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

[HarryB]

While I think the Tongxin a great little motor, I would not recommend using the 190 rpm version with anything greater than a 26 inch wheel. There will be too much slippage at start up and anybody thinking about the 190 rpm/700c combination should be reminded about this.

On the li-ion battery issue I am grateful that this has been picked up and pay tribute to Flecc for doggedly pursuing this issue. Grizzly Bear please don't belittle this issue just because your wife has not had a problem. There are enough of us out there for it to be a real problem (and an expensive problem to boot).

All the best

Hal

 

[frank9755]

It's quite a good comparison because both of these problems arise not because the Tongxin motor or Lithium batteries are somehow bad, but because they are misused in the wrong application: too much torque expected from a Tongxin or too much current drain from a lithium. Respect those limitations and you should be ok.

With the Tongxin I don't think there would be problems with a high rev motor in a larger wheel as long as you don't expect it to start the bike from a standstill, go up steep hills or use it on motor power alone. Hill starts without pedalling is asking for trouble!

Griz, correct me if I'm wrong but I think I recall your motor is not very high rev one in a 26" wheel and that you mainly use it as pedal assist, not making it do all or nearly all of the work. Therefore I'd expect it to be ok - and hope it continues to thrive.

There is merit in pointing out to those who might consider the motor that it does have limitations, but there is a risk that those limitations are exaggerated and those who could get a motor that would be the best for them are scared off.

Frank

 

[Honk]

While I think the Tongxin a great little motor, I would not recommend using the 190 rpm version with anything greater than a 26 inch wheel. There will be too much slippage at start up and anybody thinking about the 190 rpm/700c combination should be reminded about this.
Hal

Well, I'm not looking for a standstill start up motor. I just want it to
contribute the top speed. The low speed I can handle myself.

 

[Honk]

With the Tongxin I don't think there would be problems with a high rev motor in a larger wheel as long as you don't expect it to start the bike from a standstill, go up steep hills or use it on motor power alone. Hill starts without pedalling is asking for trouble!
Frank

Exactly my words. I don't want standstill or extreme hill climbing capability, just top speed
help at limited power input to prevent the motor from overload damage.

 

[HarryB]

Well, I'm not looking for a standstill start up motor. I just want it to
contribute the top speed. The low speed I can handle myself.

I am sure it will work fine for you and you certainly have been told the limitations. If you could electronically limit the input at low speeds that would be one solution. Also it would work better outside city conditions. For me there are plenty of occasions in town when I need the power of legs and motor for safety and at low speed you will get slippage if you ask for power from the Tongxin (and you don't have time for the finess of balancing the throttle input). I have certainly noticed that the motor no longer freewheels as well as it did when new so doubtless there has been some damage - even with the best of intentions.

 

[flecc]

It's quite a good comparison because both of these problems arise not because the Tongxin motor or Lithium batteries are somehow bad, but because they are misused in the wrong application: too much torque expected from a Tongxin or too much current drain from a lithium. Respect those limitations and you should be ok.

Frank

I think that sums it up perfectly Frank, and as you say, no-one should be scared off a motor that can be so good when used correctly.

I only get a little concerned when there's a possibility of it being used like the Suzhou Bafang motor in Torq or Quando fashion, since it's clearly not right for either of those usages.

That obviously doesn't apply to Honk though, but it certainly did to Schwinn who were being very optimistic in the way they configured their bike's control system, doing the motor a disservice. A to B didn't actually report it, but they burnt out two controllers on it's Nano during their Schwinn test.
.

 

[Grizzly Bear]

I knew you were in Wales Griz, but I don't see the Torq problems as related, since it has no motor gear drive issue.

All I'm saying is that when a problem has been experienced by a few, I mention it, and it's not knocking to do that. I've done so with the Torq, with the Li-ion battery issue, with the old Panasonic unit and with many others. Therefore the Nano won't be exempt. There are many owners of Torqs and old Panasonic units who haven't had problems just as you haven't had Nano problems, so I'm just being equitable.

For example I haven't had front brake and judder problems on my Torq, nor did my Twist's Panasonic unit ever let me down, but I mention the problems in answering posts since those have happened to others.

And surely you are not saying that the li-ion batteries haven't had any issues on powerful bikes? If so you could hardly be more wrong, since even two manufacturers now admit to them and are doing something about it. Your wife's bike probably uses one of the low consumption Panasonic units I take it?

At the outset you asked why we were knocking, and I'm just showing that I'm not knocking, just reporting, nothing else.
.

Could you tell me who exactly has experienced drive failure with a Tongxin/Nano? how many people have been let down by their Torq or had an unpleasant riding experience due poor design/manufacture? My wife's bike is actually faster than my machine, and I'd say is the absolute maximum allowed by British law, I don't know what make of motor it is, I've never had to look at it, it's down there under the pannier bags somewhere, quietly getting on with it's job.
The thing is I get the impression that you take particular issue with the Nano, outside of early controller problems it's very reliable. My example has a very hard life, steep hills, freezing temperatures, torrential rain, heavy loads etc. as yet absolutely faultless.

 

[frank9755]

I only get a little concerned when there's a possibility of it being used like the Suzhou Bafang motor in Torq or Quando fashion, since it's clearly not right for either of those usages.

That obviously doesn't apply to Honk though, but it certainly did to Schwinn who were being very optimistic in the way they configured their bike's control system, doing the motor a disservice. A to B didn't actually report it, but they burnt out two controllers on it's Nano during their Schwinn test.
.

Flecc,

Thanks for your comments. I think we agree that the Tongxin, like lithium batteries, will work fine if its limits are respected (like most of us probably!). The question then is to define what those limits are, and I feel they may be broader than your conclusion implies and that the Schwinn failure is not a good example to use. My recollection of the AtoB report is that the Schwinn failed through controller, not motor, defects, and that the Schwinn bike used a 190rpm motor - ie not overgeared vey much (Tongxin's range being from 160 rpm, designed to give about 15mph in a 700c wheel, to 260 rpm, which gives a shade under 15mph in a 16 inch wheel - ie the 'Nano').

The reason I'm so interested in this is that my own Tongxin plan is to do exactly what you describe! I have fitted a 260rpm motor to a 700c wheel. That is overgeared! Actually to a similar extent to the Suzhou Bafang motor in the Torq.

I would not recommend this configuration for anyone who didn't want to pedal much, wanted to use the motor from stationary and who had hills to contend with. However I think this will work very well for me and the way I want to use the bike. I'm a reasonably strong cyclist doing 25 miles per day on flat terrain, and I'm happy to pedal the bike to c 8mph before using the motor.

Initial tests gave amazing performance but the controller failed and replacement is still not with me - so the jury is still out.

I hadn't intended to describe it so fully until I had proven (or disproven) the application, but you hit the nail on the head!

Frank

 

[frank9755]

Griz,

I think your example is a good illustration of the Tongxin having quite broad limits of application. A normally geared one is clearly coping fine with Welsh hills.

I researched the Tongxin quite a bit before I bought it. I found a fair bit of evidence of controller problems but only the occasional reference to drive slip - and always in the context of high torque applications.

Hal,

I'd be really interested to hear more about your Tongxin experience - how it was set up, what you've used it for, what worked, what didn't, etc.

Frank

 

[frank9755]

Honk,

I've just been thinking about your post a bit more, and wanted to spell out that I think 10mph from you + 10 mph from the bike wont give you 20mph! It'll give you something nearer to 15 - because air resistance increases significantly at higher speeds.

For example, I can pedal my Wisper at 10 mph on flat ground with no motor power very comfortably. If I stop pedalling and use the motor, it will do about 15 mph on full throttle. Add the two together and I don't get 25mph, but something around 19.

That's why I think you might need a little more power to get the performance you want. I also think the Tongxin could cope ok with a bit more.

Frank

 

[Honk]

Honk,

For example, I can pedal my Wisper at 10 mph on flat ground with no motor power very comfortably. If I stop pedalling and use the motor, it will do about 15 mph on full throttle. Add the two together and I don't get 25mph, but something around 19.
Frank

Have you considered your motor being RPM limited at higher speeds?
Simply that the wheel is turning faster than the motor and the motor
wont help you once you get past 19mph?

 

[frank9755]

Yes but I still think it is the air resistance, because when I go into a strong headwind, these figures scale down to below the motor's revs limit:
Me + motor only gives 16mph.
Motor alone maybe 14 mph
Me alone, say 8 mph

 

[flecc]

The thing is I get the impression that you take particular issue with the Nano, outside of early controller problems it's very reliable. My example has a very hard life, steep hills, freezing temperatures, torrential rain, heavy loads etc. as yet absolutely faultless.

My posting record shows clearly that I do not take particular issue with the Nano and I've made very few posting on it. On the other hand, it does show a huge number of postings about the issues on the model one Torq, going back well over a year, so the point you keep trying to make isn't valid. Those postings have of course diminished since the model one with those issues was discontinued. Just as invalid is your contention that lithium batteries have no issues because your wife's one is ok.

I cannot give credence to arguments that if something you own doesn't give trouble, it cannot give trouble to others. Such arguments are clearly wrong, and I've already illustrated as much.

The drive slippage problems on the Nano were mainly reported in the USA where it was marketed well before it was seen here. Therefore I can only mention them, not knowing any particular detail, but since owners here have observed the phenomenon, including yourself, it is valid to mention it.

I repeat, that is not knocking, just statement of fact.
.

 

[HarryB]

Hal,

I'd be really interested to hear more about your Tongxin experience - how it was set up, what you've used it for, what worked, what didn't, etc.

Frank

Frank I have PM's you this morning about my experience.

I think that Honk will reach 20 mph with pedalling if he overvolts the 24V motor with 36V. Normally the 36V motor will freewheel to 20 mph but of course there is no power at the upper end of the rev range and the reality is 17 mph with power alone and easy to pedal at a constant 18 mph. With the extra volts I would expect it to be able to cruise at 20 mph. Hopefully the extra volts will push the power further up the rev range. The problem of course will be balancing the bikes power and pedal power so they are in some equalisation but Honk will be building his own controller with power limiting so has an advantage over the rest of us. Anyway I am very interested in what will happen and if the theory holds up and how you made the controller etc.

 

[frank9755]

Yes, good point - I'd forgotten you were building your own controller, Honk. If it's not giving you enough speed, you can probably tweak it pretty easily to up the power.

 

[Grizzly Bear]

My posting record shows clearly that I do not take particular issue with the Nano and I've made very few posting on it. On the other hand, it does show a huge number of postings about the issues on the model one Torq, going back well over a year, so the point you keep trying to make isn't valid. Those postings have of course diminished since the model one with those issues was discontinued. Just as invalid is your contention that lithium batteries have no issues because your wife's one is ok.

I cannot give credence to arguments that if something you own doesn't give trouble, it cannot give trouble to others. Such arguments are clearly wrong, and I've already illustrated as much.

The drive slippage problems on the Nano were mainly reported in the USA where it was marketed well before it was seen here. Therefore I can only mention them, not knowing any particular detail, but since owners here have observed the phenomenon, including yourself, it is valid to mention it.

I repeat, that is not knocking, just statement of fact.
.

It is the nature of the motor that there is a very slight slippage under the highest load situations, it is not a problem, neither is it a failure. You admit that you don't know any particular detail, I would guess that the problem is mainly down to the weight of the American riders and not a fault of the motor as such, and could easily be rectified by a calorie controlled diet. I think that the comments you have made about the Nano may well have put people off buying possibly the best motor available for use in this country.

 

[Honk]

I have planned a flexible & easy adjustable controller to find the sweet spot.
I will be able to adjust the top power level on the fly while peddeling.
And I will also be able to switch the controller sens level between current
coming from the battery or power going into the motor.
If I choose to detect the battery output current level then the motor will get
240W continuously regardless of the peddeling speed.
But if I choose to detect the current coming from the controller going
into the motor, then the wattage will be dependent on my peddeling.
The less I peddel the less wattage is going into the motor & vice versa.

Btw, I'm going for the eight wire Tongxin motor with hall sensors.
I've heard to much about controller problems on the sensorless versions.
And it's a lot easier for me to build a regular BLDC controller usings halls.

 

[frank9755]

I have planned a flexible & easy adjustable controller to find the sweet spot.
I will be able to adjust the top power level on the fly while peddeling.
And I will also be able to switch the controller sens level between current
comming from the battery or power going into the motor.
If I choose to detect the battery output current level then the motor will get
240W continuously regardless of the peddeling speed.
But if I choose to detect the current comming from the controller going
into the motor, then the wattage will be dependent on my peddeling.
The less I peddel the less wattage is going into the motor & vice versa.

Btw, I'm going for the eight wire Tongxin motor with hall sensors.
I've heard to much about controller problems on the sensorless versions.
And it's a lot easier for me to build a regular BLDC controller usings halls.

Sounds like you know what you are doing!
I believe you are wise to go for the more standard set-up with Hall sensors.

 

[flecc]

I think that the comments you have made about the Nano may well have put people off buying possibly the best motor available for use in this country.

It's precisely because I recognise the good parts of the Nano design that I don't want to do a hatchet job and therefore only mention the possibilities, but now you leave me no option but to point out how wrong you are in this. Here's the facts with some examples.

Geared hub motors and their controllers are extremely reliable in general. The Powabyke and Heinzmann motors have run for many years in all sorts of wheel sizes, the Heinzmann on two different voltages. The eZee Sprint motor has been very reliable in two power formas and in 20" and 26" wheels. The Suzhou that eZee uses is very reliable in the 20" wheel Quando and the 28" wheel Torq, and in both those cases without hub gearing changes. Out of the very large number of these sold, there's been very few controller failures, and in a couple of cases they've been due to high over volting experiments. Similar motor reliability is true of others such as Crystalite and Puma in different wheel sizes and voltages from 24 to 72 volts.

Direct drive motors are even better yet, running seemingly for ever since they have very little to go wrong, and even the very cheap motors and controllers on bikes around £200 to £400 normally outlive the junk bikes they're in and are resold on ebay and the like, then used in various wheel sizes and ways.

None of those have any restrictions on wheel size, on torque applications, on the weight of rider, on the software, or any other of the excuses trotted out.

The Tongxin Nano cannot be so liberally used as Frank and others have observed, it's good within certain parameters at present. It has suffered drive slippages and drive failures, connector and wiring problems, and the controller problems are legion. All this on a product that's only been around a very short while and which has very few examples in use yet on this country, and we have no idea of it's long term prospects.

Reliability being of primary importance, far from being one of the best motors on the market, it is one of the worst as I've unequivocally shown, and a very good case could be made for saying it is the worst.

I have to be even handed in my postings for them to have any credence, and I therefore won't be swayed by one owner's single experience against the whole of the evidence.

The Tongxin Nano design has some endearing advantages, primarily high efficiency and silence, but they've been bought through an engineering compromise which means it remains a potential for the present, rather than a well proven solution.
.

 

[Grizzly Bear]

It's precisely because I recognise the good parts of the Nano design that I don't want to do a hatchet job and therefore only mention the possibilities, but now you leave me no option but to point out how wrong you are in this. Here's the facts with some examples.

Geared hub motors and their controllers are extremely reliable in general. The Powabyke and Heinzmann motors have run for many years in all sorts of wheel sizes, the Heinzmann on two different voltages. The eZee Sprint motor has been very reliable in two power formas and in 20" and 26" wheels. The Suzhou that eZee uses is very reliable in the 20" wheel Quando and the 28" wheel Torq, and in both those cases without hub gearing changes. Out of the very large number of these sold, there's been very few controller failures, and in a couple of cases they've been due to high over volting experiments. Similar motor reliability is true of others such as Crystalite and Puma in different wheel sizes and voltages from 24 to 72 volts.

Direct drive motors are even better yet, running seemingly for ever since they have very little to go wrong, and even the very cheap motors and controllers on bikes around £200 to £400 normally outlive the junk bikes they're in and are resold on ebay and the like, then used in various wheel sizes and ways.

None of those have any restrictions on wheel size, on torque applications, on the weight of rider, on the software, or any other of the excuses trotted out.

The Tongxin Nano cannot be so liberally used as Frank and others have observed, it's good within certain parameters at present. It has suffered drive slippages and drive failures, connector and wiring problems, and the controller problems are legion. All this on a product that's only been around a very short while and which has very few examples in use yet on this country, and we have no idea of it's long term prospects.

Reliability being of primary importance, far from being one of the best motors on the market, it is one of the worst as I've unequivocally shown, and a very good case could be made for saying it is the worst.

I have to be even handed in my postings for them to have any credence, and I therefore won't be swayed by one owner's single experience against the whole of the evidence.

The Tongxin Nano design has some endearing advantages, primarily high efficiency and silence, but they've been bought through an engineering compromise which means it remains a potential for the present, rather than a well proven solution.
.

I am sorry Tony but I am not seeing the point of your arguments, answer my previous question, "drive failures" what failures? don't side track here please. You say you don't have an issue with the Nano, that's not coming through with your statements. As far as the comparisons you are making, remember that the Nano is UK legal. I have previously warned on this forum, that we ALL need to stay within the law for all our sakes, otherwise we will ALL be legistated against, which will be a great pity, 15mph and 200 watts max. to be classed as a bicycle remember?