throttle control modes and pedaling

[E-HP]

I've read a few threads on throttles and throttle control modes since I'm moving from my KT controller with PAS to a PowerVelocity controller without it (unless you add a CA). My main concern is that my preferred method of riding is to use PAS, which gives me great range.

To see if I'll be able to adapt to throttle only, I set the PAS to 0 on my KT and tried different techniques to try to replicate how it functions with PAS. With PAS, I usually stay at level 1, which provides about 275 watts of assist. 275 watts without pedaling will bring the bike to about 14-15 mph, and I pedal up to 17 mph very comfortably. Well, if it try to replicate this by applying throttle and then pedaling, the resistance is much greater, like the motor is working against me.

Clearly I need to understand the relationship of the throttle and pedaling more, or possibly how different throttle control modes (torque, speed, power) can affect how the system behaves when adding pedal power, but I'm not sure which. It also makes me wonder how the CA handles this, since it supports PAS via the throttle signal (so therefore, will the PAS behavior be different between controllers depending on the type of throttle control mode?).

If I need to learn a new technique for extending range when using throttle only, I'm fine with that, since I wont' be adding a CA for a little bit. Or if this odd behavior is something limited to KT controllers, and if the PowerVelocity controller will work fine "pedaling up" to a higher speed than throttle only, that would negate having to do more research on this. The worst case would be to invest in the CA later and find that PAS doesn't function as expected.

Thanks for any insights into the throttle modes or specifics around riding with throttle only and pedaling, especially with a PowerVelocity controller would be greatly appreciated. In the end, how well PAS via the CA on a PowerVelocity controller is really the 64kW question.

EDIT: my KT controller has the PAS mode set to "imitation torque control" rather than "speed control" if that factors into anything.

Another thought is whether adjusting the power and speed setting for the three speed switch, by having a lower power setting and higher speed setting would allow me to "pedal up" to the higher speed, with the contribution being limited by the power setting would work? (this will be my first three speed switch too)

 

[john61ct]

I bet a "as new barely used" CAv3 would sell close enough to new price to make the experiment pretty inexpensive.

And IMO very likely to give you what you want anyway.

 

[E-HP]

I bet a "as new barely used" CAv3 would sell close enough to new price to make the experiment pretty inexpensive.

And IMO very likely to give you what you want anyway.

You’re probably right. I tried playing more with the throttle this morning and got something closer to what I want, but I had to manipulate the throttle a lot to do so (I’m sure the CA should be capable of doing that seamlessly, I hope).

After 35 years of marriage, we buy our own presents, so I count the controller for Christmas, and I’ll wait for my birthday for the CA (we’re self regulating with how much we spend, but I figure I spread out the fun this way, since I think a programmable controller will keep me occupied for a while).

Of course if Grin ever has holiday sales....


Sent from my iPhone using Tapatalk

 

[john61ct]

Just skip a few meals eating out and it's paid for, along with an extra nice Xmas prezzie for the Happy Life

 

[E-HP]

Just skip a few meals eating out and it's paid for, along with an extra nice Xmas prezzie for the Happy Life

On the other hand, all I want from the CA is PAS, so if I find that I can pedal and extend my range without it, without much work, then I can avoid adding a big display to my bike. I do like the bluetooth phone interface though, since changing settings and monitoring everything else is easy to access quickly. I figure that of the throttle only camp here on ES, that still pedal, have techniques that I have yet to discover.

 

[john61ct]

On the other hand, all I want from the CA is PAS

Then it's a matter of spending more on a controller that does it well.

I bet if you get the CA you'll find other features that turn out to be very useful, and you can keep all that while trying out different controllers.

 

[amberwolf]

To see if I'll be able to adapt to throttle only, I set the PAS to 0 on my KT and tried different techniques to try to replicate how it functions with PAS. With PAS, I usually stay at level 1, which provides about 275 watts of assist. 275 watts without pedaling will bring the bike to about 14-15 mph, and I pedal up to 17 mph very comfortably. Well, if it try to replicate this by applying throttle and then pedaling, the resistance is much greater, like the motor is working against me.

That sounds as if the controller is attempting to regulate the speed of the bike based on the amount of throttle input, so when you begin to exceed the speed of the bike as set by the throttle, it tries to slow you down by applying regen braking.

IIRC the CA even has a mode like this; I"m sure some controllers do, too. No idea if the KT or PV does.

If the throttle controls purely the amount of current or power, this shoudln't cause such a result, becuase it's just controlling the motor's usage. If the motor uses less current because of your pedalling, it should actually *increase* the motor's output, *decreasing* the resistance to pedalling, assuming you hold the same throttle position demanding the same amount of current into the motor.

If the throttle controls purely open-loop PWM, it's just controlling the voltage sent to the motor, so pedalling faster than the motor would feel more resistnace once you reach the motor's speed, because you are now providing power rather than freewheeling the chain drive. It shouldn't feel too bad, because it won't feel even as much as if you just pedalled to that speed without the motor.

It also makes me wonder how the CA handles this, since it supports PAS via the throttle signal (so therefore, will the PAS behavior be different between controllers depending on the type of throttle control mode?).

THe CA does *all* of the controlling of a controller via the throttle output signal. It doesn't have any other form of communication with any controller, regardless of connection method.

Thus, controller throttle input response determines what happens regardless of whether you use PAS or throttle or both to control the CA.

If the controller uses an open-loop PWM control throttle method, then everything the CA does is going to control the voltage to the motor, roughly equating to controlling it's speed. This is how the CA is designed to deal with controllers, becuase this is how most controlers still work, and just about all ebike controllers worked this way when it was designed. This is like the CA's normal throttle mode.

If the controller uses a closed-loop PWM control throttle method, then it responds to any throttle input as if it was a percentage of the max speed of either the system as a whole, or the max speed the controller is programmed to allow, if it is capable of that. This is like the CA's "speed throttle" mode.

If the controller already uses a torque / current control throttle method, then everything the CA does is going to control the motor current. This is like the CA's Current throttle mode (when used with a basic generic open-loop PWM controller).




Thanks for any insights into the throttle modes or specifics around riding with throttle only and pedaling, especially with a PowerVelocity controller would be greatly appreciated. In the end, how well PAS via the CA on a PowerVelocity controller is really the 64kW question.
If the PV does actual motor phase current control based on throttle input, then the CA whether using PAS or throttle should be pretty smooth, depending on the type of PAS you use and the setup in the CA. Using a 24pole cadence sensor, and the % of throttle mode, will probably work well, since the CA won't need to monitor feedback from battery current / etc to modify the output--it just has to convert the PAS cadence into a throttle voltage output.

I'll know more about exactly how that will work with a pure current-control-method controller soonish, once I get the SFOC5 reinstalled on the trike, as I have this type of PAS setup on the trike right now.

Another thought is whether adjusting the power and speed setting for the three speed switch, by having a lower power setting and higher speed setting would allow me to "pedal up" to the higher speed, with the contribution being limited by the power setting would work? (this will be my first three speed switch too)

Depends on how the switch works on the particulare ocntroller you're using it with.

Some of them just act as a "throttle multiplier", so it's like 100% throttle on the middle position, and 120% throttle on the hgih posistion, and some lower-than-100% throttle on the low position. The typical generic open-loop PWM controllers are usually like this. That basically makes this a "speed" siwthc, because the low position limits speed to about that percentage of normal, middle lets you get the nromal speed, and hgih gets you the actual max the contorller could possibly do.

SOme are programmable in what they do, kinda like the CA's "presets"; some do other things. They may contorl the amount of current, or power, or some combination of parameters.

There are a few threads discussing 3-speed swithc operation; this search finds a few (including yours).
https://endless-sphere.com/forums/search.php?keywords=*speed+switch*&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
though not all are relevant.

 

[amberwolf]

On the other hand, all I want from the CA is PAS, so if I find that I can pedal and extend my range without it, without much work, then I can avoid adding a big display to my bike.

You don't have to put the CA on the bars. It doesnt' even have to be visible at all, unless you happen to want to see stuff it's displaying. You can add buttons or a knob or a "3 speed switch" connected to the CA3 to remotely change parameters or presets on it.

If you like you can even remove the casing and display itself entirely, and just put the main little PCB into something weatherproof--though doing this means to change settigns you'll need to use teh USB-serial cable and the Grin setup program on a PC or Mac.

 

[john61ct]

Wow dude that's all super helpful, really above & beyond, kudos & thanks much. . .

 

[E-HP]

On the other hand, all I want from the CA is PAS, so if I find that I can pedal and extend my range without it, without much work, then I can avoid adding a big display to my bike.

You don't have to put the CA on the bars. It doesnt' even have to be visible at all, unless you happen to want to see stuff it's displaying. You can add buttons or a knob or a "3 speed switch" connected to the CA3 to remotely change parameters or presets on it.

If you like you can even remove the casing and display itself entirely, and just put the main little PCB into something weatherproof--though doing this means to change settigns you'll need to use teh USB-serial cable and the Grin setup program on a PC or Mac.

Thanks. This is very helpful info. Sounds like I won't know how the new controller implements the throttle until I get it (it's sitting at the post office now). I'm hoping it will function like a torque/current throttle. My other thought was to use cruise control and pedal on top of that, but I'm guessing a similar thing may happen depending on how that functionality is implemented.

 

[amberwolf]

Sounds like I won't know how the new controller implements the throttle until I get it (it's sitting at the post office now). I'm hoping it will function like a torque/current throttle

PV should be able to tell you; in fact it should be listed in the PV sale thread for that controller, though it does not say in it's first post description for the three I found. :/ It may be buried in the questions and answers posted in the thread over the years...but PV ought to be able to answer directly.

I don't know which of PV's controllers you've gotten, so I can't tell you which thread to look in:
https://endless-sphere.com/forums/viewtopic.php?f=31&t=85156
https://endless-sphere.com/forums/viewtopic.php?f=31&t=75888
https://endless-sphere.com/forums/viewtopic.php?f=31&t=81020

From ElectricGod's review thread, second post, back in 2017 (so an older version):

It's pretty much a linear throttle all the time with some very minor low speed throttle damping. If you set regen braking too high (that's regen when you let off the throttle) and then don't do throttle damping, the EV becomes virtually uncontrollable as it goes from accelerating to stopping and back to accelerating all within seconds. However that's your fault, and not a controller malfunction.

My other thought was to use cruise control and pedal on top of that, but I'm guessing a similar thing may happen depending on how that functionality is implemented.

The CA can do that, too, if the controlelr itself cant'.

 

[E-HP]

The CA can do that, too, if the controlelr itself cant'.

Ugh, yes, I know, it does everything. Leave it to the ES forum (and YouTube videos) to provide the stimulus to press the "buy" button. I guess it's happy birthday to me early, since the CA V3.1 is ordered !! Thanks for the nudge :lol:

 

[john61ct]

Worth it just for the Ah counting and thermal limiting. . .

 

[amberwolf]

Ugh, yes, I know, it does everything.

Unfortunatley, it does not. (though it does many, maybe even most, of the things people need on ebikes).

THere are a number of things it can't do that I need, such as using torque sensor to startup from a stop, and then use cadence to control once started. Instead, it requires cadence above a certain amount before it will pay attention to the torque sensor. Somewhere on ES (probably in the CA v3 beta thread or my trike thread) I have a list of things it can't do that I need, some of which could be worked around with external hardware, and some of which require either a software change of the CA itself, or simply starting from scratch with something like an arduino or other MCU, and ditching the CA, if I could do such a thing.

 

[j bjork]

Thanks. This is very helpful info. Sounds like I won't know how the new controller implements the throttle until I get it (it's sitting at the post office now). I'm hoping it will function like a torque/current throttle. My other thought was to use cruise control and pedal on top of that, but I'm guessing a similar thing may happen depending on how that functionality is implemented.
[/quote]

If it isen´t the new controller( that I don´t think is released yet), it is one of the cheep chinese speed throttle controllers. It will probably be resisting to go faster than the set speed in cruise control.

 

[E-HP]

If it isen´t the new controller( that I don´t think is released yet), it is one of the cheep chinese speed throttle controllers. It will probably be resisting to go faster than the set speed in cruise control.

Luckily now that I ordered the CA3, I won't need a workaround for PAS.