Video of driving 3E - Electric Honda HR-V

I have recently posted a video of driving my EV on YouTube. Put some music on it from local electronic music band "Mind Engineers" . Enjoy.



I am still working to make the car street legal. We had preliminary inspection with transportation experts and agreed on several main points to be done before final certification:
- Emergency disconnect "Red Button"
- Comparing information of cabin air heater element, brake booster and power steering between original components and new replacements
- Protection cover of power cables underneath the car from physical damage (stones, etc.)
- Marking on high voltage cables with with bright colour (orange or similar)
- Informing driver by sound if he's leaving a drive-active car
- Safety procedures modification for starting and running the car in accordance to EN-1987 standards
- Check the charging connector for compliance to EN IEC-62196
- Preparation of technical documentation of the modification
- Some other smaller ones

As I am the first one to go through such certification in my country it is a bit of learning curve for all of us. But I work with people who have good willing approach and we are gradually solving the problems in our way.
So I am quite busy to finalise these things and finaly get my car certified. I will update the blog with new posts of modifications as I go.

3E - Ecologic, Economic, Electric; electric Honda HR-V in exhibition

I had 2 busy weeks lately: first - preparation for showing the car on exhibition BaltTechnika 2010, second - participation in exhibition itself. My friend Marius, professional designer, has prepared the design for the car and materials for exhibition. During that the new name for this car has developed - 3E - Ecologic, Economic, Electric which has become a logo of this car. So my working project name "HR-EV" is now 3E.
New web site has started http://www.emobilis.lt/ for the car and activity which is just basic info about the car and the controller for it which is named EVMS - Electric Vehicle Management System. This is the name for the development the management system which previously called BCMS (until I included the motor controller in it as well). Info in lithuanian was put first.
The exhibition was quite successful with a lot of attention from visitors and media. This might inspire further development of the product or some more EV conversions in our country.
Here are some photos from Exhibition.

Some more photos of the car outside:

The photos of components arrangement inside:

And here are some pictures of EVMS (Controller, BMS, safety systems in one) touchscreen display which is implemented on Windows mobile device Ipaq hx4700.
The display graphical user interface software is flexible so it can be arranged in many different pages with different indicators on each page showing the parameters sent from main controller module. The layout, indicators, colours, graphics can be adjusted to liking and match the interior of the car.
Here is the Main page showing battery voltage, current, power, energy, momentary and average consumption, distance traveled today and estimated distance left.

Here is the battery cells status screen showing voltage, temperature and balancing voltage of each cell plus average and total voltage of all cells.

Here is the consumption screen showing battery charge, estimated distance left, distance, energy consumption of this trip and today plus average and momentary consumption.

Here is the screen voltages. It shows voltage, current and power of main battery, motor and 12V battery plus position of accelerator pedal at the bottom.

This Charging screen shows charging stage. It shows voltage, current and power set for charger and actual. It also shows cells minimum, average and maximum voltages. Two buttons at the bottom allow you to select the charging rate: slow for 220V/10A socket and fast for 220V/16A socket.

Here is Temperatures screen which shows temperatures of controller (IGBTs power stage), motor, battery minimum and maximum, interior and exterior.

And lastly the main menu which allows to select you the information page you want. The time on stock car clock is wrong as I forgot to set it right :). Note the small card at bottom left? That is the SD card which carries the screen configuration and recorded parameters log files. It records the files constantly producing one file per day.

Here is a short movie of display in action:

BMS Charging System Works!

I've been working intensively on my battery modules, BMS and charger to get them working together. So here's the story in sequence.

Fun with SMD microbs

My battery modules are made from small SMD components which I was never working with before. My previous electronics experience was with bigger sized and DIP components. So it was a new learning experience as I had with many other areas on this project - a lot of fun and satisfying moments.
On the first PCB I tried soldering these components with fine tip soldering iron which worked but I wanted to try a different way. Popular way which is also used in industry is placing components on the PCB with SMD soldering paste and treating it with heat at which solder melts. In serial manufacturing the boards are soldered by putting them in special owens.
Alternative for manual soldering is soldering with hot air. I used the hot air way although owen method should work too if had an owen. In the beginning I used some small Portasol gas soldering iron with air blower tip. It worked fine but I was not happy that I cannot control the temperature of the air and I can only have a rough estimate of this temperature. So I bought a hot air soldering station which I know I'll use in future too. Soldering the boards with it was an easy job. The tedious but not difficult part of the process was putting SMD paste and placing the components on the boards before blowing them with hot air. No problem with shaky hands and sight. Surprisingly to myself I found it easiest to do it without any magnifying goggles although I had them. My wife said I could be a surgeon. I guess I could :-)
Anyway I liked the process and I think it would have taken me notably longer with traditional components with all legs bending, sticking, soldering and crimping. It has taken me around 2-3 hours for soldering each board consisting of 10 battery modules. So manufacturing 45 modules was not bad at all.

Here is one batch of 10 manufactured boards

And here is a massive array of 36 as 9 others were already sitting on the cells as I was taking this photo :)

Battery module features

I'd like to list features that my designed battery modules have. It was quite long and iterative design and development process and I am happy I finished it. I like the final result.

Here is the list of battery module version 1 features:
- Balancing type: shunting current controlled by microcontroller
- Microcontroller: ATMEL ATtiny25V
- Operating voltage range: 2...5V
- Shunting resistance: 2.35Ohm 10 Watt
- Shunting current control: Pulse Width Modulation
- Communication protocol: custom serial protocol with LIN style sync frame
- Comm. bit rate: 2400bps (may work up to 9600bps or more)
- Comm. line: 1 wire going from module to module in chain - very easy and tidy installation
- Communication isolation: 1 Optocoupler on first module on the 2-wire input from BMS and 1 on the output to BMS over 2 wires back
- Measured parameters: Cell voltage, Cell temperature and shunting PWM value
- Voltage measurement accuracy: +/- 0.01V
- Temperature measurement accuracy: +/- 5C
- Parameter read commands: Read Voltages from all cells, Read Voltage from specific cell, Read Temperatures from all cells, Read Temperature from specific cell, Read PWM values from all cells, Read PWM value from specific cell
- Parameter write commands: Write balancing voltage to all cells, Write balancing voltage to specific cell, Write temperature calibration to all cells, Write temperature calibration to specific cell, Write max allowed temperature to all cells, Write max allowed temperature to specific cell, Write max allowed PWM to all cells, Write max allowed PWM to specific cell, Write cell IDs to all cells and read back the cell count.
- Automatic cell enumeration and counting via Write cell IDs command from BMS
- Automatic microcontroller sleep on idle (no comm from BMS for some time - like 60 seconds) to save power
- Automatic shunting current control via PWM to keep preset balancing voltage
- In-circuit microcontroller reprogamming capability via 1-wire debugWire interface
- LED indication of communication activity and PWM balancing mode
- Voltage spikes protection of the circuit supply, input and output signals
- Low cost due to carefully selected components and their count on each module

BCMS prototype board upgrade with CAN bus and Real-Time clock

I've added Microchip's MCP2515 CAN controller with Philips PCA82C260 CAN interface to be able to communicate with my new PFC 3kW charger from www.hztiecheng.com. My ATmega640 talks to MCP2515 over SPI interface. After few evenings of programming I made CAN bus work and my BCMS started talking to the charger. I can set charger voltage and current and enable charging. Charger returns me actual voltage and current plus the status with info such as overtemperature or battery fault flags. The charger model I have is named 144V/16A but as I learned it is capable of producing currents up to 20A.
Then I worked on programming the charging algorithm which would be suitable for my battery pack. It was done quite quickly to the point where I needed to have some reliable timekeeping. So I decided to finaly implement the real time clock (RTC) into my BCMS.
The RTC is made on Maxim DS1307 chip which is talking to my main processor over I2C interface. It has a Lithium backup button battery to keep the clock running when all the batteries are disconnected.

Here is the photo of the board with the processor off

And here is with the processor on

BMS charging demo

Finally here is a short movie demonstrating my BMS working with charger to charge and balance the battery pack


At this point I will be starting to put all electronics into control box, test it and then put into the car and connect to the motor. I'll put battery boxes with batteries in the back trunk first to have test drives and tune the system. Later I'll put them under car's belly as intended.

Batteries are home!

Long waiting is over - batteries arrived to where they belong :) I've received 45 TS-LFP90AHA batteries for my HR-EV after more than two months waiting. They've been sailing from Shenzhen in China to Hamburg in Germany and then to Klaipeda in Lithuania - a long trip.

I've taken them from warehouse after customs clearance in my trusty Subaru.

Shortly after I've opened the boxes to see what's inside. I found nicely printed manual and quality certificate. Quality certificate has lots of useful information in Chinese :) User nice manual was the same as pdf available from ThunderSky site. Beneath white cover I found a surprise - batteries :).

Here's a video shot from breathtaking moment :-D


The look at the battery itself.

All the batteries read voltage of 3.30V or 3.31V - GOOD!

The road to the future :)

While I was waiting for the batteries I've been working a lot on BCMS prototype electronics and programming. Here's a brief update about the progress:
- RealTime OS launched on ATmega640
- Serial communications programming wired and programmed - talking to PC now
- Connected to battery modules (at bottom) via opto-coupled serial port and launched battery voltages reading for BMS operation. It ballances Lithium Polymer cells within 0.02V of each other.
- Wired and programmed MLX90215 sensor (small board assembled on the left) so I can measure current of up to 10 Amps to test the concept. The finished sensor will be able to measure up to 700A from batteries and to the motor.
- Wired a contactor control circuit (simple IRL3705 MOSFET switch) and programmed its control
- Wired and programmed 12V line voltage measurement using mega's ADC
- Wired and programmed DS18B20 sensors for BCMS, Controller, Motor, Outside, Inside and Batteries temperature sensing.
- Started wiring a slot for SD/MMC card where the HR-EV's parameters log would be stored
- Some small stuff...


There are many things left to do on electronics until I start the first test of the car:
- Finalize battery module schematics, programming and PCB design, try final prototype on real battery and then order parts and PCBs
- Make schematics/wiring and programming of opto-isolated battery voltage measurement
- Make motor RPM sensor using MLX90217, wire it and program RPM calculation
- Wire gearbox speed sensor and program the speed calculation
- Make throttle sensing and control schematic and programming
- Wire digital inputs like key switch, charger on, throttle idle, gearbox neutral etc.
- Program the safety and control. Basically it should shut off main contactor if any important parameter goes critically off.

Well, there is much much more. One thing - I still haven't got the charger. In the beginning I thought about Zivan NG3 but now I'm not so sure. Still have to decide... and order it.

Of course there are lots of mechanics works to do as well. I'll update as I progress.

Motor installed, HR-EV has made her first run!

The end of 2008 was really busy working on my HR-EV. I've reached one major milestone of the project! But let's go in sequence.
I picked up the shaft coupler disk and spacers from workshop where they've been thermally hardened.
I've marked the spots for two fixing nuts on motor's shaft and drilled two dimples on both sides where the coupler disk's fixing bolts would sit in.
Next we put adapter plate spacer disk on the motor and pressed on the shaft adapter disk onto Warp9's motor shaft. We used 20-ton garage press to press it on. It was going stiffly but smoothly - it wouldn't go anywhere. Below Gytis is happy with the result :)

Here is the closer view

Then I assembled the shaft coupler on it and locked the coupler disk on motor's shaft with two hex fixing bolts. I used thread locking glue to make fixings bear the vibration.

And then I bolted on the gearbox adapter plate using the imperial/metric threaded studs and secured everything with thread locking glue.

A closer view

Then I've put the gearbox on and secured it with the bolts. The shafts and alignment rings fit like a glove without a fight. Phew, what a relief ... :)

Then my photo camera battery died and I used the video camera to shoot the further process. On this occasion I've compiled a small video from latest material together with some old video footage from the progress on HR-EV. If they say a picture is worth a thousand words then video should be worth a million. This is my first published video for this project. Have fun :)


In short later that night I've installed motor and gearbox in Honda and did the trial again using battery charger.
Then next day I took 100Ah 12V lead acid deep cycle battery and put it in HR-EV. I've wired it to motor via contactor relay. The relay is activated with simple pushbutton switch pressed by the driver :) No controller yet. This allowed to make the first ride in HR-EV and it will be used to drive the car into garage on its own power when needed. This is because Gytis' garage has to earn money working on other customers cars while HR-EV is an after-work hobby activity slotting in when car lift is free, etc.
And of course this allowed to have some taste of EV grin :)
This is quite symbolic as it was done on the last day of 2008 and I have had really nice feeling meeting the new year.

Happy New 2009 Year to All!