This week we begin testing the new CALB gray cell, the CA180FI. As I mentioned in the last post, these new cells sport some interesting improvements.
The most minor, and most welcome, is they are labeled with a serial number and a tested Ah capacity. The cells are manufactured on a newer, much larger production line and are much more consistent than the previous SE series. Consistency from one cell to another is probably THE key element in maintaining a series pack successfully. The more closely matched the cells are from the beginning, the less problems you are going to encounter over time. I’m told that 99% of the
new cells test out at between 195 and 200 Ah. In our first shipment of 100 cells, we had two cells marked 194 Ah and one cell marked 201 Ah. So 97%. We found 67% fell between 196 and 198 Ah.
Dimensionally, they were almost exactly identical to the previous SE series and we were delighted to learn that the regular M8 1.25 x 16mm bolts and Nordlock washers work perfectly with the 70mm braided copper straps.
Unfortunately, in our first test, the random cell was marked 198Ah and we tested it to 190.5Ah. We had charged it quite fully to 3.60 volts and 9 amperes. This is per spec with regards to voltage and termination current. But we did much of the charging at 100A instead of the 0.3C (60A) standard charge rate.
This was a very sharp charge curve. The voltage above 3.50 shot up in about a minute to our 3.60 CV target. But what was more amazing was how very steeply the current had to be dropped to maintain that voltage. Normally, charging at low levels of 15 or 20 amps, you are much closer to fully charged when you hit the magic CV voltage and so the current decline is often pretty rapid to maintain it. But at higher currents such as this 100A, we usually see even a slight decrease in current stabilizes the voltage quite smartly. In this case, with the power supply IN CV mode, and with us manually assisting by turning down the current, it was almost no time down to 9 amps where we terminated. I can actually see these cells challenging some chargers to reduce current fast enough to maintain constant voltage.
Things were slightly more normal on the discharge side. Again, standard discharge rate is 60 amps for these cells and we discharged them at 100A. Why do we keep doing that?
First it makes the test easier. These are very smooth graph curves for a reason. I’m sitting there writing down the Ah and the voltage EVERY MINUTE for about two hours at 100A. At 60A this would be three hours. Secondly, and as important to my way of thinking, is this is kind of how we drive our cars. If I just go drive mixed city freeway driving, I get about 1:45 to 2:00 hours of driving. That means I’m AVERAGING about 100A out of the pack. This is a very rough statement, as there are endlessly variable ways of driving. But in just doing a lot of drives, that is my sense. Your mileage may vary.
We are accustomed to things after 3.00v moving pretty rapidly, particularly at 100 amps. It would appear in this case that they move VERY rapidly at 3.10v. And indeed, CALB indicates that on these new cells, 3.10v indicates 90% discharge.
We also discharged a random new SE180AH cell for comparison. Surprisingly, we got 195 Ah from this cell. Here’s the discharge at 100A chart for comparison.
Frankly, you have to look pretty closely to see that the CA starts slightly earlier, and then falls slightly more sharply, than the SE. Not really much between them.
So aside from consistency and a slightly flatter curve with sharper ends, three of the more interesting claims of CALB:
1. Better cold weather performance.
2. Nearly 70% greater power output.
3. Much greater cycle life.
We’ll probably tackle better cold weather performance next. We can cold soak these cells and do another discharge test to compare them pretty easily.
As to greater power output, that gets difficult. Things in the battery lab get pretty dicey above 400 amps. We start melting things and blowing up test equipment pretty handily as we learned with our A123 tests. We usually have to do a couple of cells in series to maintain sufficient voltage to keep a high current into our loads. We have ordered five of the 40Ah cells. While performance between different sizes does not track exactly, we think we might manage some high current testing of the 40Ah cells. We have demonstrated 8C in a car with the SE cells. But the CALB claims would imply a 12C output of these new CA cells. Even on a 40Ah cell, that’s 480 amperes. We’ll give it a try.
Cycle life testing is something we just haven’t done. It really requires more automation than we are accustomed to using, and more importantly it requires some faith that charging and discharging 24×7 won’t burn down your facility. Unless I want to sleep down in the shop for a month or so, I”m a little hesitant to tackle this. Our Revolectrix Cell Lab 8 does a pretty good job of a charge/discharge cycle and can be automated with a PC. The display, however, shows in milliamperes and they apparently didn’t foresee use on such large cells. We generally find the results truncated and not displaying the two most significant digits after a cycle. That doesn’t do much good. Then too, it is limited to about 35 amps and that kind of heats up the wires. Even standard discharge on a 180Ah cell would be 60 amps. But we might cook something up on one of the 40 Ah cells.
This week we also took delivery of our 1974 VW Thing. And we sport an update from Jeff Southern of Kenesaw Georgia. Jeff is kind of interesting. He’s been kind of a fan of electric cars for some years, but leery of the lead acid battery issues. After watching the show for awhile, he’s taken the plunge – ALSO with a VW Thing. He has the slightly pricier Acupolco edition – normally done in stripes with running boards. And he’s leaped right in. I’m not certain doing a video project on our Thing will add much to what he’s doing. He’s sourced almost all of his components through us and is doing the build essentially exactly the way we would do it – AC50 with Curtis 1238-7601 650A controller, hydraulic brake pressure transducer, and 36 180Ah CALB CA180FI cells. We would probably have gone with 38 CA100Fi’s if we do the build – the THING is only 2000 lbs. But in Kenesaw, he needs the range as it is 50 miles or so to work. So he’s rather jumped in on his first build with both feet and is likely to pioneer some instrumentation that while on the expensive side, could be an eye opener. Quite beyond the Arduino, the industrial process controller he provides tech support for at his day job is endlessly extensible through various sensor cards. He very generously sent us one. My main complaints are that it runs on 24vdc and has a learning curve. In the scope of things, both are pretty trivial. The power requirements are really very low and a 12-24 or 120v to 24v DC-DC converter at those power levels is trivial. Maybe if I slow step on the learning curve, he’ll hook a brother up with his resulting software later and I can skip some of the heavy lifting. He doesn’t’ really sell these things, and they are priced more for factory automation gigs that Arduino aficionados will NOT likely find attractive. But they are also pretty bullet proof. My experience with Arduino is that it pretty much looks for bullets. You have to add a lot of protection diodes and zeners and so forth to keep them from failing regularly. Case in point, the 150 to 10 vdc sensor transducer that provides isolation for his system to measure pack voltage. This thing would likely survive a lightning strike.
We had previously floated Anne Kloppenburg’s Glastron boat first drive. In this episode we show some of his assembly work prior. He’s using a Kostov motor, which we know little about. And he rather went to town on the battery pack, bottom balancing, and the Revolextrix Cell Lab 8.
We continue to innovate at EVTV and I fear some of this will cause some inconvenience. This week we have moved the blog from GOOGLE BLOG to a Word Press instance running on Amazon’s EC2 and Cloudnet – this is where we’ve always hosted our video files proper. But we’re moving the online store there as well and the blog. Amazon now sports a streaming function for video that will let you skip ahead or go back while watching the video just by clicking the timeline at the bottom. We continue to suffer the vagaries of HTML5, JWPlayer, and mobile viewing for Apple iPhone and iPad.
Note that on our main web site screen we have subtly altered some hidden features you might find useful. The video “flipper” at the top continues to require Flash and JWPlayer to work. We think it’s visually unique in that you can flip through the past few episodes and start the video easily.
Below that we typically have six of our most recent videos with thumbnails. If you click the thumbnail, you view that video in the flipper. But if you click the DATE under the thumbnail, you can download the entire high resolution video in the background. Then you can view it at your leisure. We’ve added a function to download the mobile or low resolution version if you click the TITLE. We’ll be posting all future videos in this fashion. So mobile users can simply click the title below the thumbnail to download a 750MB or so version formatted for iPhone/iPad.
Bear with us while we work out the bugs on the new blogger. Another learning curve with WordPress. Our thanks to Christopher Fisher for a lot of hard work and learning curve in getting this deployed on Amazon’s service. I am utterly enthralled with the Cloud services Amazon is providing. The scale, scope and reach of this makes running a web site on anything else look child like. But it’s pretty techie to deal with. I can hardly wait for Christopher to get through the 10,000 pages of really pretty excellent documentation on the subject. We’ll both be retirement age at that point, but it was a great career right?
We have expanded the online store a right smart and now carry the CA series cells from CALB. WE also carry both the Netgain/Solitron drive train and the HPEVS AC-50 equipment. We are attempting to add value with documentation, accessories, and to try to make each function of EV component procurement as easy and complete as possible, while allowing the flexibility you need to build YOUR car YOUR way.
One thing that has always annoyed me was to order one thing online, wait for weeks to get it, and then find out I need ANOTHER little bit for it to work at all? Why didn’t they tell me? Or better, include it in the first place?
There’s a very good reason. Most of the vendors are seeking to display the lowest price, whatever the ultimate cost complete might be. This is because many of the people who build EV’s are just very thrifty people and shop really hard. I fall into this trap myself. The result is that you always get the LEAST they can get by with, and if you want the other part, you can always come back and order again.
The delays are caused by two things. One is that most of the vendors don’t’ actually stock anything. They have created a master web of drop ship agreements with a web site front end. They do very little themselves actually. You enter the order, it gets sent to the real provider of the goods, and so it goes from there. The guy you bought it from doesn’t really know when you are going to get it because he isn’t’ sending it to you in the first place.
The other aspect of shopping hard is that these guys have little margin on their products. Usually undercapitalized in the first place, they get into a weird thing of robbing Peter to pay Paul. They use the new order funds to order and pay for fulfillment of the previous guys order. As they fall further and further behind, the timeline stretches out. They’re not really out to cheat anyone. They are just caught in a financial trap of their own device.
We intend to stock most parts, although we will drop ship some heavier items like motors and batteries in some cases – though we may wind up this month with a larger onhand stock of CA cells than CALB itself in Pomona. ANd we’re going for the upscale machined billet 6061 style stuff while eschewing the often serviceable lower priced items.
Or fixing them. For example I’ve always liked the inexpensive Chennic DC-DC converters. We’ve added a 100A diode and a 100uH inductor to it to prevent the blowups many have encountered from pack dips and ripple. This is a case where it is easy to be too soon old and too late smart. But we’ve already been through it.
The result is I will personally guarantee that you can find almost EVERY piece and part we offer at a lower price elsewhere if you but shop a bit. We’ve been very gratified to see that many of our viewers want to support the show and to ensure it’s economic viability and some of the more savvy have learned the hard way the value of a trusted source for components and support.
But as I’ve said in the past, there are always a few intent on putting the floater in the swimming pool. It’s already come up with a couple of very cunning power shoppers who have informed us that they’ve found better prices on batteries and major components elsewhere, but still want us to do the design consulting for them and they’ll be glad to purchase piece parts we offer that are unavailable elsewhere.
Thanks guys. Where it occurs we’ll just refund the Paypal order and move on. Not everyone in EV land “qualifies” as an EVTV customer. Our mission is to support the guys doing great builds on desirable cars that will further the movement. The guys building thrifty electrojunk just aren’t’ part of our crowd.
We similarly hear from a lot of people who want to attend EVCCON 2012 but isn’t’ there a way to beat the game and get in free or for seven people to share a “bringing the car” discount? Very little here is by accident and very little of it really has much to do with EVTV making money. If you haven’t noticed, I tend to gloss over that part of our operation actually.
We did trade shows for nine years. And since I had to host them, we found that the expenses of taking time off work or your own business, the expenses and arduous nature of travel, the hotels and so forth were pretty horrendous all by themselves – something we could do little to alleviate. But the higher the price we charged, the better we could treat the attendees when they WERE there. That was the concept.
But a secondary result turned out to be much more important. We wound up with a much better grade of people at our events. A lot of the value of the event came from interaction between the attendees among themselves. If you noticed at EVCCON 2011, the result is a very positive group of very positive people, truly enthused over the mission of taking over the world with electric drive, and almost all of them successful and confident people from their own careers and lives already. By far the majority are just FASCINATING people to talk to and spend even a few minutes with is a privilege.
These are players. People who actually do stuff. Who have interesting experiences. Interesting lives. They build businesses. They innovate. They change the world they live in. In a world where the glass is always half full or half empty, they find it is the wrong sized glass in the first place,, and in the wrong place, and made of the wrong materials, and they have a better idea about containing water anyway. And why water? Why not whiskey?
Bottom line is THAT is who I want to meet and hang out with. If it’s elitist to NOT want the event cluttered up by a bunch of loser bottom feeders who whine about the polish on every farthing they dig out of the trash, then I’m elitist. But this “attitude” worked out fabulously for ten years among the ISP crowd, and from our first year at EVCCON, it works exactly the same way again. Sorry, but its great to be 57 and understand how these things work and not be a kid any more.
The reason you had such a good time at EVCCON 2011 wasn’t because of where you were, or who we are. I’m an old fat guy in lime green shoes and Cape Girardeau isn’t Maui. It was because of who you were there with. So kind of a price filtered stone soup.
The end result is our viewers are the BEST viewers in the world. Our customers are the very best of our viewers. And our convention attendees are the very best of our viewers and customers. And it’s a god damned privilege just to be me all day long because of them.
Now if I can just get Peter McWade’s order right ONE FREAKING TIME IN A ROW, life will be good. I think he’s ordered six different times and we’ve never gotten him the right part the first time. As it turns out, We are ourselves truly AMERICAN parts suppliers in the finest tradition.