[tomofreno]

I'm getting fairly well along on conversion of a 2001 Suzuki Swift so thought I would start working on a conversion thread. First a summary of the goals:
1) 50 mile (83 km) range at 55 mph (92 km/h) and 70% DoD
2) Around $20k total conversion cost including donor
3) AC motor for electric braking
4) Zero to 60 mph (100 km/h) in < 12 seconds plus shifting time
5) Less than 1C current draw at 60 mph
6) Less than 3C current draw during max acceleration
7) Complete conversion in about 3 months

Goal (1) pretty much meant lithium cells or a "lead sled" pickup. I decided on lithium hoping they really do last 3000 cycles at 70% DoD, so cost/mile is not much different than sealed lead acid cells (didn't want to deal with floodies). Lithium and goal (2) meant a light vehicle to lessen the required battery capacity to meet goal (1). Goals 2, 3, and 4 are difficult to meet together but I think the motor/controller I selected will do it. The light vehicle permits meeting goals (5) and (6) without too large Ah cells, so there is some chance of fitting them in the small vehicle. Goal (7) meant no custom vehicle, buy a donor and convert it.

So I ended up with:
"Donor":2001 Suzuki Swift, 1895 lb (861 kg) curb weight, 2624 lb (1193 kg) GVW, 1.3 liter ICE 79 H.P. peak at 6000 rpm, peak torque 70 lb-ft at 3000 rpm. Interior and exterior in very good condition.

Motor/controller: HPGC AC50/Curtis 1238-7501, 90 lb-ft max torque out to 3000 rpm, 51 peak H.P. at 3200 rpm with 96V pack sagging to 85V, 15 H.P. continuous. I was told 17 H.P. continous by email from HPGC, so 15 is likely conservative.

Batteries: 36 SkyEnergy 180Ah cells purchased from evcomponents. The Curtis is nominally 96V max, but shutdown is at 130V. Fully charged cell voltage is 3.6V per SE spec, or 129.6V, but I plan to charge them to around 3.45V to leave some room for regen.

Charger: Manzanita PFC30, about 35A max at 240V.

DC/DC converter: No name from Cloud Electric, 30A

Estimated performance: These numbers are from a spreadsheet I created which is available at electricnevada.org under "evcalculator". Note the spreadsheet uses 96V dynomometer data for this motor. I modified it to estimate performance with the higher pack voltage, 115V nominal.

Range at 55 mph: 50 miles (83 km)
Zero to 60 mph in about 13 seconds plus shifting time, so maybe 16-17 seconds?
150A current draw at 60 mph (0.83C)
550A max current draw during acceleration (3.06C)
Max torque 90 lb-ft out to about 3500 rpm
Peak 60 H.P. approximately

Some photos:

Main battery box installed and painted (16 gauge steel), wheel well behind it:
SDC10029.JPG

Decking installed around main box. Box lid open with carpet pulled up:
SDC10052.JPG

Insulation and most of the cells installed in the main box along with two 400A fuses which divide the 36 cells into 3 groups. That is a battery heater where a group of 3 cells is missing. Cells are clamped in groups of 3, 5, and 6:
SDC10062.JPG

Lid closed and carpet (Home Depot 16$ for 6'x8') down. The line in the carpet is a photo artifact. The rear battery box sticking up out of the wheel well holds 8 cells (since been painted gray to match interior):
SDC10049.JPG

Front battery box (under hood) with 4 of 8 cells in place and battery heater visible on RHS. AC50 behind and below it, box for charging plug on the front of it:
SDC10060.JPG

Motor controller mounted on motor end mount bracket (1/4" steel) with 150 cfm axial fan (update: changed to 250 cfm), and aluminum shelf where the charger, electronics box, and DC/DC converter will mount:
SDC10057.JPG

Close up of motor on bracket showing about 5/16" space between controller and bracket for air flow from axial fan which blows through a 4.5" hole in the bracket:
SDC10056.JPG

All cells are now installed and I am finishing up wiring up the electronics box - main contactor, shunt, relays, potbox. Next up will be to pull the steering wheel and dash to install the heater core and TBS and Curtis gauges, then hook up the Voltblochers.

[PatricioIN]

that looks very interesting. One questions about the heaters: It was my understanding that Lithium batts weren't as affected by cold as LA; do you think the battery heaters will make much difference?

[tomofreno]

It was my understanding that Lithium batts weren't as affected by cold as LA; do you think the battery heaters will make much difference?

Yes. According to the SkyEnergy spec charging is above 0 C or 32 F. Dave at evcomponents told me it is difficult to charge the cells at low temperatures, and they only take about a 60% charge at around 30 F. Night temperatures where I live are many times in the twenties (F) and sometimes around 5 F. The heaters are powered by 120VAC. The plan on cold nights is to plug them in prior to charging with the thermostat set to around 60 F and turn on the charger when the sensor gets to about 45 F - hopefully in an hour or so. They will be off the rest of the time. The temperature sensor is bolted to the battery clamp on one of the set of four cells in the front box. Each heater, which heats about 4 cells is only 35W, so will provide only gentle warming. I'm hoping that the insulation, small amount of heat generated by the cells during vehicle operation, and daytime temperatures typically above 35 F will keep them above 50 F or higher the rest of the day. One problem will be equalizing temperature of the front box with they other two since it is exposed to more air flow when the car is moving. I'll see how this setup works, and modify if necessary. I can add insulation to the outside of the front box. During summer I'll remove the front box top for cooling, and I have a 145 cfm bilge blower to put a bit of air through the other two boxes. Have to see if it requires more. Have to start somewhere and gather data.

[80N541]

great work!

[vpoppv]

To see that engine bay with those lithium cells.....I'm so jealous!!

[JRP3]

What are you using for a pot box, PB6? I'm looking for other solutions, probably make my own or modify something.

[dtbaker]

I can't wait to see how this compares in price, performance, and (eventually) battery life to my 'lead' version of almost the same car.....

[tomofreno]

Yes, PB6. HPGC said they use the PBF6, F for foot pedal. I've seem some postings of complaints, particularly non-linearity, but they seem to work well with Curtis controllers as they are designed for them. There are a lot of them out there, so you might expect some bad ones to show up. Hope mine is not one of them.
Tom

[tomofreno]

Hey Dan,

I think the main difference will be in acceleration at highway speeds, due to lighter weight (lithium cells) and higher current controller, 550A versus 400A. If you put a Curtis 500A controller in yours performance would be quite close I think, but a bit different due to the weight difference. I wouldn't expect to notice much if any difference driving on secondary roads and in town - unless you want to lay rubber. There is also of course the range difference due to pack energy/weight. Cell life is the big one to me as I am hoping for cost/mile similar to sealed lead acid cells. That is why I designed for max 70% DoD and 1C or less current at 60 mph.

Tom

[madderscience]

looks like good engineering and a great build. bravo. I hope a BMS will be involved to protect your battery investment.

If you get the Rolling Resistance and Aerodynamics dialed in on that sucker you will probably be looking at somewhere around 180 to 200 wh/mile at 55mph easy. This will mean with 15KwH usable battery capacity you will probably be looking at more like 70 miles of range.

I usually say good luck here, but you don't need any. You engineered it.