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hi.. there Answered

we  want to couple 125cc engine with electric motor  to make hybrid vehicle can any suggest how to couple them both so that vehicle can shift from motor to engine while running



set a speed sensor circuit so that when it hits a certain speed of preset level it turns the starter motor of the engine on and turns the electric motor off using a relay and thus turning the engine on to obtain power from engine

Your not going to get anything lighter than using a clutch to connect between the two drive units - BUT engineering wise this isn't going to be easy.

I worry that you skill set is such that you don't already know about this.

When I design something I spend weeks thinking, reading and drawing to come up with some kind of working design. I look at what others have done, I look at commercial examples, I look at theory. Then I try to select out those ideas that might fit what I want to do.

Asking general, open questions here isn't getting you down that road.

We don't know your skill set, we don't know your budget,

We don't know how far you have already got.

We don't know what materials or workshop facilities you may have access to - All these things makes a huge difference.


You could magnetically link the 2 motors to the drive shaft so 1 could disconnect allowing the other to run on. Connecting both would allow the motor to charge any battery you have.

You could use a hydraulic motor and drive 2 pumps from the 2 motors - simple valves would allow changing drive from one to another.

You could build 2 large gyroscopes. each driven by one of the 2 motors. Arrange them so that the gyro can precess freely in the forward direction but at the front limit they couch a track. This cause the shaft to run backwards along the track imparting a forward motion to the vehicle.

At the rear end the track lifts up so that the gyro goes into precession again moving forwards to repeat the process.

Now Valid or not, your not actually going to do any of these because they are complex, heavy and expensive. So start reading, drawing and thinking.

PS as a generality this isn't worth the effort any hybrid system that can be driven by a 125 cc motor is going to be so heavy it will outstrip the value of the hybrid system better look at -


This is the second request for this information.

Your best bet is drive a generator with the engine and charge a battery. Make the kart permanently electric powered and the engine supply electricity to keep it running.

Weight is a huge issue in small electric vehicles so a true hybrid system isn't going to be effective on something small that uses a 125 cc engine.

rick we r using 6 feet kart and 1500 rpm motor with more than 20 amps/h current and 3 lead acid batteries with more than 44v total

Same weight considerations still apply. Not to mention how hard and expensive it would be to get your hands on a hybrid transmission. Your best solution is to use the motor to keep your batteries charged and keep the thing electric. Beyond that you'll want to contact vehicle manufactures and see if you can order the transmision you need.

can u give me any estimation of how much it will cost?