Motor Stuttering

I know there's been many posts on this before in the past and I've tried searching up on them yet mines slightly different in that it was working before I took the bike apart.

So I recently made a battery box and installed a new rear brake so my electric bike came to bits. Once I've put it all back together i'm getting stuttering when I apply throttle.

I had this problem when I first put the bike together however I fixed it by just playing around with a few of the connections and now I have the same problem again with the stuttering.

So my first response was to check all the connections and make sure there's no loose ones (i'm 99% sure it isn't because any of the hall or phase wires are ordered incorrectly because they are plugged in identical to when I took the bike apart when it was working) so that eliminates loose connection or wrong hall/phase combo.

The only other thing I can think of is shorted phase wires but I just wanted to get other people's opinion on this. I don't have a hall tester to see if its any blown halls, although I doubt thats the problem because it was working before I took the bike apart.

Details about the bike:
MXUS 3000W V2 motor, 30amp sine wave controller, 11.4aH battery made out of Panasonic NCR18650PF cells

Any help is appreciated, Cameron.

Don't need a tester to qualify Hall sensors but be very careful applying too much throttle until you get it figured out. Try these links to sort out your issue: http://www.ebikes.ca/learn/troubleshooting.html

I'm 99% sure that somehow, you do have a poor connection. But double check your order, I've had them mixed up when I was certain sure I did not. Some times I just have to sleep on it, then look again in the morning. Ohhhh.

I have had a wire looked good, but they broken the wire under the covered plastic and or cut by the connector. Look for back out pins. Do you find out what connector it was the first time ?

I'll test to see if all the halls are working tomorrow with a multimeter, thanks for the link Ykick.

I'll triple check the connections tomorrow but unless its something I cant obviously see then i'm sure its not
Would a wrong hall combo result in the stuttering? maybe there's a 1% chance I plugged them back in wrong..

I'll report back tomorrow, thanks for all the replies.

It's usually something you can't see...you have to measure them and test the connections.

Just like other threads about this have shown, it can be hidden inside the insulation with a broken wire, on any of the wires (phase, hall, etc).

Okay so to give you an update...

I did a lot more diagnosing today yet I still cant find the problem..

I've tested all the halls and they're all giving correct voltages when I spin the wheel round by hand, so not that.. I then decided to swap some of the halls around and see if that got rid of the stuttering, any other combo I tried just locked up the wheel, so I definitely have the right combo.

I then moved on to inspecting all the connectors again, so I desoldered the anti spark connector I have for the mains power and soldered a new one to it, inspecting all the wire along the way to make sure it was in good condition.. still stuttering.
I then desoldered the phase wire connectors and resoldered it inspecting the wire along the way.. still stuttering.
I then moved onto inside the controller to see if maybe one of the wires had come loose inside the controller.. all looks good inside the controller.

I'm now stuck as to what to do next? any further help??


EDIT: I just thought as previously mentioned.. would it be best to take a multimeter to inside the controller to find out maybe which wire could be damaged? what would show up on the multimeter if one of the wires was damaged?

Thanks.

Use the test for blown MOSFET in that link.

Also, you can easily test if Motor phase windings maybe be open by disconnecting the phase wires from controller and then short a pair of the 3 phase wires together and spin the wheel. Any pair you short together should make the wheel noticeably harder to turn. Very unlikely but it's so easy and simple to do, why not just to rule out the possibility a phase wire has opened or come unsoldered inside the motor hub.

If phase wires are shorted you will not feel any difference in resistance turning the motor by hand. This assuming you have a DD (direct drive) hub motor. A geared hub motor will only turn the motor in reverse direction due to the freewheel clutch.

camerons98 said:

I'm now stuck as to what to do next? any further help??

Click to expand...

Did you measure continuity of the wires from inside the motor to the controller? (preferably inside the controller where they solder onto it, and do this while the motor and controller are plugged into each other).

Many multimeters have a little .>) or ))) or "speaker" looking symbol, for one of the settings in the Ohms section, and that is continuity beeper. When the leads are touching, it'll beep, to test the function, and then you can test the wires and connection by touching each lead tip to each end of the wire to be tested. If it doesn't beep, there's no connection, and the wire is broken somewhere inside the insulation or at a connector (bad crimp, etc)

If you dont' have that function, you can still test using 200 ohm range, and if you get a reading near zero it's perfect, upwards of a few ohms it is still ok, but if you ahve one that's a lot more than the others or "out of range" it is likely the problem.

To give you all a quick update, i've been super busy but managed to do a bit more testing today.

I measured the continuity from basically just outside the motor to the point where the phase wires are soldered in the controller (didn't feel like opening up the hub motor) and everything was fine.
I then shorted each pair of phase wires together and tested if the motor had more resistance.. it had way more resistance when I shorted any pair of the phase wires, so wires inside the motor must be fine still.

I will test to see if I have a blown mosfet later but I thought I should add that the motor spins fine with no load however when I sit on the bike it stutters..

Not sure if that helps at all.. thanks.

EDIT: Just checked for a blown mosfet and they all look okay...

camerons98 said:

I will test to see if I have a blown mosfet later but I thought I should add that the motor spins fine with no load however when I sit on the bike it stutters..

Click to expand...

That usually points to either a wrong phase/hall combination or FET issue, a poor connection in phase or hall wire (all of which should be eliminated from what you've said so far), or a problem with battery supply to the controller, possibly causing the LVC of either controller or battery to kick in and shutdown the motor, then restart it when the load disappears, in a cycle. If it's a fast stutter it's probably not an LVC thing, but it could be a connection between battery and controller.

If voltage doesn't drop at the controller power input connector, then that's probably not it.

But really, since you had a problem originally that went away with messing with wires/connectors, and then this restarted after moving them during the upgrades, it is still most likely that it's still the original problem and it is still most likely a wire broken inside the insulation or a bad crimp or other connector problem, that is simply working during your measurements but not under high current.

You might be able to isolate it by setting up the multimeter to read voltage from one end of each phase and battery wire to the other end of the same wire *while you are on the bike putting a load on the motor*. You should get 0V on every one that way. If not, then the one with a voltage across it is your problem.

I can't find the damn problem and it's starting to annoy me now!
I don't have any spare parts that I can just swap out to try and find the problem..
I believe it could be the hall wires inside the motor potentially shorted together somehow.. I might crack open the motor tonight and take a look inside to see if I can spot anything.

Cameron.

If you can wrap your head around the concept of a “pull-up”resistor (10k or so, not too critical) use a 5-30V battery or power supply and test motor Hall sensors without relying on the controller being connected and powered up.

I would do that test before cracking the motor open.

Here’s a golden oldie where you can see pics of how I manually tested Hall sensors in a 9C motor.

https://endless-sphere.com/forums/viewtopic.php?f=3&t=57053&hilit=+hall+sensor+resistor

I tried googling about pull-up resistors but looks way out of my league.. i don't have much knowledge in electronics at all.

I've shot a quick video on youtube to outline my setup and see if you can spot any obvious area's which might need a look into. My largest suspect for the possible cause is the controller right now. Apart from that i'm completely lost.

https://www.youtube.com/watch?v=FGsS8UR7CtY

https://endless-sphere.com/forums/viewtopic.php?f=3&t=74554&p=1127336#p1126604

Sorry amberwolf forgot to reply to your post. Logically I'm thinking it can't be a FET issue otherwise it wouldn't have started working again the first time round? and it definitely can't be a LVC because I've LVC on the controller before and it takes at least a second for it to kick in again and these stutters are much faster than that.

Will it be okay to keep a constant current applied to the motor to do those tests to the wires even though its stuttering? dont want to damage anything.

Thanks

This video is private...
[youtube]FGsS8UR7CtY[/youtube]

Pull-up resistor is not that difficult but I understand if you don't feel comfortable setting up a Hall sensor switching test. In that case you might buy one of the eBike testers which perform many of the tests that needs to be done here.

Here's a search to give you an idea - http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=ebike+tester&_sop=15

Forgot to make it unlisted, there you go, should be able to view it now!

EDIT: Just purchased a tester, should be here in a few weeks, once that arrives i'll update you all.