Motor stutter

[mwhens]

I have a 407 Crystalyte with 48v controller.
I was a happy e-bike user for 4 months untill now.

In the morning I cycle to work. It was rainy.
When I arived I checked the connections and all for water, everything was dry, no problem during the trip also.
Than 8 hours later I was going home, but even before I was getting on the bike I noticed a heavy stutter.
I was just pushing the bike forward with battery pluged in. No throttle.
Normally I always felt a little stutter (verry little), mostly when I pushed the bike backwards.
This time, a heavy stutter forwards. Then I tried to throttle, and it was even harder, just at 40W.
I lifted the front wheel, and throttle up, the wheel was shaking and stuttering.

Then I wanted started to pedle home, then stuttering disapeard when cycling without throttle (battery still pluged in for lights).
1km later, it started to stutter again without throttle. Then disconnected the battery.
And even then when I was going faster than 10km/h it started to stutter.
Then I connected the battery again. And than it was gone again, but only with throttle (even 30Watt) it was suttering.
I stoped three times unplugging cables, nothing helped.
But I was trying all the way, and only the last km it seemed to work again and was ably to go full power.
When I was home, I listened to the free spin with throttle, and there is still some weared stuttering left.
Sound is clearer the more power you give.

The stuttering at 10km is around 5hz I gues. And goes faster the faster you cycle.
It's like the hub turns on and off verry fast. And not giving smooth continues power.
I can go forward, but with heavy shaking.

I already tried disconnecting cycle analyst, cruise, throttle, speed switch, it did not help.

I have no idea what it can be.
Any idea's? I don't hope I need to remove the hub or something

## update ##

After some reading, I think it's an hall sensor shorting because of water inside the hub.
I have only cycled 3 time in rain. It seems they are verry suseptable to water.
Sould I just wait for it to dry on it's own? Is there a change I don't have to open the hub?

 

[NeilP]

Nt saying it is this..but worth a look
Are the hall connectors between motor and controller outside on the frame or hidden inside a box or pannier.
It is always possible that it is just a connection issue, especially if the connectors are exposed to the elements, a bit of corrosion may have set in on the plug

 

[mwhens]

On my way home I disconnected and reconnected the hall sensor plug, no effect.
I had taped in the connector, perfectly dry, no corosion.

If it's water in the hub thats shorting a hall sensor, if the water is gone and it works again...
Are there any ways to make it more water resistand?
Water resisting tape, spray sealend or something?

 

[NeilP]

possibly water dispersant spray? WD40? but i am not sure as to its other properties in relation to electronic components like the halls

 

[neptronix]

I had this occur when one of my hall sensor connections had came loose.

 

[John in CR]

Sounds like a phase wire short, not hall related, since it happens without throttle. If you have a drip loop you shouldn't have much water in there, though you can easily pop one cover to check. Put alignment marks on each cover and at the same place on the magnet backing ring to easily get the cover(s) aligned with the same holes during reassembly.

You do not want to power it up or try to ride it until you get it sorted out, because a phase short will easily blow a controller. It sounds like it's getting progressively worse, maybe a wire rubbing at the wheel where it exits the

To track it down, start with motor disconnected from controller. Make sure phase wire ends don't short together. If wheel spins easily then attach the controller, but don't turn it on, and check the wheel for more turning resistance. Some controller failures result in a short in the phase wires. Check all other connections.

 

[NeilP]

Ah yes, well spotted John, I read that comment, but it did not register that comment. If it happens while un powered, it must be phase wire rather than hall wires

 

[mwhens]

Thanks for all the help,
I did not had time to test anything.
But if it's a fase short, is there a way to measure that somehow?

 

[NeilP]

unless you have very accurate lab type test gear, all you can really check for is a short from any of the phase wires to the axle.

if there is any continuity from any of the phase wires to the chassis or stator, then you have a problem.

Check insulation of the phase wires and see if you can see any damage especially on corners or where wires are tight

 

[dogman dan]

Most likely phase short is either salty road water in the plug, or a nicked wire, usually at the exit from the axle. But check the whole wire, I've had the short occur when a wire rubbed the tire.

Lastly, it could be a fet shorting in the controller.

1st fast check, unplug the phase wires and see if you still get heavy cogging. If no, then the problem might be in the controller if it comes back when you plug it in, still unpowered. Like John said.

 

[mwhens]

It's fixed. I think it had something to do with water. The problem just disapeared.
I now need to make the hub more waterproof.
I have a anti corosion spray thats also water resistand, but I'am not sure if it wil be effective.
I also can use waterproof tape, but thats hard because it's not a flat surface.

 

[Drunkskunk]

Welcome to the down side of the 40X series. Its very not waterproof. Likely you got a little water in the hub and shorted things out a bit. as long as it doesn't blow the controller, it should be fine when it's dry. I've had this happen a few times from riding in the wet.


The cure is to Silicone seal around the wires where they go under the bearing in the groove of the Axle, and make sure that groove is pointed to the ground. you also want to lead the wires out of the motor to form a drip ring.

I also found it helpfull to pack the bearings with marine grease; the stuff they use on boat trailer axle bearings. they are "sealed" but the seals pop off with a toothpick, so repacking them with good grease is easy.

 

[John in CR]

The first order of business is a drip loop. Without one water runs right down the wires and into the motor.