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

[frank9755]

My new controller arrived, I refitted it to the bike, and managed to complete the test ride I started a month ago - using a different battery!

I'll do a full write-up when I've had a few more trials and got more miles on the clock, but performance was excellent - exactly what I was hoping for. If the Tongxin proves reliable, I may not be using my Wisper much in future!

Frank

 

[Honk]

I have ordered 3pcs of the Tongxin hub motor directly from china.
The Tongxin sales woman was very polite and told me that the price and
shipping on 3pcs 190RPM/24V/Hall fitted motors will come to 2370 RMB.
This translates into 167 GBP, or 327.5 USD, or 224 EUR.
Very price competitive compared to the pricy Nano motor at 285 GBP
for just one single motor with no shipping.

I hope I'll get as happy using this motor as the other users at this forum.

 

[flecc]

Just so long as you don't get caught out by customs duties Honk, though it would still be cheaper. With luck you might not, but please keep us informed on that.
.

 

[johnp]

Hi jeremy. How did you get on with your fitting of this of this tongxin(nano) motor? I am thinking of fitting one to a Brompton if I can find out where to buy one JOHN

 

[Cyclezee]

I'm also thinking of fitting one to a Dahon folder with 20" wheels any advice welcome?
Honk, Would also like to hear how you get on with importing the motor?

John

 

[Jeremy]

John,

The TongXin is fitted to a new 20" (406) front wheel and the bike is ready to go as soon as I replace the battery pack that I inadvertently blew up last week (see the "Battery Fire" thread for details).

I'm still thinking about the replacement battery at the moment, as I'm torn between just buying some more NiMH packs or risking a LiFePO4 set-up.

I purchased my motor and controller from Justin at www.ebikes.ca Homepage of the revolution, but others here have purchased direct from TongXin and got a better price. The motor is the same as a Nano used in the Brompton Nano, but TongXin sell it directly for a fraction of the price that the Nano sells for.

The only snag with buying direct is the difficulty if anything goes wrong - China is a long way away if there are any problems. If the price difference is great enough this still looks to be a reasonable option though.

Jeremy

 

[Cyclezee]

Thanks Jeremy,
I saw this SYNERGIE NANO Folding E-Bike Electric Bike Bicycle on eBay, also, Bikes, Cycling, Sporting Goods (end time 08-Feb-08 10:07:52 GMT) and wonder what motor it has? For that money could it be TongXin/Nano motor or is Nano just the model of bike?

John

 

[frank9755]

My experience of buying direct from Tongxin was great. The only snag is that it takes a while for the thing to arrive. I would definitely recommend it.

Frank

 

[frank9755]

Thanks Jeremy,
I saw this SYNERGIE NANO Folding E-Bike Electric Bike Bicycle on eBay, also, Bikes, Cycling, Sporting Goods (end time 08-Feb-08 10:07:52 GMT) and wonder what motor it has? For that money could it be TongXin/Nano motor or is Nano just the model of bike?

John

Doesn't look like a Tongxin to me; looks like a pile of .... !

 

[Cyclezee]

I think you were going to say a pile of oh no no no no Frank?

John

 

[Jeremy]

The motor maybe be one of the Chinese (aren't they all?) wheel motors, maybe a Golden Motor. It looks as if other electric bikes they sell may be using the Golden Motor hub motor, so this seems like a reasonable bet.

I doubt that there's any connection between this bike and the "Nano" name as we know it though.

For more info on the range of Golden Motor products take a look here: hub motor, brushless motor, electric bike, power wheelchair,wheelchair controller,electric wheelchair, golf trike, electric bicycle,golf trolley,µç¶¯ÂÖÒγµ,¸ß¶ûµÇ¿Æ¼¼ÓÐÏÞ¹«Ë¾

Jeremy

 

[Honk]

The special Tongxin controller is soon finished and ready to be tested.
Once tested OK I'll upload the schematics and gerberfiles for the PCB.
I hope some of you can make good use of it. Myself I hope to enjoy it very
much when peddeling at 22mph, being assisted by the motor and controller.

 

[Jeremy]

Excellent! I'm really looking forward to seeing how you've tackled this, as I'm quite keen to make a custom controller for mine.

I've just been out trying to measure chain tension, using the system Kinetics use for their power meter. I hooked my baby laptop (an Asus Eee) up to a USB data logger (a USB Instruments DS1M12), which was connected to a home made magnetic coil pickup, like a guitar pickup, placed just under the chain top run.

The chain data is very messy, so will need some serious processing to make sense of the chain tension fundamental frequency to derive tension. It does look as if this method of measuring pedal effort can be made to work, although it seems like a lot of work to get a simple pedal-assist control system. I reckon that I would need to sample the signal at a pretty high sampling rate, do a Fourier transform on the result and then pick the frequency bins carefully to extract each component.

I've decided that an easier method, for me, will be to make a new mount for the idler wheel under the seat on my 'bent. If I can devise a way of strain gauging this, then I should be able to use the downward force, exerted by the chain as it changes direction around the idler, as an indirect measure of pedal force. Hopefully this will be an easier signal to process into a usable throttle signal than the very messy chain one I've just tried to measure.

Jeremy

 

[Honk]

Just to enlighten you all, this controller is not sensorless.
It will require the Tongxin motor with Hall sensors.
It is the eight wire motor with halls I'm referring to.

I have named the current vs peddeling auto adjust feature to "Smooth Ride Technology"
Simply meaning, the more you peddle the more assist you will receive from the motor.
This feature will prevent damaging stand still start-up at high power levels.

 

[Jeremy]

At long last I managed to get my 'bent sorted out this afternoon with the TongXin motor. It's running on some of my secondhand SLAs, but nevertheless gave a good account of itself.

This is a 260rpm motor, running at 36V with a 36V, 15A controller. Control is via a much modified thumb throttle, fitted to a small extension on the end of the right hand handlebar. This extension has had the added advantage of raising the mirror, making rear view a bit better. I ran the throttle wiring down inside the underseat steering handlebars, for a neat install. I had to do this, as I have SRAM twist grip changers on both sides.

I've fitted a "dashboard" to the front "upright" on which the front dérailleur mounts. This contains a modified RC electric model watt meter, the power and light switches and a cycle computer. The home made front light and reflector are also fitted to this.

I've tried to keep the wiring hidden as far as possible, so have sheathed it in black sleeving and fitted it under the main "spine" tube. The controller is strapped under the seat, together with the wiring connections. At the moment the batteries are sitting in a pannier, but when I decide on the final pack I will try and fit them in the recess under the seat moulding, if I can.

Performance on 36V, with the motor fitted in a 20" wheel, has been surprisingly good. I haven't had a chance for a full test, but a brief whizz up and down the lane showed that it pulled very well from low speed up to about 20mph. It seems to pull well up the modest hill I tried and was quite happy to pull off from a standstill without pedalling. The front wheel unloaded speed, at full throttle, was just over 25mph (measured with the front wheel held off the ground). Current demand seems modest, about 5A or so cruising, rising to 15A when pulling off without pedalling.

I will try and take some pictures tomorrow to show how I've tried to hide all the electric bits. Meanwhile I'm very pleased, as the bike still rides very well with the power off, in fact the motor drag seems to be near zero.

Jeremy

 

[flecc]

Sounds good Jeremy, looking forward to the pics.

It will be ideal if you can get the final batteries behind the seat, always the least conspicuous and best balanced place for them on a recumbent, bike or trike
.

 

[Jeremy]

I've managed to take some pictures:

Side view of bike

"Dashboard" with power meter

"Dashboard" side view, with home-made LED light/reflector

Bar-end thumb throttle and mirror


All works well, except that my temporary, low capacity SLA batteries cause the controller to cut out due to low voltage under load. These are small, second-hand SLAs, so this isn't surprising, I'm only using them to test the system. As soon as the voltage dips below about 32V the controller cuts out and it doesn't take long for the batteries to get to this stage, so proper performance testing will have to wait until I get some new batteries. I'm still undecided as to what type to get. Now that I have the panniers fitted I could go for something a bit bulkier.

Overall I'm very pleased with the result. The performance seems to be just what I'm after, gentle assist with no tyre spinning as I had with the Crystalyte. This makes starting off from a stand still a very easy affair (starting is a bit difficult on a 'bent usually), as it doesn't really matter if you've remembered to get into a low gear before stopping or not, the motor pulls away gently without any drama or tendency to fall over sideways.

Jeremy

 

[tgame]

It looks really great, Jeremy. You've certainly got a good return for all your hard work.

 

[flecc]

Thanks for the pics Jeremy, looks good and sound good too. That controller cut-out at 32 volts is identical to the eZee one. Difficult to know what battery at the moment, with NiMh moving into the doldrums and some suspect Li-ions around. Most up to date good capacity one is Wisper's latest 13 Ah Li-ion with a hybrid cobalt/manganese cathode, though I don't know if you want one as large as that. Tony Castles at Electrodrive seems to have access to some smaller capacity types, though I'm not sure if any are 36 volt.
.

 

[Jeremy]

Thanks for the comments, chaps, much appreciated.

I'm leaning towards LiFePO4 batteries at the moment, as they generally seem to stand up well to ebike use. The difficulty is in making the choice between the uncertain quality, but good price, of some of the Chinese suppliers, or the known quality, but very high price, of eMoli or A123 cells.

Prismatic cells would be easier, as I can get them to fit neatly in the 110mm wide recess under the seat, and it seems that some of the people on the Endless Sphere forum are getting good results with them.

I think I'll sleep on it for another day or two before deciding!

I've discovered that three of my 12V NiMH packs from the fire look to be OK, so as an interim measure I may try a split arrangement, with both the SLAs and a small NiMH pack wired up together via a dual Schottky diode. Hopefully this will stop the voltage sagging quite so quickly and allow some further testing.

Jeremy