OwnerGary Ellis
LocationAustin, Texas United States map
Web/EmailWebPage email image
Vehicle1990 Mazda Miata, MX-5
Miatas are a lot of fun to drive and make a great EV conversion project.
MotorAdvanced DC 203-06-4001A 8-inch Series Wound DC
DrivetrainOriginal 5-speed transmission, with the clutch.
ControllerCurtis 1231C-8601
Batteries10 Discover EV31A-A, 12.00 Volt, Lead-Acid, AGM
System Voltage120 Volts
ChargerRussco SC18-120
HeaterCeramic core heater in place of the original heater core.
No A/C.
DC/DC ConverterIota 30A
InstrumentationCustom interface to original gauges:

Oil gauge = ammeter, which is tuned to show 70A to 150A range. Basically, anything less than 70A is good for the pack, so the gauge just lets you know when you're driving too hard.

Gas gauge = pack voltage, F = 130V and E = 115V.
Top Speed70 MPH (112 KPH)
The car keeps up with traffic just fine and does 70mph on the highway. For full-range driving, however, I find that 45mph is best and I average about 30mph, with stops and starts.
AccelerationNot breaking any drag racing records and my 0 to 60mph time is in the 20-30 second range. Good enough for regular traffic.
Range30 Miles (48 Kilometers)
As with all EVs, this is very sensitive to how aggressive I drive. I coast a lot and avoid long hills to get the most out of my range. I've pushed the car to about 36miles, but normally won't go past 15miles as my turn-around point to make sure I can get home.
Watt Hours/Mile454 Wh/Mile
I measure about 2.2 miles per kWhr of charging. Although it is best if I don't fully recharge each time the car goes into the garage. That is, if I make several trips per day (work, back home, out shopping, back home, etc.) I always plug the car in but it never fully charges between trips. This is most efficient and I'll get closer to 2.5 to 3.0 miles per kWhr because the charger spends most of its time in bulk-charge mode (12A constant current).
The pack holds about 14kWhr and the car adds less than 300kWhr to my monthly electric usage (less than $20 per month, in Austin).
EV Miles
Start:189,162 Miles (304,361 Kilometers)
Current:189,787 Miles (305,367 Kilometers)
Total:625 Miles (1,005 Kilometers)
    As of 8/19/2009
Seating Capacity2 adults
Curb Weight3,200 Pounds (1,454 Kilograms)
The car gains about 300lbs with the battery pack (700lbs of batteries). 4 batteries up front (280lbs) and 6 batteries in the back (420lbs).
Tires45psi (filled to max rating).
Conversion TimeAbout 40 hours of work (part-time over two months).
Conversion Cost$15,182.27 total
(about $3,300 for the Miata and new paint, and another $11,800 for the cost of conversion).
This car is currently for sale:

(sorry, I see that the URL gets a little messed up here)

code by jerry