What can a Grin controller + cycle analyst do that KT controllers + KT display can't do?

From my research, most Grin motors have temperature sensors in them, and the cycle analyst is able to read internal motor temperatures. Undoubtedly a very useful feature.

But what else?

Don't know KT controllers. Do they have thermal roll back, can you log data from them, do you have control of PAS on the fly, different profiles. Need more?

Better to phrase it

do KT controllers offer any of the dozens of features that CAv3 does

Vasili for example is scathingly vehement that his Nucular controllers have no need of, should never be used with a CA

ZeroEm said:

Don't know KT controllers.

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I thought they are the de-facto standard of not big label (non Trek/Bosch/...) Chinese made electric bike systems. Most common by number of product sold.

ZeroEm said:

Do they have thermal roll back

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If motor manufacturers do not put temperature sensors in the motor, that would be difficult.

ZeroEm said:

can you log data from them, do you have control of PAS on the fly, different profiles. Need more?

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I think no, no, and no. I do need more as I'm a tinkerer and making a decision what to invest in. :thumb:

Grin CAV3 can datalog, like twenty channels at once, 10x / second. GPS connected speed and trip mapping too.

Comrade said:

From my research, most Grin motors have temperature sensors in them, and the cycle analyst is able to read internal motor temperatures. Undoubtedly a very useful feature.

But what else?

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The KT controllers with osf can do most of what the CA can do, be it logging and PAS profiler change on the fly as well as phase current monitoring.

However, the system is not as mature as the Grin system, which seems more user friendly. I use the KT and it is actually pretty good, but hard to set Up.

I'm not knocking KT controllers. Should get myself one. The CA is not a controller it is added features. If your controller does everything you need then don't need one. But having one around is just another tool in the basket. I like the cycle feature for telling how many times I have charged up and how many miles on that charge. It has more features than I use.

Have look around for KT controllers but fear don't know what i'm looking for. If you want to compare the KT to something then how about another controller with features and not a throttle modifier.

Note: Most motors can have tempter monitoring added to them if you can get another wire in there. Don't expect the KT to monitor the motor temps that is what a CA is for. Know some controllers do. Don't limit yourself.

ZeroEm said:

Note: Most motors can have tempter monitoring added to them if you can get another wire in there.

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That's what I was thinking of eventually doing. Just a simple 10K thermistor, with a single signal wire coming out, ground should already be out in the harness.

If you like working on eBikes most things can be done. Takes time and a little figuring out. Which most of the members do. Just can not leave well enough alone. :lol:

Keep in mind that the CA3 can be used with basically any controller. It controls the bikes throttle but the controller doesn't know that. The temp rollback comes from the sensor in the motor. The CA3 just limits the throttle its commanding based on motor temp.

I see no reason that you would have to use a grin controller with a CA if you have a KT you like. Sounds like the original question is lumping them together as a set.

DanGT86 said:

Sounds like the original question is lumping them together as a set.

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Yes, I was under the impression that using a Grin controller with a CA was more than just thermal rollback as far as functionality.

And I'm interested in understanding what I could miss with KT vs CA. As much as I love data I don't think logging would be useful. Total energy out also, not so much, as I can just keep track of energy in on the charger. Sounds like a temperature sensor can be retrofitted.

I guess I won't know what I'm missing until I build an ebike and start riding it.

The CA does not need to plug into the controller. It does not control the controller. The controllers that have a CA plug in shares the internal shunt and connects directly to throttle. Nothing you can't do yourself with any controller. You can buy an external shunt for the CA and just plug it into the throttle and some power and your on your way.

ZeroEm said:

The CA does not need to plug into the controller. It does not control the controller.

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I thought both CA and KT type displays do program the controller to some degree. Or are they purely passive and only display information?

One thing that annoys me with my KT bikes is the lag or delay on throttle. Haven't flashed any with OSF so I'm not sure if there is a way to get rid of that, But I hate when I am getting on the throttle coming out of a turn and it just does nothing for a half a second. Then again, I've heard a few guys say that the cycle analyst also adds a noticeable delay

I'm sure the KT display controls the the KT controller.

The CA is nothing like other displays. It only modifies the throttle input to the controllers. you could have both if you wanted to. It just needs inputs like motor or wheel speed and watts/amps from the battery. Tempter if available.

The CA is not make for any one controller like the KT display. Does the KT display work with ASI controllers?

Acutally you can very much plug a ca onto your kt controller. Required modifications are quite easy, and kt sine wave controller with stock firmware are good enough for many cheap hub motors.

Comrade said:

Yes, I was under the impression that using a Grin controller with a CA was more than just thermal rollback as far as functionality.

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As has been made clear from many responses, yes that is true.

But as has also been stated, the CAv3 is not just designed for Grin controllers, nor v/v.

CA works with any controller, including KTs

It is not just a display, can be installed to work buried in headless mode.

It does not affect the controller at all, just takes input from it plus other sensors, and then controls (only) the motor throttle.

Download the CAv3 manual and read it.

In my experiences, when connecting a motor to a controller ... 3 heavy phase wires of course ...
5 smaller wires = 3 sense (yellow blue green to match phase) + (1) 5v (red)+ (1) gnd (black)

ONE WHITE TEMPERATURE WIRE may be present.(= 6 smaller wires)
The controller must "know" temperature to roll back.
If the controller or motor does not have 6 wires it is unlikely thermal rollback could be possible. Assuming motor temperature rollback is the issue.

The idea that the controller could rollback performance due to internal temp. (not motor temp) would take a different approach to determine.

Don't get me started on battery temperature monitoring and management.

The CAv3 adds temperature protection throttle rollback.

It is a "meta" controller does not try to communicate with the "dumb" controller

justs adjust the throttle input.

john61ct said:

But as has also been stated, the CAv3 is not just designed for Grin controllers, nor v/v.
CA works with any controller, including KTs

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It might work with other controllers, but it does not appear that it will program controllers, since say KT uses a proprietary protocol.

So if someone buys a KT controller, they would still need to buy a KT display to program it to make it work with the specific motor that it is connected to.

Comrade said:

It might work with other controllers, but it does not appear that it will program controllers, since say KT uses a proprietary protocol.

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Yes, if there is a display used to program a given controller, it is proprietary, that is true for all controller brands.

The CAv3 is not such a device. It has nothing to do with programming any controllers.

The user must get the controller working with the motor as a completely separate process, nothing to do with CAv3.

Its many functions work to "meta control" the bike via controlling the **throttle input to** whatever controller the bike is using.

by Comrade » Nov 23 2021 9:47am
It might work with other controllers, but it does not appear that it will program controllers

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CA is an addon and uses the controller's shunt, halls signal and power to operate. It does not talk back to the controller or gather information on what the controller is doing. You can add an external shunt and monitor wheel speed to have very little to do with the controller.

Don't see anywhere or anyone claiming that the CA talks to controllers and is able to change settings in some, most or any controller ever made or any that will be made. The CA is like a solar panel it uses sun light but does not talk back to the sun.

The CA collects data, based on that data it varies the Throttle signal to the controller.

Again The CA is not an interface to your controller, no matter what brand or model it is or what proprietary protocol the controller is using.

The CA was not developed to replace your proprietary protocol interface with your controller. You can add a CA as it is a add on for more features and it will not interfere with your proprietary interface but again it will not interact with it only modify the Throttle signal.

Comrade said:

And I'm interested in understanding what I could miss with KT vs CA.

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What specifically do you need your bike to do for you, and how do you want it to do them?

What specifically do you need your bike to be able to tell you (via display)?

If you make a list of these things, then we can help you figure out what system (or systems) are needed to do those things.


If you just want to know what the CAv3 can do, the Grin site and manual do a fair job of listing the major features. There are ways of combining various features to do specific jobs in specific ways that may not be listed, but there are so many possiblities I can't just make you a list.


Knowing what you want to do, with enough specific detail, we could tell you if that can be done with the CAv3 or not.



Essentially, the CAv3 takes in a number of sensor and control inputs, processes them thru whatever settings you've put into it for the various functions, and outputs a throttle signal to the controller based on all of those things. Since it's only output is a throttle signal, then it is directly compatible with any controller that has a throttle input (whether that is a PWM RC throttle or a variable-voltage throttle within the 0-5v range). To perform some functions, it may need other external hardware depending on what's already available on your bike.

The specific things it can take as inputs are listed in the Grin documentation, as are the specific settings available in the various menus.


The CA is NOT a display.

(just to make that absolutely clear to any readers now or in the future)

It is not designed in any way to communicate with any controller in any way other than sending it a throttle signal. It can only display the information that is monitored or created within the CAv3 itself, nothing that comes from a controller. It can't program anything outside of itself. If your controller requires programming, setup, or mode changes either initially or at the start of every power-on cycle, then you would still need whatever hardware is required for that by that specific controller.

(if that hardware is only needed for initial setup, then you don't have to mount it on the bike, but you still have to have it).

amberwolf said:

The CA is NOT a display.

(just to make that absolutely clear to any readers now or in the future)

It is not designed in any way to communicate with any controller in any way other than sending it a throttle signal. It can only display the information that is monitored or created within the CAv3 itself, nothing that comes from a controller. It can't program anything outside of itself. If your controller requires programming, setup, or mode changes either initially or at the start of every power-on cycle, then you would still need whatever hardware is required for that by that specific controller.

(if that hardware is only needed for initial setup, then you don't have to mount it on the bike, but you still have to have it).

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That's the part that wasn't clear when I initially posted. I thought it can an alternative to a display, rather than an add-on.

But now that I own a KT-LCD8 display, I understand why a KT controller would never run properly without it.



I did find an interesting feature. Apparently LCD8, or maybe even other displays in the KT series, can display internal motor temperature. From what I read online, it apparently uses the same method CA does, to "multiplex" the speed hall sensor (usually white wire) with a 10K thermistor, so the amplitude of the square wave from the hall sensor represents temperature.

Did Grin come up with this idea and KT followed? Or other way around? Or neither one and it came from somewhere else?

It seems like Grin customizes motors that they sell, by putting in thermistors, which I have not seen mentioned by other motor sellers.