TongXin (a.k.a. Nano) motor project

[giguana]

In all my searches I never found a website to order from - but it was 9 months ago and all the sites I did find said a minimum of 100 units.

They might have thought it was a sample, in any case when dealing with Chinese companies you should always ask them to ship by UPS, this guy offered me some really good kit but he quoted a giant overland shipping cost because he didn't realise UPS air was less.

Jeremy-Your idea might be very easy to actualise, using a variable resistor fixed to the pedal movement to send a sinusoidal throttle signals through the throttle. generally speaking, the body adapts very well to the movement of the bike to be so similar to walking, oval chainsets supposedly improve total efficiency by perhaps a couple of percent although there are no conclusive studies. generally I find a motor to go fast enough that the legs never really have to put in lots of effort.

 

[frank9755]

They did not seem to have the old sensor-wire motor in stock.

Sorry - I've just checked. What I said earlier was wrong; they do still have the 8-wire version.

Frank

 

[HarryB]

Sorry - I've just checked. What I said earlier was wrong; they do still have the 8-wire version.

Frank

Approximately how much did you pay Tongxin for the motor alone out of interest - were the shipping costs reasonable?

 

[frank9755]

Similar price to what Jeremey said Renaissance is selling them for. Motor + controller + extras (throttles, brakes, etc) came to just over £110 including delivery and money transfer. If it all does what I want, the price is very reasonable.

My wheel is being laced at the moment so I've not even tested the motor. When I've got it all built up I plan to do a detailed post describing the bike, my objectives, how well it meets them, where I got everything, etc. But I don't want to make any recommendation of any sort until I'm happy that everything works properly!

Frank

 

[Grizzly Bear]

Hi Frank
I've been running a Tongxin for a while now, you are not going to be disappointed, in my opinion the best hub motor. They are a perfect balance of assistance verses power consumption.

Griz

 

[flecc]

Hi Frank
I've been running a Tongxin for a while now, you are not going to be disappointed, in my opinion the best hub motor. They are a perfect balance of assistance verses power consumption.

Griz

Are you running on 24 volts Griz?
.

 

[frank9755]

Hi Frank
I've been running a Tongxin for a while now, you are not going to be disappointed, in my opinion the best hub motor. They are a perfect balance of assistance verses power consumption.

Griz

Griz,

Thanks for the encouragement! I remember your bike from a few months ago and that was one of the success stories that made me explore Tongxin. Glad to hear you are still happy with it.

Frank

 

[Grizzly Bear]

Hi guys
my bike runs on 36 volts, it's done well over one thousand miles now, I use it back and fore to work every day, down hill into work, guess what on the way home. It's amazing how much power it has for it's small dimensions, I may have a good one, I don't know.

Griz

 

[HarryB]

Small confession

I too have been trying out a Tongxin motor for a few months now. It is truely an amazing little motor, incredibly quiet (you cannot hear it over the wind noise as you are cycling) and little drag. The downside in using it in a larger wheel (700c - 190rpm motor) is that roller drive weakness - full throttle from standstill on a hill is a no no, but if you ease it in it does pick up well and takes full throttle from about 4 mph. I was interested to see they did a 175rpm version that would reduce the loading but I avoided the 160rpm because of rumours of a faulty batch.

Anyway, still an experiment that is, so far working for me (until it breaks).

 

[Grizzly Bear]

Hi Harry
it's all an experiment to me, I have a 190 rpm motor on a 26" wheel, my bike is very light and so am I. I think the Tongxin is best suited to this combination. The label on my motor says it's 160 watts by the way, not 180 as advertised.

Griz

 

[Honk]

Hi. I'm new here but I have lots of experience and interest of electronic
motor controllers. I'm using a 28" bicycle and would like to mount a small
hub motor onto the front wheel. I'm very interested of the Tongxin motor.
I'd like to design the hub motor controller myself & I'll use Ni-MH batteries.
Later I'll post the schematic and gerberfiles on the controller here at Pedelec.
I have some questions that some of you might be able to help me with.

1) What RPM is best at 28" wheels? There is no steep hills & I like to go fast.
2) What is the model numbers of the older 8 wire Tongxin hub motors?
3) Is the older motors just as good the the newer sensorless motors?
4) Is there any advantage/disadvantage in the choice between 24 or 36V?

Regards / Honk

 

[flecc]

Welcome to the forum Honk.

I can't give specific model number details, but Schwinn are using the 190 rpm Nano in a 28" wheel for fast performance. Unfortunately their controller was a bit of a disaster and the bike was withdrawn from the market in the USA immediately following the launch.

There is an issue with the roller drive slipping under load, and this seems to occur more when using 36 volts, as you might expect.

That's about the limit of my knowledge of these motors.
.

 

[HarryB]

Hi. I'm new here but I have lots of experience and interest of electronic
motor controllers. I'm using a 28" bicycle and would like to mount a small
hub motor onto the front wheel. I'm very interested of the Tongxin motor.
I'd like to design the hub motor controller myself & I'll use Ni-MH batteries.
Later I'll post the schematic and gerberfiles on the controller here at Pedelec.
I have some questions that some of you might be able to help me with.

1) What RPM is best at 28" wheels? There is no steep hills & I like to go fast.
2) What is the model numbers of the older 8 wire Tongxin hub motors?
3) Is the older motors just as good the the newer sensorless motors?
4) Is there any advantage/disadvantage in the choice between 24 or 36V?

Regards / Honk

I would say that if you are after speed the Tongxin is not the right choice. Theoretically you should put in a 160rpm motor as this will give you the top speed of 15 mph (legal top speed in the UK) but I have heard of some reliability issues from Tony Castles (Nano-motor) and he would not recommend one. If you go for the 190rpm version in a 28 inch wheel your top speed will probably be around 17mph but you will put quite a strain on the roller drive every time you start off. According to Tongxin there is a 175rpm version that might be suitable but you will probably have to email them about it (and I don't know whether it comes in the sensorless version). I don't think there is much difference between sensorless/sensor version except there is slightly more to go wrong with the hall sensors (but I am told they are incredibly reliable anyway).

 

[Honk]

Thankyou for your great answers.
I have another one for you.

1) If the top speed is 17mph at 190RPM in a 28" wheel, is this when assisting?

2) My goal is 20mph with assist, while the motor does half the effort.
Is this possible. Should I maybe increase the voltage from 24 to 30 to
increase the top RPM at higher speeds?

Regards / Honk

 

[HarryB]

The 190rpm motor in a 700c wheel tops out at 20mph under no load. Once you put it on the road with a rider of average weight, you will get a top speed of around 17mph, without pedalling. With reasonable effort you can cruise at 19mph perhaps 20 mph (although it will depend on many factors such as your weight and fitness level). But this combination of motor/wheel will give you a problem with the roller drive - I am not convinced that it would be reliable and you should try another motor. I think the motor in the Torq would suit you better if you can get hold of it (and it is not a standard size while the Tongxin is). I am not sure what country you are from by the way.

I ended up experimenting with the 190rpm Tongxin motor because I got one cheap (£50 in the end) and I was specifically not after power and speed, just gentle assistance. I am not expecting much in the way of long term reliability judging by the way it squeals on take up.

 

[Honk]

Hi, I got some more questions (being a newbie)!

1) What is this roller drive?
Is it inside the motor or is it the bicycle Drive Roller Chain?

2) What is the Roller drive problems you are talking about?

3) Will the motor breakdown at higher speeds but within the rated power output?
This is what I meant earlier about increasing the voltage from 24 to 30 but also
carefully measuring the power going into the motor to prohibit it from overheating!
On paper this should allow assist above 20mph. Could this be a good solution?

I'm from Sweden and the country where I live is almost flat.
I just desire the motor to add half or one third of the power needed
when going at 20mph. I really want to paddle a lot while getting
assisted by the motor.

 

[flecc]

Hub motors usually have epicyclic gears like these, which take the motor drive to a toothed ring in the hub shell, shown here.

The Tongxin Nano only has smooth inner and outer tracks like railway lines, and the rollers are also smooth like railway wheels, and the grip depends on the pressure between them. If the strain gets too great, the drive can slip, just like a railway locomotive's drive can slip.

Why do they make it like that? Because it's very quiet, almost silent, where gears make a whining noise.

In a flat area, drive slip will be less of a problem, especially if you accelerate the motor gently.
.

 

[HarryB]

Thinking about my previous answer the speeds quoted will be a little lower if you are using NiMH batteries - with nominally 37V with a Li-ion battery not 36V as with a NiMH. Not a great difference though.

The roller drive is the internal gearing for the motor - there are no planetary gears. This gives the advantage of quietness and low freewheel drag but the take up (like a clutch) is metal on metal contact and does not like high loadings. Even if you over-volt the 24V motor with 30V you are going to have the same problem - it does not like full throttle (high power) at take off and this will make the motor unreliable. While this motor does run cool and I am sure it could take the extra voltage in the windings, the rest of the motor does not have a good reputation for reliability (internal magnets coming adrift, the hollow spindle is fragile and easily bent etc).

It will be difficult to cycle with this motor at 20mph because at that speed the motor will not be making any (useful) contribution powerwise. If you want this speed you will have to go for something like the 260rpm version but I wouldn't have thought you could get off the line without pedalling (perhaps to 8/9mph) and then easing the motor in. I think this is a non-starter so I would suggest another motor. If anybody has a different solution then they may be able to advise you.

PS Flecc got there first so some overlap.

 

[frank9755]

Honk,

You ask some good questions!

I'm working on my own project at the moment for a bike for high speed with considerable pedal assist in a flat area.

I don't yet know how exactly my Tongxin motor will perform. As others point out, it does not cope with applications which require high torque and can slip in these situations. When you understand how it is made, as Flecc describes, it is easy to see why this is the case. I therefore agree with Hal (HarryB)'s analysis on over-volting the motor; don't do it to get more torque, but it may get you more speed. I believe the motor is suited to delivering high speed and, if you can accept the torque limitations, which I think will be as Hal describes, it could be a great motor.

My wheel has just been made up so I will post when I have something to report!

Frank

 

[HarryB]

Frank, yes it would be good to get some real world experiences of this motor. My experience shows me that the 190rpm version is at its limit in a 28 inch wheel and maybe the motor is more suitable in a smaller wheel like the Brompton Nano. It could be that mine is not representative example and I may be being unduly pessimistic, so let us know how you get on.