Tuesday, May 31, 2011

Is clutch required or not in electric cars? And how to convert cars to electric?

I've seen some converted to electric cars on the youtube, but i'm not sure that to use clutch or not. Some people haven't in their converted cars and the rest i'm not sure.



And furthermore how did they converted automatic transmission. I think the automatic transmission requires some pressure pumps driven by the engine which by created pressure, change gears according to speed.



can anyone give me a complete and professional advice.



Thanks in advance.Is clutch required or not in electric cars? And how to convert cars to electric?
While the torque characteristics of an electric motor do not require a clutch or a transmission they are often not taken out of a vehicle prepared for conversion. The main reason the transmission is left is to keep a reverse gear. Typically a reverse gear is a different ratio making it easier to go slower and the electric motor will not have to be reversed electronically. The speedometer is also often connected to the transmission. Keeping the clutch may make connections easier but the inertia of an internal combustion engine is more than that of the replacement electric motor. In many instances shifting the manual transmission may not require the clutch.



The conversion process typically removes the engine, exhaust and fuel systems. The transmission is left in place as well as the associated bell housing and/or clutch if a manual transmission. An adapter plate is installed over the housing. The electric motor is installed and anchored to the frame. Batteries are positioned and installed in series and a motor controller is connected to the former gas pedal. Most modern batteries will benefit from a battery management system. Some method has to be provided to charge the batteries. One battery is often isolated to operate the 12 Volt electronics of the car: lights, horn etc. This will need its own charging circuit.



The only pump for an automatic transmission but external to it might be a cooling fluid pump. Electric pumps for power steering or power brakes may be added if necessary.Is clutch required or not in electric cars? And how to convert cars to electric?
Fully electric cars have no need for a clutch or typical transmission. Electric motors have variable power so you can drive the wheels directly.
The reason that most cars have a transmission is because a internal combustion engine can only run efficiently over a narrow range of rpms while the wheels must turn at a wide range of rpms. An electric motor can efficiently run at any rpm so it can drive the wheels directly without a transmission. If a car does not have a transmission, it does not need a clutch.
The transmission must be kept in a converted car because of the gear ratios that were used when it was powered by an ICE. I'll use my converted Mitsubishi pickup as an example. In 1st gear you can only go up to 15mph, but it only takes 150 amps to get it going. In 2nd gear, you can go up to 35 mph, but it takes 300 amps to get it moving from a stop. 3rd gear goes up to 55 mph but it takes over 400 amps to get it to move from a stop. In all cases, the amps go down as speed increases. So in the interest of conserving power, I normally start out in 2nd gear and shift to 3rd until the batteries are about half discharged. I then start off in 1st gear and shift to 2nd, then 3rd. As for the clutch, I decided not to use one because I didn't want the extra weight of the flywheel and clutch assembly. The transmission shifts fine without the clutch, but it takes an extra second or so to make the shift because of having to wait for the motor to slow down and the gears to mesh. Automatic transmissions are extremely inefficient in any case and should not be used in a conversion. Research the many conversion kit suppliers and visit evalbum.com to see the many different vehicle that can be converted. Also there are many good books that can be read to get information on doing your own conversion. See my truck at www.evalbum.com/2340

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