Escooter troubleshooting: Display works but not the throttle/motor

[samuraijack255]

I got an escooter from a friend that I’m trying to bring back to life. He said someone told him the controller was damaged. I ordered a similar one from Amazon. Now the display powers on but the throttle doesn’t activate the motor.

I ran tests on various parts with a multimeter and still can't find the issue. Reaching out to y’all to see what else I can do or if one of my tests was incorrect.


Battery Voltage
Voltage is 41.2V (rated 36V) so it seems fine. However, the battery alert icon is blinking on the display, even after charging for 4hours. Not sure if that’s a glitch or a sign that something is wrong.

Motor
I did a resistance test. Wheel rotated reasonably well when all phase wires were disconnected. When I shorted 2 phases at a time, the wheel resisted rotation, as expected.


Hall Sensors
The sensor voltages are varying from 0-4.96V as I rotate the wheel. So I assume the hall sensors are working fine. Further, the voltage on the controller side hall wires is a constant 4.9V (when controller is powered and hall cable is not connected to the motor). So the controller side hall wiring seems fine.

Controller MOSFETs
The reverse resistance is high (19.7K Ohms, each phase wire to negative battery connector). The forward resistance is high (1 ie OL, between each phase and positive batt connector). Thus, the MOSFETs seem fine.

Throttle and Brake Signal
The throttle and Brake signal wires are sending the right voltages via the signal wires. However, the throttle doesn’t directly connect to the controller - it connects to the display circuit that seems to have its own ICs. The display in turn connects to the controller. It looks like the display and controller communicate via a TX-RX pair line.

I checked the voltage on the TX line and gnd and noticed that normally it is 4.56V. When I press the brake, it goes up to 4.59. When I do a full throttle, it reaches 4.59V. Does this mean the display circuitry is working fine and that the issue has to be further downstream?

Phase Wires
I’m wondering if the problem is in the last step - controller not sending the appropriate signal/voltage to the windings. Is there a way to test this? I checked the voltage between each phase wire and battery gnd. It is a constant 0.63V. Varying the throttle does not seem to change this. Shouldn’t the voltage increase in proportion to the throttle? Or should I be measuring the current?



Is there any other test I can do?

Maybe the answer is already here and I've overlooked a detail.

 

[amberwolf]

Battery Voltage
Voltage is 41.2V (rated 36V) so it seems fine. However, the battery alert icon is blinking on the display, even after charging for 4hours. Not sure if that’s a glitch or a sign that something is wrong.

Based on the voltage listed on the Lenzod controller label that should be correct for a nearly full battery for it.

Throttle and Brake Signal
The throttle and Brake signal wires are sending the right voltages via the signal wires. However, the throttle doesn’t directly connect to the controller - it connects to the display circuit that seems to have its own ICs. The display in turn connects to the controller. It looks like the display and controller communicate via a TX-RX pair line.

Was the display replaced with the controller? If not, it may not work with it. Most display/controller pairs are not intercompatible, different protocols / languages /settings / etc even if same wiring (not always same wiring).

What was wrong with the original controller? (what symptoms did it have before replacing anything?)

I checked the voltage on the TX line and gnd and noticed that normally it is 4.56V. When I press the brake, it goes up to 4.59. When I do a full throttle, it reaches 4.59V. Does this mean the display circuitry is working fine and that the issue has to be further downstream?

TX and RX should be about 2.5v using a DC multimeter, because they're constantly toggling from 0 to 5v with data on them. If they're just at one voltage, no data is being sent.

 

[samuraijack255]

Was the display replaced with the controller? If not, it may not work with it. Most display/controller pairs are not intercompatible, different protocols / languages /settings / etc even if same wiring (not always same wiring).

I was not aware of this. This is probably the issue. I've ordered the compatible controller from the manufacturer so hopefully that'll fix it.

While I wait for the part to arrive, is there any test I can do on the motor to be sure the motor is fine?

What was wrong with the original controller? (what symptoms did it have before replacing anything?)

I'm not sure since all the tests I did passed and yet the throttle wouldn't turn the wheel.

 

[amberwolf]

Just because it might help make sure you're replacing the right parts:

Other than what's listed in the first post (which is presumably for the new controller?) which tests were done on the system originally (original controller), and what were their results?

Was the only symptom with the original controller that the throttle didn't turn the wheel, regardless of mode or other setting, etc?

If it's a kickscooter type, some of them might not engage the motor via throttle unless you first start it moving by pushing it forward with your foot (safety mechanism, probably lawyer-related).

Some scooters have a form of antitheft that requires a BT connection to your phone and running an unlock app on it from teh manufacturer, with a keycode specific to that scooter. It's not very common, but there are a few people that have asked over the years about defeating that for one reason or another.



For motor testing, other than what you've already done, there's not a lot you can do beyond checking for cable damage or connector problems. If the motor doesn't smell funny it's probalby not been overheated and so problaby doesn't have damaged windings, and since it rotates smoothly without resistance when not connected to anything, it should be ok.

If it is a sensored motor (three fat wires for phase currents, and 5 or more thin wires for sensors) you can test the hall sensors. One method is via the info on ebikes.ca in Learn - Troubleshooting - hall sensor tests.

 

[samuraijack255]

Yes, my observations are for the new controller.

which tests were done on the system originally (original controller), and what were their results?

Forward resistance is 1 (OL) and reverse is 6.65K. I think this may be on the lower side but since all 3 phases are the same 6.65, I'm assuming this value is good and normal for the old controller.

I could not do any powered testing on the old controller since some of the pins and wires are damaged.

Regarding your other comments:

• Antitheft: That can't be a possibility since this model does not connect to any app ( I checked the manual and site)
• Sensors: Yes this one has hall sensors and I've tested it, no issues there
• Kick-push: I already tried a few kick tests, but in a narrow hall way. Maybe it needs a longer or more powerful 'runway'? Unlikely, but I will take it outside and test just to be sure.
• Motor: I don't smell any burnt or foul odors. I did consider opening the wheel for an inspection. I've done so much testing and learnt so much, might as well see the motor too. Problem is, I couldn't figure out how to open it. If the new replacement controller doesn't fix the issue, I'll look into this more. If you have any suggestions or videos on how I can open this wheel to access the motor, please share (pic attached). The side reflector panel is tightly attached so I don't think that can be opened. Maybe I should open the screw in the black plastic housing right above the wheel?

 

[amberwolf]

• Motor: I don't smell any burnt or foul odors. I did consider opening the wheel for an inspection. I've done so much testing and learnt so much, might as well see the motor too. Problem is, I couldn't figure out how to open it. If the new replacement controller doesn't fix the issue, I'll look into this more. If you have any suggestions or videos on how I can open this wheel to access the motor, please share (pic attached). The side reflector panel is tightly attached so I don't think that can be opened. Maybe I should open the screw in the black plastic housing right above the wheel?

Most likley the black plastic at the bottom of t he reflector area is a snap-on axlenut cover, and then the axle hardwaer can be loosened and the motor removed.

The entire reflector unit probalby comes off as it appears to be a cover for t he axle wiring, ut it might not come off until the axle hardware is removed.


The motor side ocvers probably come off via teh circle of philips screws, but you might need an impact driver to undo those--it's not ucnommon to loctite them.