Need help getting motor working

[undertow]

Hey all,

Long time reader and first time poster, so sorry if there is another section dedicated to issues,

I have been at an ebike project for almost a year now and have so far converted a 24v 250w no name chinese bike i picked up from uni to a monstrous 48v 1500w monster, and since transferred everything over to a dual suspension mountain bike.
Anyway, my issue is that every now and then, the motor seems to slip and then give a lot of resistance at times during my test rides. The other time it happened, i throttled the motor a number of times and it sorted itself out, but this time it has been ongoing.

Anyway I made a video showing the bike and my gear, as well as the problem. seems to be a short somewhere, but every time i use the throttle, i hear a switch sound in the motor as well as the controller. only thing is, at certain points in the shaft rotation does the motor produce any torque, which then shorts out.

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

Ive gone through most my wiring, last thing to do is open the shunt and see if anything is wrong in there. If anyone has any suggestions, please post below!

Thanks everyone!

 

[Icewrench]

Probably a problem with a phase circuit.
Is it in the motor or the controller?
Disconnect the phase wires and spin the motor.
If the motor is smooth to spin the problem may be in the controller.

 

[undertow]

Undid the phase wires, spun the shaft and its smooth.

I opened the controller and had a look at all the wires and connections (to the extent i could with it still wired to the bike) and there is only 1 suspect spot in the controller. Its the positive connection from the battery into the unit. I took some photos, but as you can see, its not too bad. there are no other sus looking solders or anything else i can see.

I know its a cheap ebay unit, should i consider replacing it with a better one?

 

[Icewrench]

Ya melted solder is not a good thing to see in a controller.
The easy answer is to get another controller.
Just for general knowledge connect two phase wires from the motor together and try to turn the motor.
It will not be easy to turn.
Then reconncet the motor phase wires to the controller and give it a turn.
Still hard to turn it will confirm a problem in the controller.
So order another one then open up the old one and take more pics.
We love pics.

Welcome to the Sphere.

 

[fechter]

Remove more screws and slide the board out for a look. It shouldn't be getting hot enough to melt the solder.
If you're lucky, they just did a bad soldering job and the joint heated up and it can be resoldered.