Bafang Motor replacement

[dariusf2]

Hi, my Bafang M800 failed after almost 3k miles with what looks like a torque sensor issue. Started with pedal assist randomly not engaging once in a while and now it maybe engages 3-4 times on a 30-40 mile ride. While I'm waiting on Bafang to look at it as part of warranty, I got another brand new M800 (same 43v). Before I just connect it, I was wondering if there is anything else I need to do. Is it just plug an play or do I have to "pair" or configure anything for it to work with the display?

 

[Gionnirocket]

The M800 is a fairly new motor.
I would check with whomever you purchased the bike from.

 

[dariusf2]

I think M800 was released in 2018 and no longer sold and replaced with M820. Will reach out to the Bikes Direct as well.

 

[Gionnirocket]

I think M800 was released in 2018 and no longer sold and replaced with M820. Will reach out to the Bikes Direct as well.

You're probably right... I was thinking M820.
From what I understand the motors are plug n play, but Bafang support and firmware changes are a real issue so there are no guarantees.
I don't think any harm can come from trying.

 

[dariusf2]

You're probably right... I was thinking M820.
From what I understand the motors are plug n play, but Bafang support and firmware changes are a real issue so there are no guarantees.
I don't think any harm can come from trying.

I assume the mileage is tracked on the motor itself and the display only show whats there. I guess things like shift points etc, is all programmed in to the motor so it may behave differently to my old one.

 

[Gionnirocket]

I assume the mileage is tracked on the motor itself and the display only show whats there. I guess things like shift points etc, is all programmed in to the motor so it may behave differently to my old one.

I believe the display holds the milage... at least with the UART motors.
I believe yours is only available in CANBUS so it may be.
I haven't seen much discussion on here on the 800's

 

[dariusf2]

Yes, its CANBUS, I guess I will plug it in and see what happens Hopefully Bafang will repair or replace the other motor under warranty and I will keep this one as a backup or for spare parts

 

[dariusf2]

I installed the M800 motor and everything appears to be working fine. I'm not sure if there is any programming required like wheel size or shift point. I only took it around the block and plan to take it on a longer ride tomorrow.

 

[m@Robertson]

So you received a replacement motor?

 

[dariusf2]

So you received a replacement motor?

No, I got a new one on AliExpress. Bafang California diagnosed issue with torque converter and can repair but waiting for part from China and there is cost for the part and replacement as the motor is out of warranty I will most likely just buy the part from them and change myself and then keep it as a spare as I enjoy the bike, invested in many upgrades and plan on keeping it for a while.

 

[Gionnirocket]

I installed the M800 motor and everything appears to be working fine. I'm not sure if there is any programming required like wheel size or shift point. I only took it around the block and plan to take it on a longer ride tomorrow.

Since the motor is Canbus any changes to the controller need to be done by a Bafang authorized reseller and they in turn need access to the software as it requires a Bafang log in.

You should have access to basic settings such as wheel size. Assuming you're using the same display you should be all set... but I'd double check them.
What do you mean by shift point?

 

[dariusf2]

Sorry I meant assist levels, I'm new to this so not sure what potential custom settings there might be in the motor for that specific bike. I can adjust wheel size in the head unit and its same as it was. It does show 3k miles which I guess is just tracked in the head unit itself but do not see a way to reset that. I messaged my contact at Bafang regarding that. I could buy BESST tool to play with it.

 

[Gionnirocket]

Sorry I meant assist levels, I'm new to this so not sure what potential custom settings there might be in the motor for that specific bike. I can adjust wheel size in the head unit and its same as it was. It does show 3k miles which I guess is just tracked in the head unit itself but do not see a way to reset that. I messaged my contact at Bafang regarding that. I could buy BESST tool to play with it.

Even with the BESST tool you won't be able to access controller settings without official Bafang log in credentials.
I don't believe the mileage can be reset in the head unit easily... though a search may reveal someone who has hacked the display. Or you could buy a new display for the new motor and save this one as back up or if you ever put the original motor back in service.
I'd ride and see how things work... You may be all set.

 

[dariusf2]

Thanks, yes I understand you need Bafang login which I may not be able to get. Still waiting for reply from my Bafang service contact. I guess in the end the optometer value is really not that important unless I'm going to sell the bike otherwise I just count miles on the new motor from the last recorded total Other then that I track rides on Strava so does not matter that much and only really use it to track service. I check chain and brakes regardless and the miles only really matter to me for the Suntour Mobie 45 suspension fork lowers and damper service.

 

[dariusf2]

Well no go, I did a 26 mile loop yesterday and the pedal assist activated only a 2 to 4 times. Tried everything I could think of. Interesting is that walk assist mode works fine every time, motor activates and propel the bike and I can see the motor watts on the display. My DP C260 display shows both motor and human watts. Everything else display fine, like speed, time traveled, distance, etc. Battery percentage went down to about 89% for the few times it activated. Its basically same experience as with the other motor and it would be one bad luck to get a new motor with same issue. The only thing I can think of is the head unit. I ordered a different one from China so will have to wait for it. For now I guess I leave the battery at home and ride unassisted. The singletrack should be partly dry tomorrow after lots of rain on Friday so will be all mountain bikes anyway.

 

[Gionnirocket]

Easy to play Monday morning quarterback... but yeah, the display is probably the most likely gremlin.
Regretfully there's not whole lot of documented troubleshooting out there and parts changing is what we are left to do.

 

[dariusf2]

Its a bit crazy how little support there is from the vendor and lock of service places. I work on all my bikes including full builds, shock can, fork lowers and full damper service and it's really frustrating how little I can do to diagnose this. Fingers crossed its the display.

 

[m@Robertson]

Unfortunately, this is why most private DIY builders avoid the Bafang CAN bus motors like the plague. Bafang used the switch to CAN to try and lock out the aftermarket and individual builder and lock people into a dealer-supported ecosystem. And since Bafang wrote the book on absent support for the end user, they aren't particularly good at it with dealers, either. They do their best work mass-producing stuff that is reliable enough they don't have to be bothered after the fact... but that reputation came from their time building motors with UART controllers that anyone can get into.

 

[dariusf2]

Thats a problem for sure, the dealers are not ready or tooled to support the products, good example is biksdirect where I got my bike. Its a great bike at a great price, when it works. Its a shame as they got good motors.

 

[m@Robertson]

I have built 9 bikes with BBSHDs, and I have a few with Bafang hub motors (some with both!). They are both strong and reliable... but you couldn't pay me to touch a CAN motor that I can't get into and change all the settings on. Thats another thing... Bafang sucks at doing factory settings to produce a smooth-running, smooth-starting motor that doesn't run away from you if you are pedaling. A CAN motor means you take what they give you and cannot smooth over the rough edges.