Does anyone have a throttle on a KT controller?

I have a classic Chinese thumb throttle on my KT, and it works just fine, but not with the KT.

Before I installed the throttle, the hall sensor inside was drawing 4.8mA @ 5V and it was outputting 0.824v @ 0% throttle, and 4.24v @ 100% throttle. Everything looks good here.

Now when it is connected to the KT controller, I get 0% torque until about 50% throttle, then torque is actually variable but it is already at 100% at maybe 60% throttle. So the whole torque range is concentrated in a very narrow throttle range.

What's going on here?

Does the KT work with a different throttle?

Or...are there any settings in the display you have regarding throttle / PAS operation, or assist levels, that could do what you see?

amberwolf said:

Does the KT work with a different throttle?

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That's the only one I have. There is nothing wrong with it since I tested the output out of circuit.

amberwolf said:

Or...are there any settings in the display you have regarding throttle / PAS operation, or assist levels, that could do what you see?

Click to expand...

Nothing that I see that could be related to input levels from the throttle.

I don't know a thing about what the controller SHOULD be drawing, but I can tell you that the 3 KT controller equipped bikes I have now, and the several others I've had in the past, NONE have been real picky about the throttle in use.

I will also share that I have the "imitation torque control" enabled (P3=1). This enables power based pedal assist, where the bikes speed has NO effect on the amount of power going to the motor...

There is also an odd thing I've noticed regarding power with the throttle. If I'm riding along, say in PAS 1, while pedaling, and I add throttle, the throttle will act like an on-off switch. Use it while pedaling, and you're going to get full power (wide open throttle) no matter the throttle setting. If I stop pedaling prior to using the throttle, I get the resolution most will expect when using the throttle. I don't use the throttle much, especially when pedaling, so it rarely becomes an issue/something I notice, but I know it's there....

Been riding KT equipped bikes for several years now....

AHicks said:

while pedaling, and I add throttle, the throttle will act like an on-off switch. Use it while pedaling, and you're going to get full power (wide open throttle) no matter the throttle setting.

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So your controller goes into full torque as soon as you touch the throttle? Even at 1% throttle?

Have you guys tried setting P3 to 0 to see if the throttle behaves itself better?

“P3 parameters affect the power assist control setting. When the value is set to 0, the throttle is dependent on the PAS Gear Ratio. This means when the PAS gear ratio is 1, the throttle will provide the least amount of power, whereas when it is 5, the throttle will provide the most power. If the P3 parameter is set to 1, the throttle will provide the maximum power regardless on the PAS gear ratio chosen”.

AGS said:

Have you guys tried setting P3 to 0 to see if the throttle behaves itself better?

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When P3 is set to 0 it seems like throttle at 100% results in 100% torque of the currently selected power assist mode. Not 100% of maximum torque.

When P3 is set to 1 then the throttle supplies 100% of maximum torque. The problem is it's almost like an on-off switch.

Yes, I have throttles on 4 or 5 different KT controllers, 25A, 20A, and 17A, and sine/square wave versions, I set P3=0, and the throttle really only makes itself known on the two 25A boxes. .

Comrade said:

So your controller goes into full torque as soon as you touch the throttle? Even at 1% throttle?

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No. Not at all. 1% throttle = 1% of the available power (not torque!) 25% throttle = 25% available power, etc.

Your use of the word "torque" is not correct in the context of this conversation I don't think....
The display should give you a very good idea of how much power is being supplied to the motor. Something down below 100 watts would be a walking speed. Max power/full throttle is going to depend on your other equipment and how many amps your controller is rated for. As an example, one of my 500 watt geared hub bikes, using a 22a controller (KT22a) and a 14.5 ah battery, will supply nearly 1000 watts at full throttle.....

AHicks said:

If I'm riding along, say in PAS 1, while pedaling, and I add throttle, the throttle will act like an on-off switch.

Click to expand...

That's what my throttle feels like.

AHicks said:

If I stop pedaling prior to using the throttle, I get the resolution most will expect when using the throttle.

Click to expand...

But I don't have this. It always feels like on-off. Pedaling or not.

Comrade said:

That's what my throttle feels like.

But I don't have this. It always feels like on-off. Pedaling or not.

Click to expand...

Is this while actually riding the bike, or are you testing with the rear wheel off the ground?

Doc's been riding KT a lot, so I trust his opinion even if it's different than mine. So let me ask, have you tried P3=0 and P3=1 to see if it changes your issue? Have you done a reset to default settings (C10=y) to see if something is set incorrectly?

Comrade said:

When P3 is set to 0 it seems like throttle at 100% results in 100% torque of the currently selected power assist mode. Not 100% of maximum torque.

When P3 is set to 1 then the throttle supplies 100% of maximum torque. The problem is it's almost like an on-off switch.

Click to expand...

I don't have the greatest memory, but I think I used to use P3=0, P4=0, C4=0

AHicks said:

Is this while actually riding the bike, or are you testing with the rear wheel off the ground?

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On the ground. I've had this throttle work like on-off switch for about a year. It's a little annoying, but not that much since the controller has soft start. It works just fine for getting across an intersection quickly, but I'd still like to fix it somehow.

I'm in P3=1.

P3=0 only allows the throttle to go up to the currently selected assist mode it seems. So if my assist is set to say 100W max, throttle even at 100% would not go over that. In P3=1 throttle goes up to my maximum set current on the controller.

How about trying a resistance throttle instead of a hall throttle?

Or even a Hall effect twist throttle instead of a thumb throttle for better control. They are much cheaper than resthrottles.

Comrade said:

I'm in P3=1.

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Yup, looked at the manual and P3=1 sounds right. Bad memory.

Just to take the throttle output testing a bit further...

Those throttle output voltage numbers look great to start with, but perhaps you'd like to take it a bit further...
Sounds like they are from a bench test. I'd be curious whether you'd get the same numbers with it connected to the controller. Using the controller's supplied regulated 5vdc power going thru the harness and checking voltages at the PCB wiring landing spots.

And does your output profile look similar to the one below? The voltages in the middle can be just as important.



Tips on profiling throttle output can be seen in this thread...

Guide to Hall Sensor Throttle operation, testing, and modification.


Regards,
T.C.

Comrade said:

When P3 is set to 0 it seems like throttle at 100% results in 100% torque of the currently selected power assist mode. Not 100% of maximum torque.

When P3 is set to 1 then the throttle supplies 100% of maximum torque. The problem is it's almost like an on-off switch.

Click to expand...

This is the same problem I'm having. The KT-based throttle is not 100% off/on, but it's relatively crude and unrefined. You need to really fine tune the thumb pushing to get it right. It will not even start any watts until you are 1/4 through the throttle's range, then there is some little sweet spot of say 25-50% throttle travel, where you can actually modulate SOME power, then after 50% throttle travel it's at the max watts. That's not very linear!

Also, if you are going up singletrack there is absolutely no way to throttle only smooth because your thumb is needed on the handlebar grip and not on the throttle. It's too awkward and you are being forced to concentrate on not stalling or spinning out instead of what you are supposed to be doing: looking at the technical features of the trail climb and adjusting the rest of your ride accordingly. That's why so many dudes out there prefer torque-sensor based controllers. I get it. Just trying to somehow save this setup before I give up on it.

Another issue is that if you set it up with P3 at 0 (throttle power is linked with the PAS level) even at PAS 4 there is not enough power to climb normally. For example, if a bike is nominal 500W and the PAS 1-5 levels are 150, 250, 350, 450, 850, then 450 watts should be enough and should climb almost anything up to 12% grade. But if you are trying to throttle only with what you 'think' is level 4 and 450 max watts, it's still not enough, even with C14 set to strong power 3. My C5 is usually 12 but right now I have it on 18 and PAS 4 is still too weak. No idea why level 4 would not climb better. If this could work, it would be a lot easier because you could match the throttle travel sweet spot with a specific watt range that's linked with PAS 1-5. But you can't.

I'll keep messing around with these parameters. My backup plan is that I have an SW900 display and what I think is a DC Moto Controller or equivalent from EBikeling (they have discontinued that controller), but the throttle is a lot smoother. I can switch the controller, display, and actual throttle over and live with that. It may be easier than messing endlessly with the KT throttle. KT makes PAS smooth but I don't think they really care about the throttle or they would explain how to smooth it out in English. They certainly do not explain it.

I live in Southern California I have a box of throttles I don't know which are good or which or not but if you come by you can check them out and have one. Not my QS throttles as I bought 6 when I found a good shipping price.
But yes 48v BMC more then two you don't need the volt meter and many others.

docw009 said:

Yes, I have throttles on 4 or 5 different KT controllers, 25A, 20A, and 17A, and sine/square wave versions, I set P3=0, and the throttle really only makes itself known on the two 25A boxes. .

Click to expand...

Yup, the KT controller's throttle is pretty soft and easy to control running at 14S or below. The quickest way to develop better throttle control is to switch to 20S for a week or two, then managing a throttle at 14S is a piece of cake. What is a quarter turn at 14S is like an eighth turn at 20S.
Once you develop a higher level of throttle control (which happens pretty quickly if you stick with it), then even 20S becomes easier. I slightly tame the throttle ramp with the cycle analyst, but just enough so I can control it. Anyone else who rides the bike will be on their back in a split second, so basically my throttle is a theft deterrent. For single track, I crank the power down, and leave the throttle as is. I guess for the KT, you could choose the setting where the throttle power output is adjusted by PAS level, and use a lower level for better throttle control, but I don't think it needs it.

Not to bump the thread or anything but now I'm having a different issue.


P3 = 1 (imitation torque; cannot stand speed control)

P5 = 17 (not that it matters for this discussion, but I think I figured out what P5 really means --- they are asking for the battery's Ah)

C4 = 4 (throttle power tied to PAS level on display)


In C4 even when the throttle is tied to the PAS display level for power, PAS 5 throttle can sometimes be too strong up something steep or when climbing switchbacks. So I put C4 to 4 and thought OK if PAS 5 can peak at around 900 watts, PAS 4 is around 425 watts (I have an LCD5, will put on an LCD3 for watt measurement later this week). Here's the problem: yes PAS 4 throttle climbs nice and slow and steady at around 400W uphill. For about 10-30 seconds. And then fades to maybe 200W and eventually to nothing. PAS 5 throttle DOES NOT FADE. So I want to make it clear that I don't think it's an overheating issue. I have felt the motor and controller. Motor is cool. Controller is a bit warm but nothing to worry about. I'm wondering if this square-wave KT controller is simply a piece of crap and it has an internal problem. On a different but very similar KT controller (as in probably same model) when I used to do real PAS 4 w/o throttle, I could go up 400 foot hills with zero issues, zero fade on a geared hub drive. The watts were consistent all the way up. Now with a mid-drive I get PAS 4 throttle fade? Cannot figure it out. PAS 5 throttle may fade a little after 30 seconds up something steep but it doesn't just quit like the lower PAS throttle-tied levels do. Due to issues beyond the scope of this post, I cannot do real PAS with this bike's setup, it has to be throttle only.

UART 30A sine-wave controller & SW900 display in the mail. Throttle modulation MUCH better with those. Sorry but KT throttle-only sucks. Unless you can wave a magic wand at the LCD parameters. My 3rd KT controller, and throttle-only has sucked each time. Thrice-bitten, quadrice shy.