Undersized Controller ??

[GodsWarrior]

If the watt meter is working as it should...and its truely pulling 250w...something is really bogging down ur motor...like its being forced more than normal to spin...

 

[GodsWarrior]

What happens when you give it full throttle? Does it move quickly as it should or????

 

[markz]

Yeah there is resistance, something jamming the motor or mismatched combo in hall and phase, or burnt windings which I dont know about unloaded being high wattage but jittery for sure for burnt, or darker windings.

 

[dannydibbert]

No noises at all when running motor with bike upside down although the motor only draws 250 watts max when bike is upside down (no load basically).

There's either something seriously wrong with the wattmeter, or the phase/hall wiring combination is wrong. It shouldn't draw more than around 1-2 amps max for no load, which would be at most about 100w (which would still probably be pretty high). If you're getting twice that (more like four to five times as much as would be typical), and the wattmeter is accurate, either you have a physical problem causing drag on the motor somewhere, or you have the wrong combination of phase and hall wires (a "false positive").

I checked the no load Watts again and it is like you said, it goes up to around 200 watts as the rear wheel is spinning up then goes down to zero and stays there. No grinding noises at all. Got the tool from FeedBack Sports to remove the cassette spline nut but the bore is still too small to get over the nut/washer. Gonna file down the nut/washer.

 

[dannydibbert]

What happens when you give it full throttle? Does it move quickly as it should or????

Under full throttle is takes off really strong from stand still and I am 260 lbs, 6'4". While riding whenever I give it full throttle it kicks in right away with no grinding noise until the wattage approaches 900+ watts, then pretty constant grinding until I let up on the throttle a bit. At that point it is drawing 19+ amps which I suppose creates "lots of magnetism" in the windings which could rattle/vibrate a fixed position permanent magnet which is rotating really fast in the rotor. I can pretty much always make it happen but not while the bike is upside down.

 

[dannydibbert]

Progress .... got the Shimano cassette tool to work by filing down the nut from basically a 6 point to a 12 point and then filing 2 opposite flats on the bigger washer so it would slip thru the tool sideways. The other washer was small enough already. Cassette came off easy (no chain tool needed). The security Torx screws came out easy. Bafang is out !! My Bafang 750 is a true 750 with the bigger inside vs. the RAD Bafang 750 which is actually a 500 inside. I am working the motor disassembly right now and will post what I find with pics later.

 

[amberwolf]

I checked the no load Watts again and it is like you said, it goes up to around 200 watts as the rear wheel is spinning up then goes down to zero and stays there.

I don't recall saying anything like that.

So to be clear, the motor previously took 250 watts to spin it with no load.

Now, something has changed, and it takes 200 watts to start it spinning, but then it takes zero watts to keep spinning it at the same speed?

Neither one of those things is correct motor operation. 250 watts of no load power, wheel off ground, is two to five times as much power as it should take.

Zero watts of no load power is not nearly enough.

So either something is wrong with the wattmeter, or something is wrong with the motor, controller and/or wiring.

 

[dannydibbert]

Maybe it was another person making that specific comment. Either way, the rear wheel spins right up (bike right side up - holding rear wheel off ground) with full throttle for maybe 20 seconds to max speed (clean smooth sounds with no grinding). The watts display is generally much less than 200 watts during spin up and then displays zero but the full throttle is engaged. I think maybe the watts are so low to keep it spinning that the display defaults to 0. It could be related to a cheapo controller but I am not concerned except that I suspect that the controller is a POS.

I just completed the close to full disassembly of the the Bafang 750 hub motor. Pics below. Everything I saw (no bench powered testing) indicate that all is well with the motor. Magnets are nice and tight. Hand spinning exhibits no interference (magnets to coils). Everything is very clean looking (the bike is new with maybe 100 miles on it). I am going to leave it apart for now in case anyone has any suggestions. Pretty sweet and compact motor design IMO.

Again, the fault condition is only when I go full throttle and the watt display approaches 900+ watts which is around 18+ amps and the controller is rated at 11 amps with a max of 22 amps. The design should be sufficient but the 4 inch tires are pushing around my 260 lb self. Probably should cut down on my IPA beer anyway. Thinking of an upgrade to the 35 amp max programmable controller and color display for $200 anyway (the RAD upgrade kit).

 

[GodsWarrior]

Why is the case with gears all scratched and scuffed up ( behind the white gears)??

 

[fechter]

Why is the case with gears all scratched and scuffed up ( behind the white gears)??

Those are just strings of grease that flew off the gears. The motor looks great inside.

 

[goatman]

are these the disc brake screws?

 

[fechter]

I think those are part of the clutch.

 

[GodsWarrior]

Well its hard to say what it could be..sometimes u just have to drive it till it breaks.... U know ,im having trouble also with my scooter...i added dual motors and dual controllers and 1 day just mashing the full throttle for a few lights when i got home my motors started making weird noise and significally lost power...mainly in the bottom end...i cant take off full throttle anymore cause they just buzz really bad...u gotta build up speed....sux.

 

[dannydibbert]

Finished with improved results.... I inspected everything I could in the motor and all seemed fine. After some research I decided to fully lube up the planetary nylon gears with Red Lithium grease (pic below). Put everything back together being careful with alignments, etc and used blue locktitie. Went for a full throttle ride and the normal motor noise seemed noticeably quieter and detected only very minor grinding noises at full wattage. I think its as good as its gonna get.

One thing I noticed is that with the bike upside down full throttle spin up was maxed at about 30 watts and continuous spin was around 10 watts (on the display). When I repeated that with the bike upright and holding up the rear wheel, the max wattage was higher and the continuous wattage went down to zero even though I had full throttle going. Strange but I can live with it.

Thanks for all the suggestions.

 

[GodsWarrior]

....

 

[EV_Ron]

Your post was a great Christmas gift, thanks!

My KU63/failed (R1 overheat after 7 years, ~1000 miles), so tried an ebikeling 500W controller i bought cheap (after setting it down to
7A by changing C5=3.)

Motor chattered and stopped after 5 secs.

Came here, searched "chatter", found your outstanding post, pulled the Hall plug, turned the throttle and... at least the motor runs "normally" now!

Now to research sensored vs. sensorless.

Thanks!
Merry Christmas!
(Hope the gods of ES don't threaten me with "off topic" again like they did 7 years ago.)

Without seeing or hearing it, I'm going to take a wild stab that it's a badly tuned sensorless start. If it is, it will judder and hum a bit while lurching you forward a little, then be perfectly smooth and fairly quiet once you've moved more than about 1/3rd of a rotation of the wheel. I went to the Lishui site, but can't find your exact model, but all their eBike controllers support both modes, so it's possible that it was designed for a sensored start, and hence the sensorless settings were never set up, but the hall sensors aren't working so it's falling back.

If it makes the chatter/scrape noises while you're cruising on partial throttle, you can completely rule this out as the problem. However, if it also occurs while you're moving, and change from a closed throttle to an on-throttle, it's still a likely candidate.

 

[EV_Ron]

For anyone who's just replaced a controller and having issues like chattering or clunking of your hub/BLDC motor, and maybe you pulled the Hall sensor plug and now the motor runs, check your Hall plug pins:

My Q100 motor's Blue & Y pins on the Bl-G-Y row are reverse from the new controller's Y-G-Bl!
I simply swiped the Y & Blue and reconnected the Hall sensors back into the controller plug & boom: motor runs normally. I mean, I know it's not rocket science, but this might give one or two people the idea to check Hall sensor sequence when their motor chatters after a controller change.

Merry Christmas.

 

[999zip999]

There's an old chart that shows 36 different combinations.

 

[TommyCat]

There's an old chart that shows 36 different combinations.

Perhaps like this one...

 

[999zip999]

Like that but only switches phase wires and still b16 more or so if switching hall wires. I know JohnCR switch any two wires six times. But with an old bmc 600 hs geared motor only two combos worked.
OK I found the footnote about hall sensors in the bottom.