240SX EV Conversion

So I have my Warp 9 mated to my tranny, a T-REX 1000 A controller, plenty of 2/0 cable, and a clean car ready to be converted. The next step is to pick and order the batteries. The goal is to go 30 miles at highway speeds (60 mph). Since I can’t afford Lithium’s, it looks like I need to use floddies. I would like to keep the battery weight down to around 1100 lbs to limit the need for suspension upgrades.

With this in mind, I tried 144V of US Battery 8VGCHC XC the EV calculator shows my conversion would get about 18 miles. I used an RX7 which has very similar characteristics. This assumes low rolling resistance tires, 144V of T-875’s to 80% DOD. If I used US 8VGCHC XC, they have 10% more capacity over the T-875’s, getting me to 24 miles. Quite a bit shy of the 30 mile goal and I would not be able to use Air Conditioning. According to the calculator, I’d need 1465 lbs of 6V T-105’s for 35 mile range. That’s 24 rather large batteries. There goes the back seat!

As a real-life compariason, I found a Fiero which uses low resistance tires and 120V of T-125’s and claims a 65 mile range at 60 mph. Plugging these into EV calculator shows a 37 mile range. I used a Ford Escort which is very close to the Fiero in weight and drag. Not sure I can believe the calculator.

Note the weight of a Fiero is the same as a 240sx but it’s drag coefficient is 0.35 compared to 0.31 for the 240sx.

The controller will be a DC Power Systems water cooled T-Rex 1000. It’s a bit overkill for the car but gives the greatest flexibility for selecting battery configurations.

It features:

• Non Contact inductive throttle position sensing, 100 million cycle life
• Rev limiter regulates RPM at selected maximum speed
• Tachometer Drive output, operates “4-cylinder” tachs
• 50-100mS Shift Blanking for crash-box or automatic transmissions
• Failed open, short and floored-on-startup throttle lockout
• External battery contactor control with capacitor precharge delay
• Microprocessor controlled, water cooled
• Tach Sensor, Throttle Sensor and Remote Display included
• Input Voltage Range 96 – 336 VDC Nominal (60 – 400 VDC max)
• Switching Frequency 18Khz
• Rev Limit 4000, 4500, 5500, 6500 RPM
• Weight 20 lb.
• Dimensions 6.75 x 9 x 12 (HxWxL, inches)
  

The conversion goals are:

• Obtain range of 30 miles per charge, mostly highway driving 60 mph, flat terrain.
• Acceleration performance should be the same or better then original.
• Conversion cost less then $7,000
• Complete by 11/15/08