Adventures in assembling a custom ebike - electrical challenges

[CloudPine]

Greetings community,

I could use some friendly advice.

I got a cheap but loaded C Inverter Leo bike off of amazon to replace my daughter's beloved Gen3 Stride which was stolen.

The bike did not have 750w motor as advertised but a 350w motor with 16-18amp controller. My daughter was sorely disappointed with the bike's lack of torque for going up hills on her way to school.

So I decided to upgrade the motor to a new Shengyi 500w motor that I had lying around. I re-laced the motor into the wheel. The motor even worked fine with the controller that came with the bike. But the low amperage controller was hardly getting the most out of the motor and the bike still lacked torque.

So I decided to upgrade the controller to one with a higher amperage - a Sinewave 22amp KT with WP connectors. I even found one with a 4pin WP Julet connector for a rear light with a brake signal. The thing is both the new motor and the C bike controller had a rather rare Z1013B Linkwe cable connection. So I figured I could splice a cable to go from the controller Z910 connector to the Z1013B connector of the motor cable.

Once everything was connected and a new cable was spliced according to wire colouring, the NC-81F display would power up but immediately show a 09 error code. This code continued whether the motor was connected or not. I'm guessing that there might be a compatibility problem between the display and the new controller.

So I purchased a KT display that I knew would work with the controller. But the display won't even power up when connected. I'm now thinking that the C inverter wire harness between the controller and the display might have its own wiring protocols and is not delivering power to the display.

To make matters worse, I tested the switch on the independently powered headlight and the light briefly came on then stopped as I heard a popping sound. It seems I fried something. Again now the original display won't even power up anymore. Did I fry a mismatched cable or the controller or both?

I'm feeling that I might have bitten off more than I can chew. There seems to be more variables than I expected between display, controllers, motors and cables. Apparently I can't just mix and match them.

I'm now thinking I should purchase a whole new set of matched controller, display and cable between the two. I found a Z1013B to SM connector cable for the motor. I would still very much like to keep the 4pin rear brake light function and I would very much like use the independently activated light and horn (on a separate switch) that came with the bike but I'm really getting lost in trying to identify the right controller and cable setup which would allow this dedicated light/horn function independent of the controller. (The light and horn work even when the display is not powered up.)

Navigating the ebike parts resellers on aliexpress was already pretty damn confusing before. I can only imagine the chaos now that there is a full-out trade war brewing with China.

Any comments or advice for me about how to get my daughter back on a fully operational and reasonably torqued bike?

Much appreciated.

 

[docw009]

Just my thoughts

When the NP-81F fired up on the old harness connected to the KT controller, it just means that power/ground were in the right place, It doesn't mean the other three pins were the same. All controllers will pick up power/ground and power up. Then they put power on a 3rd pin, That 3rd pin is used to power up the controller, The other two pins are 5V data pins. If those three pins are not the same, you battery power goes to those data pins and they pop.

Here's the layout of a KT display's WP connector,

Even if the pins are the same, the NP-81F is a foreign display to a KT controller, and any data sent between them is gibberish, Your Error 9 is probably a comm error?

----------------------------------------------------------------------------

How about seeing if your KT controller still works? KT controllers will work without a display if jumpered. They will run the throttle and one PAS level. Let's assume you did the motor connections right,

Since you don't have a KT harness, this diagram might help. It's for the 8 pin connector that goes to the handlebars. The 9 pin is the same, except the center pin is for lights,

First check for battery voltage between the battery pin and ground. You jumper it by connecting a wire between the battery power pin and the controller start pin. When you have a display present, turning on the display switches battery power to the start pin, Jumper simulates same effect,

Then check for 4.5V on the throttle voltage pin, That means the controller pwoered up. The throttle signal will be zero, if you measure it with no throttle. You can connect a three wire throttle there, if you have one available. Anything that puts 3-4 volts on the signal pin will spin the motor, Resistor bridge. A diode between power and the input, Even the power pin and the output pf the throttle alone (no ground needed) will do it, If motor spins, that's good.

Usually, KT puts the light output on a circuit that can blow up without killing the rest of the controller. The light output is just a low current 5V line. It's intended, I believe, fpr use with LED's, or with relays if higher volatge/current is reuqired.

 

[CloudPine]

Okay. Thanks for the tips.

I've set up like you suggested. I've wired the hot lead of the battery to the controller start.

It's giving off 50v when I connect it back to the ground terminal of the battery. (Makes sense off of a 48v battery, I think)

I'm also reading 50v on the throttle voltage however. Not 4.5v as you suggested. (I'm still completing the circuit with my multimeter from throttle voltage back to the battery ground.)

After this, it's not clear to me what I'm supposed to be doing. I'm not understanding these points:

You can connect a three wire throttle there, if you have one available. Anything that puts 3-4 volts on the signal pin will spin the motor, Resistor bridge. A diode between power and the input, Even the power pin and the output pf the throttle alone (no ground needed) will do it, If motor spins, that's good.

What am I supposed to connect next to see if the motor will spin?