East (SF) Bay EAA Chapter
Miata Sportscar Conversion
Saturday, April 28, 2012
Participation: 25 members
There were about 25 people at today's meeting, including four to six
people that hadn't attended an EBEAA meeting in the past. A couple of
people said they would go to
to sign up.
Miata EV Notes
EV idea came first, then decided that a Miata would be an ideal 'fun' platform for a conversion to electric. Why the Miata? Parts are available for this vehicle that enjoyed a significant production run as an IC vehicle, and many donor cars are available for less than $1,000. The basic vehicle is also lightweight and fun to drive.
Their system is more of a 'mom and pop' shop with five employees. More of a tool/process supplier than a supplier of parts. The original idea stemmed from research that revealed a limited number of kits available, and most of those were based on old vehicles - Porsche 914, VW rabbit, VW beetle, Geo Metro, etc.
Although 'universal' kits exist, they are neither universal nor complete kits. Many parts required for a successful conversion using Universal kits need to be engineered by the person performing the conversion.
The basic model for Miata conversions is the NA model, built from 1989 to 1998. Pat and his team are working on a kit for the newer 'NB' version (1999 - 2005) as well. One of the main reasons why the Miata makes a good donor vehicle is that the frame rails in the Miata are large and sturdy, affording many places to attach battery racks, etc. One thing that is often done with other conversions is to remove the gas tank. In the Miata, removing the gas tank is quite difficult, and requires dropping the rear end and transmission to remove. Most people that convert a Miata simply leave it in the vehicle.
There are several 'flavors' of conversion that can be done. In general, the owner decides what motor/controller/charger is needed, and once those items are decided, EVMiata.com personnel put together a kit to match those components. EVMiata does not supply the motor, controller and charger; those items are purchased by the converter wherever they decide is best for them.
The first Miata Pat converted used Optima D34 sealed lead-acid batteries. These batteries gave the Miata about a 20 mile range. Most people opt for lithium cells these days, and the range with lithium cells can be from 58 to 90 miles, and about 300 pounds lighter than when using a lead acid pack.
One problem encountered with lithium is that each manufacturer uses a slightly different form factor for the cells they produce. This requires a different battery rack configuration, depending on battery manufacturer.
The basic price for a 'phase 1' kit is $2,500 plus $45 for the conversion manual. The guide sells about 5 or 6 copies for every kit sold, so many people buy the manual either to study how it is done, or to reverse engineer the process.
Pat Mackey works with Luscious Garage in San Francisco to convert Miatas for those that don't have the time, or are not comfortable with doing the conversion on their own. Miata conversions have attracted interest worldwide , to countries including Finland, Italy, Australia, Germany and New Zealand.
EVs were on display in the parking lot after the meeting. Including a BMW Active E, driven by a past president of the San Francisco EAA chapter, who now lives in Alameda.