The "ultimate" conversion

Electric cars are the future of the automotive industry and quite a few manufacturers are introducing them in 2010. The BMW mini electric & concept active E, the Chevy volt, Jeep EV wrangler, Dodge ENVI; just to name a few.

                           mini cooper ev        concept active E        chevy volt     Jeep wrangler ev       Dodge ev

The issue with electric cars has always been trying to achieve more miles between charges. Several manufacturers use lithium-ion batteries. These are expensive and are only good for a few hundred cycles. BMW's active E gets about 150 miles on a charge. Some manufacturers are also utilizing a small internal combustion engine; it's only purpose is to recharge the batteries. Another option is to utilize regenerative braking. The British engineering firm that originally electrified the mini cooper used a battery and ultra capacitors. Electrochemical capacitors (super or ultra capacitors) can store much more energy than batteries, charge up quick, and can cycle 500,000+ times. We believe that they are the answer to this problem. The bottom line is that these cars (from the manufacturers) will be expensive. Doing your own conversion is not as difficult as you might think, is a lot cheaper, and (if done right) you can achieve results that will rival what the car manufacturers can do. The advantage of converting to electric are that you no longer have an ICE and the maintenance that go with it: gas, oil, tune-ups, etc. When you consider this, having to recharge your car every few hundred miles is a minor inconvenience and an acceptable compromise.

 

Electric conversion

Motors: AC vs. DC

There are several (online) companies that are offering conversion kits. They are dc conversions and use dc motors. We do not offer kits. Instead, we tell you what is available and provide information to help you make an informative decision about each component. This way you can get exactly the components you want instead of pre-assigned components in a kit. The major car manufacturers'  electric cars are AC and is a better drive system than DC but will cost more. They are more preferable in a hilly terrain. These are the advantages:

Regenerative braking without any extra equipment

You can recover a LOT of your battery power during the normal driving process. A few DC systems can do this to some extent also, but they don't do it nearly as well and it always makes them more complex and expensive.

Favorable torque

AC electric car motors can be well matched to your ICE's torque curve so that you don't inadvertently murder your transmission with your normal driving habits. An internal combustion engine is considerably different than an electric DC motor, and the drive system your donor was born with is not designed to withstand the low-end workout your series DC motor is capable of delivering. AC motors provide constant torque over a wide range of RPM. Top rotor RPM speed of a typical DC motor is about twice as low as for an AC motor requiring you to shift gears, thus loosing torque at the wheels. Normally vehicles using DC systems avoid the need for shifting by starting in 3rd or even 4th gear so the RPM at freeway speeds remains manageable. This, however, aside requiring a very large motor (to provide high starting torque at the wheels while on 3rd gear), greatly stresses transmission components normally not intended for such abuse, sometimes resulting in broken gear teeth, stripped splines, twisted shafts, damaged CV joints....AC setups don't have these issues.

No motor brushes

There are all these issues with brush advancing, seating, commutator arcing and self-destroying at high RPM; and they're no good in a regenerative braking environment. If electric reverse is used, the requirements for brush advance for forward and reverse rotation direction are contradictory. If you want to avoid these problems altogether, use an AC motor.

Programmability

Now, a DC controller COULD be programmable, but usually isn't. AC inverters are perfectly matched to the motor they're sold with, and you can set all the software parameters yourself to best fit your driving style and your batteries. You can set the battery voltage to maximum for regen and minimum for driving (for battery protection), max battery current for driving and regen separately, throttle response profile, off-throttle regen option, tachometer output, creeping current, power mode and economy mode limits, acceptable inverter and motor temperature, electric reverse, safe motor RPM range (separately for forward and reverse) and much more . All programmable parameters can be displayed on a PC/laptop screen in real time in digital and analog graphic form as you drive, so you can optimize the settings while in the vehicle. Configurable graphs plotted and can be stored for later analysis and comparison.

Safety

If a DC controller's power stage fails, the entire pack voltage - all 120 or 140 volts or whatever - is applied to the motor. In contrast, power stages of an AC inverter are used to "generate" power for the motor, not "regulate" it. So in case of a failure, AC generation just stops and the motor just looses power.

Electric reverse is as easy as adding a small toggle switch on the dash

All it takes for an inverter is to swap sequence of 2 phases, so the rotor runs in opposite direction. It's a bit more complicated with DC electric car motors.

Ease of installation

Contrary to popular opinion, AC systems are easier to install than DC systems...not harder. Yes, the AC inverter itself is a complicated instrument, but then, so is the DC controller. They're both using computers, but that's nothing unusual, since so is your typical ICE. To wire a Siemens AC system you have to make 6 connections: 3 phases to the motor, 2 cables to the battery and plug encoder cable. The rest is low voltage wiring: +12V DC-DC output - to 12V wiring system in the car, 3 wires to the ignition switch,  3 wires to the throttle pot, 3 wires to the direction switch, and 2 wires to the (optional) start inhibit switch. This wiring harness is pre-fabricated and included.

OR

A typical setup for a DC system with series wound motor: Two cables from the battery to the main contactors. Three jumper cables for reversing contactors. Two cables from the main contactors to the controller. Two cables from the controller to the motor. One cable to jump the field and armature of the motor. Two wires to the DC-DC converter input. Low voltage side: 3 wires to ignition switch. Two wires to the throttle pot. Two wires to the pre-charge contactor coil. Two wires to the reversing contactors coils. Two wires to the power resistor pre-charging capacitors in the controller. Two wires for start inhibit switch. One heavy wire to ground DC-DC converter neg. side, and one - to connect its output to the 12V system in the car. Two wires from the motor temp switch to the light on the dash. Typically, no harness exists or is included; you come up with your own.

There are two situations where a DC drive system drive system is preferable to an AC system.

The first is the EV drag racer who won't be going more than a quarter-mile at a time...

And the other is the hobbyist converter who just wants to get something running on batteries as cheaply as possible. There's no shame in this, a lot of the EVs on the road today are in this category.

Permanent magnet DC motors

The biggest drawback with permanent magnet DC motors is that they're noisier. Like all brushed DC motors, the brushes generate electrical radio interference. But unlike other types of brushed electric motors used in electric cars, like the series wound DC motors below, which have windings which provide natural filtering of electrical noise, the PM motors have no natural filtering effect in their design...so they're noisy.

FAQ's

When it comes to electric car motors, the most commonly asked questions start with: "How many horsepower...?"

• How many horses do I need per pound of car?

• Why does the same electric car motor have different horsepower in different conversions?

• What's the difference between "continuous horsepower" and "peak horsepower" ratings?

• Do I need a transmission? (manual vs. automatic)

The Corolla question: Why does my Toyota need every single one of its 120 horses to push its light little body around, while a 24hp WarP 9 in the same car would give it twice the power?

Answer: Efficiency.

Electric car motors are much more efficient than internal combustion engines. Most of your Corolla's 120 horses are being used to get from 0-35 mph, which gas engines are not that good at - it takes them a while to find their torque. Electric car motors (especially series wound DC motors like that NetGain WarP 9), on the other hand, are good at low-end acceleration.

• Weight to power ratio:
  When you're selecting electric car motors, figure 6-8hp (continuous) for every thousand pounds of finished, loaded vehicle weight. That means figure in the car's curb weight - along with the load of batteries, passengers, etc. More hp is required for higher speeds, heavier vehicles, and steeper terrains.

• Electric Motor Rating:
  They're rated at their maximum efficiency, which is designated "continuous", although they are capable of short bursts of power 2-4 times greater than their continuous rating (without damaging the motor), called "peak".

• Voltage and Horsepower:
  The horsepower goes up with the voltage. Motors are rated, not only "continuous" and "peak", but at a given voltage, as well. There's no way to figure an EV motor's horsepower without knowing the voltage of the system.

• Over-and Under-powered Motors:
  Don't worry if you get a motor that's a little oversized for your car, that's what the controller is for. DO worry if you get a motor that's a little undersized, because it's bound to fatally overheat sooner or later.

• The Need for Speed:
  If you like to drive on the freeway, you'll need more horsepower per pound. It takes four times the hp to go 70mph than it does to go 35mph.

Transmission:

To prevent overloading the motor and controller at lower RPM's, it is helpful to use a lower gear to get the motor RPM's up to improve efficiency, torque and motor cooling. At higher speeds it is desirable to use a higher gear to keep the motor from over-revving. Since it's there already and is usually in pretty good shape, you're better off to keep it.

Manual vs. Automatic Transmission: 

Most EV conversions are manual transmissions because they are more efficient than automatic transmissions and provide greater range, require less motor torque, require no transmission cooler, and are easier to convert. The problem with an automatic transmission is that it shifts at about 2000 rpm; the electric motor is usually designed to operate efficiently between 4000-5000 rpm. Consequently, the automatic transmission is a poor choice which results in decreased range. If you buy a vehicle with an automatic transmission, you can replace it with a manual transmission. The additional cost is $150 and up depending on the transmission and used auto parts dealer. Consider trading the automatic transmission. As stated above, it is helpful to use a lower gear to get the motor RPM's up to improve efficiency, torque and motor cooling. At higher speeds it is desirable to use a higher gear to keep the motor from over-revving. So if you decide to keep your automatic transmission, you will still have to do some shifting.
 

Below are some of the main components available for both AC and DC conversions.

DC motors

D&D Motor systems	D&D Motor systems	Netgain	ADC motors
AES-15	ES 31-B or ES-63	warP 9 (see all models)	(AC or DC)

 

AC motors

Sevcon	Brusa	MES-DEA	MES-DEA	ADC
		(air-cooled)	(water-cooled)

 

DC Controllers

 

Alltrax	Curtis	Sevcon
7245 72volts/450amps.(see all models)	1231C 144vdc/400amps. (see all models)	Millipak 4Q (see all models)

curtis/albright	Tyco	Tyco
(see all models)	101-LEV200A4ANF (side mount)	101-LEV200A4NAA (bottom mount)

Zivan	Zivan	Zivan	Zivan	Brusa
BC1	NG1	NG3	NG5, NG7, NG9	NLG 5        (see all models)

Brusa	Sevcon	Curtis
(see all models)	(see all models)	1236 (see all models)

All of these throttles use are resistance type (potentiometer) with a range of smooth continuous control range of 0 - 5k - 0. The Magura slides on to your 7/8" handlebar. The    PB-6 Pot Box is designed for cable actuation from a foot pedal. It is outfitted with a microswitch which may be optionally used for various control inputs.

Sevcon	Brusa	MES-DEA
(see all models)	(see all models)

Sevcon	Sevcon	Sevcon	EVision displays
power gauge	smartview gauge	Clearview

   Download spec sheet

We advocate the use of  ultracaps for EV conversions in addition to a traction battery. They take up less room, charge faster, and weigh less than batteries which will improve your miles per charge.

	Maxwell ultracaps                     650-3,000 Farads  2.7 volts
	Maxwell ultracap module 16v. BMOD0250PO16B01                        (mm.) 416.2L x 67.2W x 103.2H          (in.) 16.648L x 2.688W x 4.128H    weight: (4.45kg.)  9.79 lbs.
	Maxwell ultracap module 16v. BMODO500PO16BO1                      (mm.) 416.2L x 67.2W x 156.7H           (in.) 16.648L x 2.688W x 6.268H  weight: (5.75kg.) 12.65 lbs.
	Maxwell ultracap module 16v. BMODO500PO16BO2                      (mm.) 416.2L x 67.2W x 156.7H           (in.) 16.648L x 2.688W x 6.268H  weight: (5.75kg.) 12.65 lbs.
	Maxwell ultracap module 16v.   (mm) 260.1L x 154.9W x 79.3H        (in.) 10.4L x 6.196W x 3.172H           weight: (2.7kg.) 5.94 lbs.
	Maxwell ultracap module 75v.   (mm)  515L x 263W x 194H                      (in.) 20.6L x 10.52W x 7.76H         weight: (25kg.) 55 lbs.
	Maxwell ultracap module 125v. (mm) 762L x  425W x 265H              (in.) 30.48L x 17W x 10.6H          weight: (59.5kg.) 130.9 lbs.

Many states have incentives as part of a federal nationwide program that encourages the use of alternative fuels in vehicles.