Cheap Brompton Conversion Kit?

[jerrysimon]

I have looked via the website but they do not mention the name Tongxin motor. Is this the right one?

Hangzhou outrider technology Co.,Ltd.

Btw, can I choose higher RPM (let'sa say 328) to improve the speed? as my commute route is pretty flat and the speed is my main concern.

Yep that looks like the right one though, they have a better waterproof connector now. Just mention to her that you want the one for V brakes (I got a couple of roller brake ones once when I did not specify them correctly which was a challenge) and say its for a small wheeled bike. Cici will send you a PI (order sheet) which should list and have photos of what you are ordering.

As I said you may have to wait 4-8 weeks especially if they need to make one with 28h. 36h ones are fine but you will need to use a Sun CR18 rim which are stronger (does not matter given this lower powered motor) and are more of a challenge to get the smaller 16" tires on and off.

260RPM is the maximum though as I said some over volt them to get a higher top speed.

Regards

Jerry

 

[patpatbut]

Don’t forget the Cute Q85 motor is also available in 83mm width. Not as silent as the Tongxin but about the same size and weight and is 328rpm, so slightly faster. I’ve been very pleased with mine in a 20” wheeled Dahon.

You’d need a 36 hole 349 rim for a Brompton as I think the motor is only available in 36 hole.

The KU63 or KU65 controllers work well with it.

Jerry How about the reliability of both motor Tongxin and Cute?

For me, it seems Cute 85 is a better choice considering the power and weight.
Just wondering why did you not pick Cute 85 over Tongxin for your brompton?

For the battery, is it any good?

36v 20Ah
http://www.ebay.co.uk/itm/36V-20Ah-LiFePO4-Battery-Electronics-Bicycle-DIY-New-Energy-by-SAL-air-mail-/130713417143?pt=US_Rechargeable_Batteries&hash=item1e6f2075b7&_uhb=1#ht_2311wt_1397

Thanks.
Pat

 

[cwah]

How many km do you plan to do Pat?

On a cute85, I would say you would use around 7wh/km if you peddle. With this pack you would have 36V X 20AH = 720WH / 7wh/km = 102 km autonomy?

Do you plan to do more than 100km daily? You can probably get a 10AH and "only" have 50 km distance if you peddle.

This pack is probably overkill for this motor.

 

[patpatbut]

How many km do you plan to do Pat?

On a cute85, I would say you would use around 7wh/km if you peddle. With this pack you would have 36V X 20AH = 720WH / 7wh/km = 102 km autonomy?

Do you plan to do more than 100km daily? You can probably get a 10AH and "only" have 50 km distance if you peddle.

This pack is probably overkill for this motor.

Yea it is overkill but how about 15ah? I am tempted to use throttle only for traveling 20 miles each way.

 

[cwah]

Ok, if you cycle at legal speed (15mph), on throttle only you would use 15wh/miles.

So for 40miles you would need 15wh*40miles = 600wh battery.

Considering you would need about 20% additional power to preserve battery, a 720Wh battery would fit you.

So for your case, a 36V20AH battery would work better for you, if you do 40 miles/day and no peddling at all.


Do you really want to do 40 miles/day?

I'm visiting flat now and I've found one at 13 miles from my workplace. I tried to cycle there with my Bromped (it goes 25 mph) and it's furiously long. 50 mn!!! The place was nice but no way I'm going to do 1h30/day commuting. And my bum hurts after such a long distance.


For you, at legal speed, and you won't be able to go much faster than 15mph because you'll have a small geared motor, it means 90mn minimum each way.

So more than 3 hours / day commuting?


If it's just occasional only, I could understand... but, 20 miles each way, I would almost never do that.


ps: I also have an overkill pack of 1320wh. It means the double of your 36V20AH pack and weight 11kg lol. But I selected this pack because I needed high voltage. Somehow it makes me feel very zen to always have enough power to go home

 

[jerrysimon]

Yea it is overkill but how about 15ah? I am tempted to use throttle only for traveling 20 miles each way.

For twenty miles each way and throttle only, I would NOT recommend you use either a Brompton or a Tongxin setup.

Regards

Jerry

 

[Deleted member 4366]

I can't see any small geared hub motor sustaining 15mph for 20 miles with throttle only unless the journey is very flat, there's no wind and the rider is quite light. 12mph would be more like it.

On my bike, with lazy pedalling, I use between 9 and 12 aH for 30 miles round trip commute at an average speed of 15mph. One time, my crank came loose, so I came home without pedalling and consumed about 10aH one way at 14mph, althoughit was slightly uphill for most of the way.

My reckoning then is that you need at least 20aH at 36v and you'll need to pedal for 40 miles. I've done 70 miles on 10aH before, but it took a lot of pedalling and conditions were good. On a windy rainy day it would be a different story.

Another thing: Once your commute goes over 10 miles, you'll need a bike with proper quality full suspension. Without it, regardless of what saddle you have, the constant pummelling of your backside starts to hurt at about 45 mins, then the pain goes up exponentially with increasing time. The suspension absorbs the bumps so it doesn't hurt as much.

 

[benjy_a]

Small input with my experiences.

I commute 30 miles per day on my Brompton, I always pedal but not hard enough to sweat. I have a crystalyte g series motor running on 48v (13.8Ah). This combination is capable of 23mph unassisted with a Lyen controller running at full boost. Mine is restricted with current and top speed to remain legal.

I use between 6 and 8Ah and my route has a few terrible hills. Average speed is 17-18mph, I can easily pedal beyond the max assist and cruise at 15-20mph on the flat and 25mph anywhere which is downhill. On one very lazy windy day I used 10ah for the same route.

I have done 70 miles round trip but that was too much on the Brompton to be comfortable.

I would say that suspension is not necessary depending on your body composition... I'm ok up to an hour and a half in one hit on the Brompton with little discomfort. I can tour for a whole day on my Giant hybrid which also has no suspension.

 

[Deleted member 4366]

I use between 6 and 8Ah and my route has a few terrible hills. Average speed is 17-18mph, I can easily pedal beyond the max assist and cruise at 15-20mph on the flat and 25mph anywhere which is downhill. On one very lazy windy day I used 10ah for the same route.

Just to make it clear to anyone that doesn't figure it out: That's at 48v, so equivalent at 36v would be about 8 to 11aH and going up to about 13 in worse conditions,which is about the same as what I get in terms of watt-hours. I cruise at about 17-18mph. but average speed is 15mph because my 15 mile journey takes about an hour. Is that the same for you? I'm relatively heavy (100kg), but my BPM motor is probably a bit more efficient than your Crystalyte - especially if you've restricted the current.

 

[patpatbut]

For twenty miles each way and throttle only, I would NOT recommend you use either a Brompton or a Tongxin setup.

Regards

Jerry

Hi Jerry,

thanks. I am just kidding really I like to peddle rather than throttle it. Just wondering what would happen if use the throttle for long period of time?

Pat

 

[patpatbut]

Thanks D8veh

My coummute is nearly flat (90% of the route) and the road is not very bumpy. The actually commute is around 15 miles but I just like to pick a longer route for riding

For the suspension of the bike, my brompton is nearly none. I have seen a seat post with full suspension.
Have you got any experience of it?

 

[patpatbut]

Ok, if you cycle at legal speed (15mph), on throttle only you would use 15wh/miles.

So for 40miles you would need 15wh*40miles = 600wh battery.

Considering you would need about 20% additional power to preserve battery, a 720Wh battery would fit you.

So for your case, a 36V20AH battery would work better for you, if you do 40 miles/day and no peddling at all.


Do you really want to do 40 miles/day?

I'm visiting flat now and I've found one at 13 miles from my workplace. I tried to cycle there with my Bromped (it goes 25 mph) and it's furiously long. 50 mn!!! The place was nice but no way I'm going to do 1h30/day commuting. And my bum hurts after such a long distance.


For you, at legal speed, and you won't be able to go much faster than 15mph because you'll have a small geared motor, it means 90mn minimum each way.

So more than 3 hours / day commuting?


If it's just occasional only, I could understand... but, 20 miles each way, I would almost never do that.


ps: I also have an overkill pack of 1320wh. It means the double of your 36V20AH pack and weight 11kg lol. But I selected this pack because I needed high voltage. Somehow it makes me feel very zen to always have enough power to go home

Hi cwah,

I have a friend cycling to work with brompton (not electric) for a 1 hr everyday and he is quite happy with it. For me, my shortest route is 15 miles so also takes about a hour as well.

What do you think if I peddle 50% and throttle 50%, 36v 10ah would be enough?

Thanks
Pat

To be honest, I wont use the throttle all the way through just curious really. Thinking about the possibilities what can be done on this tiny little bike

 

[jerrysimon]

The Brompton already has rear suspension so little/no point in fitting a suspension seat post. It does not have front suspension though.

For long rides I use this 20" bike with front and rear suspension

Its fine for work commutes as it splits and goes in my office.

Not as portable as the Brompton for going in and out of shops. With small wheels/folders its always about compromise. Do you need the bike to be portable ?

Jerry

 

[Deleted member 4366]

What do you think if I peddle 50% and throttle 50%, 36v 10ah would be enough?

I think you need to get something in perspective: You're talking about a Tongxin Nano motor, which is not a particularly powerful motor, so you'll be able to do 30 miles with 10aH 36v, but not at 15mph, and you'll be pedalling fairly hard. To cruise at an average of 15mph without pedalling hard, you need more power. Therefore you need a bigger battery. If you really want to maintain 15mph average, then you need to consider a more powerful motor.

Also, both the Tongxin and the Goldant motors are rated at 260 rpm = about 12mph in a Brompton, after which power tails off rapidly, so at 15mph. you'll be pedalling on your own. A Cute Q 85 or Q100 comes in 328 rpm version for 15mph, or Benjy's Crystalite, but all of them will need to go to at least 12S lipos, or better still, 48v to get the speed you want.

 

[patpatbut]

Hi jerry

It does really. My workplace wont allow me to leave a folded bike within the office area for health and safety reason but My brompton can fit nicely under my office desk so no issue with that.

Also, my car is Fiat Panda so the boot is quite small to fit a folded bike that bigger than brompton.

Thanks Jerry for your advice. I still want to go for the Tongxin motor. I could scarify the power for max 15 mph but 15 miles each way is a must. btw I have not got any reply from cici yet...maybe she is busy on doing a big business

 

[patpatbut]

Hi d8veh

How reliable are the cute 85 and 100 motors? It seems they are not big 83mm and the speed matches what I need. For having constantly 15mph, is 48v battery a must?

I can charge my battery at my workplace so I believe 36v 15ah battery would be enough for 15 mile commute with average 15mph?

 

[Deleted member 4366]

I've never tried a Q85. It's smaller than a Q100 so I guess less powerful.

The Q100 can maintain 15mph without pedalling, but not up hills. 15mph is approx. 201 rpm in a 26" wheel, so 328rpm in a 16" wheel will be approx. 328/201 x 16 / 26 mph at 36v = 15 mph as well. A 36v battery spends most of its time at about 39v so the actual speed will be 15 x 39/36 = 16.25mph. The power will fall off at about that speed, so average speed will be about 14mph. 48v will give a 33% increase in speed, so that will take it to about 21mph, which is where I have mine. The downside is that it will use more battery to maintain the higher speed, and the motor will be working harder than it's designed for, so might get hot. You'd need to see how it gets on, and maybe use a bit less throttle. It'll be OK at say 16mph and won't get so hot as long as you don't labour it up long hills.

If you want the lower speed a 10aH 36v battery will get you both ways if you can charge it at work. Atbthe higher speed, a 48v 10aH battery might just get you both ways if you pedal moderately.

These are all estimates based on my experience with the Q100. My idea of pedalling hard might be different to yours, or if your routes are flatter or if you're a lot lighter than me, itcould be better for you.

 

[patpatbut]

I've never tried a Q85. It's smaller than a Q100 so I guess less powerful.

The Q100 can maintain 15mph without pedalling, but not up hills. 15mph is approx. 201 rpm in a 26" wheel, so 328rpm in a 16" wheel will be approx. 328/201 x 16 / 26 mph at 36v = 15 mph as well. A 36v battery spends most of its time at about 39v so the actual speed will be 15 x 39/36 = 16.25mph. The power will fall off at about that speed, so average speed will be about 14mph. 48v will give a 33% increase in speed, so that will take it to about 21mph, which is where I have mine. The downside is that it will use more battery to maintain the higher speed, and the motor will be working harder than it's designed for, so might get hot. You'd need to see how it gets on, and maybe use a bit less throttle. It'll be OK at say 16mph and won't get so hot as long as you don't labour it up long hills.

If you want the lower speed a 10aH 36v battery will get you both ways if you can charge it at work. Atbthe higher speed, a 48v 10aH battery might just get you both ways if you pedal moderately.

These are all estimates based on my experience with the Q100. My idea of pedalling hard might be different to yours, or if your routes are flatter or if you're a lot lighter than me, itcould be better for you.

Thanks. D8veh. For you setup, why did you pick Q100 over Bafang SWXK5? I believe Bafang motor is more reliable even with more power input and the width is the same as Q100.

If I manage to get 48v 10AH on brompton to reach 20mph, is it quite hard for brompton to handle this speed?

Btw, I weight 10 stones and my route is nearly flat (I would say more than 90%) so for your recommended setup 48v 10ah should fit the bill (For high speed setup)

If I buy the 48V 10ah, what discharge current should I get? 30A-60A?

Pat

 

[jerrysimon]

Pat I think with a Tongxin Nano motor and a 36v 10Ah battery, you could easily do 15-20 miles recharging your battery at work providing as you say your route is 90% flat and you pedal assist as well. Probably more so in that I am 52 and weigh just over 13 stone

With mine (I live in Cambridge which is pretty flat) I can easily get to 15mph with pedaling and use of the motor putting in less than a 1/3 of effort required if I did not have a motor. The beauty of the motor is that it really helps you with starting up and getting going (note with these Nano motors you should always pedal a little first before engaging the motor) and once up to 15mph on the flat you can then switch off the motor and easily maintain it quite comfortably. Obviously if its windy or raining then you need (and I always use) the motor to keep you going with limited effort. Note in the small wheel application these motors seem very reliable as I have now covered nearly 4000 miles on mine in 3 years.

I would say that I can quite comfortably commute the 5.5 miles each way at an average speed of 15mph applying a 1/3 of the effort required if I had no motor. My top speed on part of my commute is about 21mph down one of the inclines with motor switched off as the motor is not assisting over 14mph anyway. Up steeper inclines this drops to about 12 mph but again I am only applying about 1/3 the effort.

Interestingly the Tongxin Goldant motor (the later smaller lighter version of the Nano) although specified at 260RPM I think is actually higher and I have actually seen it specified as 340RPM which fits with my real life experience of a higher 16.5mph unassisted over the 14mph of the Nano 260RPM motor.

Finally with the Brompton remember you want to carry it, so you will thank yourself later for keeping weight of both battery and motor down.

Regards

Jerry

 

[patpatbut]

Pat I think with a Tongxin Nano motor and a 36v 10Ah battery, you could easily do 15-20 miles recharging your battery at work providing as you say your route is 90% flat and you pedal assist as well. Probably more so in that I am 52 and weigh just over 13 stone

With mine (I live in Cambridge which is pretty flat) I can easily get to 15mph with pedaling and use of the motor putting in less than a 1/3 of effort required if I did not have a motor. The beauty of the motor is that it really helps you with starting up and getting going (note with these Nano motors you should always pedal a little first before engaging the motor) and once up to 15mph on the flat you can then switch off the motor and easily maintain it quite comfortably. Obviously if its windy or raining then you need (and I always use) the motor to keep you going with limited effort. Note in the small wheel application these motors seem very reliable as I have now covered nearly 4000 miles on mine in 3 years.

I would say that I can quite comfortably commute the 5.5 miles each way at an average speed of 15mph applying a 1/3 of the effort required if I had no motor. My top speed on part of my commute is about 21mph down one of the inclines with motor switched off as the motor is not assisting over 14mph anyway. Up steeper inclines this drops to about 12 mph but again I am only applying about 1/3 the effort.

Interestingly the Tongxin Goldant motor (the later smaller lighter version of the Nano) although specified at 260RPM I think is actually higher and I have actually seen it specified as 340RPM which fits with my real life experience of a higher 16.5mph unassisted over the 14mph of the Nano 260RPM motor.

Finally with the Brompton remember you want to carry it, so you will thank yourself later for keeping weight of both battery and motor down.

Regards

Jerry

Thanks. I know you have tired both Tongxin nano and Goldant motors for your conversion.
Which one do you prefer?

For Goldant seems interesting as you said before it is smaller, lighter and can be faster (340rpm).
Would this motor fit what I need?

15 miles each way, 10 stones myself, 90% flat route, above 15mph ideally and I could pedal 1/3 of the effort.

Thanks again. you are a star!
Pat

p.s.
I have checked the web site you gave me
98 Front no hall motor_Motor-OutRider Eshop - EBike Kit Supplier-Complete Electric Bike Conversion System
One thing that surprises me is I can chose the width of the motor (either 80mm or 100mm), how could that possible? Does it mean they have made two different sizes of the motor with the same power?