Tuesday, January 25, 2011

Speedster Redux and the Zeva2 Fuel Gage

This week we go a little bit more in-depth with Ian Hooper's Zeva2 fuel gage driver.  I'm quite enamored of this little device which he apparently is still building by hand.  And improving.

In the latest incarnation, he's solved the fuel gage direction problem by using a 20 turn potentiometer.  The direction is indicated by which side of pot center you are on and the discharge rate, or really capacity of the cell, is indicated by how far from center you adjust it.

There are two other features I'm particularly excited about. First, it provides an instantaneous current indication as a series of pulses designed for a tachometer. A pair of little microswitches allows you to set your pulse count as in four cylinder, six cylinder, eight cylinder, etc. And the device automagically and with NO calibration puts out pulses to correlate 100 amps with 1000 rpm.

We set this up with a switch on the dash to switch either our normal RPM from the RECHARGECAR magnetic pickup on our motor, or this Zeva2 current output. I can switch between them at the press of a button.

I cannot express how much of a difference this makes.  Digital displays of rapidly changing current loads are just not very useful.  They update at the update rate of the display, and the result is just a dancing number, meaningless and without form.  When you put this on a BIG needle on a BIG gage, suddenly, it has all the missing rate and direction information - trend if you will.  We may only hit 1000 amps briefly.  But we'll get to see it.

Actually, as it stands, we won't.  We have a 6000 rpm tachometer and so our max display would be 600 amps.  I have a 10,000 rpm tach on order with Speedhut.

The fuel gage output is a rough AH count.   It uses a hall effect current device to measure current and integrates by summing instantaneous current outputs over time.  I've read endlessly how inaccurate and "drifty" this is.  Methinks they are letting the perfect delay and obscure the good.   Comparing hall effect output at different temperatures to the more conventional current shunt meters such as the TBS ExpertPro, I've found them within fractions of an AH after 100 amphours in and out.  Yes, it differs.  Yes, they drift.    But we're not building a piano here.  PLus and minus an amp hour would be plenty.

But charge and recharge errors can be cummulative over time.  We don't want to "get lost" on our pack SOC.  The answer is of course to reset the counter at the end of a charge cycle.  It would be nice if this were done automatically, but it is easy enough to do.

Unfortunately, the Zeva2 is a little crude in this respect.  You simply remove 12v power from the device and it resets. Also unfortunate, if you hit your maintenance switch to do some maintenannce, it also resets the device and you lose your AH count.

The solution was the addition of three components:  A LiPo battery backup, a diode, and a switch.  The LiPo powers the box when it loses system 12v.  The diode keeps the little LiPo battery from trying to power the car in this event.  And the switch lets us reset the device when we want to.

The Zeva2 is also a bare PCB with the hall effect mounted directly on it.  So we need to get it out of the weather.  That requires a plastic enclosure.  Since the conductor has to pass THROUGH the hall effect device, it also requires a couple of LARGE gland nuts or nylon domed cord grips to pass the cable through the box.

Finally, the Zeva2 provides an adjustable LED warning light driver you can use to turn on an LED when SOC reaches an adjustable level.  This is a five volt pullup with a 1k resistor.  We'll have to use a MOSFET or Darlington or some sort of thing to convert that into a 12v switch to actually do something useful, like disable our controller or switch a resistor across our throttle output to put it in limp mode.

I would prefer the LED circuit to actually provide a 3A relay.  But it is what it is.  At $179, that's pretty good.

In this episode, we also show some progress on Speedster Redux.  Our belly pack worked out pretty well, we have it installed beneath the frame quite securely.  This aluminum structure only projects 1.75 inches down, still leaving us with 7.5 inches of clearance, and provides room for 11 cells.  That's a 36 volt pack at 180AH for 6480 wH or an additional 28 mile range, more or less.

Matt Hauber engineered a front battery box allowing us 18 cells vice the 16 we had at that location in Speedster Part Duh.  And he built two rear battery boxes featuring 11 cells each instead of the 10 cells in each box we had in Duh.

We moved the Soliton1 to an aluminum shelf mounted to the motor and adapter plate.  This shows off the Soliton1 look very nicely.  It also made room for six more cells up on the shelf with a terminal strip and easy access to the cells and connections.  

We're also using EVWorks braided cell straps, with our own M8 bolts and NordLock washers to strap up.  These are working out marvelously.  The straps make a very flat, very strong connection between cells and the Nord Locks have just been a find.  They really grip it - forming a very tight connection that does not seem to loosen at all over the brief period of time we have been using them.  Infinitely superior to the lockwashers we once used.

For 180AH CALB cells, the 80mm straps seem to be the most useful.  Occasionally a 70mm strap is necessary to keep from humping up.

For cabling, we're using some yellow 2/0 from Genuindealz that is really quite good.  It's tinned and intended for marine use.  This makes it just about all you can squeeze into a 2/0 lug, but if we DO do 1000 amps briefly, I want the metal to handle it under that insulation.  It certainly was a pleasure to deal with the 1AWG we used a lot of in the much higher voltage, much lower current Mini Cooper.  But Speedster Redux probably needs the larger, albeit stiffer cable.  It's too bad I can't get this tinned marine cable in the proper International Orange color.

In this week's show, we also show my somewhat crude mounting of a J1772 inlet in the Mini Cooper.  I've grown to like the solid feel of the J1772 Yazaki plug.  We have it on the Texaco Fire Chief Plasma Ball Charge station now.  And we've added an interesting voltage/current/power meter from http://www.lightobject.com to that charge station.

Jack Rickard

Thursday, January 20, 2011

This week we welcome Anthony Bagnulo as a visitor from Ottowa Ontario. Anthony came down for 10 days to work with us and see the EV thing first hand. Apparently, we're not showing the full metal jacket EV building experience in sufficient detail.

In this edition, we have a bit of fun with an oversized plasma ball and digress into plasma ball history and a description of plasma. This will be our indicator to indicate a live cord on the Texaco Fire Chief J1772 charge station.

We also update Speedster Redux which is what we're calling it now. A simple controllerectomy has gone beyond major surgery into a total rebuild. We have a lot of fun stuff going on with it and are really having a ball building this one.

Matt Hauber has just gotten to be quite good at eeking out the final millimeters from a battery box. He worked in two more cells in the front of the car, two more in the rear battery boxes. I added 11 underneath with our "belly pack" which so far has worked out surprisingly well. We have up 1.75 inches in the center of the car from a 9 inch clearance.

Additionally, we decided this week to mount the Soliton1 over the motor, and I must say, it does show off this really quite gorgeous design very well. It also freed up the shelf where we have installed SIX MORE CELLS and a terminal block along with some gland nuts for routing. The result is a very neat installation and a cell total of 57 for a nominal pack voltage of 191 and a pack capacity of 34,380 watt hours. At our previous 225 wH/mile rate, this would indicate a max range of 153 miles.

Unfortunately, we'll be a little over 200 lbs heavier and so roughly 2400 lbs on the road. But it sure has me scratching my head what a 1600 lb version with carbon fiber and aluminum would do.

The center of gravity should be much lower and the polar moment should be somewhat reduced - both good things in Sports cars.

The power available will also be basically TRIPLED. This is almost obscene. The Mini gets up very nicely at 100kw and 3500 lbs. This 170kw estimated at 2400 lbs on Speedster Redux is just overkill - bad design to my way of thinking frankly. But Matt and Brian are talking about taking it to Monacco for the ALT FUEL races in April. I don't know about that.

Implementing J1772 in the charge station is a bit more of a task than in the car. But I like to cheat. I've kind of genned up a circuit I'm toying with. It won't make the 1khz square wave to indicate current available. But it would detect a change from +12v to +6v on the control pilot line as we implemented it in the cars. Understand this would NOT actually comply with SAEJ1772-2010. But it would allow us to hook up to the car with a safely dead line, press the manual switch at the car, and thereby energize the charger without having to walk over to the pump and flip the switch. The plasma ball should be sufficiently visible to tell us we succeeded. And this little circuit could be replaced at any time with a more robust one that actually implements the standard.

If you see any obvious errors, I'd like to know about it before I build and test it. It's a simple comparator. If you press the switch in the car, the 12v through the 1K resistor will drop to about 6 volts from 12v. That will trigger a transistor to turn on a small relay that in turn energizes the two contactors that apply both phases to the J1772 cordset and of course one of the phases to the plasma ball. The manual switch on the side of the Texaco Sky Chief will still work as well.

We're also working on instrumentation - even though this vehicle features the EVISION it had previously. We received our Zeva2 fuel gage driver and added a matching Speedhut fuel gage to the dash. This gage sweeps through about 300 degrees of a full circle - giving us a lot of definition. The second version of this sensor also features a tachometer output for instantaneous current.

It needs some things. It needs a battery backup so you don't lose your AH count when you hit the maintenance switch on your pack. And it needs a reset button so you can synch it up with a full charge once in awhile to reset the cummulative errors that inevitable with this device over time. We're going to do a segment on building a little box with all that in it next edition.


Jack Rickard

Tuesday, January 11, 2011

Tesla's Dirty Little Secret

We've made no secret of the fact that I'm a bit of a fan of the Tesla Model S. I've taken a significant position in their stock and in fact have done well enough in it that it will basically buy me a Model S. Put in my reservation this morning actually.

I recently received another version of the oft repeated request that we examine making battery modules out of itty bitty batteries after the fashion of Tesla. We typically get 100-110 wH per kilogram with our stodgy old CALB or Thundersky Prismatic cells, while Tesla enjoys 200 mile ranges and over 200 wH per kilogram with their magic sauce battery pack.

There are actually a number of reasons.

The first, is that making that number of connections flawlessly is a herculean task. And as you know, I'm suspicious of connections anway. I actually did by a spot welder and have experimented with it modestly, and we do play around with this a little. I have some K2 cells on the way and we'll probably let Matt weld me up an equivalent battery and do some tests just for your entertainment.

The second reason is that that higher energy density requires quite a bit of cobalt in the cathode. Cobalt is expensive, it is hard to come by, and my problem with it is it is a little bit negative temperature coefficient wise. They are not thermally safe to my way of thinking, at least not in the league with LiFePo4.

Then too, they tend to have limited POWER capability. About 2C is what you can do to these cells, and so you do have to have a lot of them.

But none of that is the real reason I eschew these cells. Tesla of course uses Panasonic 18650 cells. These are little cylinders of 18 mm diameter and a length just slightly over 65 mm.

Let's take a look at a spec sheet for Panasonic's typical recent 18650 lithium ion cell.

Here's the real problem - 300 cycles. LGChem version of the same cell - about the same. Actually, LGChem states >75% of minimum capacity, further fudging the factor.

The bottom line is these are 300 cycle batteries. We could reasonably expect 3000 cycles. A world of difference. Why would I pay DOUBLE the cost of the same size pack, to get 1/10th the life?

The cycle life is the central issue with these cells. It is true that they offer a serious weight and volume advantage over lead acid or NimHd cells, making an electric car viable really for the first time to my way of thinking. But of course the price difference is discouraging. More discouraging is having a reasonably operating lead sled car that in three years is uselss without a new battery pack. LiFePo4 cells pretty much are a lock to 7-10 years if you don't murder them with a BMS. That makes the operation of the car a very different expense.

So after weight and volume, my big item is cycle life. And 300 isn't really any better than lead. Tesla never really mentions the life expectancy of their proprietary pack.

I think I'll like my Model S when it arrives. But I'm not going to be very happy paying Tesla for a proprietary pack every three years. That's the dirty little secret nobody is really talking about. And the Roadsters haven't really been out there long enough for it to come up - though there HAVE already been some under-warranty pack replacements.
It should make Tesla very profitable selling razor blades for these cars - a recurring revenue stream.

Jack Rickard

Sunday, January 9, 2011

First Show 2011

Well, we have posted our first show of 2011 and it is pretty good, if I mention it myself. An hour and 48 minutes.

We had recently posted a couple of photos of a horrific electric vehicle fire that occurred on an Oslo Ferry, burning up the car, the car next to it, and extensively damaging the ship they were on.

It was an almost suspiciously serendipitous occurrence then that a couple on an around the world tour in an electric car, just happened to be passing through Cape Girardeau Missouri the very next week, and in an identical car from the same company. As such, we got to both examine the car in detail, and put our shop at risk by allowing them to charge there overnight and unattended. Living dangerously.

Predictably enough, the car features a REAP Systems BMS controlling two Brusa NLG chargers. I found it odd that with sufficient chargers to be running at 20 amps, the car only charged at 9 amps. The laptop Hjalte hooked up to the BMS actually had a MARVELOUS and very informative display - if it were not for the part about burning down cars, buildings and battery packs, I think I would like this REAP Systems thing.

I found it EXTREMELY interesting that they noted that two of the cars had burned up and that the company, who could program their car remotely, had set it to this 9 amp value because of the fear of the fires. Second clue, they also noted that the company was very unhappy with this BMS and would be changing to a new system from Lithium Balance.

So it appears Soren Ecklund's public pronouncement of an adapter cord being the cause of the fire on the Oslo Ferry was a bare faced lie to cover his embarrasment, and he KNEW FULL WELL the real cause of the fire was the REAP Systems BMS. He already has plans to replace them, and to TRY to preserve life and limb on this world tour vehicle, he's remotely programmed it to cut the charge current in half - unnecessarily DOUBLING the charge times for this poor couple's journey.

The irony of course is that the Brusas, well able to charge this system at over 20 amperes, would pose no fire hazard at all if they could just put them in automatic mode, which Herr Ecklund could easily do by satellite if he had a clue.

Splendidly poor behaviour by a conversion shop on all fronts and I might as well publicly decry it as a sterling example of cowardice in the face of very nearly nothing.

But the visit with this lovely couple was very uplifting and we had a great time. They joined us at the house Sunday evening for dinner of Beef Stew which my wife actually does extremely well.

We also received 50 of the CALB LiFePo4 180AH cells this week and 30 of the 100AH cells from their new CALIB facility in Pomona California. Notably, we ordered those on December 23, received them on January 6, didn't have to do squat about shipping/import duties although of course we ultimately paid for it, and paid on American Express. Keegan Han has been a delight to work with and we can recommend this battery source quite enthusiastically. You can pay easily with recoverable funds in the event of mishap/nondelivery, we got them in two weeks, and they are direct from manufacturer.

It also provided us an opportunity to compare a brand new cell fresh from China to our existing stock of 180AH cells which we received in October 2009 - some 15 months ago. Voltage of the new cells: 3.300. ALL of them are at exactly 3.300. Voltage on the cells that have been stored for 15 months: 3.298. ALL were 3.298 or 3.297. The myth of self discharge and all you need to do to care for these cells in storage: BUSTED. If you see someone online going on about charging and equalizing and so forth to preserve these cells: note as moron and disregard all future postings.

Brain and Matt have been struggling to make my dreams of Porsche Speedster Belly/Battery/Box come true. They won. It projects a scant 1.75 inches below the existing frame of the car, is quite secure, holds 11 cells, and is essentially invisible. I had plans for the cables to and from: unnecessary. Our wiring tunnel bisects the box - an obvious fact I had mislaid mentally of course.

So we are at 171 volts and 51 cells on the Speedster rebuild. I haven't mentioned it to Matt and Brain yet, but I have an idea about mounting the Soliton1 on top of the motor, freeing the rear shelf for another six cells, which would bring us to 192volts and a pack size of 34,560 wH. We would undoubtedly have a shot at a 150 mile drive on a single charge.

AND about 175kw of power to the motor, including sag, for 234 HP to the wheels. This is OVER THREE TIMES the power we recorded on the dynomometer in this car previously. It provided exhilarating acceleration and top speed then, so I'm not sure what the point is. Perhaps will take on Tesla at Monte Carlo in April????

We also mounted a J1772 connector in the car, our two rear battery boxes holding 11 cells each, and are just generally making famous progress on this rebuild. It will be grossly overpowered and a bit overweight to my tastes, but with a very different level of range for bragging rights.
Really more of a can we instead of a should we, I do fear.

We've also started a new Texaco Fire Chief charging station for the 601 Morgan Oak facility, with J1772-2010 plug in this case. We're going to have a couple of Kilovac contactors for the phases, a 12v power supply to control them, a NEMA 14-50 in addition, a power meter, etc. It should be good for giggles - a better thought when drinking heavily of course.

But that's what we like to do - get liquored up, play with high voltage, and then drive our cars. Not PC, but whatever.

Jack Rickard

Sunday, January 2, 2011

Looking for an Interesting Visit

We've been in contact with a somewhat interesting pair who are on a worldwide tour in an electric car.

Hjalte Tin and Nina Rasmussen left Compenhagen on June 25 on a 41,000 mile trek in a Nissan QashQuai converted to electric drive by AFUTURE Electric Vehicles They are driving around the planet on a year long odyssey and plugging in where they might.

This morning, they are at a campground in Poplar Bluff and advise us they could use a charge and a place to stay. So we expect them this afternoon and we'll have them join us for dinner.

The AFUTURE Nissan Qashqai is an SUV converted to elecric with a range of up to 250 km. Recall that this was the car that burned up the ferry in Norway. I hope it doesn't do in our shop. BMS all over the place driving two helpless Brusa chargers. It will be interesting to have a look at the configuration.

The couple is detailing their tour on a web site called MotoMundo

They are on their way from Dallas to St. Louis and someone from our own Gateway EV has arranged for their charging there. Then on to Detroit in time for the Detroit Auto show.

I rather gather that AFUTURE is funding all this to demonstrate their cars. They seem to be trying to raise as much media and press attention as possible and doing a fair job of it. I would as soon paddle a canoe around the world but it is interesting that they are doing it I suppose.

In any event, we look forward to an interesting visit. We'll let you know what we find. Maybe we can shoot a segment or something for next weeks' show.

Jack Rickard

Saturday, January 1, 2011

J1772-2009 Charging for Your EV

This is our last show. Actually our last show for 2010. We'll meet this weekend to decide what to do about 2011.

In this episode we continue the fascinating work of building battery boxes for the Speedster. While not an exciting topic, in converting almost any car to electric drive, most new builders are surprised to learn that making the car run on battery power is almost trivial. But 50% of the work centers on placing batteries and building structures to hold them.

The other 50%? Almost entirely environmental. Heat. Cooling. Lighting.

Mounting a controller and motor and getting it to run - you can nearly enough phone it in.

So to avoid making this episode a total yawnfest, we've decided to tackle a probably useful element we promised almost a year ago when we did our episode on the new J1772-2009 standard/plugs/connectors. That is, how to wire your car to actually do J1772 charging.

With the Chevy Volt and the Nissan Leaf finally shipping....er.... more or less shipping....we think you'll finally begin to see some J1772 charging stations begin to appear.

We build our cars to charge quite automatically from either 120VAC single phase or 240vac two phase power. And we almost always use a NEMA 5-15 recessed male connector on the car so that we can universally connect the car anywhere and to virtually any ordinary household extension cable - albeit you do generally want to use a heavy one.

This is mildly illegal in most respects. First, NEMA5-15 is entirely meant for 120vac operation at 15 amperes or less. In practice, we charge the Speedsters at about 25 amperes and 240vac. We simply make up a cord or "adapter" with a NEMA L6-30 or NEMA 14-50 connector on one end, and the usual NEMA 5-15 female on the other.

This is not good frankly. But it is very convenient. If you go to gramma's house, you can still plug in and get a toke on her good juice, even though there's no charge station there. We buy the best cables and connectors we can find, and while they get warm, so far no incidents.

But it isn't really kosher. And soon it will even be a disadvantage. As J1772 charge stations start to appear, at the least in the garages of friends with Nissan Leaf or Chevy Volts, and potentially public charge stations as well, we would be left out of the party.

For a "standard" I am perplexed by how "closed" all this is. The greed is palpable as the charge station vendors strive to "protect" their ground so they get prices as high as $5000 for what is little more than an AC receptacle. The "standard" does provide some safety features to keep the cord dead until it is connected (which I put in our Texaco Fire Chief charge station nearly two years ago). And the plug and connector ARE kind of quality. But it is amazing how difficult it is to find the basic connector hardware - nearly a year after adoption.

Indeed, SAE itself has been piggishly greedy - you can't find an SAE J1772-2009 PDF online anywhere. They are "selling it" on their web site with digital rights management and dire warnings about copyright infringement. Copyright infringement on a public standards body? This is just inexcusable.

In any event, there IS a conspiracy to control these charging stations and maintain high profit margins on the charge stations. The connectors are a couple of hundred dollars each depending on how long and what kind of cable. None of it warrants $5000 or even $2500, I don't care how many approvals it carries. And the whole concept of having a licensed electrician and permit to install it is laughable. Some of them actually just plug into an existing NEMA receptacle just as we do with our cords. In any event, adding a 60amp or 100 amp circuit breaker to your panel, and running a piece of AWG10 orange 3-wire plus ground to a convenient place in your garage, is work ANYONE can do AND SAFELY.

There are numerous home wiring books at the local hardware store, the wire, the NEMA receptacles, and the circuit breakers. And in almost all localities you are entirely legal to do such wiring ON YOUR OWN RESIDENCE without license or permit.

But back to the car. If you buy a J1772-2009 inlet connector and mount it on your car, and connect the two phase pins and the ground pin to your charger, you won't ever be able to charge your car at any of these charging stations.

This is because the car has to provide some "signals" to the Electric Vehicle Support Equipment (EVSE) aka Charge Station to turn it on. These mysterious "signals" are actually trivial They are actually a single diode, two resistors, and a switch. Here's the diagram:

Click on the diagram to blow it up.

For those who find wiring two resistors, a diode, and a switch, a challenge, you can buy ready made adapters from Rush Dougherty at http://www.TucsonEV.com. He has the connectors you'll need anyway, including a nice plug with a full 8 meter (25 foot) long cord. And he has made a little adapter box with switch and light as well.

With our wiring, or Rush's box, you simply connect the J1772 plug to your car, and then turn on the switch. This drops the sense voltage to 6 volts in the EVSE and triggers the unit to turn on the 240vac power.

When you're done charging, you hit the switch to shut OFF the power, THEN remove the cord. Very much a safety improvement over our current methods.

And it will allow you to configure YOUR electric vehicle to use the new charge stations wherever you find them.

In a future video, we'll go into some detail about how you can set up a J1772 charging station of your own, for HUNDREDS of dollars instead of thousands. We're just going to add a cord to our Texaco pump, and switch on the power manually after you connect the cord as we do now.

But another viewer, David Kerzel of Modular EV Power LLC is working on a printed circuit board control circuit for a home charge station with all the bells and whistles of J1772-2009. We'll follow his progress and hopefully have something to show in a future episode for you to build your own charge station at much less cost. His design will use all UL listed components in the contactor and connectors and so forth, and he intends to include instructions on how to get it permitted and inspected and approved if that be your hearts desire.

See you next year.

Jack Rickard