Two motor two controller one bb torque sensor

[MarkB]

First post. Looks like a knowledgeable forum here. Been lurking for a while and decided to join, stumped for an answer and here is my query.

Have two Wired ebikes, a Predator and Warrior. Warrior works fine. Predator is the problem child. Everything works except when using torque pas, and it is lacking in both sensitivity and power. I am thinking the bb signal is lost somewhere. I've changed out the bb and both controllers, same results, maybe changed minutely but hasn't fixed the issue. I have the Warrior set up exactly the same, except it doesn't have the dual hub motors, dual controllers, and the motor switch that changes from front, front and rear, and just rear. The Warrior works great in torque pas.

So is there something funky that happens when two hub motors are operated off one bb torque sensor? The cadence pas works great on the Predator as does the throttle. There are watt meters on the display so I can watch how much assist there is. I can pedal along on the Warrior at just a little over 500 watts and doing the same thing with the Predator it will be a little over 300 watts and take a little more leg to keep things going.

I am thinking resistance in the wiring design or too many circuits for the signal to travel through. Strangely, the bb wiring feeds the controller to the rear motor, and it was the rear motor that was weakest in torque pas and the front was strongest, with both motors operating in between.

Thank you for any insight!

 

[amberwolf]

You'd have to specify how you have this system designed and wired up, what the specific parts used are, how it is programmed to respond to the BBTS, and any other details you can about each system, listed as two separate bikes so nothing gets confused between them, for us to help you figure out what you haven't setup correctly in them.

It may also help to know the specific riding conditions / terrain / etc used for the tests, as well as the total system/rider weight and actual angle for any slopes, as those all matter for how much power it takes to do a certain job.


As an aside, I use the Cycle Analyst v3 to read a cadence sensor on a BB TS (have also used the TS itself in previous tests), and feed it's single throttle output signal to two phaserunner controllers that each drive an old Ultramotor recycled from A2B bikes, to run my SB Cruiser trike. With the controllers each setup equivalent to the other, and each running an equivalent motor, the single control signal properly tells each of them to do the same job at the same time.


If the motors are different, or the wheel sizes are different, or the controllers are different, betrween one powered wheel and the other on the same bike, then even with identical control signals you'll have different demands on each one and differnet outputs.

 

[MarkB]

That is interesting. I didn’t set them up, they are production bikes, other than variable settings on display. I am using my experience with two Specialized brand ebikes and one of their Wired brand production bikes as to how the torque pas should operate, both of which operate very similarly. I have replaced the controllers and BB but not familiar with what wires are what, just substituting plug and play. Would I be wrong in expecting the dual motor bike to work similar to the single motor bike even though cadence pas work the same in the single motor and dual motor bike, even changing from front, both, and rear motor operation.

 

[stancecoke]

which operate very similarly

You never know, how the firmware of the controller processes the cadence and the torque signal. Do you have photos or links to you components? You could use the torquesensor emulator to see how the controller reacts to a cadence and to a torque signal.
But it is not available commercially and of course you have to know the pinout of the connector.

 

[MarkB]

This last controller change out they said adjustments had been made but I am starting to wonder if they are just sending out parts in hope of a remedy.

The rear clutch is starting to squeal which is a recurring issue. Am thinking that may affect mph but wouldn’t affect watts being used which is lower than the other bike, being the BB is independent of this. Just a different issue.

 

[E-HP]

This last controller change out they said adjustments had been made but I am starting to wonder if they are just sending out parts in hope of a remedy.

The rear clutch is starting to squeal which is a recurring issue. Am thinking that may affect mph but wouldn’t affect watts being used which is lower than the other bike, being the BB is independent of this. Just a different issue.

Do you have a multimeter? As a first step in troubleshooting, I would try to determine what types of signals are passed from the master controller and the slave. Starting with the throttle, you could look for continuity between the throttle input connector signal wire, with any of the conductors that interconnect the two controllers, to determine whether there is a straight pass through of the signal or whether there's some processing of the signal being performed by the master, before sending the signal to the slave. You could do the same with the PAS signals as well.
It could be that the torque signal is not passed to the slave controller, but processed by the master, then output to the slave via a throttle signal, similar to how amberwolf described the cycle analyst does, processing the signal and outputting a throttle signal. Determining what the master controller does and then outputs to the slave would be the first steps that would help in determining what can be done. If the master is passing everything to the slave via a throttle signal, for instance, that would allow the addition of a potentiometer circuit that could adjust the throttle signal to balance power between the two controllers, etc.
How many cables or conductors are there between the master and slave controllers?

 

[MarkB]

Thanks for that input, pretty indepth responses here. I'd have to open it up to find out how many direct connecting wires. The person I am working through said they made adjustments to the controllers.

Right now the front motor is working better in torque pas than the rear, it is more sensitive anyway, easier to keep power transmitted. The rear is not as sensitive. The BB wire goes to the rear controller first. The rear controller is larger, 65A I believe and the front is 45A, I'd have to open it up to be sure. The issue is the sensitivity in comparison to another one of their bikes that is rear motor only, just takes too much pressure.

Had another thought. The rear motor clutch is starting to squeal, think that is what is going on. I don't know how the clutches are set up, but if both motors are not in sync or close to pulling when under power, was wondering if the clutch can be damaged. The motors are Hentach.

Next time I open the controller box I'll follow the wires and see where they go. It is kind of a jumble and very cramped getting the wires in there.

 

[MarkB]

First time they sent a BB and front and rear controller. Replaced with no noticeable improvement. Sent front and rear controller that were supposed to have been tweaked. Maybe noticed a little improvement. Still not in the same league as the other torque sensing ebikes I have. Gonna let it rest for a while and consider it either a throttle or cadence bike.

Thanks for all the tips, I may come back to them. Right now just tired of working on stuff. Fixed the anemic rack by riveting plates on both sides, that took a bit of time and patience. Winter right now so plenty of time til spring to do something, if something is done.