What does this hub noise indicate? (video)

[Anthony King]

When my motor is under a lot of strain I get the noise in the video below accompanied by what I can best describe as motor power "pulsing" rather than a steady pull. If I back off the throttle the motor smooths out. Happens on flats and hill.

Setup is eZee front hub in a large diameter front wheel (751mm rim + tire). 25A eZee controller. 36V battery.

Sorry, working on embedding, here's the link.

http://www.youtube.com/watch?v=fqyYzz4IadQ&feature=youtu.be

 

[amberwolf]

I can't view the video due to bandwidth here, but my guess from your description is the same as before:
http://www.endless-sphere.com/forums/viewtopic.php?t=52537#p780798

I would guess that the type of overload you are seeing, with "stuttering" of the motor, is either the current limit of the controller or the BMS of teh battery, trying to roll back the power being delivered. Most likely the controller.

You can test that theory by watching your wattmeter's V and A readouts during this stuttering and seeing if it also stutters. You'd see V go up and A go down (as load is cut off), and the reverse when load is reengaged, if the controller is doing the limiting.

If it's at the BMS or the battery you'll see V cut out or dip severely.


It's also possible it's just a connection at a phase or at main power from batt to controller somewhere, that isn't quite able to handle the hiigher current and causes a voltage drop across the connection due to resistance. You'll see heating there, too.

 

[MadRhino]

From the sound of the vid, you have a rubbing noise that should be easy to locate.
Proceed by elimination, external first of course, of all the mechanical rubbing possibilities.
You may be lucky and find a simple external cause, of you could have to open the motor to find out.
Rubbing leaves marks, external causes are very easy to find when the bike is dirty.
If it is inside you will probably see scratches and wear on metal parts that are rubbing.

 

[Anthony King]

Hmmm. Voltage stays fairly consistent but stuttering only happens when A goes over 50. It then will drop to 45ish, then back to 53ish, and back and forth until I back off the throttle or the grade flattens out. I have a 25A controller with CA set to 50A for the maxamps setting. The fact that A will always jerk back down after exceeding 50 could be coincidence. But I'll test it by changing the maxamps setting in the CA to see if this changes the point at which the stuttering begins.

Motor never gets hot at all and controller only gets mildly warm on very steep sections of road, so I don't think I'm wrecking anything.

There's definitely no external rubbing and the fact that the motor is smooth under 50A makes me suspect is isn't internal rubbing either.

If my battery spec says the max. discharging current is 60A can I safely put my CA maxamps setting at 60A?

Sorry, trying to learn this electricity stuff but until four weeks ago I'd never dealt w/ anything other than plug-and-play electronics.

 

[ambroseliao]

Do you have another EZEE motor or controller that you could swap out and see if the problem goes away?

 

[Anthony King]

Do you have another EZEE motor or controller that you could swap out and see if the problem goes away?

Unfortunately, no. First build. I do plan on going to a 35A Infineon soon, but I don't have one in yet.

 

[ambroseliao]

Did you buy it from Grin Technologies (ebikes.ca)? If so, I'd give them a call.

 

[Anthony King]

Ponder on this one: What you have on your bike *is* plug-and-play, for advanced ebikes. Most of what's out there is quite a lot harder to get it all working together if you know nothing about it.

Oh yeah, I know. Aside from installing some plugs, my kit has been plug and play.

I'll check shunt calibration and monkey w/ CA setting so see what happens.

 

[Anthony King]

Yeah, I feel like an idiot, but the problem is fixed.

Amp reading in CA was distorted b/c I never set the shunt resistance. CA was modulating when I was over the maxamps threshold, causing the herky-jerkiness.

I think on the initial setup when I came to Advanced Settings. I thought "Advanced sure as hell doesn't describe me, I'll skip this part." Might have also thought/hoped the CA was pre-calibrated. In any case shunt resistance was at 1.00 mOhm. Set it to 3.49 and the motor is smooooooth.

Thanks again ES.