Brompton M2L-X (Titanium) - Super Lightweight Pedelec Conversion

GaRRy

Esteemed Pedelecer
May 18, 2012
1,019
3
Tamworth

jerrysimon

Esteemed Pedelecer
Aug 27, 2009
3,292
112
Cambridge, UK
cwah didn't you use to have a motorised skateboard before you got into ebikes ?

Jerry
 

cwah

Esteemed Pedelecer
Jun 3, 2011
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I think it's 2000W peak for hills and acceleration. A lot of hobbyking small RC motors also have high power. It's a dual 1000W motor.

But top speed is 20mph so it shouldn't use more than 500W constant.


I did have a small kid scooter. But motor failled and it was too obvious it was motorised. I was getting too much attention from police so I get rid of it :(
 

monkeyhumanoid

Just Joined
Jan 10, 2013
1
0
Thanks for the update piotrmacheta. I prefer to fit a cutout brake to prevent the delay in the motor stopping when I stop pedaling. I also have an on off switch to bring the pedelec in when I want assistance.

Look forward to seeing a write up/some pics of your Birdy conversion. I am also in the middle of a conversion of a Dahon Uno using a Goldant motor. Like you said needs a couple of spacers to get it centered in the forks, but the motor all but drops in to the Dahon forks. You will probably get a little more than 15/16 mph (17/18 mph) on your Birdy given its nearer 19/20mph in a 20" wheel.

Jerry
Please forgive my ignorance but is it possible to fit brake controls to a road bike with gear shifter brakes? This is the thing that puts me off jumping in to a conversion.
 

cwah

Esteemed Pedelecer
Jun 3, 2011
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Do you still use both the Tongxin and Keyde motor?

Or are you only using the Keyde one?
 

jerrysimon

Esteemed Pedelecer
Aug 27, 2009
3,292
112
Cambridge, UK
Do you still use both the Tongxin and Keyde motor?

Or are you only using the Keyde one?
Yes I have moved to the KeyDe ones for my lighter folding bikes. I will be doing a write up shortly.

I will probably continue to use the Tongxin on my original Brompton in the winter though.

Jerry
 

jerrysimon

Esteemed Pedelecer
Aug 27, 2009
3,292
112
Cambridge, UK
Yes. If you have cable brakes you can use in-line sensors like these, which go at the brake end of your cables next tothe caliper:
HWBS - Hidden Wire Brake Sensor 1pcs - BMSBATTERY
Dave you don't have any of these do you ?

I would like to try one out on my Brompton ?

Ps I guess I could order a few other bits from BMS to make it worth while.

Regards

Jerry
 
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cwah

Esteemed Pedelecer
Jun 3, 2011
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179
www.whatonlondon.co.uk
Yes I have moved to the KeyDe ones for my lighter folding bikes. I will be doing a write up shortly.

I will probably continue to use the Tongxin on my original Brompton in the winter though.

Jerry
So keyde for exercice and tongxin when you're lazy? :)

I'm in contact with the manufacturer they told me they have a speed 5 that might allow 30km/h max speed with minimal pedal assist. Is it true?
 

cwah

Esteemed Pedelecer
Jun 3, 2011
3,048
179
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Dave you don't have any of these do you ?

I would like to try one out on my Brompton ?

Ps I guess I could order a few other bits from BMS to make it worth while.

Regards

Jerry
I have one and it's too big to fit on the brompton brake area. It has to be cut but I'm not sure how to start it
 
D

Deleted member 4366

Guest
Dave you don't have any of these do you ?

I would like to try one out on my Brompton ?

Ps I guess I could order a few other bits from BMS to make it worth while.

Regards

Jerry
I've got a pair that I can pinch from one of the controllers I'm selling on Ebay. £15 inc postage. PM me your address if you want them.
 

jerrysimon

Esteemed Pedelecer
Aug 27, 2009
3,292
112
Cambridge, UK
So keyde for exercice and tongxin when you're lazy? :)

I'm in contact with the manufacturer they told me they have a speed 5 that might allow 30km/h max speed with minimal pedal assist. Is it true?
CWAH,

Not sure my contact at KeyDe is Sky.

The Tongxin is more powerful in the winter when it is windy, but of course is larger and has a +0.6kg weight penalty over the lighter KeyDe Goldant.

Jerry
 

cwah

Esteemed Pedelecer
Jun 3, 2011
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Thanks Jerry. My contact is also Sky.

He said he can have 260RPM max at 36V. It's a bit annoying for me.

I'd like to have a real lightweight for travelling. And my normal brompton on normal days. I'd like to have at least 20mph. I think the Tongxin is the one for me.
 
D

Deleted member 4366

Guest
Sky's a very pretty girl, not a bloke. I met her in Shanghai.

BTW, your noisy charger problem. If you put your charger on a table or other hard surface, the sound gets amplified and travels through the walls. Like that, it can sound louder in the next room than the one it's in, Did you try putting something soft underneath it, so that the sound can't be transmitted?
 

patpatbut

Esteemed Pedelecer
Apr 25, 2012
859
79
Thanks Jerry. My contact is also Sky.

He said he can have 260RPM max at 36V. It's a bit annoying for me.

I'd like to have a real lightweight for travelling. And my normal brompton on normal days. I'd like to have at least 20mph. I think the Tongxin is the one for me.
Is Tongxin able to spin that fast without damaging it?

Pat
 

cwah

Esteemed Pedelecer
Jun 3, 2011
3,048
179
www.whatonlondon.co.uk
I've read some dude managed to put 360W constant on the tongxin without problem. i'm hoping to overvolt it to 48V and do the same.
 

jerrysimon

Esteemed Pedelecer
Aug 27, 2009
3,292
112
Cambridge, UK
Yep it appears you can over volt them, but will certainly need to keep the current down below about 12A on the Tongxin and round 8A on the Goldant

Jerry
 

jerrysimon

Esteemed Pedelecer
Aug 27, 2009
3,292
112
Cambridge, UK
Sky's a very pretty girl, not a bloke. I met her in Shanghai.
Yes I was about to say I thought it was a woman lol

Dave I am so envious of your visit. Did you just go there as an enthusiast to look round the shows ?

Jerry
 
D

Deleted member 4366

Guest
Cwah. You need the narrow Tongxin for the Brompton. I doubt that it can be run at 350w. I bet that dude had the 100mm version. What about stretching your forks and using the Q100 which is the same weight as a 100mm Tongxin, but is known to be able to handle decent power. The 24v 201 rpm at 48v should do it for a top speed of 20 mph.
 

jhruk

Esteemed Pedelecer
May 13, 2009
318
68
Cwah. You need the narrow Tongxin for the Brompton. I doubt that it can be run at 350w. I bet that dude had the 100mm version. What about stretching your forks and using the Q100 which is the same weight as a 100mm Tongxin, but is known to be able to handle decent power. The 24v 201 rpm at 48v should do it for a top speed of 20 mph.
[FONT=&amp]Another option would be the narrower 83mm 328rpm 36v Q85. I’ve been using one in a 20” wheel with a 14-15A controller for a couple of years now without any problems. It’s about the same size as the Tongxin and would probably take a bit more power if required.[/FONT]
 
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