WattWagons UCP with M630

[ak907]

I'm looking for feedback on the new Bafang M630 motor. Specifically, I'm wondering if it would be a suitable fit for the WW Ultimate Commuter Pro frames and how well it performs in that application.

I'm currently on my second and third M620 motor rebuilds, as they seem to require major work after only about 6,000 miles. My first M620 failed due to an electronics issue, and upon disassembly, I found the pawl had stripped a significant number of teeth on the inner main gear. The motor I replaced it with now has a nasty grinding sound while pedaling, and I suspect the bottom bracket/axle is the cause.

That motor also recently experienced intermittent torque/pedaling detection failures and surging after being ridden in the rain, though that problem eventually resolved itself. Consequently, I no longer trust the M620's weather resistance—a significant issue for a primary commuter vehicle.

I use only pedal assist (never the throttle) and have not modified the motors for increased power. Given the nearly $800 cost per motor and the high price of replacement parts, this is becoming frustrating. Repairs are also costly and time-consuming; I can't find e-bike mechanics for less than $100 per hour, which, when combined with parts and extended downtime, doesn't make financial sense.

 

[Gionnirocket]

From what I understand the M630 is very similar, but more powerful. This may impact your drivetrain reliability.
A few questions.
Are your current M620 motors UART or CANbus?
If UART did you do any programming modifications?
Have you opened them up to grease the gears?
Do you have any mechanical skills to make repairs yourself.
I'm not there yet but have two M620 with 4000mi and 4500mi and I'm just loving them. Last I opened the original with 4000mi on it, everything looked brand new.

 

[ak907]

Yes, I understand. My goal would be to get it for the "improvements" and underpower it and hope that the design for more power and the quoted improvements make it more reliable.

UART, which is a good point I guess I would probably need a new wire harness which would be quite annoying to do. I did no perform any changes to power output. I mainly ride in eco 3-5, occasionally do use sport 5 to get up hills. I do pull kid trailers regularly but usually for short distances and much lower speeds, most of my milage is stop and go high speed (city commuting).

I have opened bother motors up at this point. The motor from WattWaggon's was supposedly tuned up'd and greased before delivery. After it failed around 6000 miles (stopped providing power under peddle assist (If I remember correctly walk mode still worked), still turned on) I ordered a second after no being able to figure out the issue fast enough with the very very slow shipping of parts.

I greased the second very thoroughly with cornhead based on recommendations here. It made the motor significantly quieter which was nice. It lasted again ~6000 before starting to fail (grinding with every peddle stroke).

I finally got to trying to fix the first with the second having issues and I found that about 1/4 of the teeth for the motor clutch had broken off, the pawls interestingly were perfect. Also the gear first in line from the power shaft from the motor had pretty decent almost 1mm ridges from deformation. The grease was not impressive in volume. I have new gears on order (I already have new electronics).

I have been able to get the second motor up and running again by replacing the bottom bracket/peddle axel. Again I had greased it heavily with cornhead. I found there are two missing teeth in the inner part of main gear where the pawl is. The gears otherwise look good. I have cleaned it and re-greased it and am back on it as it will be a while for parts from GBK.

Perhaps I am unlucky, but it seems like there are issues. Particularly with the gears for catching power via the pawl clutch. But I have also had failures in the axel/and electronics.

 

[Gionnirocket]

Well I'm not at 6000mi yet so perhaps I have some trouble coming?
I too follow the philosophy to underpower these motors as one I don't find full power necessary and then to also add some reliability.
If your current motors are UART I highly recommend tuning them as you can definitely make the acceleration curve more natural and less stressful on components. I've set my global current down from 30a to 28a but more importantly I have my first four PAS set up tight together with minimal increases and to be very natural feeling and without large current in rushes. These first four are also my most used by far and 5 - 8 are only for the much steeper hill climbs. I've never appreciated the eco/sport option and use a display that allows for straight line 9 PAS. 9 being full power but mostly reserved for throttle implementation.
I find it interesting that the ratchet gear used with the pawls failed... If I'm thinking about it correctly aren't they only under the stress of pedaling and not the motor?
I made a mistake in the first post....
My first motor greased with Mobile SCH100 looked new when opened after 4000 mi and has a total of 5550mi ... but the grease didn't offer any of the quieting affect.
The second motor greased with cornhead hasn't been opened in the last 2600mi but it sure is quieter and has a total of 3400mi. I plan opening it again sometime in the next month or so. It's perfect riding weather now so I'm not gonna mess with it until things start getting colder.

So this all said... Having the UART programability was my main reason for choosing this motor and now that it's tuned to my liking I find it a joy to use. I also think my tweaks may be contributing to its durability. The M630 is CANbus and since I don't need more power I'm happy to stay where I am... but I can understand what you want to do.
That said my mind might change in 2000mi