[SOLVED] Stuttering hub motor ... n..n..nooooo!

[Slipstream]

Cheap chinese hub motor ...



https://www.ebay.co.uk/itm/48V-1000W-Electric-Bicycle-Motor-Conversion-Kit-Bike-Cycling-Hub-26-Rear-Wheel/224126209805

Perfect a day ago and only 200 miles total ... now working too hard, rough on take-off, and developed a growly grindy noise and feel at low speeds. Happened gradually over the course of today. Particularly noticeable taking off on a hill.

My instincts say it's a bearing?

How long till it gives up entirely?

What to do???

 

[John in CR]

What to do???

New noises on an ebike should always be investigated right away to avoid full failure when it's least convenient.

I've only had a set up motor bearings wear out once, and that was almost 10 years ago with a motor abused on bad roads with heavy loads on a hardtail cargo ebike. To diagnose if it's a bearing problem get the wheel off the ground and turn it by hand and apply lateral forces to the wheel. If the bearing is going, then it should be readily apparent with some play in the wheel and noise. Maybe you got unlucky and whoever assembled the motor used some crap quality bearings or damaged them by not pressing them into the side covers correctly. It's a fairly simple repair to DIY.

If it's not the bearings, maybe you had a hall sensor go out or a bad wire, and the controller supports sensored and sensorless operation which would account for the noise and stuttering low speed operation. Unplug the hall connector and if it still runs with the same symptoms, that's the problem. Who knows, maybe you got lucky and it's just a poor connection at the connector that plugging it back together fixes.

 

[Slipstream]

Thanks John ... I think you n...n...nailed it ... had n..n..not considered it could be a problem with electrical dimensions!

Yes... I will check the bearing by your method this morning but I see n..n..now it is most likely a hall sensor fail from symptoms described elsewhere here. Arse.

1) check the cabling (might be unplugged!)
2) work out how to do a hall sensor check without dismantling the bike.

3) ... I miss the silent engine and smooth takeoffs ...
but will this frack my bike up in the end? and if so... how long till it gives up? what will die first?

Side n..n..notes:
Riding back last night the n..n..new n..n..noise turned heads in a way that the n..n..nearly silent 'tick-tick-tick' of the rear stator did not - people can n..n..now clearly tell the bike is powered where before they could n..n..not!

Also, now recall hub and power diodes were warmer than usual and I seem to have used more battery than usual for the length of journey?

:?

 

[Tommm]

Possibly dislodged magnet. You can glue it back if you haven't grounded it down yet by riding while dislodged.

 

[Slipstream]

Thanks Tom - it developed yesterday and, yes, I rode a further 10 miles or so after I first realised (up some very steep hills!)

 

[TommyCat]

... work out how to do a hall sensor check without dismantling the bike.

Hi Slipstream,

For information on how to electrically check the motor's hall sensors, with or with-out a controller attached. As well as other BLDC motor testing and wiring configuration, see this thread...
https://electricbike.com/forum/foru...-motor-s-phase-wiring-hall-sensors-and-wiring

Regards,
T.C.

 

[Slipstream]

thanks guys - recharging batteries now will let you know tomoz how it is.

 

[E-HP]

Perfect a day ago and only 200 miles total ... now working too hard, rough on take-off, and developed a growly grindy noise and feel at low speeds. Happened gradually over the course of today. Particularly noticeable taking off on a hill.

Check your phase wire connectors/connections. Might not be the issue, but I had something similar and it was a loose Andersen connector.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=97742&p=1432105&hilit=phase#p1432105

 

[Slipstream]

So... a look at my wiring in daylight revealed scorches around the three phase wire (UVW) connectors from controller to hub. It seems the insulating sleeve on one of these had ridden down allowing one to short, heat up and melt the rest. Totally not what I was expecting.

A bit of tape around the scorched area and bike is as good as new ... or at least as good as before!

Thanks to all for the indications to an electrical problem - it might have taken me a long time to realise.

Here's a picture from the middle of a 20km round trip through Exeter and along the Exeter Ship Canal today.



And one of a sunset - who could resist?!?



Slippy.

 

[E-HP]

Pretty lucky that your controller survived a direct short of the phase conductors!

 

[Slipstream]

It's worse than you think ... I still haven't found a fuse holder I like so ... fuseless!

:?

 

[Hardergamer]

Exeter Devon? I'm just down the road lol, You can't leave the phase wires like this with just some tape, it will not be safe, and you will end up blowing up your controller, etc. I have linked you some thick Heat Shrink Tubing 3-1 12.7mm which will go over the ends. But you may need thinner tubing... I would do 3 or 4 layers say 5 to 10cm long each https://www.ebay.co.uk/itm/BLACK-HE...BBEV2bDemotion&_trksid=p2047675.c100005.m1851

 

[Slipstream]

The connectors appear to have fused solid from the short so I will probably have to cut them off and replace with something suitable. I will post some pictures later.

Exeter, eh? I hesitate to say it ... Exeter Chapter of ES?