The sad story of the batteries

Battery boxes came next, and so did may first set back. The TIG welder decided to pack it in, and the repair bill was just less than a new unit. Funny how they make that workout. The intent was to build aluminum boxes that would seal the batteries from the elements and provide a level of psychical protection.
The first design was for 100 CALB CA60 batteries. I went ahead and ordered 6 batteries to use as models to size the boxes. As soon as I finished construction of the last of the 7 boxes, I tried to placed the order for the remaning batteries only to find out that they where nolonger available. The next larger size however was still being manufactured. And here is where it went south. Each dimension of the larger battery was different the CA60 battery the boxes had been designed for. As hard as I tried, cut an little here, add a little there, it was no use. New boxes would be needed to house the batteries.

So this time I purchased all the batteries that would to be used in one order up front. CALB CA100 batteries this time around. The capacity of each cell had increased by 40%, but so had the size. As the car has limited space, and I am unwilling to give up cargo space, the number of batteries was reduced from the original plan of 100 cell, to 75 cell. Range will actually increase, as the pack kWh is has increased, but sad to say acceleration performance will suffer a little as the weight has also increased.

Building the box lip for a box that is to be fitted where the gas tank was.

The floor of the trunk was opened up and prepared for a pair of boxes. A single box would have been ideal, but a structural brace for the rear bumper was in the middle of the space.

Removing the engine

The engine is actually very cool, great engineering and a wonder to look at, but it had to go.

After engine, gas tank, exhaust, and last of other gas engine support stuff was removed, the cleaning started. Gas engines messy!

Completely forgot, but it does live on!

So, since the last post what has happened?
The conversion was put on hold for a year to allow the car to be used as a normal car. In the mean time plans were formulated, designs were made, ideas there dreamed up, and as time went on all was forgotten.

So before removing the engine I captured a lot of data from the CANBUS on the car. I though this would be helpful in the future in keeping the rest of the car happy without the engine installed, and to allow for the stock instrument cluster to be operated with spoofed messages. This is what I have so far.

BMW Z4 2003 PT-CanBus Messages

Not all message have been validated

Message label

0x153 (ASC1)

0x1F0 (DSC, ABS)

0x1F3

0x1F5 (LWS, Steering Angle)

0x280 (?)

0x316 (DME1, Digital Motor Electronics)

0x329 (DME2, Digital Motor Electronics)

0x501

0x545 (DME4, Digital Motor Electronics)

0x613(KOMBI, instrument)

0x615(KOMBI, instrument)

PT-CAN

DME – Digital Motor Electronics
DSC – Dynamic Stability Control

EPS – Electronic Power Steering

KOMBI – Instrument Cluster

LWS – Steering Angle Sensor

K-BUS

CID – Central Information Display

CVM – Convertible Top Module

EWS III – Electronic Immobilizer

GM 5 – General Module 5

HiFi – HiFi

IHKA – Automatic Climate Control

IHKS – Integrated Heating Control

IHS – Integrated Heating Control

LSZ – Light Switch Cluster

NAV – Navigation

PDC – Parking Distance Control

RADIO – Radio

RLS – Rain/Light Sensor

SM – Seat Module

SZM – Center Console Switch Cluster

TEL – Telephone

VM – Video Module

ARBID: 0x1F0 (ABS)
Individual wheel speeds:

-B0 Left front

-B1

-B2 Right front

-B3

-B4 rear

-B5

-B6 rear

-B7

Signal wheel 1: startbit 0, bit length 12, Intel LSB, unsigned, gain 1/16 (0.0625) (byte0 + next 4 bits of Byte1)
Signal wheel 2: startbit 16, bit length 12, Intel LSB, unsigned, gain 1/16 (0.0625) (byte2 + next 4 bits of byte3)
Signal wheel 3: startbit 32, bit length 12, Intel LSB, unsigned, gain 1/16 (0.0625)
Signal wheel 4: startbit 48, bit length 12, Intel LSB, unsigned, gain 1/16 (0.0625)

The above translated to .xls syntax.
Wheel speed 1: (HEX2DEC(B0)+BIN2DEC(RIGHT(HEX2BIN(B1),3 maybe this 3 should be a 1))*256)/16*0.621
Wheel speed 2: (HEX2DEC(B2)+BIN2DEC(RIGHT(HEX2BIN(B3),3))*256)/16*0.621
Wheel speed 3: (HEX2DEC(B4)+BIN2DEC(RIGHT(HEX2BIN(B5),3))*256)/16*0.621
Wheel speed 4: (HEX2DEC(B6)+BIN2DEC(RIGHT(HEX2BIN(B7),3))*256)/16*0.621

ARBID: 0x153 (ASC1)
-B0

bit 0; 0x01 = tire pressure set is off

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08

bit 4; 0x10 = Brake Pedal pushed

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80

-B1

bit 0; 0x01 = tire pressure set is off

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08 = LSB speed, bit 0

bit 4; 0x10 = LSB speed, bit 1

bit 5; 0x20 = LSB speed, bit 2

bit 6; 0x40 = LSB speed, bit 3

bit 7; 0x80 = LSB speed, bit 4

-B2 Speed MSB: start bit 0, bit length 8; MPH = (LSB+MSB)/16*0.621371
-B3
-B4
-B5
-B6
-B7

bit ? tire pressure warning light on red

DTC on

Speed MPH

=(BIN2DEC(LEFT(TEXT(HEX2BIN(B1),"00000000"),5))+(HEX2DEC(B2)*32))/16*0.621371

ARBID: 0x1F5 (steering Angle/Velocity Sensor)
-B0

            bit 0; 0x01 steering angle bit 4

bit 1; 0x02 steering angle bit 5

bit 2; 0x04 steering angle bit 6

bit 3; 0x08 steering angle bit 7

bit 4; 0x10 steering angle bit 0

bit 5; 0x20 steering angle bit 1

bit 6; 0x40 steering angle bit 2

bit 7; 0x80 steering angle bit 3

-B1

bit 0; 0x01 steering angle bit 8

bit 1; 0x02 steering angle bit 9

bit 2; 0x04 steering angle bit 10

bit 3; 0x08 steering angle bit 11

bit 4; 0x10 steering angle bit 12

bit 5; 0x20 steering angle bit 13

bit 6; 0x40 steering angle bit 14

bit 7; 0x80 sign bit steering angle

-B2

bit 0; 0x01 steering velocity bit 4

bit 1; 0x02 steering velocity bit 5

bit 2; 0x04 steering velocity bit 6

bit 3; 0x08 steering velocity bit 7

bit 4; 0x10 steering velocity bit 0

bit 5; 0x20 steering velocity bit 1

bit 6; 0x40 steering velocity bit 2

bit 7; 0x80 steering velocity bit 3

-B3

bit 0; 0x01 steering velocity bit 8

bit 1; 0x02 steering velocity bit 9

bit 2; 0x04 steering velocity bit 10

bit 3; 0x08 steering velocity bit 11

bit 4; 0x10 steering velocity bit 12

bit 5; 0x20 steering velocity bit 13

bit 6; 0x40 steering velocity bit 14

bit 7; 0x80 sign bit steering velocity

-B4

-B5

-B6

-B7

ARBID: 0x316 (DME1) 
-B0

Bit 0; 0x01= Key on

Bit 1; 0x02

Bit 2; 0x04 = Ignition on, DME ready

Bit 3; 0x08

Bit 4; 0x10 = starter on

Bit 5; 0x20

Bit 6; 0x40 = AC Clutch engaged

Bit 7; 0x80

-B1 current throttle opening
-B2 RPM LSB
-B3 RPM MSB [RPM=(hex2dec("byte3"&"byte2"))/6.4]
-B4 Desired throttle opening
-B5
-B6
-B7

ARBID: 0x329 (DME2)
-B0
-B1 coolant temperature in C = .75 * (hex2dec(byte01) - 48.373)
-B2
-B3

bit 0; 0x01 = clutch pressed

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08 may appear after 30 seconds of engine operation

bit 4; 0x10 may appear after engine start

bit 5; 0x20 = Cruise control + button press, momentary

bit 6; 0x40 = Cruise control - button press, momentary

bit 7; 0x80 = Cruise control on/off, momentary
-B4 Cruse control throttle command
-B5 Throttle position (00-FE).
-B6

bit 0; 0x01 = Brake pedal depressed

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08 = Cruse Control On

bit 4; 0x10 = Cruse Control Resume

bit 5; 0x20 = Cruse Control Being Activated

bit 6; 0x40

bit 7; 0x80
-B7

ARBID: 0x545 (DME4), 
-B0

bit 0; 0x01

bit 1; 0x02 = Service Engine Soon light on

bit 2; 0x04

bit 3; 0x08

bit 4; 0x10 = EML light on

bit 5; 0x20

bit 6; 0x40 = Check Gas Cap light on

bit 7; 0x80

-B1 Fuel consumption LSB
-B2 Fuel consumption MSB. Values just cycle from 0 to FFFF then start over at zero. Fuel consumption is the rate of change.
-B3

bit 0; 0x01

bit 1; 0x02 = Yellow Oil Level light set is off

bit 2; 0x04

bit 3; 0x08 = Coolant Temperature Alarm light on

bit 4; 0x10

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80

-B4 Oil temperature in C = .75 * (hex2dec(byte04) - 48.373), formula not correct maybe hex2dec(byte4)-48.373
-B5

bit 0; 0x01 = Oil pressure light set is off

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08 = A/C switch

bit 4; 0x10 = Battery light set is off

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80

-B6

-B7

bit 0; 0x01

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08

bit 4; 0x10

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80 = Oil Pressure Light on

ARBID: 0x613

also sent from the instrument cluster if 0x615 is acknowledged.
-B0 Odometer LSB
-B1 Odometer MSB [Convert from Hex to Decimal. Multiply by 10 and that is Odometer in Km], only send data every 10 Km
-B2 is fuel level. Full being hex 39 Fuel light comes on at hex 8. Then values jump to hex 87 (or so) and then go down to hex 80 being empty.
-B3
-B4

-B5

-B6

-B7

ARBID: 0x615 sent from the instrument cluster. 

-B0

bit 0; 0x01

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08

bit 4; 0x10

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80 = A/C switch, could also be byte 1 bit 5
-B1

bit 0; 0x01

bit 1; 0x02

bit 2; 0x04 = headlight parking lights on

bit 3; 0x08

bit 4; 0x10 = AC fan speed

bit 5; 0x20 = AC fan speed

bit 6; 0x40= AC fan speed

bit 7; 0x80 = AC fan speed

-B2
-B3

bit 0; 0x01

bit 1; 0x02

bit 2; 0x04

bit 3; 0x08 = OAT, Convert from Hex to Decimal. Temperature in C. If decimal value greater than 128, then subtract 128 to get temperatures below 0C.

Examples

hex 30 = 48 degrees C

hex 0D = 13 degrees C

hex 84 = -4 degrees C

bit 4; 0x10

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80 A/C on
-B4

bit 0; 0x01 = Driver Door open

bit 1; 0x02 = handbrake engaged

bit 2; 0x04

bit 3; 0x08

bit 4; 0x10

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80
-B5

bit 0; 0x01

bit 1; 0x02 = Left turn Signal

bit 2; 0x04 = Right turn signal

bit 3; 0x08

bit 4; 0x10

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80

-B6
-B7

bit 0; 0x01

bit 1; 0x02 = key information (if 1, key information available)

bit 2; 0x04 = key number (00 = Key 1, 01 = Key 2, 10 = Key 3, 11 = Key 4)

bit 3; 0x08

bit 4; 0x10

bit 5; 0x20

bit 6; 0x40

bit 7; 0x80

Why?

So why convert a car that has a perfectly good gas engine to electric power? Well I enjoy building things, and the more the project has to do with engineering the more enjoyable it seems to be for me. I have in the past built an airplane, a number of racecars and various remodel project around the house. My day job has me build and develop all kinds of thing, so the idea of an electric car seemed to be a perfect project. Not paying a oil company for gasoline is a bonus.

So choosing a car. I started thinking about the type of car I would like to drive. No sense in completing this type of project only to have a car that is not enjoyable to drive. Two seat convertible sports cars it is then.

The list of potential candidates included;
Porsche Boxster
Mazda Miata
Honda S2000
Audi TT
Pontiac Solstice
Mini
BMW Z4
Mercedes SLK
Corvette
Porsche 911
and a few others...

After a number of test drives and looking at specification, including the weight of the car, room for batteries, the systems in the car and so on, I choose the BMW Z4. During the winter of 2013 a not so fine example come on the market. It was one of the coldest day we had in a long time and I when to look at the car. December seemed like a to time to be a buyer of a convertible. It was at a price that would be very hard to bet. So I returned home with the car to start the project. The fantastic deal turned into only being a reasonable deal as there where many, many items broken on the car, including;

• Passenger window switch
• Replaced steering wheel, gear shift knob, and hand brake leather
• Repaired driver door interior card
• Recovered seats and added seat heaters
• Replaced third brake light lens
• Replace both head lights
• Replaced front bumper
• Replace left front inner fender well
• Replace under engine tray
• Replaced oil pressure switch
• Repaired hood latch
• Replaced convertible top hydraulic motor
• Repaired electrical limit switch wiring for convertible top
• Replaced water pump and thermostat
• Added aux input to stereo
• Outside air temperature sensor

Well I suppose that the cars is fairly well shaken out now and the project can get underway.

So what about the plan. By the time I got the car working it was well into summer here and it didn't make sense to but the car in the garage during the nice driving weather while the conversion took place, so the plan to convert electric power was put on hold until the fall (2014).

But the project continues. I started finding sources for all the items that I would need. I settled on a conversion that will use a three phase AC motor, as opposed to a DC motor. The AC motor seems to be the choice of the manufactures that are being to make electric cars. So it would be goo enough for me too. It also offers less maintenance and more control options that my perception that the DC motors have available.

The electric motor was purchased from www.evtv.me . It is a AC three phase unit manufactured by Seimens. Originally made for the Azure Dynamic Ford Transit Connect van. Azure Dynamic took the van from Ford without a gasoline engine and install this electric motor. But as sales did not met expectations Azure Dynamics went bankrupt.  The is where EVTV stepped in purchase the remaining inventory.