They’re light - 2116 lbs - which means less mass for an electric motor to move around
They are fairly aerodynamic - .038 cd - which helps at freeway speed
You can find them in good shape inexpensively
Most have manual transmissions, which is required for an electric conversion
Being a convertible, in most climates they don’t need air-conditioning.
Most are well cared for - they were an "IT" car that some people gladly paid a premium for
Parts are easily available, including body kits, low profile headlights, roll bars, etc.
Their styling is classic, some say iconic
They are fun to drive

What's included in the kit?

The kit includes all the pieces that needed to be fabricated to fit the first generation (NA) Miata.

Three battery racks

· Nose rack

· Top rack

· Trunk rack

Motor mount

Brackets

· Controller bracket

· High Voltage Enclosure bracket

· Charger bracket

Detailed Installation Guide

The motor, controller, charger, batteries, etc. are all available off the shelf from a number of suppliers. Rather than try to compete with these business, we decided to focus on the custom parts. This method provides two great advantages:

you can find the best deal on the components
you are free to make purchases as your budget allows

Are the battery boxes aluminum or steel?

Our battery racks, actually all our components are made of steel. We believe the weight savings of using aluminum wouldn't be substantial given the overall weight of the vehicle. Plus, we believe that steel will protect the batteries much better in the event of an accident.

What kind of tools are required to build the kit?

Our kit is designed to be assembled using common hand and power tools. There are two tools required that most people don't have in their shop which can be either rented or borrowed.

Engine Hoist - this is used to remove the engine from the car and to install the motor. It's a common tool for home mechanics and can be rented from most tool rental shops
Cable crimper - this is used to make your battery cables. This is a less common tool, but you may be able to rent one, or borrow one from a local EV club.

Also, our kit doesn't require removal of the gas tank for two reasons

removal of the Miata gas tank requires the rear subframe (differential, rear suspension and brakes) to be removed. This is a big job that would be best to avoid.
we didn't want to put batteries in the cockpit for safety reasons

With our kit, the gas tank is drained but remains in place. It's not heavy enough to negatively effect the car's performance. Weight distribution is maintained by balancing the pack between front an rear.

How long will it take to build?

There are a number of factors that will determine how long a conversion will take.

· Your mechanical abilities

· Availability of parts

· Availability of tools

· Your schedule

If you have good mechanical skills, all the parts, all the tools and could devote 8 hours a day to the project, it's estimated to take 3 - 5 days to complete the kit. If you have average mechanical abilities and are planning on working on the project only during weekends, plan on 3 - 6 months to complete the project.

How much does the entire project cost?

In round numbers, the entire conversion will roughly cost from $14,000 to $23,000, depending on the battery type.

Please see the project estimate for a breakdown of the costs involved.

Is the motor AC or DC?

DC, the kit is designed to use a 9” WarP DC motor made in Illinois for EV applications. These are very popular motors for EV conversions and are often seen powering electric drag racing cars.

Does it have regenerative braking?

No, AC motors provide regenerative braking more easily than DC and have a higher range, but at a much higher cost and with fewer choices of components. DC also provides better acceleration, which was a key criteria for the design.

Is the motor hooked right to the wheels?

No, the kit uses the standard 5 speed transmission. You'll keep it in 2^nd around town and 3^rd or 4^th on the highway. It drives a lot like an automatic - since the motor doesn’t idle you rarely need to use the clutch.

As an option, you can choose to go clutchless. This option doesn't use a flywheel, so it reduces the weight and drag on the motor substantially. Shifting requires a little more attention than when using a clutch, but a lot of EVs are setup this way and for the most part, the owners are quite happy with it.

How many batteries and how many volts is it?

The lead acid version has thirteen 12 volt deep cycle Optima AGM batteries – 4 in the nose, 4 above the motor and 5 in the trunk, all wired in series for a total of 156 Volts. These are sealed, they never need to be watered and won't leak or splash acid even if punctured.

Of course, Lithium batteries are also sealed and don't need maintenance like watering. Our kit is designed to use Thundersky Lithium Iron Phosphate (LiFePO) batteries which do not have issues with thermal runaway.

The 40 Amp Hour Lithium option uses 96 cells (half wired in parallel) for a total 154 volts

The 90 Amp Hour Lithium option uses 57 cells for a total 182 volts

How far can you go on a charge?

The Lead Acid version gets about 20 miles per charge.

The 40 amp hour Lithium version is estimated at 45 miles per charge.

The 90 amp hour Lithium version is estimated at 60 miles per charge.

How long does it take to charge?

The Lead Acid version with the Zivan charger takes about 6 hours to charge when the pack is fully discharged. Since a good amount of this time is spent conditioning the batteries, the charge time is estimated at 8 hours for the 40 Amp and 10 hours for the 90 amp version.

What’s the car's top speed?

The top end is estimated at 95 mph. Speed, however, reduces your range substantially.

How much does it weigh, and does it handle okay?

The weight of the converted car depends on the battery configuration you choose. Here’s a chart to give you an overview:

	Total Weight (lbs)	Weight over stock (lbs)	Front Weight (lbs)	Rear Weight (lbs)	Distribution
	Total Weight (lbs)	Weight over stock (lbs)	Front Weight (lbs)	Rear Weight (lbs)	Front	Rear
Converted car without batteries	2082		1092	990	52%	48%
Lead Acid:	2680	564	1460	1220	54%	46%
40 Amp Hour LiFePO	2399	283	1277	1122	53%	47%
90 Amp Hour LiFePO	2484	368	1325	1159	53%	47%

In general, the converted car handles well, as the weight distribution numbers indicate, though it will feel a little heavier than stock

Do you need suspension modifications?

No, you don't have to upgrade the suspension since the battery pack isn’t much heavier than stock and the weight is well distributed.

What are the little boxes on the batteries?

Those are regulators. Since the batteries are in series they all charge together and some will “fill up” faster than others. The regulators keep the full batteries from getting overcharged while allowing the batteries that aren’t fully charged to “fill up”. This applies to both Lead Acid and Lithium battery types.

How do you deal with the power brakes?

In an ICE car, the power brakes work off of the engine’s vacuum. In an electric car, we need to add a vacuum pump to create the vacuum. The vacuum pump mounted below the battery rack on the passenger side beside the motor. It is plumbed to a vacuum switch, so when the brake booster needs more vacuum it turns on to keep the brakes working.

How do you deal with power steering?

Miatas come with manual and power rack and pinion steering. Rack and Pinion is a very efficient design and, though the front of the car is heavier than stock, it's quite manageable with manual steering. Most conversions will either use the manual steering or if the car came with power steering, remove the power steering pump and loop the lines back to the steering box so that it doesn't run dry.

If you do need to go with power steering, there are a couple of options: I

You can add a small electric motor to drive the pump or put a pulley and belt on the tailshaft of the motor.
The Toyota MR2 had an electric power steering pump that could be used. I understand these are available from junk yards and from auto part stores. Here's a link to a conversion where they used the MR2 pump: http://www.driveev.com/jeepev/convpgs/psteer.php
You can also buy a complete kit to add power steering: http://www.evsource.com/tls_steering.php

As for placement, there is room under the Nose Rack or beside the IOTA DC/DC converter. Another option is to mount the pump where the vacuum pump is located - under the Top Rack on the passenger side - and move the vacuum pump to another location.

Even with an electric pump, power steering will impact your range. We would recommend choosing a battery option that had at least 25% additional range to provide adequate power.

Can I keep the air conditioning system in my converted car?

In general, air conditioning systems take a lot of power. One of the reasons a Miata makes such a great electric conversion is because it is a convertible. Hot weather is a good opportunity to put the top down and enjoy the breeze. Another option is to leave the top up, but lower the windows and unzip the back window. This will keep the sun off but allow the air to flow through the cockpit.

If you live in an area where air conditioning is a necessity, then you may want to consider using a unit like the Cool Blue: http://www.electricbluemotors.com/coolblue.html

We haven’t done an installation of the Cool Blue with one of our EV Miata Kits, but they are compact units and may be able to be adapted to work.

How do you warm the interior in cold weather?

A heater of some sort is needed to defrost the windshield and warm the interior in cold weather. An ICE can is warmed by the waste heat created by the engine. This heat is transferred to the cooling system which is connected to a small radiator (heater core) mounted under the dash. Since an electric car doesn’t have any waste heat, another solution needs to be devised. You can replace the heater core with an electric unit, add a small electric water heater and pump to route the heated water through the heater core. A more common solution is to install a hair dryer in line with the vent pipe under the dash behind the glove box. The power can be provided from the battery pack, since the dryer will work on either 120 or 220 volts. A switch mounted on the dash can turn the dryer on and off.

In any case, you will find that the car heats up quickly under electric power.

Does cold weather affect the car’s performance?

In general, batteries don't hold their charge very well at low temperatures. We would recommend wrapping the racks in insulation if the car will be in below 40 degree weather for extended periods. A battery warmer is a good idea as well. There are a few battery warmers on the market and here is a link on how to make your own: http://www.instructables.com/id/EV-Battery-Warmer-Part-1/

Battery warmers could be installed below the Nose and Trunk Rack. The Top Rack doesn’t have the clearance below, so the warmer would need to be installed in the rack below the batteries. The battery hold down straps would then need to be modified since the batteries would now be higher than originally designed.