Further ideas about no power to motor?

[Parker]

Hello good people, here is my story.

feat. old Raleigh mountain bike with ebay rear wheel direct drive "1000 watt" brandless hub motor
Risonmotor KT36/48 controller (KT36/48SVPRK-SLS02G)
KT LCD8H Display
Hailong style 48v20ah battery

I had a slow speed collision with an SUV, she came out of a dentists offect driveway pulling into a large road and basically pushed me over by the knee with the front bumper. The bike fell to the right, I went down with it. I got a sore knee, some other scraps and stiffness the next few days. The bike got damage on the end of the right grip, the battery bent to one side and the handlebars turned. The bike still worked and so did I so I considered it a close call. I should have made eye contact with the driver, I usually do that. I was deep in thought listening to a book by Irvin Yalom about death anxiety.

None of this might have any bearing on the issue I'm having but I'm giving context just in case it does.

The next day I decided I would change the back tire as it was worn out and because it would allow me to looking things over. The controller is under the rack on the back. So I took it apart unplugging most of the controller wires and put it back together with a good tire just like it was before(I thought). But now, even though the display lights up there is no power to the motor. Finding my harbor freight multimeter I wondered if it was dead or the screen was just blank(I usually don't use it). When I put it to my bike battery a bunch of sparks and a half vaporized tip on the red lead let me know that was a bad way to test it out. I might need a new multimeter.

I ordered an ebike testing device(Bo Ai Zhi a white box with LEDs, it looks like many others) and some 9v batteries for the multimeter. Today I got it and tested things with the bike tester. The motor hall effect sensors and phase wires seem good, the LEDs light up in the expected ways. The alligator clips on the tester made it so I could not test the throttle(and I could not remove the pins from the connector by slipping a sewing pin in like I saw to do in a video) However, the display says "throttle" when I turn it. When I unplug the throttle wires it does not do that. When I put a different throttle on it also turns on the "throttle" text on the display when turned. The brake cut off symbols light turn on when I pull the brake levers

When I attached the testing to the controller(hall effect plug and alligator clips to the phase wires) and turn the throttle it is not lighting as it should. The 5v LED is on but no other LEDs light up when I twist the throttle. Maybe something got disconnected in the controller after having the impact of falling over then being jostled round as I took off the back tire. So I opened up the controller to see if there was an obvious disconnections. Everything looked connected and no evidence that anything was changed from the fall.

I am getting to the point of considering starting to just change out parts. I see a new controller is like this one is about $70. But I would really rather know what is going on.

I hope this is enough info that it makes it easy to help me. I would hope to get possible culprits to the problem or what to test next, or good ways to search for pre existing info on this board. "no power to the motor" is for sure not a fine grained enough search.

 

[Parker]

Attempted posting pictures of controller

 

[Parker]

Re: the multimeter I think I had it set on the lowest DCV setting, I had tried to get a reading off a AA battery at first but I didn't know if that battery was good. Then I thought, oh I know a battery that has a charge for sure! I took the bike battery off and stuck the probes to the + and - of the batter and... big sparks, for a second or less. I put the battery back on the bike and the display still says it's at 54.1, so pretty much fully charged. I felt relieved, the carbon blackness on the battery connector did not affect the connection it seemed. I did file the stubby tip of the short red multimeter probe so it's back to kind of pointy.

I am thinking this brief short through the multimeter did not damage the battery. This is a fairly new battery. I have another one that was draining fast(close to the end of its life, not a flaw) So I could test that one on the bike but I have to deal with the fact that I changed the connectors to XT60 from Andersons on the old one. So I would have to cut and stripe wires or something to temporarily connect the old battery.

The problem with no motor power was happening before I got the battery and meter together for sparky time, and this was off/away from the rest of the bike.

I do not know a way to reset the controller to default. I will try so search on that

Earlier I was thinking of taking of cover off the hub motor and looking for flaws but yes the tester is giving good results for the motor

 

[Comrade]

That's a Kunteng controller. First thing I did to mine before installing it is pouring some epoxy under the capacitors. They were not even tight on the board, just flapping side to side on their leads. That's not acceptable in any way for something that would be shaken and tossed, like an electric bicycle.

 

[fechter]

You probably should buy a new multimeter. They usually blow up if the meter is in the amps or milliamps mode when connected to a battery.

I would check the throttle signal voltage. There may be damage somewhere in the throttle wire or throttle itself. If the throttle signal goes too high or too low, it will disable the motor. A bad hall signal or brake signal will also disable the output.

 

[E-HP]

swap two of the three phase wires and see if you get any movement.

 

[amberwolf]

The next day I decided I would change the back tire as it was worn out and because it would allow me to looking things over. The controller is under the rack on the back. So I took it apart unplugging most of the controller wires and put it back together with a good tire just like it was before(I thought). But now, even though the display lights up there is no power to the motor.

That almost always means the wiring did not get reconnected the same way it originally was, or that one or more of the connections has a problem (not fully plugged in or a contact has backed out of a shell a bit, or wire is not fully connected to the contact itself, etc).

Sometimes it means the axle-exit wiring is damaged from activities performed while changing the tire; or from an impact with something (like a bike falling over and the axle wiring being pinched between the something and the axle), this can be just a broken wire (usually a thin hall wire) inside the insulation where you can't see it, or multiple wires' insulation damaged allowing them to short to each other (often visible) or to the metal of the axle right at the exit where the edges are sharp.

If moving the wire at the axle changes the problem, it is probably damaged at the exit. Otherwise the problem can be anywhere between controller and motor.

Finding my harbor freight multimeter I wondered if it was dead or the screen was just blank(I usually don't use it). When I put it to my bike battery a bunch of sparks and a half vaporized tip on the red lead let me know that was a bad way to test it out. I might need a new multimeter.

A few points:

If the display is blank (not even a decimal point or polarity sign) even if the HF meter is on and switched to a measuring setting instead of the off position (if it has one), the meter will almost certainly need a new battery (the one they come wiht is pretty crappy and is sometimes dead while still on the store shelf). The meter can be dead, completely, but that's rare (I've abused a few of them and only actually destroyed one of them).

For voltage, it doesn't matter what range it is set to, it wouldn't cause sparks or failures, as long as the voltage is within the range the meter itself tolerates. It just won't read correctly in the wrong range (usually either 1. or OL on the screen if the voltage is too high).


Regardless of what you set the meter to (V or A or what range), if you plug the meter leads into the meter's A and Common/Ground sockets and attempt to measure V, it will short circuit the voltage source you're measuring, and as high a current as that source can output will flow thru the meter leads and current shunt, which often damages or destroys the meter and leads, and sometimes the voltage source. This is unfortunately a common occurrence.

The meter may still work (with new leads, if necessary) on it's V socket and common/ground, but the A socket may not work anymore (sometimes it's a fuse, but the HF meters have no fuses on that port, so what usually happens is the solder on the shunt melts and it falls off the board, or it vaporizes if the current is high enough suddenly enough).

 

[docw009]

KT controllers/Displays will throw an Error 03 if any of the three Hall signals isn't working and they throw an Error 01 if the throttle is miswired. I've not seem any of the other errors pop up. I'm not aware of any errors that happen with a broken phase wire.

You can try walk mode, in case you doubt your throttle or PAS wires, to see if the motor works. I often do that when I hook up a controller, and don't have throttle or PAS connected yet.

Since your meter has probably blown a fuse, you cannot check for 5 volts. I think there is a way to use your ebike tester to do that. Hook up a Hall or something, and if you shut off the 9B power, the 5 volt LED stays lit.


By the the way, my ebike tester can be hooked up to the controller via the three phase bullets and 2x3 Hall connector. With a working controller, the throttle will give one revolution of the LED's as they flash in a circle. If the phases are not matched or Halls out of sequence, the LED pattern is different from the normal one. This doesn't help the casual use, since we don't know what it is supposed to look like, but it's an interesting feature and probably is useful to someone who tests 10 bike a day,

 

[Parker]

Hello again,

Thank you

I had put this aside for a while(since I got temporary access to a car).

So I am back now figuring how where I was at with this. I did buy a new multi meter so I have that. I tried plugging in a different throttle I had. That one also makes "throttle" to appear on the the KT controller screen but does not make the wheel turn. One clue I did notice is that when the hall effect plug from the controller is plugged into the motor the motor wheel is much stiffer to turn. I tried flipping some phase wires as was suggested but that did not make a difference. There is no error code on the display I am seeing, which I was told it would if there was a hall effect wire damaged.

I will re-read your comments and continue to see if I can't understand what is happening.

 

[Parker]

I was doing some searches here and found this in a tread:

"Turn the motor by hand with it connected but switched off. Is it hard to turn. Disconnect it from the controller. If it's now easier to turn, your controller's had it."

This would seem to indicate that my controller is at issue

 

[fechter]

Yes, it sounds like one of the FETs shorted inside the controller.

If you disconnect the motor and battery, you can measure OHMS between each controller phase wire and both the positive and negative battery wires coming out of the controller. If you find a combination that reads near zero ohms, you have a short. A normal controller will measure like a diode between the phase and battery wires. It's normal to see a time-varying reading in one direction as the capacitors charge.

 

[Parker]

Ok I did some testing

Multimeter set at the 2000 OHM range
Red lead to controller Black power wire all three controller phase wires read 362 or so
Black lead to controller Red power wire all three read about 358 or so
Other combinations give no reading (I tried going down to the 200 OHM range, no difference)

Turning the wheel is moderately stiff with a subtle bumpy sort of feeling when plugged into controller

I repeated my test with the ebike testing box to the motor. The hall LEDs light up as they should, flowing along. The phase LEDs blinked rapidly when I spun the motor wheel, a seemingly good result.

I also unplugged the break cut off wires and the pedal assist sensor wires and tried to get it going and still the same result.
That is, display on and looking normal, no power to the wheel, display says throttle then throttle is turned to that signal is going from the throttle through the controller to the display

I really would like to definitively find the issue. But I did end up browsing and found a very similar controller on eBay (shipping time from China though https://www.ebay.com/itm/333619822933
I also found myself browsing whole new kits. I am not ready to give up quite yet.

 

[fechter]

That's pretty strange. Your test shows none of the FETs are shorted, yet it behaves like a shorted one.
Can you disconnect one phase wire at a time and see if the turning resistance goes away?

 

[Parker]

So I come back to the bike today and plug in the 2x3 hall effect conector(the connector that before when unplugged allowed the wheel to spin freely). However plugging it in did not immediately cause the wheel stiffness. I turned on the power and plugged in the throttle and after some minutes it became stiffer to turn again.

I tried disconnecting each of the phase wires individually but that did not make any difference, still stiff

I unplug the hall connector and it frees up and spins.

Maybe a capacitor in the controller drained overnight? (Is is just speculation from my not particularly in formed self)

 

[fechter]

That's interesting.
It tells me that one or more FETs is being turned on at the wrong time. The FET gates can hold a charge for a long time and keep it on after the battery is disconnected. This would indicate a bad FET driver or improper commutation from the MCU chip. You could try tracing the FET gate lines to the driver and look for a bad solder joint or cracked trace. If the chip is bad or software corrupted, it's usually bricked.

 

[Parker]

I was finally able to buy a new KT controller. I plugged everything in and still have the same issues as before. I feel like crying.

I did not break out the multimeter yet. I thought for sure that we had narrowed the issue to the controller. I guess I should go back through and do the test I've tried before. Maybe I should do a recap on the story here on this thread.

I fear I am am going to have this bike upside down in my space for more months until I can just buy a new hub motor or kit if I can't get the hub wheel by itself.