Author Topic: Bafang got cheaper...  (Read 3073 times)

Altema

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Bafang got cheaper...
« on: August 01, 2022, 04:36:25 PM »
I mentioned in another thread that I did a motor swap in Delaware. This was due to a hall sensor failure, but as things turned out, I'd ordered a replacement motor that was supposed to arrive after my trip, but it arrived the day before the trip, so I took it with me! The new motor worked fine, but after a high speed ride alongside gas bikes, I noticed an odd noise that sounded like gears slipping. I pulled the motor apart and found the nylon gears were fine, so I switched the clutch out, and still had the noise.

The ring gear tested fine as well, then I saw it: The replacement motor was missing the internal lacing! That's the string-like cord used to secure the coils and other bits. Without it, the wires are subject to vibration and movement, and this leads to metal fatigue and failure. This is common is cheap throwaway motors, but motors built to last usually have the internal lacing, I was surprised Bafang went in this direction. The only reason to do so is because it's cheaper and saves time and materials. The motor itself works fine, and although the motor on the right is better made, it's out of commission due to the sensor failure. So I went to the hardware store, got some appropriate string, laced up the critical spots, glued the knots, and tested it. The noise is gone and I can use full power again, so we shall see how it holds up!


JTK77

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Re: Bafang got cheaper...
« Reply #1 on: August 02, 2022, 12:43:13 PM »
I mentioned in another thread that I did a motor swap in Delaware. This was due to a hall sensor failure, but as things turned out, I'd ordered a replacement motor that was supposed to arrive after my trip, but it arrived the day before the trip, so I took it with me! The new motor worked fine, but after a high speed ride alongside gas bikes, I noticed an odd noise that sounded like gears slipping. I pulled the motor apart and found the nylon gears were fine, so I switched the clutch out, and still had the noise.

The ring gear tested fine as well, then I saw it: The replacement motor was missing the internal lacing! That's the string-like cord used to secure the coils and other bits. Without it, the wires are subject to vibration and movement, and this leads to metal fatigue and failure. This is common is cheap throwaway motors, but motors built to last usually have the internal lacing, I was surprised Bafang went in this direction. The only reason to do so is because it's cheaper and saves time and materials. The motor itself works fine, and although the motor on the right is better made, it's out of commission due to the sensor failure. So I went to the hardware store, got some appropriate string, laced up the critical spots, glued the knots, and tested it. The noise is gone and I can use full power again, so we shall see how it holds up!

Not sure If its intentional or lack of QC.
What I recently noticed that the gluing of motor magnets was not accetable and failed. Now after fixing this issue together with other mods the motor is way better than new 😄

JedidiahStolzfus

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Re: Bafang got cheaper...
« Reply #2 on: August 02, 2022, 01:58:34 PM »
Do you see that black part with the 3 legs on the left side of each motor?  That's the hall effect component.  I'd bet it's a fairly common device that could be easily replaced if you just have a soldering iron and some solder wick to remove the old solder. 

Altema

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Re: Bafang got cheaper...
« Reply #3 on: August 04, 2022, 01:58:13 AM »
Do you see that black part with the 3 legs on the left side of each motor?  That's the hall effect component.  I'd bet it's a fairly common device that could be easily replaced if you just have a soldering iron and some solder wick to remove the old solder.
Yes, I just need a source for the sensors. I wonder if the sensors from the Bolton motors would fit, since I have three of those failed motors on my workbench right now.

Altema

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Re: Bafang got cheaper...
« Reply #4 on: August 04, 2022, 01:59:33 AM »
I mentioned in another thread that I did a motor swap in Delaware. This was due to a hall sensor failure, but as things turned out, I'd ordered a replacement motor that was supposed to arrive after my trip, but it arrived the day before the trip, so I took it with me! The new motor worked fine, but after a high speed ride alongside gas bikes, I noticed an odd noise that sounded like gears slipping. I pulled the motor apart and found the nylon gears were fine, so I switched the clutch out, and still had the noise.

The ring gear tested fine as well, then I saw it: The replacement motor was missing the internal lacing! That's the string-like cord used to secure the coils and other bits. Without it, the wires are subject to vibration and movement, and this leads to metal fatigue and failure. This is common is cheap throwaway motors, but motors built to last usually have the internal lacing, I was surprised Bafang went in this direction. The only reason to do so is because it's cheaper and saves time and materials. The motor itself works fine, and although the motor on the right is better made, it's out of commission due to the sensor failure. So I went to the hardware store, got some appropriate string, laced up the critical spots, glued the knots, and tested it. The noise is gone and I can use full power again, so we shall see how it holds up!

Not sure If its intentional or lack of QC.
What I recently noticed that the gluing of motor magnets was not accetable and failed. Now after fixing this issue together with other mods the motor is way better than new 😄

What glue did you use? I used CA on mine, but that glue has failed on other motors.

JTK77

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Re: Bafang got cheaper...
« Reply #5 on: August 04, 2022, 09:47:48 AM »
I mentioned in another thread that I did a motor swap in Delaware. This was due to a hall sensor failure, but as things turned out, I'd ordered a replacement motor that was supposed to arrive after my trip, but it arrived the day before the trip, so I took it with me! The new motor worked fine, but after a high speed ride alongside gas bikes, I noticed an odd noise that sounded like gears slipping. I pulled the motor apart and found the nylon gears were fine, so I switched the clutch out, and still had the noise.

The ring gear tested fine as well, then I saw it: The replacement motor was missing the internal lacing! That's the string-like cord used to secure the coils and other bits. Without it, the wires are subject to vibration and movement, and this leads to metal fatigue and failure. This is common is cheap throwaway motors, but motors built to last usually have the internal lacing, I was surprised Bafang went in this direction. The only reason to do so is because it's cheaper and saves time and materials. The motor itself works fine, and although the motor on the right is better made, it's out of commission due to the sensor failure. So I went to the hardware store, got some appropriate string, laced up the critical spots, glued the knots, and tested it. The noise is gone and I can use full power again, so we shall see how it holds up!

Not sure If its intentional or lack of QC.
What I recently noticed that the gluing of motor magnets was not accetable and failed. Now after fixing this issue together with other mods the motor is way better than new 😄

What glue did you use? I used CA on mine, but that glue has failed on other motors.

Permabond ET5441 heat cured after 24h  in 85?C 30min.

Omidia Ramin

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Re: Bafang got cheaper...
« Reply #6 on: August 04, 2022, 01:22:38 PM »
I hate to hijack a thread, and I?m not sure if this counts, but I think you?se have the answer (those on this thread:-) )

I have a motor (the one out of the mini 4) with a broken axle. It?s been replaced, but I?ve kept the motor, if for nothing else wall was art.

How feasible/possible is it to replace an axle on these things?

Would be nice to have a spare and send like a shame since the rest works.  Should I perish the thought or what??

Anyways, thanks for any thoughts!!

JedidiahStolzfus

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Re: Bafang got cheaper...
« Reply #7 on: August 04, 2022, 01:52:13 PM »
Do you see that black part with the 3 legs on the left side of each motor?  That's the hall effect component.  I'd bet it's a fairly common device that could be easily replaced if you just have a soldering iron and some solder wick to remove the old solder.
Yes, I just need a source for the sensors. I wonder if the sensors from the Bolton motors would fit, since I have three of those failed motors on my workbench right now.

If the head of it lifts off the board, then look at the number, chances are Mouser has it.  I might even have some in my parts. 

Altema

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Re: Bafang got cheaper...
« Reply #8 on: August 05, 2022, 06:36:03 AM »
Permabond ET5441 heat cured after 24h  in 85?C 30min.
Thanks! I've got 4 motors I needs to do... any tips on cleaning the old glue off?

Altema

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Re: Bafang got cheaper...
« Reply #9 on: August 05, 2022, 06:44:29 AM »
Do you see that black part with the 3 legs on the left side of each motor?  That's the hall effect component.  I'd bet it's a fairly common device that could be easily replaced if you just have a soldering iron and some solder wick to remove the old solder.
Yes, I just need a source for the sensors. I wonder if the sensors from the Bolton motors would fit, since I have three of those failed motors on my workbench right now.

If the head of it lifts off the board, then look at the number, chances are Mouser has it.  I might even have some in my parts.
I found the sensors and ordered them off eBay last night. Also ordered a DC motor tester that can tell which of the three sensors is bad.
It's funny that I saw a motor advertised which had dual hall sensors for backups, and I thought "who would need that?". Now I know... 😂
Also realized I could have just configured my Phaserunner to run the motor sensorless on the trip.
« Last Edit: August 05, 2022, 06:47:18 AM by Altema »

Altema

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Re: Bafang got cheaper...
« Reply #10 on: August 05, 2022, 07:19:11 AM »
I hate to hijack a thread, and I?m not sure if this counts, but I think you?se have the answer (those on this thread:-) )

I have a motor (the one out of the mini 4) with a broken axle. It?s been replaced, but I?ve kept the motor, if for nothing else wall was art.

How feasible/possible is it to replace an axle on these things?

Would be nice to have a spare and send like a shame since the rest works.  Should I perish the thought or what??

Anyways, thanks for any thoughts!!
I loaned my original RadMini motor out so can't check, but on my other Bafang motors, it looks like you can remove the axle. It will be complicated though because you'll have to remove the wiring that goes through the axle, feed it back through, and resolder it. Might not be worth all the work.

Altema

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Re: Bafang got cheaper...
« Reply #11 on: August 06, 2022, 01:20:32 PM »
I hate to hijack a thread, and I?m not sure if this counts, but I think you?se have the answer (those on this thread:-) )

I have a motor (the one out of the mini 4) with a broken axle. It?s been replaced, but I?ve kept the motor, if for nothing else wall was art.

How feasible/possible is it to replace an axle on these things?

Would be nice to have a spare and send like a shame since the rest works.  Should I perish the thought or what??

Anyways, thanks for any thoughts!!
I loaned my original RadMini motor out so can't check, but on my other Bafang motors, it looks like you can remove the axle. It will be complicated though because you'll have to remove the wiring that goes through the axle, feed it back through, and resolder it. Might not be worth all the work.
Hey, I just found a video on replacing the axle! Here's a link if you want to see what's involved in this job...

https://www.youtube.com/watch?v=Tb3mXqU1CJs

JTK77

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Re: Bafang got cheaper...
« Reply #12 on: August 06, 2022, 02:14:46 PM »
Permabond ET5441 heat cured after 24h  in 85?C 30min.
Thanks! I've got 4 motors I needs to do... any tips on cleaning the old glue off?

Cleaned first with acetone and scraper tool. Then prepared surfaces with 400 grid and removed dust.
Just before applying the epoxy cleaned the surfaces with acetone again.

JTK77

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Re: Bafang got cheaper...
« Reply #13 on: August 06, 2022, 02:20:34 PM »
I hate to hijack a thread, and I?m not sure if this counts, but I think you?se have the answer (those on this thread:-) )

I have a motor (the one out of the mini 4) with a broken axle. It?s been replaced, but I?ve kept the motor, if for nothing else wall was art.

How feasible/possible is it to replace an axle on these things?

Would be nice to have a spare and send like a shame since the rest works.  Should I perish the thought or what??

Anyways, thanks for any thoughts!!
I loaned my original RadMini motor out so can't check, but on my other Bafang motors, it looks like you can remove the axle. It will be complicated though because you'll have to remove the wiring that goes through the axle, feed it back through, and resolder it. Might not be worth all the work.
Hey, I just found a video on replacing the axle! Here's a link if you want to see what's involved in this job...

https://www.youtube.com/watch?v=Tb3mXqU1CJs

The most hardest part is to source new axle (with decent price).

Rad Power Bikes Owners Forum

Re: Bafang got cheaper...
« Reply #13 on: August 06, 2022, 02:20:34 PM »