Electric reverse trike

[HydroJim]

I'm thinking of building an electric reverse trike with either solo or tandem seating, but I'm not to familiar with electric drive trains. In fact, I know nothing about them beyond the fact that batteries power a controller which moderates the power flow to the motor.

I could easily build a reverse trike with an engine, but I'm thinking that using electric would make the car more fun to drive and the drivetrain would be 90% efficient instead of tuning an internal combustion engine to try and get 30% efficiency. Plus, I want to learn something new. But I'm not sure where to start with the electric drive train.

If anyone wants to help point me in the direction of components like controllers, motors, batteries, transmissions, etc. please help

[Daox]

EV converters rarely alter any part of the drivetrain besides removing the engine. The drive system (motor/controller/pack) is what I assume you are unfamiliar with.

What kind of specs were you thinking about (range, horsepower)?

To get some idea of prices you can look at:
EVolve Electrics, Electric Vehicle Parts
ThunderStruck Motors - Electric Vehicles, Accessories and Components

[Daox]

Any updates?

[HydroJim]

Since a Kawasaki 250r has about 30 HP, should I go for a motor that also has 30 HP? It seems like with electric I could get away with less HP because I have to worry less about acceleration with the torque of the electric motor. Let me know what you think.

I'm still not decided if I want to go with the stock 250cc gas engine or convert it to electric, but it'lll be good to get as much information as I can to make an informed decision

[HydroJim]

As far as range goes, I guess 140 miles at highway speeds would be good. This would allow me to go somewhere an hour away and come back.

[sheepdog 44]

EVAlbum: Search Results

Take a look here. For what ever you want to build there's a 99% chance someone has already made almost exactly that. Then look at what components the person used to build it with, the cost, wh/mi, range and top speed. It gives you a good idea of what is needed to meet your own goals.

Maybe an electric motorcycle would be ideal for you? simple to convert, better or equal efficiency than most electric reverse trikes.

[HydroJim]

I'm thinking direct drive would be the best way to go because it gets rid of the need for a clutch pedal and shifter which simplifies the trike build.

But I'm not really sure what kind of motor I would need to cruise is 65 mph efficiently. I don't want to be straining the motor at highway speeds.

How exactly does direct drive work? is this controlled through the controller? The way I'm thinking about it, it will be like dropping the clutch in a car and spinning the wheels.

[puddleglum]

I'm not the best person to give advice on an electric drive because I haven't done one yet, but I know a little of how they work. Regarding direct drive, this simply refers to how the motor is connected to the wheels, not how the motor is controlled. The controller varies voltage and current to the motor based on throttle input to control speed. At zero throttle the motor is in neutral and freewheels. Since most electric motors make peak torque at zero rpm, the trans is not a necessity. You will need to get the motor size and gearing just right, though, if you want good acceleration and high speed performance.
If you want to be able to do 140 miles at 65 mph, you will need a large (read expensive and heavy) battery pack and you would need to go lithium. How big is this trike you are planning? If it's based on a 250, I'm guessing not very big. If you built a super aerodynamic shell for it, it would cut your power need but adds to the complexity and expense of the project. Your budget may dictate your design choices as much as power requirements. It's nice to see you're starting young though. Here is another link to some good info. EV Information - DIY Electric Car Forums

[fb_bf]

Be careful about assuming that because an electric motor has torque a zero rpm you can simply eliminate the transmission. The torque is proportional to the current. If you only use 4th gear, and the original transmission had a 1st gear that was geared to be 4 times lower in 1st, then you''ll need 4 times the torque of the gas engine to feel the same acceleration without the transmission. This requires you to use very high currents, which can hurt the batteries depending on the type of cell. I see many people going without a transmission, but in my car I kept the clutch and transmission. I have a mg midget that drives just like the gas version. I also don't abuse my batteries because I can accelerate without drawing a very large current. I still draw 500 amps, which isn't little, but it's just barely above the recommended 3C limit for my cells. After doing an electric conversion, which isn't easy, I see people claiming the simplified the procedure by going clutch-less., I think to myself, that after all that work, you didn't bother to make it easy to shift? It's my opinion, but I have a very enjoyable electric car to drive.

[puddleglum]

Originally Posted by fb_bf

Be careful about assuming that because an electric motor has torque a zero rpm you can simply eliminate the transmission. The torque is proportional to the current. If you only use 4th gear, and the original transmission had a 1st gear that was geared to be 4 times lower in 1st, then you''ll need 4 times the torque of the gas engine to feel the same acceleration without the transmission. This requires you to use very high currents, which can hurt the batteries depending on the type of cell. I see many people going without a transmission, but in my car I kept the clutch and transmission. I have a mg midget that drives just like the gas version. I also don't abuse my batteries because I can accelerate without drawing a very large current. I still draw 500 amps, which isn't little, but it's just barely above the recommended 3C limit for my cells. After doing an electric conversion, which isn't easy, I see people claiming the simplified the procedure by going clutch-less., I think to myself, that after all that work, you didn't bother to make it easy to shift? It's my opinion, but I have a very enjoyable electric car to drive.

I was thinking about that after I posted. Most of the motorcycle conversions I've read about are direct drive. I think it works well in that application because they are ultralight compared to a car, so there is a lot less mass to get moving and most small bike engines have very little torque off idle compared to their peak torque or an electric motors low speed torque. In a car or a heavy bike or trike I would definitely agree with you. Motor definitely must match the gearing.