This week we talk a bit more about our EVTV test bench. This is going to come slowly but I think is a necessary part of our Cadillac EXT project and will be quite useful in the future as well. It’s kind of like building a really slow electric car, with extra instrumentation and controls.
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The rest of the show is mostly about our battery pack. We talk a little bit about the various and generally confused Lithium Ion battery chemistries, why it matters, and what really causes the decrease in capacity over time when using these cells, which have a MUCH longer life cycle than the cells we routinely see them confused with online.
The confusion between these chemistries puzzles me no end and I guess I think a lot of those online and even some of our viewers have kind of missed the point. BECAUSE the U.S. battery developers don’t really have a production line, they are generally just trying to sell Intellectual Property upstream, we have all kind of stumbled onto the Chinese suppliers of “lithium” cells. This has been most fortuitous and I don’t want any of you to miss the point.
In my estimation, the LiFePo4 type chemistry is THE most ideally appropriate for vehicle use at this time. We kind of lucked into it by availability. And I actually see a segment of our community lusting after Lithium Cobalt Oxide and Lithium Manganese Oxide chemistries for their greater energy density and because larger entities such as Nissan, Chevy, and Tesla are using them.
It is my unqualified, but nonetheless strongly held opinion that generally THEY are going in the WRONG direction and WE by accident of availability have landed on the much superior solution. Our cells will last 10X longer, endure much more in the way of misuse and vehicle vibration, temperature extremes, and general bashing about, with an order of MAGNITUDE greater safety, at only a slight penalty in energy density. We did not brilliantly deduce this, but rather lucked into it. I have always been clear on this – it is BETTER to be LUCKY than SMART.
These cells are leggo blocks of amazing capacity. And they will last for tens of years – making the paltry 200,000 mile demonstrated endurance of the truly finicky NiMHd cells look like disposables.
ANd so we also announce our selection of the Winston Battery Company WB-LYP400AHA cell as the official battery of the 2008 Cadillac Elescalade EXT conversion.
We would also like to thank the Winston Battery Company Ltd for sponsoring EVTV over the next year and additionally for the contribution of the 70 400 AH cells specifically for the Elescalade. This marks kind of a leap in a number of ways. Ultimately, EVTV must be advertiser supported and the addition of such a major sponsor alters the landscape somewhat dramatically in favor of our continued operation.
But it’s also a kind of sea change in the marketing of Chinese products in the United States. We were privileged to correspond directly with Mr. Chung on this topic and found him remarkably progressive and insightful on this topic. It is not precisely the Chinese way, but Mr. Chung is making a number of moves in the U.S. He is a true believer in the necessity of altering transportation for clean energy and battery power and has been in the battery game since 1982 with his invention then of a maintenance free lead acid cell. He actually holds his own patent on the LYP cell which essentially removes him from the patent wars over the Goodenough patent.
More recently, he has acquired a 48% stake in U.S. company Balqon who now serves as their exclusive distributor in the United States. And he’s provided a $10 million endowment to the Bourns College of Engineering at University of California Riverside.
We would present Winston Battery as sponsor as a direct acknowledgement that Winston Battery is aware of what you, our viewers, are doing in Universities, entreprenurial developers, and individual garages and shops all over the country and that they wholeheartedly approve of and encourage such activities where and how they can. They are completley aware of you as a market for their cells, the difficulties you’ve had purchasing them in the past, and they are working to address that in every way possible. It’s all about you.
Another area of constant interest is selection of a car for conversion. My theory has been that you need to select a good car to start with if you intend to wind up with a good electric car in the end. This has been emotionally tested in the past. We winced hard in starting a conversion with a brand new 2009 Mini Cooper Clubman. It was just that good with an internal combustion engine in it that we discussed the crime we were about to commit before we ever first drained the tank. And I have to tell you the first steps were tremulous.
Worse, we encountered no end of difficulties and missteps in selecting suppliers and components for the car, and indeed had to redo our own design of the mounting structure and adapter for the drive train. We’ve lost cells to parasitic loads from instrumentation. And we’ve even found it difficult to learn all the buried features in this car. Further, we’ve never quite finished it. I still think I can get the fuel gage on this car to work – somehow. We still need to build an OBDII spoofer to turn off the check engine light, the tire pressure light, etc. I still want to integrate brake pressure with our controller, and tie the air conditioning compressor and water heater more closely and automatically to the environmental system.
ALl that said, I have used this car as my daily driver through this winter, and it may be the most delightful car I’ve ever owned in essentially ALL respects. It has all the modern conveniences, and is as smooth and quiet as I’ve ever experienced. Smooth acceleration is very pleasing. And I’ve got all the creature comforts. Our heating system actually works very well, and seems to keep the controller and motor cool at the same time. My point is, by selecting a GOOD car to start with, we wind up with an EXCELLENT car in electric drive.
And this takes us to the Elescalade. I already REALLY like this car. And I’m hesitant to crack it open and convert it. But knowing what we’ve learned from the Mini, that’s a GOOD sign of good things to come.
Stay with us on the journey….
33 thoughts on “Test Bench Progress – A 93kWh Battery Pack for the Elescalade EXT – Lithium Ion Chemistry Differences”
Jack & co:
Great show as usual. Just a footnote about hydroboost, which is a very cool system:
Hydroboost was developed for use on engines that develop insufficient vacuum to run a regular booster. Its not related to the amount of pedal boost, for which a gasoline engine can supply plenty of vacuum, even in a huge vehicle. Diesels, as direct injection engines, don’t have a throttle valve behind which enough vacuum is developed to run a booster. It just happens to be the heavier trucks that Matt has noticed using hydroboost- because those are the diesels. They can’t run a vacuum booster at all.
GM also fitted the system to the few diesel passenger cars it made over the years, and to some of the Buick turbocharged gas cars, which were weak in making consistent vacuum. Ford actually put hydroboost on at least one of the big-engined Mustangs, not because of vacuum problems, but because of packaging. The vacuum booster wouldn’t fit on the firewall with the big in it. The hot rod crowd loves hydroboost because modified motors with monster camshafts don’t make enough vacuum for a brake booster. They go specifically for these passenger car-based systems, which are now available in the aftermarket.
If you’re running a PS pump, hydroboost is a no-brainer in an EV. Its almost certainly a lighter set up, and simpler without a vacuum pump, reservoir or tubing. The hydrobooster itself accumulates enough PS fluid system pressure for 3-4 stops in an internal piston, so it isn’t critically dependent on the pump for constant pressure to boost the brakes. The steering box will never notice its there. I found a pretty cool diagram that shows this integration nicely:
In many EVs, an electric power steering pump, (not pulley driven off the engine, but integrated with an electric motor) like the one from a Toyota MR2 or Volvo V50, can run both PS and PB. Its an elegant solution. The only caveat is that some (older) cars need engine vacuum for things other than the brake booster- usually climate control mode selection or pop-up headlight actuation. On these cars, its probably just easier to keep the vacuum brake booster, because you still need a pump, reservoir and the rest of the vacuum lines anyway.
The big issue with Hydroboost is cost. The systems aren’t cheap, but they last forever and are widely available in the aftermarket and even junkyards, if that’s your thing. As EVs get bigger and consumers demand controls that work as they expect, I predict hydroboost will be much more common in conversions. The OEMs will employ direct electric assist on the steering and regen mixing on the brakes, as you do on the Mini, but hydroboost PS/PB is the answer for a conversion over 3000lbs or so.
Sort of a joke, but somebody at ecomodder made a Smart/Aptera hybrid (on paper of course). It should work to solve the efficiency problem with the smart. haha.
Looking forward to seeing the slow EV (bench) at work. Good to see your viewership and sponsorship is growing. Keep up the good work.
Shame about the hub motor. I was looking forward to that project. There must be another supplier out there you could use. I really liked the idea of you guys having multiple projects on the go. It makes for a better show I think, although I do like the way it is now.
– Nick F
Has Mr Chung revealed how much precision the Thundersky selection process aims for?
I’m looking at 40Ah cells.
another large format LiFePO4 company (CHL) indicated their selection process groups cells by:
within 7% internal resistance, within 0.5% Ah capacity, and within that group the cells that had the closest voltage immediately after the production process.
all shipped at 60% SOC.
At that precision you really can charge to 3.65v average as is with no playing around.
I was wondering if the Thundersky process was the same, or better/not quite as good.
basically I’m asking how much attention I need to pay on the first charge cycle, making sure the charger does transfer to CV as the first cell hits ~3.65v.
To quote Ronald Reagan: “Trust, but verify.”
I always watch on the first discharge and recharge both.
I think the Thundersky process quite good. Haven’t received any in bulk for some time. We’ll test a couple when we receive them.
I have comment on both of the axes of the last show, particularly as stressed out here on blog.
Concerning the donor car state, I couldn’t agree more – the newer the better, at least concerning european insurance company policies. I payed them a visit yesterday to discuss my conversion candidate. Been greeted for the initiative, firstly, only to be advised to reconsider such a costly operation on a car which in their catalogues has low value.
If whatever happens to the car, god forbid, insurance company wouldn’t pay more than what their books hold for the value of my vintage BMW.
For the matter of batteries I agree as well with the notion LiFePO4 chemistry is our blessing, but from a different point of view. I think these batteries will live over converted car, but hopefully, advances in chemistry technology will obsolete them sooner.
Who will resist increasing the range of the vehicle between charges if it becomes substantial, even shortly after conversion? !
The longevity of these cells will provide us with their supplement uses. Very viable use I find is, in accumulating energy from photovoltaic panels. I hope photovoltaic technology will improve as well so an average household will end up having free energy for their vehicular fleet, on daily bases.
Meaning, if we go converting a car from the fleet, one at a time, we will have a choice when renewing existing battery set of: converting another car or go for a new link in energy sustainability chain, of producing our own electricity and having it stored in old swapped battery pack.
The next swap will increase this accumulating capacity.
Maybe I am mistaking and we are far from it at this point, particularly if every battery update will target larger autonomy, obsolete pack will consistently be short, apart from its decreasing in retaining capacity over repeated cycles of charge and discharge. Mixing battery technologies might cause other problems, but I hope that’s the path for car conversion interests.
Solar energy should become part of the equation which will further improve the efficiency of our EVs. If viable, such installation could provide cheep ride for our cars and selling surplus production for additional benefit to energetic network, as already is the case in Germany.
Spain has lots of sun, yet somewhat different policies. In my opinion, lot of things will have the chance for improvement around EV conversions initiative, worldwide. Greetings to all from Barcelona.
I’m in complete agreement. Cast your keen eye on our test bench, and you will see 12 absorbed glass mat lead oxide cells with sulphuric acid electrolyte.
These cells are too heavy, store too little energy, and do not have sufficient life for an electric car. They will work great sitting on the shop floor powering the bench.
At my home in Denver, I have had a 15kw photovoltaic arrary since 2000. It featured a 50kWh battery bank of very expensive Trojan large format cells. They are shot. We have removed them from the system. But this iis an excellent place to put obsolete or run out LiFePo4 cells.
The “end of life” of these cells is by definition the point where they have reached 80% of their capacity. If I have a 30kWh pack, that would be 24kWh. I can still drive the car. But if my range has decreased and I want MORE range, I can replace them. But the 24kWh is still 24kWh. I can still use them for solar storage (or a test bench) or just battery backup for another house that doesn’t even have solar.
The point is the cells still have life and use. When you take the “motion” out of the pack, the usefulness has very DIFFERENT definition.
Our test bench doesn’t really have a range or capacity issue. In fact, we are going to use the generator to replenish it while it’s running. I just need an energy source for testing purposes.
And these “leggo block” cells lend themselves to such reuse in MUCH easier fashion than a GM Volt or Nissan battery module. These are more a commodity format that can be easily removed and restacked in another box in the garage or basement. We don’t need to tear the module apart and reconfigure the cells.
I can see a future where every utility room, in every home will have a washing machine, dryer, and a “battery”.
Winston Chung’s sponsorship is not just spending money to be heard. He obviously holds you and your team in sufficient regard to place his multi million dollar name right on your table.
Congratulations! Have you popped a bottle since?
I don’t think Mr. Chung knows a great deal about our team. But we did describe our viewership in detail and he had questions about that. I don’t think it’s a matter of being heard. I think he wishes to acknoweldge and validate the hard work of many of our viewers and assure them that he views them as a legitimate market for his product.
I do think he is sincerely trying to change the world by applying electric power technologies to transportation. And I think he views us in that same light.
Great show. Nice to get a little insight on your bench load control plan.
You might consider some wire/tubing control before it escalates too far.
You also may want to locate your remote bench control console axially to the bench looking lengthwise from one end or the other, as this will be the safest place to be when the bench goes “Weed Whacker” while you twist the 5k load pot. But put an unmanned camera looking on from the side, though. The video will redefine viral on youtube.
I think it will be ok providing one doesn’t forget the little details like some coach bolts through the table. Maybe tension bars diagonally across the table legs?
Will all that data be fairly complex to interpret?
Running it has got to be quite a ride!
I appreciate all your concerns. These are actually pretty good benches and I can recommend them highly. Solid Maple tops and very reasonably priced at $199. Good leg levelers. Sam’s Club
We applied transmission fluid yesterday and turned up each motor with 12v. This is admittedly at very low speed, but we even put a load across the generator rectifier (that slowed things down) and tested the Park, Neutral, Drive type thing with the tranny.
I was utterly stunned by how smooth and vibrration free the entire rig was. We could hit some resonant frequencies of courrse so we will be taking care.
I’m wiring up a control panel now and we hope to get the thing at least up and turning with a Soliton1 today. But we just aren’t going to have a weed whacker here at all. It’s remarkably stable so far. And we’re really getting excited about it.
Initially, we will be measuring current and voltage quite manually and probably doing the calculations on a cell phone calculator. But as this progresses, my intention is to add more and more instrumentation and eventually computers and displays, particularly to the dyno end of it. I’m trying to get efficiency curves from Siemens on the generator to incorporate into software. Eventually we will have a computer display showing current, voltage, kilowatts, horsepower, and torque with some data logging capability. That would be terribly cool to my way of thinking.
I got the CHL selection accuracy wrong, they sort to within 2.5% Ah, not 0.5%.
Another great show. Thanks!
I was just waiting for you to get across the positive and negative terminals of the test bench battery pack mounted on the edge of the bench. I’m very glad you didn’t but I was also wondering if you could see a person’s skeleton while being electrocuted like in the cartoons. -Klaus
It is very interesting about people’s perceptions of electricity. This all goes back to the AC current wars of the early 1890’s.
Edison of course was a big proponent of DC power largely because it was quite safe – you could get a tingle from 500 or even 600 volts of DC power without any real harm coming to you. But just a hundred volts or so of AC was quite dangerous.
Worse, the AC of the day often crisscrossed the city in a tangle of overhead wires at 2500 volts. Edison buried his wires in conduits buried in the street.
He even maneuvered behind the scenes to get AC current adopted for criminaL executions – the birth of the electric chair – first used in New York state.
Westinghouse was the leading proponent of AC systems. By stepping up to high voltage AC using a transformer, AC power could be transmitted many miles, then stepped down for use in the home by another transformer. This is basically the model used today.
Edison’s DC system was limited to about 1/2 mile use from the central station.
As we all know AC one the current wars. But at the price of many deaths by electrocution in the century intervening.
I would not get electrocuted at all by bridging these two terminal bars. Might get a little wake up tingle, but that’s about all.
That is not to say you should be complacent around EV power packs. The problem is not electrocution, but at the power available, shorts from wristwatches, wrenches, dropped parts etc can cause explosive results. Metal can actually be instantly gassified into a plasma ball of several thousands of degrees temperature. Just a flash burn from that can be painful (dont ask me how I know).
I’m touched by all the concerns regarding my safety. But we’re doing ok. We ran the system up to 2200 rpm today and I was just enthralled by how well balanced and vibration free this very cobbled together test bench was.
We draw arcs and sparcs pretty routinely. Somehow we survive.
Can’t wait to see this in action. I await your next video. 🙂
Looks like I got me some more education today, Jack. After reading your comments I got out my Simpson 260 analog meter, the digital Fluke 117 readings were bouncing all over the place, and measured hand-to-hand resistance. ~100K ohms wetted with tap water and ~15K wetted with salted tap water to simulate sweaty summer conditions. 10mA worse case with 150 VDC pushing it. Enough to light a LED but not enough to cause fibirallation, or so they say.
So much for seeing if cartoon renditions of electrocution are accurate.
It might be interesting to see what would happen if that can of Stag? beer you were holding got across the terminals. Perhaps, per John Wayland, we all eventually become plasma boy / girl engineers when fooling with EV’s. -Klaus
Jack, I’ll echo other’s comments on the good show. I really enjoy the whiteboard sessions.
To further beat the dead horse, the maple top on the table would be sufficient if all components were mounted to the same one. But because the load is on a different surface, the weed whacker potential is still there. After all, the massive torque of those two motors will be pretty awesome.
Jack , sorry if this is a bit off topic but just wanted to say one thing. Your right about the lifepo4 battery making the ev viable. Even electric junk like mine! Words fail me to describe the difference.
The irony was the first man they tried to fry was fed with AC. It barely worked. Edison was said he could do better with an ax(e).
Then they reverted to DC but to make it work, the victim had to be shaved, wetted and jellied up before being strapped into the chair blindfolded. (I can see public schoolboys, politicians and all the other sexually subverted queueing up for a go now).
AC has a skin effect as it travelled across poles. but DC only travels within the wire… And the man being a resistor, burned from the inside. A most cruel and unusual punishment which, incidentally is an anathema to US law.
Strapping them to Jacks weed whacker would of been a lot more fun.
Electric cars with lead acid cells are an interesting demonstration that a car can be made to move under electric power. That is not to say they are quite viable as a car.
With LiFePo4 cells, electric cars become viable for the first time. I perhaps have a tendency to speak literally and for those with an ear to hear, the shrill soundbites of commercial television simply don’t come to me naturally and I’m not moved to adopt them. We don’t have a ratings system to deal with.
I mean literally – LiFePo4 cells make an electric car viable for the first time. Whatever you thought you knew, or however much you liked the EV-1 and the RAV-4, I am not confused and didn’t stretch it with hyperbole. For those with an ear to hear, LiFePo4 cells make an electric car viable for the first time. Viable – it can be used usefully as a car. For the first time, previous cars, by comparison, could not. LiFePo4, a specific cathode chemistry of a speciific type of ionic battery.
But yes, being able to compare a lead acid vehicle to the SAME vehicle using the LiFePo4 cells, actually makes you one of a pretty select club. MOst people are familiar with one or another.
We started with a GEM we could SWITCH between the two cell sets and actually go back and forth to compare them.
This week, for example, I drove the Mini Cooper 80 miles. Not a record. ANd indeed it wasn’t even fully discharged.
What was remarkable was it was the ONLY car I drove for six days, and I never charged it AT ALL.
Cape is a small town. But it got me to the shop, the grocery store, the hardware store, the University rec center several times, and out to dinner each evening. IT wasn’t just that I made it through the day.
I made it through the WEEK.
Yes, the first electrocution was rather a messy botched job. THey shocked him and thought him dead. Within a few minutes, he began breathing again and the crowd gasped in horror as he began thrashing about. They hit the juice a second time and held it there until they pretty much cooked him dead. It was by all accounts a horror. The prosecuting attorney fainted. It was just a mess.
You can read quite a bit more interesting elements of the current wars in Empires of Light, by Jill Jonnes. You’ll understand Tesla and the why and how of him and his remarkable polyphase engine and most particuarly of Westinghouse and the role he played in the early days of the deployment of electricity.
It is somewhat hard to imagine that all of this was going on in a very new way in the early 1890’s, but by the late 90s New York had an entire taxi service running on electric cars. Electricity itself in a utility sense was a but a decade along.
Know what chemistry of Li BMW is messing with? LINK: http://www.autoblog.com/photos/bmw-megacity-vehicle/#3139113
The link tells you all you want to know. I took a look at it, located the picture with the batteries closest to the camera and switched to the largest picture available. It actually has the name of the battery written on top of it.
Here’s the link to the large pic (I hope the link works):
On the top of the batteries is written:
“60AH dummy bolt” and “SB Limotive Co LTD”.
So these guys:
-Nick F 🙂
There is an animated video on the site Nick F posted which shows charging and discharging of a LiMO2 battery. Maybe that is what is being used.
Again, thanks for your video this week and congratulations to you and your team for securing substantial support from Winston battery. That’s awesome!
Okay, I take back saying “Weed Whacker”
I meant it to be a humorous ending to a negative sounding post.
Frankly, the maple butcherblock is great stuff.
Hard wood withstands flexing and vibration without the fatigue and failure seen in metals.
My concern was the fact that it spanned 2 tables.
I’m quite certain that you’ll take the needed precautions to insure that everyone is safe.
Perhaps a peace offering is in order.
Something positive this time.
I can show how to put together a 40 amp DC-DC converter at low cost and high quality.
It will accept up to 380 vdc input and output 13.8vdc with high precision and low noise.
I use Vicor MegaPac supplies with modules such that cooling, voltage regulation and such are taken care of in the MegaPac and it takes very little effort to put it together.
It is also quite cost effective.
I spent less than $100 though a quick check on E-bay shows that anyone can do it this very minute for $250 or less.
You already do something similar.
This one is easier.
I don’t know why everyone is so worried about the tables. I’m sure Jack, Brian and Matt have figured out that you just need to connect the two tables together so they act as one. Simple connections on the legs and table tops will eliminate the ability of one table to rotate without the other. There are far more serious/difficult issues to troubleshoot with the Escalade project than the bench design.
Looking forward to the video of the bench in operation.
Indeed, we had a thermonuclear incident with the bench at 2000 rpm Friday. You’ll love it on the show.
THe bench did fine, no fatalities. But yeah, I’ll want to brace it up if we try to do any full power stuff. We’re just playing with the Soliton’s and getting things turning in the right direction at this point. Developing instrumentation.
We’ll eventually strap them together and probably anchor them in the floor.
Your reflexes amazed me, Jack.
From the start I heard some kind of whining, that disappeared at higher rpm. It worried me a bit while watching. I’m not an expert at anything, but isn’t the chosen way of connecting the motor and generator in line a source of potential destructive vibration? Wouldn’t a belt connection be a simpler and safer solution?
Again, just thinking as an amateur. Still amazed about those reflexes. Or was it broadcasted fast forward?
I’m sorry your test wasn’t boring. But your video, wow! It’s on record how the revs rose up around 500 rpm(?) when it sounded like it jumped gear. Honestly, I thought Matt was joking when he said the gearbox temperature was 132F by hand 🙁
Chris’ index function. Not seen it yet but can’t thank his efforts enough. It would save running through endless video’s to find that useful snippet of information that’s escaped someone’s attention.
I had reservations with Jims steel plate to the clutch being too stiff – but that’s only my factless opinion.