Tischer's EV project

EV Parking only 2009-06-01 Solyndra installs six Electric Vehicle Parking stations

Top speed 2009-05-31 New speed record, 98.6 MPH! The car was still accelerating, it will easily break 100 MPH on flat ground now. My previous speed record of 87.3 mph was set using 300 amps, now I'm using 430 amps. The 90hp TDI Passat has a top speed of 112mph, my new goal is to beat it!

150% Torque 2009-05-23 (This was filmed on a closed section of road in a construction zone with no other cars around). Keep in mind, I don't have a clutch, this is pure low speed torque. I can do a pretty respectable burnout using 1st gear!

Trending software Here is a graph showing 0-60 in 16 seconds (6800rpm) only using 2nd gear. Torque limit is set to 160%. Current limit is set to 275A. DC Bus Voltage (0-400 VDC) Motor RPM x 20 (0-8000 RPM) Motor current (0-400 Amps/Phase) Throttle position (0-125% torque demand) My DC Ammeter is scaled -100A to +300A, and I can peg the needle in both directions! You can see the battery voltage starts at 320v, sags to 280v, then jumps to 360v during regen. Regen torque/current is programmatically limited to keep the battery voltage below 370v. I can increase the current from 275 to 295 (see chart) but it doesn't seem to increase acceleration 60mph = 6800 rpm in 2nd, 4400 in 3rd, 3300 in 4th.

Keypad Keypad for displaying tag values in the inverter.

Update 2009-04-28 There is an article about my car in Wired magazine. The inverter and battery performace has been very consistent. A 20 mile trip to work brings the battery from 328V to 308V (about 12.3 volts per cell). The recharge requires 10 amps for 3h 20min at 230 volts. I can charge twice as fast at 20 amps, but I'm afraid the batteries may not stay balanced charging so fast.

Update 2009-04-18 I got my inverter to run in Sensorless Vector mode! I can now control motor torque using the throttle pedal (commanding the car to accelerate). When my foot is off the throttle, the car can either coast, or decelerate using regenerative braking. The regen brake force can be set anywhere from 0-150% motor torque. Setting the regen torque to zero will cause the motor to freewheel, this is how I am able to shift gears. Once I've shifted into a new gear, I step on the throttle and the drive will apply the commanded torque seamlessly. Play high res video (30mb) or click the link for the low res video (10mb) Below is a picture of the programming environment for my inverter. enlarge

My 2001 VW Passat

2008-06-14 I bought a 2001 VW Passat with a siezed cam on Craigslist for $1800. It even has a full tank of gas! The trunk and engine compartment are nice and roomy, which is great for carrying lots of batteries. Curb weight is 3141 lbs and GVWR is 4322 lbs. The cast iron engine, automatic transmission, exhaust and gas tank should free up a good 600lbs leaving me 1800 lbs to work with. Drag (Cd) is a very low 0.27; this is less drag than a 2006 Corvette, 2006 Civic, and a 2001 Prius. Landy didn't struggle too bad towing it home, she even got 14 MPG!

2008-06-14 Heated leather seats and sun roof! Germans know a thing or two about making a beautiful interior.

2008-06-15 I got the front end off. I should have done this before stripping the engine, I didn't realize how easy the job would be. The engine and tranny are ready to pull. All the fluids have been drained, hoses disconnected; alternator, and power steering pump have been removed; entire exhaust system has been removed. Siphoned the gas tank down to 1/4 tank.

2008-06-21 I pulled the engine and transmission out as one piece. I used a chain hoist looped over a beam in the garage, making sure to reinforce the beam. This picture shows the two engine mounts, the two transmission mounts, and the 2 half shaft cv joints from the automatic transmission. This pic was taken after two hours of degreasing and pressure washing. The steering rack is tucked up where the heater core hoses go. This is the perfect place for it since the rack and the steering shaft are completely out of the way.

2008-07-11 I pulled out the entire engine wire harness and brain. There are some signals I will still need like alternator light, water level, throttle position... but those are easy to find on the cars wire harness. The only toughy right now is vehicle speed and engine rpm. I have the sensors but I suspect the computer is needed to make the gauges work. Hopefully I can emulate the signals, and if Im lucky, it is just an analog signal. The cableless throttle could still open and close with the gas pedal, pretty neat.

My Transmission

2008-06-22 Today I bought a 5 speed manual transmission for $600 bucks, ouch! Hopeuflly I can sell my Automatic tranny and break even. I also found out I need different axles and transmision mounts. The 5 speed manual is much smaller than the automatic, my existing half shafts are not long enough. The manual transmission will probably be left in 2nd gear the entire time. Once the electric motor is above 3500 rpm (max torque), the motor is constant horsepower up to 14000 rpm. In this constant horsepower range, there is only a slight advantage to selecting a higher gear. A higher gear would be quieter, and a lower gear would accelerate faster from a stop. Since I am limited to selecting two gears with the automatic shift linkage, I will wait till it is running to decide which is more useful; 1st and 2nd, or 2nd and 3rd.

My motor

2008-06-23 Received my motor today. It's a Siemens liquid cooled 42hp (90hp peak) 3 phase motor. Part No: 1PV5133-4WS20 W11 215 - 380 Volt, 282 Amp RMS (400 peak) 6 pole, 3 Phase AC Induction 67 Kw peak (33 Kw continuous) 3500 - 9700 (13,000 Max) RPM Weight: 178 lbs Used on the EV Ford Ranger

The backside. The motor shaft is hollow. The EV Ford Ranger had the left side axle shaft shaft running though this hollow motor shaft. The bearings in the motor have barely any friction, it spins so easy.

This is a picture of the motor with the front cover removed. Bottom right shows the water cooling channel.

Hall effect speed feedback sensor

The tone ring and hall effect sensors

Bearing upgrade

This pic shows the tools I used to replace the bearings in the motor. The old open style bearing is shown at the base of the rotor, the new sealed bearing is installed on the motor shaft. Why did I need to replace the bearings? The motor's bearings were lubricated and cooled with an oiling system integral with the planetary gear box on the Ford Ranger. Oil was supplied by flooding the hollow shaft, little holes in the shaft would drip oil into the bearing race. The bearings must be replaced with sealed, lubricated for life bearings, since I do not have an oiling system. The mechanical limit of the sealed bearing is 11,000 RPM. The thermal limit of the sealed bearing is 70 Deg C, this coresponds to a steady state speed of 17,000 RPM. The original planetary gear box with helical gears would put a large thrust load on the bearings. Since I now have a splined shaft, the bearings will have virtually zero thrust and zero radial loading, they should be fine without the need for external lubrication and cooling. Thanks to Russ Sciville from across the pond for noticing these bearings needed to upgraded.

Motor side of my coupling

After weeks of consideration, I determined the best way of interfacing with the motors output gear is with a taper lock. The taper lock is rated to handle 1160lbft of torque. I will likely attach an adapter to the face of the taperlock and bolt it on using the 9 allen bolts. here is a closeup of the motor shaft

Transmission side of the coupling

2008-06-22 This is the clutch disc inside the transmission. I plan to drill the 12-hole hole pattern from the rotoflex coupling into the clutch disc. The rigid coupler is easier to build than my rotoflex idea, but since there is no flex, everything needs to be very precise.

Completed coupler - transmission side

2008-10-18 The non-essential parts of the clutch disc were removed. 3 dowel pins locate the cltuch disc to the coupler.

Completed coupler - motor side

2008-10-18 3 dowel pins locate the taperlock fitting to the coupling. Six bolts clamp the assembly together.

Taking measurements to make Adapter Plate

The transmission and motor were mounted in a CNC. All dowel pins, shaft centerlines, and bolt holes were located using a dial indicator mounted to the spindle head.

Bell housing adapter and motor coupling

Three dowel pins were machined into the bell housing adapter and match the existing dowel pins on the transmisison. 7 bolts will attach the plate to the transmission. The adapter plate was made from 3/4" aluminum plate. 2 dowel pins, and a centering ring locate the plate to the centerline of the motor shaft. The plate is bolted to the motor using 14 counter bored allen bolts.

Bell housing adapter - Just Married

Another completed milestone!

Motor and Tranny installed Motor mount bar Motor mount bar. I built a second motor mount using solid rubber mounts, the liquid filled VW mounts ruptured and the secret goo came out. Snub mount on front of motor

Tischer's Motor Controller Upgrade

Inverter Brains

2008-07-21 The brains to my controller were pulled out of a 2 hp industrial inverter.

2008-07-19 This waveform replicates the top half of a sine wave. That's what the signal looks like going to the input of the original IGBT. The scope is connected between Vvpc and VP. The signal is about 14 Volts peak to peak. Here is another view showing multiple cycles.

2008-07-19 Here is the same waveform as above, but zoomed in. I also have the original IGBT disconnected. The signal is now 18.4 Volts peak to peak because there is no load. The frequency is about 3kHz.

My home made 90hp AC motor controller

This is my second working prototype. The hardware in my first prototype was 15 years old. Alot of improvements have been made over the years, and I am now using the latest hardware and firmware. On my maiden voyage, I immediately noticed the car felt much more refined, especially at low speed. There are twice as many electrical components in the new inverter. They enable me to control torque and speed (the old prototype only controlled speed). The yellow cables are connected to the battery though a precharge & safety circuit. The orange and white cables are connected to the motor. There are two black boxes on the white cables, these measure current to enable the inverter to run in a vector feedback mode. The grey cable (not shown) is connected to a circuit board I designed which converts the hall effect sensors in the Siemens motor into a quadrature encoder signal. This allows me to run Closed Loop Vector mode. The yellow keypad is removeable, I have a second one on the dash. It can display "torque feedback", "battery volts", "mph"... The bundle of wires connects to my throttle pedal, ignition switch, precharge contactors, and warning lights.

Encoder signal

I was able to build a signal conditioner to convert the output from the Siemens hall effect sensor into a 5v quadrature encoder signal readable by my motor controller.

Electric power steering pump

I found a 12 volt powered electric power steering pump on ebay, $300. It is from a Renault Kangoo. I had a custom hydraulic hose made to connect to my steering rack for about $70. I made a metal bracket insulated with 3/8" rubber to reduce vibration and noise. I plan to only have the pump run when the motor is below 4000 rpm, about 35 mph.

Battery Decision Matrix

Front battery pack

I decided to move more batteries to the front of the car. There are now 8 up front, and 12 in the rear, and 4 under the car where the gas tank was located. . I used rivenuts to attach my battery boxes to the frame. I also made brackets which bolt on to the shock tower mounts.

Gas tank battery pack

These four batteries fit where the gas tank used to be. I have ribs under the battery box which snugly fit my floor jack to help safely lift the pack.

This is where the gas tank was. I refrained from cutting or welding the chassis. I used rivenuts to attach the battery box to the boxed sections of the chassis. I can fit two more batteries where the muffler was.

Rear battery pack

Here are the rear mounted batteries, 12 in all. 6 fit in the spare tire well, 6 fit in the boot. Below white cover are 6 more batteries in the spare tire well.

Battery management

Picture of my battery management boards. One battery manager is connected to each battery. Once that battery is fully charged (14.4 volts), power is dumped into a resistor. This allows the rest of the batteries to completely charge, without overcharging the batteries which are already full. The array of 10 battery management boards shown above connects to the batteries under the car, and in the spare tire well. I'm using Wago terminal block plugs and recepticals to ensure the battery connections can't accidently short out when unplugged. I purchased the parts to build each regulator (about $6) from www.voltblocher.com

Brakes

Picture of my vacuum pump, tank and pressure switch.

Sweet crimper

This crimper has 6 Tons of crimping force.

Battery Cable

I used 4/0 gauge wire and crimp lugs. This should have a continuous rating of 380 amps, well above my 300 amp max motor rating. I'm glad I oversized my wires, especially when testing my prototype controller, there were a few instances my motor cables were warm.

Battery Charger

Manzantiz Micro PFC-20 EV battery charger. I can draw 20A at 240VAC to charge my car.

Charging port

All I have to do is plug in the cord, and the car will start charging.

Calculations

Download my EV Calculator spreadsheet

From my calculations, 0-50mph should take 13 seconds. I am actually doing it in 10.5 seconds, so I beat my goal, and also beat the Ford Ranger EV (11.6 seconds)! The Ford Ranger EV effeciency is rated 356Wh/mile @ 60mph, 237Wh/mile @45mph.

Fuel gauge This graph shows my battery voltage drops about 1 volt for every 1 mile I drive. My battery generally starts at 328V, so after 28 miles, it should be at 300, which is about 80% discharged.