My e-bike suddenly decided to go back home

[User1]

While riding my e-bike today it suddenly stopped. When I pushed the throttle again it went in reverse. I tried to switch the battery on and off etc., but it didn't help, so I had to push the bike. I was happy that it happened just about 1 km from my home, but the weather was very hot and I had to go uphill, so I pushed it backwards (so that the motor could help me). I pushed the cruise control button so that the bike could maintain constant speed, but it wasn't really good idea, because I lost control of my bike and it fell. Well, it turned out to be not so bad idea, because when I picked my bike up, everything returned to normal - after pushing the throttle the wheel rotated in normal direction as usual. Does anyone know how to prevent happening it in the future or if it happens, what to do then (other than throwing the bike on the ground, of course )? A few days ago I programmed the controller using the USB cable, so it may have something to do with it. I was a bit surprised that there was some „REV” function enabled by default, but I didn't touch it, because I suspected that it's not relevant for my Magic Pie 3 (the same software is used for other motors). Should I turn this function off?

[Bikemad]

When the motor is running backwards it is most likely that the ends of the two wires that are used to switch reverse are simply touching against each other.
Carefully inspect the unused Black and Blue wires coming from the short unused lead on the motor harness and make sure the insulation has not retracted due to shrinkage and is allowing the exposed copper wires to touch against each other.



If you have LED lights fitted to the bike, the reversed motor problem could also occur if the exposed blue wire in the short lead touches any exposed metal part of the frame.

If the unused "Reverse" wires are not causing the problem, it could be a fault within the motor harness, or the controller's programmable chip causing the motor direction to be reversed.

As you don't use reverse, I suggest that you disable the reverse function with the programming software. If the problem is being caused by wires touching occasionally within the harness, disabling reverse should prevent the problem from reoccurring.

Alan
 

[User1]

Thanks for the quick answer and the explanation. Indeed, it's very possible that these wires were touching each other – I didn't bother to insulate them at all, because I didn't know that this is so important! I thought that this „Forward/Reverse Switch” has something to do with PAS (for example, that if black wire is replaced by the blue wire, PAS would only work when pedaling backwards). I think it should be made clear on the diagram that if these two wires are connected, the motor would go in reverse. Certainly I will disable this function anyway (at least I'll try to, because the software doesn't always work when I connect the motor). I wonder how much more mysteries of MP III I'm going to discover in the most unexpected moment (this is not the first one)

[Bikemad]

Certainly I will disable this function anyway (at least I'll try to, because the software doesn't always work when I connect the motor).

If the Black and Blue wires were touching each other you would not be able to program the controller as the Blue "Reverse" wire is also used as a signal wire while programming, so shorting out the signal wire (touching it to the Black wire) would also prevent communication between the controller and the USB interface cable.

I don't like the wires being left uninsulated on the end of the cable. If the Red wire (+5v) was to touch against the Black wire (Ground) it would short out the +5V regulated supply on the controller and prevent the throttle and pedelec from working and could possibly damage the controller too.

I have previously suggested that all the cables (pedelec, reverse, lighting and horn etc.) should come with plugs/sockets fitted so that lights could simply be plugged in:

Possible improvements
I think that connectors need to be a pre fitted for the pedelec and reverse function on the motor harness, rather than simply leaving the four wires sticking out, and also for the horn and light connections on the front harness.

I think that the kit would be much better if it were supplied with all connectors pre fitted, and supplied with matching pre wired plugs that could then be connected by the owner to suit his/her individual requirements.
This would make the installation much neater, and it would also be much easier to quickly disconnect the wiring when wheel removal was required for changing tyres or mending punctures etc.

I also think that GM should sell compatible LED headlamps with an integrated horn unit, which could be pre fitted with matching connectors so it could simply plug straight into the harness in seconds, without having to make any fiddly connections and possibly getting the wires mixed up by mistake too.

It's disappointing that such a good product is let down by something as simple as fitting two little connectors.

Alan
 

[User1]

I'll check if insulating cables makes programming the controller possible, but I'm afraid that it might be a problem with the USB driver.

You are absolutely right about the connectors! It took me several days of work to solder/insulate all the wires needed for LED lights, but it still doesn't work properly – the front light comes on only when I'm turning left Apparently cables disconnect somewhere. I think I'll just solder the wires without using the connectors, because I don't know how to use them properly anyway – when I remove and then insert the plug, the connection doesn't work anymore.