Random throttle cut-out Juiced Scrambler

[tybyte]

I have a juiced scrambler with an aftermarket controller upgrade from area 13. It’s hard to explain, but the throttle cuts out. And attaching a link to 2 video clips showing the issue.

Some notes to consider:
-It does this with the stock controller as well as the aftermarket controller
- It also does it whether I’m using the throttle or pedal assist

Links to video clips:

Bike throttle cut out.mov

Shared with Jumpshare

jmp.sh

Bike throttle cut out2.mov

Shared with Jumpshare

jmp.sh

I feel like I’ve tried everything except for opening up the hub motor, which I really don’t wanna do if I don’t have to. Thank you so much for taking the time to read this and respond!!

 

[amberwolf]

Does it have a display? If so, does that turn off during hte problem? Or does it remain on and the system just stop responding to user input?

Most "cutouts" are actually the battery dropping below LVC, either the BMS's (in which case all power is cut) or the controller's (in which case power remains on but the motor stops assisting).

Most battery problems are from either physical damage (crash, drop, water intrustion, etc) or from mismatched / defective / old cells.


If the controller was upgraded to a higher current model but the battery was not replaced with one that can handle that, it may be unable to provide the new one's demanded current. If the BMS is still allowing current flow even beyond what the battery was meant for, it may be damaged (shorted FETs) so it's output is stuck on and can't shut itself off to protect the cells. In that event, the higher current may damage the cells, and they may be unable to even run the original controller as before.

 

[tybyte]

Does it have a display? If so, does that turn off during hte problem? Or does it remain on and the system just stop responding to user input?

Most "cutouts" are actually the battery dropping below LVC, either the BMS's (in which case all power is cut) or the controller's (in which case power remains on but the motor stops assisting).

Most battery problems are from either physical damage (crash, drop, water intrustion, etc) or from mismatched / defective / old cells.


If the controller was upgraded to a higher current model but the battery was not replaced with one that can handle that, it may be unable to provide the new one's demanded current. If the BMS is still allowing current flow even beyond what the battery was meant for, it may be damaged (shorted FETs) so it's output is stuck on and can't shut itself off to protect the cells. In that event, the higher current may damage the cells, and they may be unable to even run the original controller as before.

No, like I stated in my original post, the behavior is the same with my stock, controller and aftermarket controller. That would mean that the moth sets are damaged in both controllers. Is that what you’re suggesting? And if I were to open the controller, is there an easy way to test it with a multimeter?

 

[amberwolf]

The battery and it's BMS (and the BMS's FETs) are not in the controller; they are a separate part, usually in a separate box or casing.

Occasionally a controller is installed inside the battery dock, but theyr'e not very common.

I already said how you could have a battery problem that appears with both stock and new. Since we don't have details on your system or parts, I can only guess whether it's capable or not, and it's typically safe to assume any battery only barely works with the orignal system, and upgraded controllers stress it or don't work with it because they pull more current than it is capable of.

I haven't seen an answer to :
Does it have a display? If so, does that turn off during hte problem? Or does it remain on and the system just stop responding to user input?
yet. That can help us help you find the problem. (as can more detailed info about your system)

 

[E-HP]

You can test the motor hall sensors without opening the motor

Testing BLDC motor's Phase Wiring - Hall Sensors and Wiring. - Electricbike.com Ebike Forum

Testing electrical components of a typical hub motor with a digital multi meter. First take a few minuets and look over the wiring going into the motor for cuts, scrapes, missing insulation and other wiring issues or poor connections that should be resolved first. Smell for...

electricbike.com

You could disconnect the PAS, and brake cutouts from the harness, and see what happens with only the bare minimum.
You could also test continuity of your harness to see if there are any intermittent connections.

 

[slaphappygamer]

Ok. I believe you’ve ruled out the controller, PAS, and throttle. If it was the battery, I would think that your display would lose power. Pretty sure it’s not the motor since in the second video the motor sounds healthy.

It’s completely possible that your issue is with the brake sensors. You could have an intermittent fault that falsely engages the brake. This will intermittently cut power to the motor. Then when the fault “clears” your motor will jump back to the acceleration the throttle position is at.

If it were me, I would disconnect both brake sensors and try again.

 

[neptronix]

Some displays have capacitors in them, so momentary power cuts may not be seen.
You will be able to tell if you shut the battery power off or disconnect, and the screen remains on for a second or more.

What you actually want is a watts/volts/amps display, which tells you in realtime what's happening with power delivery on the battery side. The displays that come with most ebikes are incapable of conveying that information, because they only show ~5 bars, instead of much finer grained numeric values

 

[tybyte]

Thank you everyone so much for your replies, I’m going yo try to respond to everyone’s comments hopefully don’t miss anything.

Yes the display stays on but the bike intermittently stops responding to my input.

Yes I’ve basically ruled out the PAS and throttle because they both do the same thing.

I’ve already considered it was the brake sensors but even with them both disconnected it behaves the same.

Another thing I think I should mention, my headlight turns on when I turn my battery on at the power switch on the battery itself, before turning on my controller. It does this with the stock and the aftermarket controller. I don’t remember it always behaving this way, especially because I know there is a long press on the down arrow to turn the light on and off.

I would think that this suggested there’s some kind of a short, but like I said, it behaved the exact same way with the stock and aftermarket controller, which each have their own wiring harness.

 

[tybyte]

Well I appreciate the responses I got initially but after my second reply, no one seems to be saying anything. Is there a trick to getting a response out of people? I understand this is a free resource, but just wondering if I’m doing something wrong.

 

[E-HP]

I would unplug everything but the battery, display motor, and throttle from the controller and test. Then do the same with the PAS only. Has the bike ever been in the rain?
Can you confirm the issue started when the bike was stock, before upgrading the controlle?

 

[tybyte]

I would unplug everything but the battery, display motor, and throttle from the controller and test. Then do the same with the PAS only. Has the bike ever been in the rain?
Can you confirm the issue started when the bike was stock, before upgrading the controlle?

I’ve done that with everything unplugged like you suggested multiple times same result. Yes it’s been in the rain. A fairly good amount. I think there’s a good possibility that that has something to do with it but has Confused that it behaves the same way with both the stock and the aftermarket controller which points to either the cable running into the motor or the motor itself. The issue started after few months after upgrading to aftermarket controller, but since it does the exact same thing when I put the stock controller back on which has its own wiring harness by the way, it makes me believe that it’s not an issue with the new controller. It’s really weird because just now I went and took it out to test it again and when I turn the throttle sometimes it’ll do nothing but if I hold the throttle then sometimes it’ll cut in after five seconds 30 seconds 15 seconds it’s really random but it seems like once I get going it continues Until I let off the throttle and then try again then sometimes it’ll keep going and other times it cuts out. I can also turn the throttle and when it does, nothing if I keep the throttle held, it’ll all sudden cut back in but again at random times.

 

[fechter]

It could possibly be a motor hall sensor problem. Depending on what kind of connectors they used, it may or may not be easy to check. If there's a bad sensor signal, the motor won't really run right when it runs. If the motor doesn't start, it might start if the motor is turned by hand or rolling the bike. To check them, you need to measure the 3 hall signal wires while slowly turning the motor by hand. Each one should toggle between near zero and near 5v. A bad one will stay stuck either high or low.

 

[tybyte]

It could possibly be a motor hall sensor problem. Depending on what kind of connectors they used, it may or may not be easy to check. If there's a bad sensor signal, the motor won't really run right when it runs. If the motor doesn't start, it might start if the motor is turned by hand or rolling the bike. To check them, you need to measure the 3 hall signal wires while slowly turning the motor by hand. Each one should toggle between near zero and near 5v. A bad one will stay stuck either high or low.

That’s what I was afraid of, I really was trying to avoid opening my hub motor. But if it was a bad sensor would it run fine continuously sometimes or would it cut out every time it reaches that position on the wheel/motor?

 

[Tony01]

Yes my mind went to motor problems as well. A bad connection or fault within the motor would do it. Halls are easy to test from the small wires in your motor cable. A controller may just not run it at all when there is a motor fault. Running Sensorless it will run badly and have trouble/low torque starting.

 

[tybyte]

you’re saying I can test the hall sensors without actually opening the hub motor?

 

[E-HP]

you’re saying I can test the hall sensors without actually opening the hub motor?

See the link i included in post #5.