interiorcabin heaterFront cell boxController mounted on heat sinkmid boxunder hood
OwnerTom
LocationReno, Nevada US map
Vehicle2001 Suzuki Swift
3 door hatchback
Motor AC50 3-Phase AC
HPEVS AC50 motor, 67HP peak at about 3900 rpm with 115V pack
DrivetrainOverall gear ratios (including rear end): 13.45, 7.16, 485, 3.45, 2.88
ControllerCurtis 1238-7501
max current 550A, max voltage 130V
Batteries36 Skyenergy 180Ah, 3.20 Volt, Lithium-Ion
36 LiFePO4 cells connected in series, nominal voltage 3.2V
System Voltage115 Volts
ChargerManzanita Micro PFC30
Max output about 38A DC at 120VDC. Typically charge at 30A DC (about 16A AC at 240VAC) at home. Usually takes 2 to 3 hours to charge, a bit over 4 if discharged 70%. Update 2010: Now charging at 26 to 27A. Charger gets too hot in 100 F ambient if charging at higher currents. Ok in winter.
HeaterFarnam heater pads and controller (kta-ev), 10 total. Work very well, kept cells at the 59F (15C) setpoint on two successive nights at -5F (-20.5C). Slow to initially heat though, about 3F/hour increase in temp. Cells in steel boxes with 1/2" polyurethane insulation. This has a very significant impact on range and voltage sag in a cold climate in winter. I see about a 25% difference in range winter to summer with the heaters set at 60 F (16C). In winter the cells typically remain at 50 to 70 F, with ambient of around 20 F (-7C). At 80 F (27 C) ambient, they get up to 90-95 F (~34C) and have lower internal resistance and more capacity when charged at this temperature. I had to tweak the voltage limit on the charger to get a full charge in summer. If the cells are unheated in winter, range will suffer significantly. The heaters are only on when the car is parked and plugged in. They will remain above 50 F for around 4 hours at 20 F ambient, when parked outside unplugged after a 10 mile drive.

Cabin heater is two 1500W ceramic heaters mounted side by side in place of the original heater core. Gives about 3160W with blower on high.
DC/DC Converter TDC-120V/12V
The 400W "no name" sold by Cloud Electric
InstrumentationCurtis 840 gauge, displays battery voltage and (estimated)current, motor and controller temperatures, motor rpm. TBS E-xpert Pro gauge, displays battery voltage and current, SOC, Ah used, has low SOC, low voltage, high voltage alarms. Great gauge! Works just like a fuel gauge. I ran the car with only this, no bms, for about 3 months. The cells remained balanced to within less than 4mV of each other typically, and I only discharge to no less than 30% SOC. I added a minibms after this, no shunts, just HVC/LVC protection, tied to Regbus of the charger, relays tied to buzzer and to resistive divider to cut throttle 50% for LVC event.
Top Speed90 MPH (144 KPH)
Calculated. Has pep in 4th gear at 75mph, so I think it will do 90.
Acceleration0-60 in 16 seconds, 1st through 3rd gear.
RangeAll at 80% DoD: 100 miles at 30mph, 80 at 40, 60 at 55 - Estimated by averaging current draw driving both directions on a stretch of road, dividing into 0.8*180Ah, and multiplying by the speed. Update 2010: The above was done in winter. Generally get about 75 miles at 50%/50% highway/secondary road driving, 60mph highway/35 mph secondary, 70% DoD in summer.
Watt Hours/MileAbout 200 to 210Wh/mile with mixed highway/secondary road. Update: Drove 65 miles round trip on 1/5/10, most at 50mph, rest 35 to 45mph. Used 114Ah and about 200Wh/mile. Update 6/10: Better range in warm weather, about 80 mile range now in mixed driving, around 190 Wh/mile. Maybe some of the improvement is due to "breaking in" the cells? Update 4/30/11: Passed the 10,000 mile mark. Average of 220 Wh/mile over 10,053 miles. That includes two 6 month cold weather periods, one 6 month warm weather period, so 2/3 in cold weather which increases energy usage due to cold drive train and use of the passenger heater. Probably the average at the end of this coming warm weather period will be more like 215 Wh/mile, as it was last fall. Total of one year five months in service.
EV Miles
Current:7,500 Miles (12,067 Kilometers)
Seating Capacity2 adults
Curb Weight2,250 Pounds (1,022 Kilograms)
Everything stock, including all suspension (only about 350 lb over original curb weight)
TiresMichelin radials (on donor)
Conversion TimeAbout 4 months
Conversion Cost$2700 for donor, about $20k for rest
Additional Features1/8" poly from front bumper to just before front axle to protect motor from water and gravel. Bilge blower (150 cfm) to ventilate mid and rear cell boxes. Axial fan (250 cfm) to cool controller - necessary to drive at highway speeds continuously in summer, or maybe big finned heat sink - update 6/10: added 10"x11" heat sink with 2.5" fins. Controller now remaining below 45 C typically in 80 F (27C) ambient. Update 6/10: cells still not going above 90 F yet in 80 F weather and no blower. Added Dimitri's minibms, sans shunts, several months ago and it works well. But now that I have the charger voltage limit tweaked in it stops charging at about 3.44V/cell every time, so the minibms is just there as backup. I set it this way so cells are charged to the start of the exponential rise part of the V versus Ah or time curve. All 32 original cells remain balanced typically to within 2 mV of each other after charge. Replaced 4 due to over-discharge by a different bms, and have balanced (individually charged) these twice in about 5 months after they became unbalanced by about 0.01 V from the others.
More details at "SwiftE" thread under Builds and Conversions forum on the diyelectricar site. Also in the "garage" at that site. An Excel spreadsheet (referred to as "ev calculator") can be downloaded at electricnevada.org. It described this car's performance very well after modification for 115V pack (gives 90lb-ft torque out to 3900 rpm), from the test data for 96V pack in the standard spreadsheet. Largest error about 5% for predicted range and current draw at various speeds, and Wh/mile. Update 6/10: the error for range is even larger for summer operation due to larger cell capacity and lower internal resistance at higher temperature. I have not re-measured current draw at various speeds at summer temperatures to see if they are significantly lower, and account for the error.

Regen was set up lower than I liked on the system as shipped. Had to use mechanical brakes more than I wanted on hills and had max of 15A to 20A regen. Purchased a programmer and changed this so now get up to 190A regen and don't have to use mechanical brakes on most hills. Control amount of electric braking by easing off accelerator pedal, and if necessary by shifting (same as "engine braking"). Control of vehicle speed is mostly by the right foot. Can stop for a light using only electric braking most of the time, by easing off the accelerator more and more as I approach the light. A very reliable car. Just get in it and go. Plug in when done with it for the day, and go in the house.

ONE YEAR UPDATE:
Total miles: 7471
Total kWh used from wall outlet (EKM meter): 1615
Average Wh/mile: 216 (from wall, per EKM)
Maximum distance driven between charges: 75.1 miles, much at lower speeds so only 64% DoD.

Roughly half of miles were driven at 50-60 mph, half at 30-40 mph. Maybe 1/4 of trips with bike on back and mostly highway driving (higher drag).

Recently changed motor max speed to 8000 rpm from factory setting of 6500 (HPEVS said no problem).
Now can go to about 35 mph in first gear and 70 mph in second gear. Two results from this: (1)Now do almost all driving, including on highway at 60-65 mph in second gear, only use first for fast acceleration, and (2)better acceleration since now can accelerate to over 30 mph in first gear putting me well up in the power band for second gear, get stronger pulling all the way to 60 mph as a result. Have not redone 0 to 60 time yet.
Update: After input from others, I decided it is likely not good to run the transmission at such high rpm for sustained periods of time, so now only drive in 2nd gear up to about 50-55 mph (~6300 rpm). Cells still behaving the same, no problems with them.

Update 4/30/11: 10,053 miles and 1 yr 5 months in service. See comment on Wh/mile in the Watt Hours/mile section above. Added shunts to the minibms boards and top balanced pack a few months ago. Working very well. Got about 75 mile range in winter, same as summer, when cabin heater not used (cells heated to 65F when garaged). About 60 mile range if cabin heater is on much of the time (two 1.5kW ceramic heaters in parallel).

TWO YEAR UPDATE:
12/5/11: 2 years operating as an ev now. 14,617 miles, 3159.81kWh energy used from the wall (EKM reading), 216Wh/mile from the wall. No issues over the past year, no down time.

code by jerry