No power level selection SW900: Always at max power regardless of any PAS or other settings.

[klinger]

KT48ZWSRK

I have an eBay 1500w SW900/35a controller kit.

I hooked up regen braking on my controller, everything worked great for 1600 miles. But I stupidly had my controller open to figure out how to put firmware on it, and shorted two of the mosfets to the case and blew it up.

I bought the KT 50A controller here:

https://www.aliexpress.us/item/3256804374385837.html

to upgrade my bike, since my 35A controller is dead.

I hooked it up, same 5-pin LCD control connector.

Error 10.

* Tried the shunt method, grounding KT switched 58v and Bat, grounded the yellow wire, hooked up the throttle. No response from throttle.
* Hall and Motor wires are hooked up, same color and plug config
* Opened SW900 display, no visible burn marks or anything out of place.
* Cable in pristine shape, worked before

I'm hoping I fried my SW900, because there is just no communication. I tried reversing the wires, the shunt, d/c the motor/hall, same Error 10.

Can I use the Open Source firmware to do something to make my Aliexpress controller work with my SW900? Or do I have the wrong controller, or is there another way to verify my controller works?

 

[docw009]

KT Controller needs a KT display. The SW900 and LCD displays do have the same pinout, but give comm errors if mixed.

Did your controller come with the display shunt connector? That will allow it to power up and run with throttle and a default PAS level Sometimes you will get throttle and a PAS to work on a KT controller with a foreign display. Depends on whether the display shuts down the controller because of comm errors.

If it''s the 5pin JST, the jumper looks like this. You jumper red to blue. That sends battery voltage to the controller to turn it on. They jumper black to yellow. which grounds one of the data lines.



If your controller uses the round modular connectors, it can still be jumped, but you have to match the pins.

 

[klinger]

I had an 'ebay special' SW900 bike kit before, and I could use the thumb arrows to set the amount of maximum power on the bike, from 0-5, while using the throttle. 3 would be mid-range, and the bike would cruise along, you could just hit up arrow, and 4 would make it faster, with 5 being max speed controlled by the throttle at all times. It was a nice cruise control feature.

I have a new 'ebay special' SW900/35amp controller 52v kit, and the PAS does nothing. It's always MAX POWER!
* No PAS is hooked up at all, as on last bike
* I tried all 3 settings of P10 Drive Mode Setting. No change for arrow key power.
* Changed P11, no change
* Changed P12, no change
* Changed P05 to bothe 3 and 5, no change

Is there something else to do to get the Power Level arrow key settings back? It was literally the best feature of this thing. These throttles are very hard to control just holding them.

 

[amberwolf]

Do you mean by "It's always MAX POWER!" that even when not touching the throttle that it's always on at full power? If so, you probably have a broken ground wire to the throttle.

If you mean that the throttle works to modulate wheel speed (or power) but that you can't reduce the amount you get at full throttle, then: do the levels change on screen as you press the + / - buttons?

 

[klinger]

Do you mean by "It's always MAX POWER!" that even when not touching the throttle that it's always on at full power? If so, you probably have a broken ground wire to the throttle.

If you mean that the throttle works to modulate wheel speed (or power) but that you can't reduce the amount you get at full throttle, then: do the levels change on screen as you press the + / - buttons?

The latter. The levels change at the PAS section, from 0-5, but the throttle always controls power, and it is always set at full power control. *Edited

In the past, the PAS 0-5 controlled by the arrows meant I could start at 1, will full throttle, and it would go slow. I could just hold full throttle and advance the PAS section with the arrow buttons to 2, and it would go faster, and so on...

 

[amberwolf]

Then I suspect that your display is not transmitting to the controller / the controller is not receiving what the display is sending, so even though the display is doing it's thing and showing the correct result, the controller isn't being commanded to change anything.

Do any display functions or commands do anything at all to change controller behavior? (other than power on/off, which isn't a comand, but a switch inside the display that turns off ppwer to the controller brain).

If not, then that's probably what's wrong. It could be a wire or connector fault, or a defect in the controller rx buffer or the display tx buffer.

It could also be incompatible firmware versions between the display and controller so the data being sent isn't understood by the controller.