The Tongxin Motor thread

[Timbo]

Does anyone know the rpm to wheel size of their tongxin? Mine is a 260rpm, 36v. It has good top end but struggles to get there. The controller cuts out sporatically-, I am thinking about rebuilding the controller.

Mine is rated the same. It is laced to a 700c rim.

[Johnbear]

Maybe part of my problem is my riding style. I am so used to the more powerful motors that maybe I am pushing the motor a bit. (I do pedal) Still though, the controller cutting out on a cool day seems a bit odd. I have only tried the motor twice so far. It is laced to a 26 inch rim. Do you find your controller gets really hot? Can you check? Thanks!

[Timbo]

Maybe part of my problem is my riding style. I am so used to the more powerful motors that maybe I am pushing the motor a bit. (I do pedal) Still though, the controller cutting out on a cool day seems a bit odd. I have only tried the motor twice so far. It is laced to a 26 inch rim. Do you find your controller gets really hot? Can you check? Thanks!

Well, I read this this morning & didn't have time to reply before setting off to work. I was going to respond by saying that the EV controller is housed in a kind of mesh pocket at front of the battery pannier & therefore seemed to stay pretty cool most of the time as it always had access to ambient airflow. I've riden to work on plenty of 30'C+ days this summer & even some 40'C+ without any problems.

As far as I know the controller does stay cool with this setup, however I did run in to some trouble today. About 1/3 of the way into my 10km commute the motor gave a fairly loud click and from that point on I only had pedal power! I sure worked up a sweat lugging the extra weight. . So, I guess I'm off to EV on Saturday morning to have them check it out .......I'm pretty sure it will be the controller that's the problem. Here's what Scott at EV had to say about the setup when I inquired before purchasing: (Tongxin=EVO3 in discussion below)

Geared motors are significantly more efficient and have no resistance when freewheeling. No comparrision to non geared motors. We test our bikes/motor on a dyno simulating real time usage conditions and test them to destruction point. Have yet to kill a motor, only controllers and connectors under extreme load.

We also run each motor through a course on a bike using a computer battery monitor called a Brain Drain to review efficiencies etc. This course follows the bike path from the Knoxfield store through Ferntree Gully then up the tourist rd to Olinda and involves a 12% grade throught the devils elbow. Both motors perform very well. Best time from Burwood HWY up the elbow to the servo at ferny creek is 7 min 13 sec's on the evo 3 Li on a dual suspension MTB with slick tyres.

Nylon and friction bearings. We have never had a motor strip a gear.

The motors are very different in weght. 2.3 kg v's 4 kg. The SLA motor
has more torque. On a light weight bicycle the EVO 3 is the way to go.
We don't offer the EVO 2 motor with Lithium Batteries. We found the EVO2 motor to be a little hard on batteries.

We use a computerised dyno to test our motors. Over a standard
undulating course. The results are similar. Start up torque on the EVO
2 motor is better however both motors perform around the same level.
Once moving.

The EVO 3 is around 10% more efficient.

Motors no longer assist after 35 km/h infact most assitance is given
between 25 - 30 km/h

I'll quizz the guys about your intermitant problem and see what they have to say.

With regard to riding style I try to get the bike moving a little with the pedals, especially if starting out on an uphill grade, but once I've got a little momentum I pretty much always have the throttle to the stops if road surface/traffic permit. I weigh in at about 55kg so I may have an advantage there....

[Johnbear]

I would appreciate that and good luck to you! Sorry to hear the bad news.

[Timbo]

About 1/3 of the way into my 10km commute the motor gave a fairly loud click and from that point on I only had pedal power! I sure worked up a sweat lugging the extra weight. . So, I guess I'm off to EV on Saturday morning to have them check it out .......I'm pretty sure it will be the controller that's the problem.

Well, I was wrong. It's not the controller. The problem is with the motor. Apparently the needle bearings push against an outer ring and the ring is most likely broken. Scott reckons he's seen this twice before with this motor - can be caused by a sudden shock like speed hump or pothole. I left the bike with him. He's going to swap the motor for a new one, no charge, and ship the dodgy one back to China. I'll collect the bike during the week. Great service - only a couple of days without the bike. If I'd bought direct from China it would probably take weeks to get this sorted out & I'd no doubt be out of pocket.

I didn't get the chance to quizz Scott about your problem - there were heaps of people in the shop and he was on his own. Hopefully I can ask when I go pick up the bike.

As an aside, there was a Vectrix on display in the shop. First chance I've had to check one out at close quarters. Sweet! I've been resisting the urge to take one for a test ride because I know I'll want one......

[Timbo]

Apparently the needle bearings push against an outer ring and the ring is most likely broken. Scott reckons he's seen this twice before with this motor - can be caused by a sudden shock like speed hump or pothole.

I just read solar bbq's comments again re. known problems with this motor. Looks like I'm one of unlucky 10%.

[Johnbear]

The motor is pretty tough in general I think, according to a thread on pedelecs.co.uk a guy got into a collision at 40mph combined speed and the motor survived (he did too). I only have 20kms on my motor. Hopefully many more to come if I can get the controller to be reliable!

[frank9755]

It's interesting to read this and compare with my situation - which I'll post to add to the store of common experience.

My Tongxin is currently off the road, with about 150 miles on the clock. I have a 36v 260 rpm motor fitted to a normal Marin hybrid bike with 700c wheels (Timbo, your installation was what I used as my model). When it goes it is wonderful but it's been laid up most of the time.

My story is that I bought the parts direct from Tongxin in December and fitted them to the bike, using an old SLA battery for initial tests. This gave me a about 5 miles before it popped a fuse. When I replaced the fuse, it popped straight away. I assumed a controller fault, sent the controller back to Tongxin and they sent me a new one. However the same thing happened with the new controller, and on another bike, so it became clear that my battery was doing strange things (possibly damaged due to high current drain from Tongxin?) so I discarded it and switched to a lithium ion one.

I then had the bike going well for a week or so then, after I had the motor fairly flat out for about a mile, the motor stopped working and the throttle lights went out. This could have been the lithium battery cutting out due to too much load (but this had not happened before so may not have been). I stopped and looked things over, and turned the battery off. The connector between the controller and motor had disconnected. I reconnected this, turned the battery on and the throttle lights came back on. The motor then worked, for about 100 yards then the motor cut out, with the throttle lights staying on this time. There were no bangs or smoke and the controller was not above a normal warm running temperature.

The battery still had plenty of charge and is is working fine on another bike. I have a 15A fuse fitted to the battery and this did not blow so there was no current surge. I've checked all the connections and they are ok.

The other thing that concerns me is that I had hit a nasty pothole about 15 mins beforehand. I was at full speed on a main road and I hit it so hard that I lost control of the bike for a second and very nearly came off. I wonder if that impact could have caused a similar motor problem to Timbo's with the outer ring then breaking a few miles down the road?

I'm not sure what to do now as I really don't know if it is the motor or controller that is not working. My electronics skills don't stretch to a component level fix on the controller. Any thoughts welcome!

Frank

[Timbo]

The other thing that concerns me is that I had hit a nasty pothole about 15 mins beforehand. I was at full speed on a main road and I hit it so hard that I lost control of the bike for a second and very nearly came off. I wonder if that impact could have caused a similar motor problem to Timbo's with the outer ring then breaking a few miles down the road?

I'm not sure what to do now as I really don't know if it is the motor or controller that is not working. My electronics skills don't stretch to a component level fix on the controller. Any thoughts welcome!

Frank

Sorry to hear about your troubles, it sounds like a frustrating series of problems. When my motor died I was on a fairly smooth strectch of tarmac. The indicator lights stayed on &, later, I discovered that power stilled flowed to the motor and without load - wheel off the ground - it would spin under power, but nowhere near the rpm it should be spinning and no hope of turning with me on the bike.

In my 900 odd km of commuting I've hit some pretty nasty bumps, but not enough to lose control like you describe. My guess is that repeated thumps have caused a stress fracture that finally gave up. Actually it was pretty bad timing cos I'd just smoked a lycra clad guy on a regular bike and then had to suffer the humiliation of him passing me.

[Link]

As an aside, there was a Vectrix on display in the shop. First chance I've had to check one out at close quarters. Sweet! I've been resisting the urge to take one for a test ride because I know I'll want one......

Resist! There are a few owners over on the V and they're having problems. Bad enough to the point to where they're considering ditching them and spending the money on something else.

Actually it was pretty bad timing cos I'd just smoked a lycra clad guy on a regular bike and then had to suffer the humiliation of him passing me.

Timbo uses item "Dran's Feather"! +3 increase to Spd! Lycra uses special move "Dash"! Lycra rolls attack die! 12 damage to Ego!

...

I honestly have no idea were that came from...

[frank9755]

[
Sorry to hear about your troubles, it sounds like a frustrating series of problems. When my motor died I was on a fairly smooth strectch of tarmac. The indicator lights stayed on &, later, I discovered that power stilled flowed to the motor and without load - wheel off the ground - it would spin under power, but nowhere near the rpm it should be spinning and no hope of turning with me on the bike.

In my 900 odd km of commuting I've hit some pretty nasty bumps, but not enough to lose control like you describe. My guess is that repeated thumps have caused a stress fracture that finally gave up. Actually it was pretty bad timing cos I'd just smoked a lycra clad guy on a regular bike and then had to suffer the humiliation of him passing me.

Interesting - thanks. Mine sounds different as it is completely dead, with wheel off the ground, wheel already spinning, etc - no noise or anything. A guy on the pedelec.co.uk forum was pretty sure that means its electrical not mechanical (ie the controller).

Bad luck on your timing! I use my bike for commuting in London along one of the main routes and there are dozens of road bikes going at 20mph+. With the Tongxin, for a few short days, I had their measure! But good luck on having support from a local dealer. You may have paid a mark-up for that but you are getting value for it now. Hope you're fixed up and back on the road soon!

Frank

[Timbo]

As an aside, there was a Vectrix on display in the shop. First chance I've had to check one out at close quarters. Sweet! I've been resisting the urge to take one for a test ride because I know I'll want one......

Resist! There are a few owners over on the V and they're having problems. Bad enough to the point to where they're considering ditching them and spending the money on something else.

Interesting. Where is this 'V' you speak of?? $15K is too much to spend if bad problems are likely.....

[Johnbear]

V =V is for voltage. http://visforvoltage.org. My second tongxin controller died today.

[Johnbear]

So I now have had a total of 33km of mileage on 2 controllers.

[Timbo]

Here's a quick update on where I'm at. Haven't been riding too much recently because of starting a new job & having to lug gear in the car and also some crazy hot weather. But I've put about 100km on the odo with the new motor & controller - both replaced gratis by EV.

Initially I was pleased that I seemed to be getting a bit more speed from the new equipment - like about 2-3 km/h - but I think it may be at the expense of range. Previously I could bet on 40km, maybe a couple more, but last weekend I ran out of go-juice at only 31. Luckily I was on the final straight & almost home, otherwise I would have been steaming!

Apparently there have been ongoing quality problems with the Tongxin and EV will be switching to another manufacturer shortly. Here's what Scott had to say in an email after I put him on to endless sphere and this thread in particular:

Thanks for this have read this one. These have been a bit of a nightmare for us. Great motor. Concept etc. Just too many quality issues. So we have a new motor we are moving to as of next container. However I have ensured all parts are available for your motor. Should you have another motor failure I will replace with the BF model. We have used the wider version of these for 4 years without any issues. 3 failure out of 200 units, so pretty good. Any how hope all is ok with your unit now. Stay in touch.

One of the other guys said that there had been some problems with earlier controllers and then went on to point out a date stamp on the back of the new controller: 080216, which I take to read as Feb 16 2008. If anyone's having controller problems maybe it's worth checking this.

[Freddyflatfoot]

Timbo,
That BF motor is really good! I have mine running at 36V, and it pulls really well. Have been 42 kph mounted in a 20" wheel. Had same motor in a 26" wheel, and it topped out closer to 50 kph, but with less torque.
It a bit heavier than the Tongxin though, at about 3 kg.
Dunno what my range is, haven't drained the battery yet, but have gotten 35 k and battery still feels strong, so I reckon I should get 40?
Anyway, interesting you say that Scott is pulling away from Tongxin. Maybe they could start getting the ezee motors!
As an aside, I am actually thinking of getting a small 24v front hub motor, to mate up with my 24v LiFePo4 pack, which is currently going unused!

[Mathurin]

Timbo uses item "Dran's Feather"! +3 increase to Spd! Lycra uses special move "Dash"! Lycra rolls attack die! 12 damage to Ego!

...

I honestly have no idea were that came from...

Pretty sure it starts with a P, ends with an n. EG:

[docnjoj]

Sorry but I had to stick in my 2 watts worth! Had an early Tongxin, went 4.5 miles and died! Used a Crystalite 20 amp controller and had mechanical failure of motor! Brett did the honorable thing and rep[laced it with a P2A, which is now going on 3.5 years ar 1000 mi/year! Tongxin sucks! My humble opinion! Brett is a Prince among men for his business practice!
Doc

[Johnbear]

I have a tongxin 3 controllers later it works, but poorly. The gear slips & the top speed is 20kph 12mph - after that it feels like you are pedaling a tank.

[fitek]

What's this p2a motor you speak of?

[Mathurin]

http://www.users.bigpond.com/solarbbq/P2-A.htm
"no longer available" May be possible to get a used one by asking on power-assist, tho?

[Freddyflatfoot]

There are other geared hub motors that are available that as good, if not better than the P2a.
Ezee comes to mind, as does Puma/BMC.
I personally use a BF motor from Suzhou Bafang P/L from China.
Feel free to contact Brett and solarbbq, he is very helpful.

[Johnbear]

After 3 controllers, the tongxin motor finally gave up. After taking it apart a bit it seems as though the ring that holds the press fit bearing is cracked. This motor and controller is crap. 2 thumbs way down.

[HTB_Terry]

The Tongxin motor is a good motor if used within specifications. It is the smallest and lightest motor out there, naturally it will not be as strong as a larger, heavier motor. It does have limitations and can not be abused. It is particularly good on smaller bikes where weight is at a premium. Schwinn uses this motor on their fullsized ebikes. They did make some improvements about 2 years ago. The weak point is a metal ring which compresses the roller bearings. If the motor is stressed beyond what it is designed for, the ring can develop a stress fracture around the mounting holes. This can be repaired however. We (http://www.hightekbikes.com) are a factory authorized and trained repair center for Tongxin and have the spare rings in stock along with the required tool to replace them. If anyone here has this issue, you can contact us (service@hightekbikes.com) to arrange to have it repaired, good as new. We also have spare controllers in stock. FYI, the new version of this motor is even thinner, and is sensorless for more efficiency. One note on the controllers, they are vulunerable to high levels of back EMF. If you go down a steep hill, the voltage generated by the motor will burn up the mosfets, I suspect because the internal diodes are conducting. The work around is to add some protection diodes on the three motor leads, to GND and Batt+. We have done this for several customers and have not heard back. Since this will pump the voltage into the battery, it will need to have over voltage and current protection (if Lithium).

[Johnbear]

The Tongxin motor is a good motor if used within specifications. It is the smallest and lightest motor out there, naturally it will not be as strong as a larger, heavier motor. It does have limitations and can not be abused. It is particularly good on smaller bikes where weight is at a premium. Schwinn uses this motor on their fullsized ebikes. They did make some improvements about 2 years ago. The weak point is a metal ring which compresses the roller bearings. If the motor is stressed beyond what it is designed for, the ring can develop a stress fracture around the mounting holes. This can be repaired however. We (http://www.hightekbikes.com) are a factory authorized and trained repair center for Tongxin and have the spare rings in stock along with the required tool to replace them. If anyone here has this issue, you can contact us (service@hightekbikes.com) to arrange to have it repaired, good as new. We also have spare controllers in stock. FYI, the new version of this motor is even thinner, and is sensorless for more efficiency. One note on the controllers, they are vulunerable to high levels of back EMF. If you go down a steep hill, the voltage generated by the motor will burn up the mosfets, I suspect because the internal diodes are conducting. The work around is to add some protection diodes on the three motor leads, to GND and Batt+. We have done this for several customers and have not heard back. Since this will pump the voltage into the battery, it will need to have over voltage and current protection (if Lithium).

That is what happened to mine. The metal ring that compresses the roller bearings cracked. At the time I was running a 36v 10amp controller I don't think I overstressed the motor. How much is the repair? I could mail you the motor. Are the replacement rings better than the stock rings? Thanks!