KU123 36v 500W Controller

d8veh

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I have just received one of these controllers from BMSBattery (Ecitypower) for my next project. It has some nice features: Cruise control, speed limit and 3 speed switch connectors. My last one was similar with cruise control but not the speed limiter and 3 speed switch. I like the cruise control, but it's difficult to set. You have to keep the speed/throttle constant for about 5 secs, which is difficult on a bumpy road and it gets cancelled each time you use a brake or the throttle. Ideally, I want to set my bike to cruise at about 12mph using the pedal sensor. My friend has a speed limiter switch on his 9FET Ecitypower controller but it doesn't work on the pedal sensor unless you hold full throttle which seems a bit crazy. So here's my questions:

1. How do I wire the three speed switch? I have one with three wires and there's three wires to the controller. How exactly does it work because there don't appear to be any components in the switch? Does it matter which wire goes where?

2. Does anybody know the logic of the 3 speed switch? Does it set 3 speeds for both pedal sensor and throttle? I've heard that on some controllers the medium setting gives higher speed than with it disconnected!

3. Does the speed limiter work on the pedal sensor and throttle, or only with the throttle open - like on my friends bike?
 
As I didn't get a reply to my previous post, I'll try it this way:
I have a 3 speed switch with 3 wires to it. I have a controller with a 3 speed switch connection with 3 wires.
Does it matter which wire goes to which?
 
Yes it does. 2 of the wires are for 5V power, positive (usually red) and negative (usually black). The other one is for signal (throttle/speed level), voltage varries from 0 to about 4.x volt, on my Infineon controller, it's green.
 
Thanks very much for that. Much appreciated. I can now understand the controller side, but the switch has three different coloured wires connected to three pins in a line. Is there any way to determine which is which?
 
If you have a separate ~5V power source (most phone chargers are around 5V), you can try by trial and error. If something goes wrong, the most you will damage is your throttle.

That said, I made a wrong wire connection from the throttle to the throttle connector (controller side). Luckily it did not ruin anything. Don't know (don't recommend) if it's the same way on your controller.
 
The cruise on my BMS controller is the white wire. Cut and place a momontary switch to engage or disengage. Works fine.

As for the 3 way switch??? Let me know if you do find how, as I am stumped. I know infieons are setup to use it. but I don't think these are as I haven't found it yet.

Dan
 
I've now connected the controller and it's not what I expected The three wires from the controller are black, red and blue. I measured the voltage on each pin and I get:
green +5v
Black +0v
Blue +5v

The three speed switch has three wires : red, black and blue. I measured the resistance between the wires with the switch in each position:
Black and red closed in position 3 (0 ohms)
Blue and red closed in position 1 (0 ohms)
all other possibilities are open

So, it seems it must work digitally rather than analogue, but I'm now totally confused.
Can anyone sort out the logic for me. Any help will be much appreciated. The controller is giving 40amps with or without the speed limit engaged, which is much more than I want. The throttle is more or less on or off.
Dave
 
I was looking at what appears to be your controller on the BMSbattery website and the connector color codes they show under the "KU123_controller_diagram" do not seem to match the connector color codes on your unit.

Here's where I found the diagram:

http://www.bmsbattery.com/controller/364-universal-brushless-hub-motor-controller.html

The PDF can be downloaded from the link shown at the bottom of the page:

KU123_controller_diagram
KU123 High speed controller diagram

Not sure what's going on here but, this wouldn't be the first time that I've seen web based manufacturer wiring diagrams and color codes that don't seem to match what they sell.
 
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