Electric drive has a character all it’s own and when taken advantage of you get a different feeling car. Some may like the difference some may not. But now you have something to sell. Tesla and EnerTrac understand this, all the other car companies just don’t get it.
Best Regards Mark
After all, the internet was not just about PC’s.
Can I use those annoying NLP words, “Embrace” & “Diversity” now?
(I never understand why almost everyone tries to build electric cars to be just like gas cars.)
They build them because it’s what is familiar to them. But when they actually build it they soon realize that it does have a different character. Thats fine. That is where the EV Grin comes in and when done they go tell their friends and take them for a ride. You look at an electric car that looks like a gas car different once you know and experience the new drive system. But you know its hard to change the look of a VW Bug to look different than a VW Bug. It sure drives different. Quiet. Stealthy. Unlike before where everyone hears you coming and knows its a Bug.
Here is hoping for a few more followers of my blog.
Engine is out, Tranny coming out. New Prostreet going in. GE motor going in the Roadster. Not the Kostov. At least not yet. The GE has a higher RPM limit. 192 volts and Synkromotive Controller. 60 100AH Hi-Power LiFePO4 Cells built in 08. Voltage limit 156 volts and using the controller to charge the batteries from any 110 outlet. Special 110 outlet will be installed at home that will allow up to 100 amp charging. Set up for DC charging from any DC source and have charged up to 150 amps into the batteries so far. Need a larger capacity stationary pack and higher voltage stationary pack. But I can charge from a 48 volt pack into a 192 volt pack and it does the CC/CV just fine. Field windings do get hot so you do need forced air cooling.
T’was just a quote but you can see the twinkle in his eye even though he does motorbikes.
Hi Jack, Brian and EVTV crowd,
Been watching the show for a while, first post here.
I appreciate your Daughter mode system, and i’m glad you understand and promote the need for some kind of “monitoring system”, to avoid calling it the 3 letters word that you don’t like.
But your solution falls a little short honestly, and with all the electronic know-how you have, i think you can do better than this, i explain:
you want to avoid any cell falling in the danger zone, but instead of measuring their voltage, you count the Ah. But what happens if your daughter or anybody do not fully recharge the pack ? Your preset AH limit becomes useless. And whit time this limit will have to be adjusted downwards.
Why not just measure each cell voltage and have a little circuit pick up the lowest value and compare it against your danger zone, then take whatever necessary action ? YOu can also display the highest and lowest value on a little LED display, knowledge is power really. Ah is not sufficient. Let’s go straight to the point-> cell voltage.
And you don’t have to call it a BMS. I’m sure you can build a neat little modular board, 6 or 8 cells at a time, with the wire harness that goes with it, the LED display, and the 0-5 v output when danger zone has been reached (incl Nord Lock washer of course, I suspect brand placement here :-)). You’ll call it JRDMS, Jack Rickard Daughter Monitoring System, and in the first week you’ll have 100 orders on line for them.
Regards from Switzerland, the cub scout.
I’ve you’ve been watchnig the show, you know we’ve covered all this about a dozen times. Despite the condescending tone, I would suggest you have no idea what you’re talking about.
First, if the car isn’t fully recharged, than the AH indication isn’t either. It counts AH both directions.
Secondly, I’ll ask you what I ask everybody with this cell voltage monitoring concept. You are going to monitor it for WHAT voltage? And you are going to do WHAT with the information.
We talk about SOC and cell voltages. But they are only significant in a static open circuit measurement. They have meaning at rest. In the dynamic world of driving a car, if you DID have a device to measure cell voltage, it would tell you that the voltage is going all over the place, from 3.25 volts down to 2.25 volts and back in wild swings of voltage that dutifully enough conrrespond exactly to wild swings in current, load, temperature, age of cell, and SOC. This “sag” under load is actually entirely different at the top of charge than it is at the bottom. Entirely different in the winter than it is in the summer. Theoretically different on old tired cells than it is with fresh new ones. And of course, we all have different sized motors, controllers, and cars by weight.
The answer is, if my daughter could monitor the voltages, she wouldn’t know what to make of it. I don’t either. The BMS designer doesn’t either. ANd the BMS itself doesn’t know what it means or what to do about it. That’s why so many BMS’s are constantly having difficulties – the designer did not foresee THIS situation, THAT situation and the OTHER situation and it is constantly changing, never mind CONSISTING of semiconductor devices that are themselves less reliable than the devices they purport to protect.
I would suggest you’re more than a few episodes behind the curve here.
But we’re glad you’re watching. As you get older, I’ll start to look smarter.
Well, I agree that building a logic circuit around these variations and take the necessary actions like reducing the throttle input is not easy, but not impossible. You could at least prevent the car from starting if any cell at rest is below a certain voltage. Or monitor the max difference in voltage between any two cells.
We cannot assume that cells are always in sync, and when relying only on Ah this is the assumption that is made. I have a 21S pack on my bike and i monitor them every ride now and see wild differences. If i monitor only the Ah i will kill some of the lowest cells and when recharging i will kill the highest cells. I tried top and bottom balancing and none of this fixed the problem.
I’m now building a 10kwh pack for a new motorbike, 32S, i just can’t imagine riding it without having in front of my eyes the highest and lowest cell value at all time, and logging it. Maybe my kids won’t look at it, but I will and this will give me the best indication on the health status of my pack, ride after ride. You do learn a lot about pack and cells behavior this way. Ah is simply not enough. And it’s not a big investment in time and money to do this. YOu can even detect frame leaks too.
The cub is 47 now, can I get promoted ?
“I just can’t imagine riding it without having in front of my eyes the highest and lowest cell value at all time, and logging it”.
Maybe I didn’t make the point with sufficient clarity in the segment in last Friday’s show: over a long enough period a simple voltage monitoring system will, in and of itself, unbalance a pack.
“We cannot assume that cells are always in sync” Cells may fail, but again maybe I wasn’t clear about behaviour otherwise in the segment. I bottom balanced a pack and tracked voltage variance and demonstrated (I thought pretty clearly) that they DO remain in sync. Let me repeat – at some point on every cycle in > 500, voltage variance was of the order of one hundredth of a volt. That strikes me as being “in sync”.
In God we trust: all others bring data.
I completely understand and believe what you did. But this is the behavior of one pack of a specific chemistry (of which cell 6 data was removed, was it a bad cell ? I forgot the reason you gave, sorry).
But I have one pack that was bottom balanced, and it does not remain in sync, despite i already removed 2 bad cells out of it. So your experiment does not influence unfortunately the behavior of my pack, and the behavior of the thousands of other packs of different chemistry out there.
As you say, cells may fail, and they do. So one should not conclude (like Jack seems to conclude from your experiment) that we don’t need to monitor individual cell voltages.
I’m not in favour of having a black-box type of BMS that we have to trust blindly. On the other hand, relying on Ah count is a step in the right direction but is not sufficient for Mr everybody to avoid problems. You will not catch that cell when it will fail this way. And cells may fail.
“So your experiment does not influence unfortunately the behavior of my pack, and the behavior of the thousands of other packs of different chemistry out there.”
You are really behind. This has been and always has been about LiFePO4 cells. No one said any different.
“As you say, cells may fail, and they do. So one should not conclude (like Jack seems to conclude from your experiment) that we don’t need to monitor individual cell voltages.”
Jack and others already came to this conclusion from other test/experiments/measurements/uses. John’s experiment just added to the support it didn’t create it.
David D. Nelson
You started yourself off as cub and it’s up to you to promote yourself. I don’t know what your using, but I can tell you that you can wear the spots off cells by watching them too much. If there are wild variations, it is you and your monitoring equipment that is causing them.
And I have seen people do this. Just absolutely wear the cells out hooking things up to them and watching them. AH IS enough. And a lot of things can be way too much.
Too soon old. Too late smart.
you do wake-up early.
you say: “If there are wild variations, it is you and your monitoring equipment that is causing them.”
my 21S is currently composed of 3x 7S packs, one has a BMS, on the 2 others I have absolutely nothing hooked up to them. I use a cell log once in a while to monitor each cell behavior, connecting it for a few seconds only. So it cannot be me really. Sorry my experience with this pack does not match what you think, but it’s a reality you cannot ignore.
I’m not in favor of connecting all sorts of black-boxes to a pack either.
But we will not agree for now,it’s ok. What is important is that people reading this thread will realise there are other opinions out there.
“my 21S is currently composed of 3x 7S packs, one has a BMS, on the 2 others I have absolutely nothing hooked up to them.”
There is your problem. One has a BMS. That will imbalance the pack over time. But, you haven’t stated what chemistry batteries you are using. If they are not LiFePO4 then maybe that is why your experience is not matching up with the rest of ours.
David D. Nelson
The problem is quite obvious. You are doing something wrong.
Perhaps if you detail all your steps of charging and discharging we can point out your mistake.
If you simply bottom balance your cells, and then undercharge them using a CC CV method so that your resting voltages 24 hours after charge is in range of 3.33 to 3.35 volts you are good to go.
You can then count ah out to protect your pack. No other measurement is accurate. To measure voltage for SOC accurately you need to wait 24 to 28 hours. To measure semi-accurately you need 5 to 10 minutes of rest. So not very practical.
Helpful to know what sort of batteries you’re killing as well.
Finished my motorcycle and had it inspected street legal. 24 pack of CALB SE40AHA in series, no BMS, just bottom balance, working like a charm. Some cells get to around 4 volts when charging to 87.6 volts total, but come down in a while and all were within 1% of 3 volts when 90% of Ah were gone. Using Cycle Analyst to count amp hours. Blog at kWsaki.com. Thank you Jack, Brian and John, for the work you’ve done.
You are overcharging your cells in my estimation. 24 x 3.5 is 84 volts. I would reconfigure my charger to charge them to that level and you will no longer have a cell up around 4.0v.
If your charger is not reconfigurable, you could add a cell to 25. 3.5×25=87.5volts.
It is important when bottom balancing to undercharge slightly and with CALB cells we use 3.5 volts per cell.
I’m aware of it now, but I happened to order 24 cells before realizing it. So far they don’t seem to mind, adding a single cell would cost relatively much and I’d have to figure out a place to put it as well. On a motorcycle things are sometimes a bit more complicated. The charger is not configurable. Perhaps if I order a faster charger I’ll either spec it different or tack in an extra cell to the order and relocate it along with a couple of the older cells.
Actually it is not important AT ALL for people to realize there are “other opinions out there.” Batteries do not care what the vote count is. They’re pretty simple creatures really, and kind of focus on being what they are – every single time.
You have fallen prey to the online concept that you can type yourself smart, and if you repeat it enough it becomes real. If you can gather 10,000 others to believe the same thing, it won’t change the battery cells by one single intercalated lithium ion. You cannot move ions with a keyboard and screen unless you interface it to a battery pack and do careful observations as John Hardy has in a controlled fashion.
Anecdotal “I saw” and generalizations such as you’ve made are actually COUNTER productive, no matter how fervently you believe them.
If you want your OPINION to be taken seriously, show us an experiment we can easily duplicate to confirm your observations. Without that, it is just an opinion and there are lots of forums that just thrive on that crap. We aren’t one of them.
After reading David’s comment i was ready to put up some experiment and share the results with you guys.
But Jack, my first post does not even dates from 24h ago, you do not know me, and yet, your comments are full of ad hominem attacks. I wonder why you get so angry easily at people, and so fast. Just because they hold a different opinion ? DO you want to be surrounded with people who hold the same opinion only ? How boring it would be.
I was warned, it took 24h only.
But I know you won’t even care about my reply, and that’s the sad part, because you are full of knowledge, you just don’t know how to disagree very well. Try to see the human behind the post, why so much anger at people ? You should not put everyone in the same bag like this. We could become good friends, who knows ?
I feel sad, really, and you won’t care most probably, because you did not take one minute to try to know me better. YOu cannot care about a name on a post, if you forget there is a human behind.
It’s true I suffer foolishness poorly. Apparently I come across to some people as very angry as I have heard this several times. I’m not the SLIGHTEST bit angry. I am trying to respond to your comments quite directly and quite succinctly. Anger isn’t any part of it. As you point out I don’t really know you and have nothing to be angry about. I’m sorry if it comes across that way, but it just isn’t so.
That said, there simply were no ad hominem attacks. I addressed specifically and directly what you were saying, not who was saying it. You insisted that a differing opinion was valuable, and I explained that I didn’t agree and why it is NOT valuable but that I hear that a lot. And I was trying to impress upon you that having an opinion doesn’t change a battery at all. Which is kind of an important point. I can show you how to wind up with a ROOM full of destroyed batteries, and they never once asked for an opinion.
You do seem bent on establishing something regarding BMS’s which we quite famously don’t use and don’t approve of. And I’m happy to discuss reasons for that, and what we do know about batteries. If you simply disagree and hold another “opinion” I don’t really know how to deal with that artfully. If you have some data or an experiment you can describe that you yourself have done and we can duplicate, we’d be happy to look at it. If it is at all possible or interesting, we might even set up and do it. And I mentioned that.
So don’t be sad. Don’t be angry. They are just batteries, and since they are yours I’m quite alright with you doing whatever you like with them. If you come on here and advocate that OTHERS should do nonsense and screw up THEIR batteries in the process, I will respond and it will be short sweet and to the point. But it would be preposterous for me to be angry about it then.
You almost certainly have not kept up to date with these findings, amongst others:
Here you can see exactly what John Hardy (The same John in here) has done to ensure his tests were absolutely accurate over many hundreds of cycles and over their supposedly normal continuous rating.
Sure he had a cell go down but it was “off” from the beginning. Same thing with Damien who uses the same Headway cells so he positioned them so if they failed he could easily change them.
From my lesser experience I have to agree with everyone else. They simply do not wander around like a herd of cats unless they are individually made to.
If after charging, you take the bike for a very short run down the road or simply put your lights on for a minute, you might find the all cells suddenly become level in Voltage?
If you can knock off the charger just a little earlier then you can evade having to add another cell?
After realising I have no need of high speed charging I’m considering a bunch of laptop power supplies and fitting a current limiter circuit to every row of five. The charge voltage will be 100V on 29 in series. 3.45V each.
Does anyone consider this a scary or stupid thing to do?
I believe the cells come down in voltage all by themselves and equalize even without any proper load. A pre-charge resistor is however always connected unless I manually break the pack with a wrench as I do for storage over a week or more. I could manually stop the charging, but then I’d have to stand there and watch paint dry. With my patience it just can’t be done.
I use a Toshiba 15 V laptop PSU as a DC to DC converter to charge and beef up the 12 V system from the main pack. It seems to use up to 0.8 A from the pack and run sufficiently well with 80V DC even though it’s designed for 100-240 V AC. If it or the old 12 V battery breaks I’ll just device a better solution.
I guess that goes for batteries as well. If one or two doesn’t make it or I do something stupid to them I’ll just replace them and that will be it. Investing more than a couple of cells worth into protecting the cells just doesn’t make sense especially since the protection in this case would probably mean a) some cells breaking sooner, b) vehicle becoming undrivable when it should actually be running just fine and c) not getting full power. The batteries are a tool, meant to be used to their full power, replaced if broken and eventually failing of old age. This will probably take about 10 years on my motorcycle though.
Laptop adaptor as a DC-DC supply!
Now I’ve learnt a little off you. Thank you sir!
Hugues – how about taking up David’s suggestion and posting a little more detail about what you are seeing? There are some able folk on this blog who can maybe suggest things to look at. I’d suggest posting:
Cell make, type and amp hour rating
CV ceiling of your charger
Cut off current in amps or C rating
Approximate number of cycles on the pack
Your normal maximum DoD
Does the JLD 404 have the ability to export real time data to something else like and Arduino? Most “retail” electric cars have a distance remaining display which in case of the daughter/wife mode would alert said daughter/wife if she can make 2 unplanned side trips on the way home instead of the 4 stops she might make before the daughter mode kicked in requiring a rescue.
It does not. I’ve been trying to get that feature but it is just not available.
Jack is going to spank my bottom if I say the Cycle Analyst can and does 😉
(AH, Volts, Amps, Speed, Distance) into USB.
My real time range calculator:
D*(P/(P-AH))-D = remaining mileage.
Where D is distance travelled,
P is chosen pack capacity
& AH used/regen’ed.
In simulation the result sometimes starts out a little wild like any mpg meter does then quickly settles down. It could be smoothed in software, show full numbers only. If you want. A DIV/0 needs to be initially caught or not calculated until the first AH reading comes in.
Playing around programming with this thing has kept me off the road.
Not at all Andyj. I don’t personally like Cycle Analyst over some accuracy and configuration issues. But I do like the large screen and what it purports to do. And at a relatively inexpensive price.
I can’t recommend it. But it’s certainly better than no AH count at all and it’s pretty easy to read actually.
Accuracy and more interestingly, drift is something I’ve not been able to ascertain from my shack.. The most calibrated tool here is my 8oz hammer.
I’ve watched one of my packs for drift over a week. Seemed ok. Would be nice to see what goes awry. As an instrument I considered it good enough for car work.
Jarkko – the bike looks great. An impressive weight reduction, and with 73 kW driving 170 Kg I imagine you have, er, little difficulty keeping up with the traffic flow. It will be interesting to see what range you get at more modest speeds
The bike had 78 kW originally with ICE. Now I have 11.5 kW continuous from the ME1003 and judging from max amps out of almost 400 A from the controller I’d say about 32 kW peak. However I noticed that the motor gets quite hot so I may have to drop the max amperage to around 300 A which would put peak output closer to the recommended 23 kW. Unless I device some sort of BlowMeTM forced air cooling into the motor like the kit Jack sells.
In any case yes, it does keep with the traffic very well. More than well, actually. You find yourself slowing down due to other drivers more than not keeping up. Quite the same as with any motorcycle. I believe it has comparable performance to my older 500cc bike. It’ll be interesting to see how the Wh/km develops. The trend seems to be down. The brushes may still be wearing in as well.
You might look at this 7″ radiator fan motor bolted onto the end of your motor:
I’m building a car using two ME0913 motors and plan on two of these pulling more air through the motors.
That doesn’t look half bad actually! Thanks!
Except thinking about it for two seconds it doesn’t allow me to put a filter on it that I’d really like to do. But it’s an option.
Jack has always said he does not care what you do to your cells, they are your cells. Hook a Elithion BMS up if you want, he did once and almost toasted his car. If you meet Jack he is actually a pretty good guy and even invited a BMS manufacturer to present at EVCCON last year. I have watched hours of battery testing that Jack has done for the benefit of the EV community, so from observation, I would say jack knows what he is talking about. If he seems a little passionate about individual cell monitoring, It’s because he takes exception to people not doing all their homework and putting products out on the market that could damage the future of the EV conversion community. Try to make it to EVCCON this year and I’m sure Jack would probably be willing to sit down with you for a few minutes over a cold Stag Beer to help you further understand LiPO4 battery care and maintenance. I think he just gets a little offended when someone comes on his blog and appears to be insulting his intelligence. Anyway, just my take on the thread.