Mwmotor brompton conversion

[patpatbut]

Dear all,

I am sure there is a lot of experts here for this conversion but I would like to share mine considering I am not engineering and I learn everything from all the friends here

I have not sourced all the parts yet as I keep on changing my mind about the build but now I have decided everything just waiting the parts to come.

Before start, I need to thanks Colin, Alan and Jane for the support about this build. Without them I am probably stuck.

I am using the same motor as Colin got from Jane from Aliexpress

Aliexpress.com : Buy 16",20",26",700C electric bike BLDC front wheel motor QMWB from Reliable front wheel motor suppliers on MW motor

Potentially it is Bafang SWXB motor as suggested by David. The only different is I ordered the black version from Jane. I mentioned the specification below to Jane and she has been really helpfully and responsive to get me this motor

Voltage: 36
RPM: 340
Power: 250W
Rim size: 16"
Spoke holes: 36
Colour: Black
Sensorless motor
cable length: 3-4m with waterproof connector

I received the motor after 10 days of ordering and it was nicely packed and no damage to the motor. The best thing is I did not have to pay VAT!




I will keep everyone update for my work.

Pat

 

[benjy_a]

Hi, what rpm is this motor at 36v?

Thanks, Ben.



Sent from my GT-I9300 using Tapatalk 2

 

[patpatbut]

340 rpm. It is actually at the first post

 

[patpatbut]

More update for the build.

Just ordered the torque sine wave controller from BMSbattery as I prefer the LCD display.

This controller seems to be able to cap any speed by adjusting the setting.

I got the rim from Colin ( spokes and nipples from Alan) and I have done the wheel build and re-trued the wheel by the friend who owns a bike shop

One of the big advantages of this rim is it is so much easier to put the schwalbe marathon plus tyre on. i did it without the lever!


While waiting for the controller, I will start widening the fork in this afternoon.

Pat

 

[Deleted member 4366]

If you look at your motor, it's not the same as the one in the advert that you linked to, and as far as I know Bafang don't use those torque washers. It seems to have an "X" logo that probably means something to someone. It's not a Xofo. Their logo's different. When I was in Shanghai, I discovered that there's loads of small factories and workshops building motors from the same components as other manufacturers. They don't seem to care about copying or being copied. I wouldn't be worried about the fact that it's probably a copy because many of the motors in bikes you buy are copies too. It looks nice, and I like the fact that both sides easily unscrew, which makes servicing a 5 minute job.

I look forward to seeing the completed build and performance figures. It should go pretty well.

 

[patpatbut]

Hi Dave,

I do discover too and Jane told me as I ordered the black one and they have to use different casing for my motor. Of course, I will try to give the full review after the full build.

I will keep everyone update for the progress.

Pat

 

[cwah]

Are you going to spread the front fork to 100mm?

 

[patpatbut]

Yes and I have done it!

I have modified the method I adopted from Colin. For his method please go to his thread to find out. I only highlight the different here.

First I used some tape to wrap around both dropouts. Putting the black lisle exhaust manifold between the fork and starting spreading slowly up to around 83mm


Keep the manifold then start inserting the turnbuckle to the dropout


Then start spreading the fork using the turnbuckle and moving the black manifold down the fork to keep the fork parallels


Spreading the fork til 130mm to get 102mm width after removing the turnbuckle and manifold

That Was it. The ideas behind is spreading both dropouts with the same force all the time to keep them parallel. I also found this method to be very manageable as well.

I will post more pics later.

Pat

 

[cwah]

How's the folding size?

Also, I decided to go through the rear dropout as they are much stronger.

On the front one, it's very easy to have the dropout broken. I found it dangerous... Unless this motor is less than 500W

 

[patpatbut]

I have not tested the fold yet but will let you when u go along.

My motor is 250w and I will cap the speed at 15mph. Also, using the TETS supplied torque washers they should protect the dropout from being separate apart

Pat

 

[funkylyn]

I tell you what, there was a guy racing a Brompton up Park St Bristol yesterday that had to be seen to be believed.....I dont know what he had done to it (aircraft engine lol ) but it really went up at a speed and power that I am sure Bromptons were never meant to see, boy, it FLEW up and did it look FUN !!

Lynda

 

[patpatbut]

I tell you what, there was a guy racing a Brompton up Park St Bristol yesterday that had to be seen to be believed.....I dont know what he had done to it (aircraft engine lol ) but it really went up at a speed and power that I am sure Bromptons were never meant to see, boy, it FLEW up and did it look FUN !!

Lynda

I wish I was there to join the fun. Well...too busy for my conversion.

Does anyone have some videos to share about yesterday show?

Pat

 

[patpatbut]

More update again!

Managed to put the motor to the bike and realised the motor cable is coming out from the left. I have been looking for an extension block and seems Colin does not stock them anymore.

The solution for me at the moment is loosing the screw slightly that links the hook. This allows me to fold the bike but only a temporary solution. I still prefer the extension block option.


I am still waiting the controller from BMSbattery so more update later once I have it

Pat

 

[patpatbut]

It has been a delay for the build but I have finished the beta conversion.

The plan was using the torque sine wave controller with this mwmotor (3 phases) but it seems this controller does not support the motor with no hall connection.

I am now using KU65 controller with PAS and half twisted throttle and it runs perfectly.

I have not tested out the top speed yet but I will report and upload some photos later on

Stay tuned!
Pat

 

[jerrysimon]

Managed to put the motor to the bike and realised the motor cable is coming out from the left. I have been looking for an extension block and seems Colin does not stock them anymore.

You can get away without the extension block if you remove the rubber cover and just wrap up the shaft end and wire with the spring cover on it with self-amalgamating tape.

Jerry

 

[patpatbut]

You can get away without the extension block if you remove the rubber cover and just wrap up the shaft end and wire with the spring cover on it with self-amalgamating tape.

Jerry

Thanks Jerry. I will try to use the tape to wrap it up.

More photos coming tomorrow for the build. However, this is not the final as I will use square wave controller to match my motor.

Pat

 

[patpatbut]

Hi all again.

Cycle to work today and pretty windy outside. The bike last the whole 15 miles journey!

The only complain is the noise of the motor. If it is running on flat the noise is not much. Once it is climbing up the hill, the high pitch noise starts to kick it. Do you think this high pitch noise is normal? Am I stressing the motor too much?

However, if I change it to medium PAS mode that high pitch noise is gone even when it is uphill.

I have tested it the motor for the perform here is the result.

The setup is
KU65 + mwmotor casing (SWXB internal) + 36V 12AH LifePO4 battery + PAS

Flat no wind throttle only = 16mp
Flat no wind + pedalling = 18mph

Sorry I could not upload the photo yet but they are coming soon.

Pat

 

[patpatbut]

Photos!

I still have not solved the problem with the hook yet. The shaft of the motor is just too long.

Not sure the solution...
Pat


Sent from my iPhone using Tapatalk 2

 

[cwah]

Who is this colin providing additional 349mm rims?

Be careful with your setup, you have probably an additional 8 kg all on the front of your bike. The hinge does not bear that well all this additional weight and may bend slightly over time.

It happened to my brompton and my heavy battery pack, now it's not that easy to fold

 

[MikeyBikey]

Hi, will front hinge really bend folding with that load? Oops, I've been putting 10kg shopping in front basket & folding So if that's overloading, electrics AND shopping will be way over :-D

Re the axle cover, see if shops still have those nylon caps with cutout, that were used on the rhs of Rear axle to protect indicator chain (and your shins ;-))? They wouldn't keep water out but might protect wiring! (for 10mm axle, yes?) If it fits with hook of course, oops2. Was old wire hook thinner?