My hybrid/tribrid

[Flapdoodle]

I have had the controller apart, and determined that the circuit board was not grounded to the case (which doubles as a heat sink). But it just occurred to me that the transistor heat sink tabs may be common to one of the transistor leads (a common practice), and therefore ground that part of the circuit. In a regular bike application that would cause no problems at all.

The interference is rather severe, so I am inclined to believe it is a ground loop. I already know the motor not frame grounded. It may be possible to insulate the controller from the bike frame with gasket material and use nylon nuts and bolts to fasten it to the mounting plate. Surely once the e-motor and its circuit are separate there should be little or no electrical noise.

Of course this is not what I had originally planned, but I really like that feeling of being pushed back by the acceleration of the two motors working together.

 

[duivendyk]

You open up the ground return of the CD unit to kill the engine?, is that to the frame?. better to get rid of frame grnd and use engine grnd return&twist pair. Can't you use a short to grnd on the WW instead ?,less junk on that.Would not hurt to put 0.1 mf ceramic cap to grnd on it.

 

[Flapdoodle]

Good suggestions. I have been thinking that the engine to frame ground may not be good since I have inner tube rubber between them. I will stick with opening one wire to the CDI though. It bothers me to short anything as a means to kill it.

The wires are short since the HT was a tight fit in that stupid Walmart frame. I have dubbed the design where they lowered the rear of the top bar so it is something in between a boys bike and a girls bike a "hermaphrobike".

 

[Happy Valley]

I have dubbed the design where they lowered the rear of the top bar so it is something in between a boys bike and a girls bike a "hermaphrobike".

Heh, hermaphrobike no kidding, huh. I despised it when production bike companies stated that trend back in the 90s. I've always been a fan of big, vintage triangle frames.

Keeping an eye on your project Bill, looking good.

,

 

[Flapdoodle]

I checked the power transistors and they are insulated from the heat sink, which means the controller case has no ground to the circuit at all, so I will not insulate the case from the bike frame. Not sure yet about the hub motor. Will be difficult to isolate from ground.

Tonight I thought it might be a good idea to braid the power wires from the battery pack to the controller. Plus 36v, ground, and the power from the key switch. Only took a few minutes, and there was quite a bit of difference. Most of the e-throttle can be used now especially when the g-motor is at a higher RPM than idle. Getting closer to what I want. Next will likely be a sprinkling of filter capacitors. I have some 600 volt paper .1µf. Really showing my age with that statement.

Bought an adjustable center kickstand on eBay today and it should be here in a few days. That should allow me to experiment in the shop with the bike stationary.

 

[Flapdoodle]

I made a shielded can cover for the CDI and soldered it to the plug wire braid. It did not help a bit. Looks cool though.

Aha! Finally a major clue. I measured the resistance between the hub motor and the bike frame and found it to be 70 ohms. I thought a jumper from the front fork to the frame would help, but to my surprise the e-motor would not run at all with the gas engine running at any speed or rpm.

I may have to insulate the hub from the fork or open the motor and see what is grounded, but will wait until my center kickstand arrives so I can make voltage measurements.

 

[Flapdoodle]

The problem with the e-motor not working if the gas engine is running has been solved.

It took shielding the CDI and braided shield on the spark plug wire connected the shielding on the braided power wires between the battery pack and the controller, but NOT grounded to the frame.

The controller is also electrically isolated from the frame (and not connected to the plug shielding), and a resistor spark plug is required.

This was a rather tedious trial and error discovery with a lot of strange things happening. What finally led me to the solution was finding that it worked smoothly if I had my hand on the spark plug shielding while riding, and opening both throttles (while watching for traffic). I don't recommend trying that.

Now it really accelerates hard if I want it to. The front wheel occasionally spins accelerating from a stop. Hang on to your hat!

 

[Jim Bounds]

Wow, how does it perform with oth motors. That is exactly what I was thinking about!

 

[duivendyk]

The hybrid setup could be quite useful on hills, or when accellerating from a stop ,because the electric motor can provide lots of torque for a short time.You might then get by with less reduction in the engine drivetrain ,thus reducing engine rpm&noise.

 

[Flapdoodle]

In addition to those JJ mentioned, I use it to get through the deep gravel driveway to the road. Before, I was exhausted pushing the bike. Not much in the way of hills here since Roswell is high desert plains.

I figure 7 miles to town, so I want at least 7 miles of electric power in case of the gas engine failure, or the chain (which has happened twice now. New #41 on the way from NAPA).

The main advantage of tri-power for me is the age and damage factor... I am just not physically able to pedal very far.

Last but far from least is the fun factor!