EVCCON 2015 - Day 3

Session: Arduino CAN_DUE Library Advanced Techniques - Collin Kidder

Collin's CAN_DUE library brings advanced CANbus handling functionality to the Arduino world.  All code written by the extended EVTV coding teams uses CAN_DUE.

The hardware has 8 "mailboxes" which can be used to send or receive data on the CANbus, and everything is interrupt driven using callback function registration, which is far more efficient than polling, although polling is available.

There are two independent CANbuses, you can run both independently at the same time.

To initialize a CANbus, use the begin() method call with the desired bus speed and the hardware pin connected to the bus.  You can also later adjust the bus speed.

Filtering of incoming messages is set using a number of method calls where you specify which message frame ids you're interested in.

The main data structure is called CAN_FRAME and contains all of the critical information about each incoming and outgoing message, including the message id and data.  A union data structure allows you to access the data by low and high int, four shorts or 8 bytes without casting and converting each time.

Sending data is done with the sendFrame() method call, passing in your formatted CAN_FRAME.

One thing to remember is that although Arduino sketches look like C++ code, it's not a full implementation.  For instance, you cannot use a C++ class' method as a callback target.

Very powerful CANbus apps can be written in very few lines of code thanks to this library.  Great work Collin!

News Flash: Charge.net.nz has announced that BMW wants to sponsor their fast charging network effort in New Zealand with €200,000!

Session: CHAdeMO Fast Charging Standard – Collin Kidder and Jack Rickard

Jack has decided to build a car-side CHAdeMO charging solution.  This can be fitted into any electric vehicle to provide fast-charging, slashing charging time and enabling long-distance driving by reducing range anxiety and objections over long charging times.

The expensive part of the kit is the CHAdeMO connector at about $900.  All that's needed in addition is two high-voltage, high-current contactors, a small automotive relay and the EVTV-developed JLD505 meter & CANbus controller, but this may be replaced by a GEVCU in the future.

The CHAdeMO specification lists output at 50V - 500V DC, but real-world testing shows some manufacturers are cheating on the spec by ignoring lower voltages in the range.  Usable range is about 250V - 500V which excludes most DC-motor enabled cars.  While this works for so-far every OEM manufactured car, a lot of home conversions will not be able to benefit from this.

Tesla appears to use the CHAdeMO protocol under the covers, running on 33.3kbps single wire CANbus.  They read the vehicle VIN number and only function when the VIN is validated against known Tesla vehicles.

Contrary to what most people would think, the car is in full control of the charging process.  The car requests initiation of charge, requests current and voltage levels and later requests termination of charge.  The car requests gradual increases and decreases in current at the start and end of the charge cycle.  The charger is supposed to follow these commands.

EVTV testing has shown a variety of behaviours from different manufacturers.  I wish that the CHAdeMO standards body would enforce all aspects of the spec.  At this relatively initial point in the rollout of CHAdeMO around the world, now is the time to get all devices in full compliance.  What we need is a Networld/Interop of chargers and cars.  Idaho National Labs has apparently hosted something like this and reported that everything is just fine, but we know that's not true.  From this paper from a couple of months ago it appears they only tested J1772 devices, not CHAdeMO.

Here is the list of Certified CHAdeMO chargers.  Note Blink is not on the list.

Session: Recording Battery Voltages into Excel using Voice Recognition - Al Gadja

Every Windows PC has speech recognition built in.  Control Panel -> Sound -> Recording -> Configure.  You can train the computer to better understand your voice.

He uses a $15-$20 headset with a microphone boom.  Speak naturally and let the computer lag a bit behind.

As he goes down the battery pack, he speaks the voltages followed by the word "newline".
Eg. 3.125 newline 3.129 newline 3.1209 newline.

Al has an Excel spreadsheet template that applies colors to different cell voltages and graphs charged, discharged and difference values for each cell in the pack.  This allows you to easily visualize the state of health of each battery, with the outliers clearly indicated in the graphs.

Session: Ladder Logic and Vehicle PLC Controllers - Al Gadja

PLCs are Programmable Logic Controllers, long used in industry to control any electrical or mechanical device.  Ladder Logic is a visual representation of the flow of control of the program.  You read the logic left to right.  You can place different device types in the ladder, set preferences and then draw lines.  When complete, you can run it in Simulation mode to see how the logic will work when installed into a PLC and run in the target device.

Everything in his Dodge Brothers truck is controlled through the PLC - nothing is directly wired.  It's from the Crouzet company and cost about $575 for the PLC, relay board and power supply.  It has 26 digital input ports and 26 replay output ports rated at 8A and 250V.

Session: Azure Dynamics eTransit Connect/heaters/AC/CAN - Byron Izbenhaard


Byron bought this van, has done two road trips and has put 2,000 miles on it.  He bought it for $6,500 from a Ford dealer who had no idea how to fix it, and had a lot of wrong ideas.  It turns out both battery pack interlocks were pulled out, and the Pre-Charge was not finishing.  Once he fixed that, the vehicle was running again.  One remaining issue was the heating unit was bad.  The coolant channels were full of goo and the electronics board was corroded.

He has changed to Evans Waterless coolant and a new heating unit from Eberspächer, taken from a Chevy Volt, about 1/3 the size of the original and about the same power level of 6.6 KW.  He made up a mounting bracket and attached it to the original heater location.  He made up a new hose set with transitions to the van's larger piping.

He then did a characterization of a new thermistor using an oven and determined the difference between the original one and the new one.  The solution was to add an 820 ohm resistor in series with the thermistor to get very close to the original profile.

The next challenge is to get an EVTV CANDue 2.0 board and software working to correctly drive the unit's heating capabilities.  After some trial and tribulation, the heater worked on the test bench.   Luckily the van already has 4 heater level CANbus messages in the diagnostic software, so he sniffed the bus with SavvyCAN to find the messages and used those to flash new firmware and drive the unit.  Byron mounted it in the van and it's working quite well.  The heating is controlled with the original dashboard controls, keeping the stock look and feel and avoiding the out-of-place looking switches that we sometimes find in EV conversions.

Session:  CANdo Battery Temperature Sensor - Nabil Henke and Ray Schaffler

There is a growing need for CANbus-based single-function devices.  After a problem with a thermal switch, Nabil and Ray have come up with a system that reads temperature and broadcasts the values across the CANbus.

It consists of a 2" x 2" x 1/2" white plastic module and up to 7 temperature sensor inputs.  It can also directly control Elcon / Chennic chargers.  Using a Bluetooth serial port configuration, you can install multiple modules in a car.  If any of the temperatures are too cold, it will inhibit the charger from starting.  Hooking up to a serial terminal port, you must set your charger target voltage and current in 1/10th of a volt, i.e. 124.5V = 1245.  It is fixed at 250kbs and Extended Addressing to match the Elcon charger but they're open to a firmware update to allow for baud rate changing.  They are available for $120 including 4 temperature sensors, and additional sensors cost $10 each.  Jack will have them in the evtv.me store when they can give him sufficient quantity.

Session:  Building The Little Lightn!ng Bike - Nabil Henke and Ray Schaffler

Last year they brought a 3 wheel bike called Banshee.  The students they mentor decided to do two 2-wheel bikes called Grease and Lightn!ng and things went downhill from there.  It's primary motor is an automotive alternator and uses a 48V / 10AH battery pack, built by spot-welding 18650 cells.  The cheap Kelly controller they used needs 3 Hall Effect sensors which were a pain to get working.  They used the 12-pole magnet ring from a CD-ROM drive.

Nabil and Ray are members of the Area 515 Maker Space in Des Moines, Iowa.

BBQ At Jack's House

We all headed down to Jack's house, overlooking the Mississippi river, for the first no-rain BBQ in EVCCON history.

EVCCON 2015 - Day 1

Session: Introduction - Jack Rickard

This smaller event is being held at the EVTV workshop, as was originally envisioned five years ago.  We have about 45 in attendance people this morning.  Even before the cancellation, registrations were only about half of EVCCON 2014.

There are big changes happening in the world of home electric conversions and the world of EVTV, Jack's trying to listen to the signals.  Cheap Nissan Leafs, the non-2016 Chevy Volt, staff turnover at EVTV, home conversion component suppliers going out of business, and many other factors, so he's moving away from specialty suppliers towards OEM components to use in your electric conversions.
If you use a Chevy Volt charger in your car, if it fails you just order another one from GM, it will be available for years and years.  We just need to know how to hook them up and control them.  We are still in the Innovation phase in the Standard Adoption Curve so things are chaotic.  The Early Adopter phase normally starts when the technology is at 2.5% penetration, we are still at only 0.7% electric vehicle penetration vs. Internal Combustion vehicles.



The auto industry seems to have settled on the use of CANbus for communication between electronic devices around the car and that standardization helps us.  The component suppliers don't generally publish the command structures for these devices so we have to reverse engineer them.

Jack thinks there is a lot of innovation left to be discovered, like urban transportation solutions.  You'll understand if you've ever tried to park in Boston.  Storm Sondors set up a kickstarter project for an electric bicycle for $500 and 55,000 people signed up.  Shipping was slightly delayed but the bikes are getting on the road.  Sondors set up another kickstarter with a $75,000 goal and now has over $1M in subscriptions.

We also have to teach the market about the benefits of electric transportation.

Tesla is a bit of an outlier as they have proven to be very innovative, beyond what most people could imagine and making it a reality.

Session: New Zealand Fast Charge Network - Steve West and Nick Smith

Steve launched Charge.net.nz to promote electric vehicle uptake in New Zealand.  Previously, he developed the DJ software called Serato.  After becoming fabulously wealthy, he now has a stable of a Nissan Leaf, a Tesla Roadster and two Tesla Model S.  Nick is a Mechanical Engineer and is in the final stages of a Mazda Miata conversion and has joined Steve in the Charge.net effort.

Steve and another Model S owner Carl decided to do a road trip from the far north to the far south of New Zealand and they quickly realized there is a big problem with the lack of EV charging in the spread-out nature of the country, which is hindering the uptake of EVs.  Steve came up with the idea of rolling out his own DC fast charging network of about 75 stations using Tritium chargers from Australia.  The goal is to have the chargers spaced about 80 km apart.

New Zealand is well-placed for EVs as the grid is about 80% renewable energy with a massive slice of hydro power, followed by geothermal and wind.  Solar is not strong there due to a lack of government incentives and low wholesale energy prices.  Many people have an easy location to park and charge their cars and the daily average distance driven is 20 miles.  This is good for a Nissan Leaf-like car, but bad for longer trips.  Hence the need for a strong fast-charge network.

The electricity market in New Zealand is broken into 4 parts: the generation companies, the grid transmission and distribution companies and the retailers.  In order to place a charger, Steve has to locate a willing partner with a strategic location and ample electric supply such as city councils, retailers, and even gas stations, come to an agreement with 4 companies to get an electricity contract, install the hardware and publicize the new station.

Every location in the country has access to 3-phase power and power is delivered at 230V at 10 amps so high-power charging is viable both at home and at charging stations.

Currently there are only 350 EVs in the country and not all of them have a DC charging port, so the business case for deploying charging stations is very poor.  It takes someone with long-term vision to make the decision to move forward with a plan, in anticipation of a strong growth curve of EVs.

Steve's pricing model is 25 cents/kwh and 25 cents/minute.  The electricity cost is about the same as a car owner would pay at home and the time charge encourages people to charge and leave quickly, making the charger available to more customers.

The Tritium Veefil charger runs at 50 KW with CHAdeMO and CCS Type 1 plugs.  It will charge a car to 80% by default and shut off or the user can ask to push to 95% full.

Customers register on the charge.net.nz web site with a credit card and can request an RFID tag.  Users plug into the charging port then log in by swiping the RFID tag, using the PlugShare mobile app or coming soon sending an SMS.

Steve has developed the backend software in an open and collaborative way so there is interoperability between other charging networks.

Session: An Introduction to CAN networks - Jack Rickard

Jack's order of 6 Brammo electric motorcycle motors arrived during lunch and one can be yours for the low, low price of $2000.  They're 40 kw peak and 25 kw continuous power, permanent magnet, water cooled and weigh 13 kg.  Sevcon offers a compatible controller that you'll have to chase down on your own.

Vector is the primary company in the world of CANbus and it is extremely expensive.  Jack's Arduino-based boards and Collin Kidder's software have nearly replicated the functionality of Vector's product.

Craig Smith did a session at DEFCON where he showed how to "hack" the CANbus in automobiles.

Bosch invented CAN in the 1980s as the solution to reduce the weight of the proliferation of wiring up many computerized devices in cars.

Jack then described the nature of the two-wire CANbus wiring, termination, device attachment and differential signaling.  He showed the standardized layout of a data packet and its sub-components.

CANbus can run at several speeds, most devices we've seen are 250 kbps or 500 kbps.  A lot of protocol overhead is handled in hardware for you by the transceiver, you as a programmer will only care about the message id and data payload.

Masks and filters are part of the protocol and are normally handled in hardware, allowing the programmer to only be notified about interesting message ids, which significantly reduces load on the software processor.  Two devices can start transmitting at the same time and the one with the lower message id wins and is allowed to control the bus.

It was mentioned that some car devices are using Ethernet for increased bandwidth needs but this is unlikely to completely replace CAN any time soon, due to the increases in wiring requirements back to a hub or router.

Session: Arduino Programming - Jack Rickard

Jack showed us the CANbus 8-button, LED-lit device that Collin found.  Each LED ring or backlight is individually controllable over CANbus.

He then discussed the customized Arduino-based controllers that Paulo and Jack have developed.  Jack decided on using the Arduino controller universe due to the open nature, the hundreds of plug-on shields and the programming tools and libraries available.  EVTV developed the "EVTV Due" board, adding isolation and protection on all input and output pins, CAN transceiver chips, an EEPROM for persistent storage and screw terminals for power and CANbus cables.

Jack then showed the Arduino programming tool, displaying a sketch program and described the various aspects of the source code.

Last, Jack showed the Arduino-compatible shield "CanDue 2.0", codenamed "Teodora" for Paulo's mother.  It contains CANBus transceivers for two CANbus buses, Single Wire CAN and has a MicroSD card for logging data.  This is useful if you already have an Arduino board in your design and want to add CANbus handling.  This is useful for capturing data from Tesla cars.

Session: Bearing Protection - Tom Brunka / Helwig Carbon

Tom is a speaker again this year, not for his company's DC motor brushes, but for a special brush that prevents corrosion of the bearings in a motor, called a shaft-grounding brush.

Any motor driven by high-frequency Pulse-Width-Modulation is susceptible.  Motors get current and voltage induced into the rotor.  This energy tries to go somewhere and it normally finds a path from the rotor, through the bearing and into the metal shell of the motor which is usually bolted to a grounded part of the vehicle.

This added brush acts as the least-resistant path to ground, sacrificing itself to save the bearings.  Testing has shown very little wear on this brush, about 1/1000" loss during 6 weeks of continuous running.  The brush on one motor in use for 10 years wore only about 1/2".  The brush material is 91% silver, so they are quite expensive.  Tom wouldn't commit to a price.

There is no need to "seat" the brush for full effectiveness.  The brushes can be mounted so they contact the shaft or the face of the rotor, depending on available space.  The "other" bearing will have very small residual current and voltage which can be completely removed by adding a brush on the other bearing also but this may be cost-prohibitive.

Tonight is hang-around-the-shop and dinner on our own.