My Tongxin kit bike

[john]

Note on axle strength

On Friday my bike was written off by a head on collision with a car at a combined speed of abour 40mph

Before everyone panics...I'm OK, no broken bones. I'll put the details in another post.

Anyway, the front wheel buckled, the fork drop-outs sheared clean off and made a couple of gashes in the motor. The rest of the bike was a mess too.

Anyway, if that wasn't going to break the axle I don't know what would. You can imagine my surprise when I re-connected it and found that the motor still worked perfectly

 

[flecc]

Full marks for the Nano spindle then John, but you really shouldn't have gone to these lengths to test it's strength.

Seriously though, sorry to hear of the write off, but glad that you are unharmed.
.

 

[tgame]

Well thank god you're all right, John. What a thing! How on earth did a car come to hit you head on???

 

[Jeremy]

John,

Sounds like you were pretty lucky not to be seriously hurt, 40mph is a heck of an impact speed.

Good to know that the little motor stood up well though!

Jeremy

 

[john]

Thanks!

Thanks guys! I didn't want to take over this thread so I have started a new one with the details.

John

 

[frank9755]

John - glad to hear that you are ok - sounds like a lucky escape.

I've had a bit of a setback which is that my Tongxin has now stopped working!

I'm not sure where the fault is. What happened was 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 bike then worked, for about 100 yards then the motor cut out, with the throttle lights staying on this time.

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.

Now, when I connect, the lights on the throttle come on but the motor will not start.

I'm not sure if it's motor or controller. I'm hoping Tongxin might have a clever answer!

Frank

 

[Badge]

Diana.

Eventually I decided to try a Tongxin,somone said Diana she about.
I tried but I think she not about.
Perhaps it's to do with the new moon!
John.

 

[flecc]

Eventually I decided to try a Tongxin,somone said Diana she about.
I tried but I think she not about.
Perhaps it's to do with the new moon!
John.

Chinese New Year holiday break probably John, akin to our Christmas holidays, many long breaks taken.
.

 

[Jeremy]

Frank, you mention that the battery has plenty of charge, but have you measured the voltage getting to the controller?

My TongXin controller cuts out at 32V, which happens easily with my old SLA pack. I've now made up a temporary "hybrid" pack, using the SLAs plus a salvaged 3.7Ah NiMH pack from the fire, coupled via a pair of Schottky diodes. I will hopefully be able to do an extended test at the weekend to see how this works.

If you can couple a meter up to the battery supply you may be able to see what's happening. If the voltage is staying above the cut-off voltage, then it sounds ominously like a controller problem.

I'm seriously thinking of buying a spare controller (or maybe a couple of them) and modifying one to be able to tolerate a bit more abuse. I think that the core design is OK, but the FETs might not be up to use at high loads. There is a thread on the Endless Sphere where a chap in Canada has stripped one of these controllers and posted pictures. Based on his experience I think I would be able to take one apart and upgrade it. That thread on ES is here: Endless-sphere.com • View topic - Sensorless controller question

You'll find at least one other member from here over there as well!

Jeremy

 

[frank9755]

Thanks Jeremy. I think I may as well keep at it and get another few controllers in! It's far more likely to be the controller than the motor, isn't it? It's my Wisper lithium that I'm using. First thing I did was recharge it and to see if that did the trick. I've not measured, but I imagine that should be giving 37+ volts on a full charge so I think something is amiss.

I've lurked on endless sphere and read some of your posts there, so shall have to have a look back and see how the debate has moved on!

Hope your bike is still going well,

Frank

 

[john]

Frank,

When I had a problem with my motor not running it was nearly always the connectors. I ended up cutting off all the low current connectors and soldering the wires together. I did have one throttle fail. You can check this by measuring the control voltage changing as you operate the throttle. The other two connections should be 0V and +5V coming from the controller.

I am told that if the controller goes then you usually know about it 'cos it goes bang and smells burnt.

John

 

[frank9755]

Thanks John - interesting. I'll check over my connectors again. I have a spare throttle so will try that too.

Regards,

Frank

 

[chantelauze]

nobody's home at Tongxin as soon there is a problem

Brett White in Australia ( solarbbq@hotmail.com ) has experimented the Tongxin motor and reported of many problems in regard with the controller ,i think he knows quite a lot about the Tongxin controllers , you might ask him since Diana Lin from Tongxin is eager to make comments on that forum when she receives compliments and remains totally silent when her clients have to face technical problems ( that's what appears to me )

 

[chantelauze]

did you try to remove the throttle , thus starting the motor only from the PAS ( Pedal Assitant Sensor ) ?

 

[frank9755]

Not had time to do any checks so far, but interesting to catch up on the threads on endless sphere, where there has been a good deal of activity since I was last there.

It does leave me a uncertain though as to whether it is the motor or the controller that has gone. I did hit a nasty pothole about 15 mins before the motor died. I was at full speed on a main road (Shepherd's Bush one-way system going West, for Londoners) and 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 the motor problem with the outer ring breaking a few miles down the road while under load?

One thing I can say with complete certainty that I'm not going to try to take apart a controller, but good luck if you do, Jeremy!

Tongxin would not be the first company to be less responsive on after sales service as opposed to sales enquiries - so I am not too surprised on that point.

Frank

 

[john]

Frank,

It sounds more like an electrical problem than a mechanical one.

If the gear ring broke, you would still here the motor turning (you just wouldn't go anywhere).

John

 

[frank9755]

Thanks John, that is most helpful.
As you can tell, I'm not an expert at this!

Frank

PS - the guy on endless sphere posted some details which back this up. His still turns if you lift the wheel off the ground but not under load. Mine is completely dead - so electrical fault! Thanks

 

[frankyboy]

I want to use this Tongxin motor to build in a variety of recumbent models and try to find out these things (I did ask Diana from Tongxin but it is not 100% clear to me and I do appreciate your opinion!):

1. Does anyone has a disc brake version or can anyone tell me if I can get this motor suitable for disc brakes?
2. does the rear wheel motor support a 7, 8 or 9 (new!) speed freewheel?
3. they have a function switch for horn or light but does this thing give 36 Volt as I think or 6 Volt as I hope?
4. Diana tells me the max speed can be controlled by the controller software (max 25 km/u europe) but how? She also tells me all controllers are the same...
5. The diagram they send me shows a speed sensor but I never seen anything like that. Would this support a speed display and or have buttons to program the controller like the BionX works?
6. There should be 3 ways to operate (1.Throttle only, 2 Throttle and PAS and PAS with sensor only?) but how and how to change from one to the other? Just plug in and out?

Thanks for your comments and help!

 

[flecc]

A quick aside Frankyboy. I said i would find the thread from Jeremy about the Nano on a recumbent, and here it is:

Motorising a recumbent
.

 

[frank9755]

I want to use this Tongxin motor to build in a variety of recumbent models and try to find out these things (I did ask Diana from Tongxin but it is not 100% clear to me and I do appreciate your opinion!):

1. Does anyone has a disc brake version or can anyone tell me if I can get this motor suitable for disc brakes?
2. does the rear wheel motor support a 7, 8 or 9 (new!) speed freewheel?
3. they have a function switch for horn or light but does this thing give 36 Volt as I think or 6 Volt as I hope?
4. Diana tells me the max speed can be controlled by the controller software (max 25 km/u europe) but how? She also tells me all controllers are the same...
5. The diagram they send me shows a speed sensor but I never seen anything like that. Would this support a speed display and or have buttons to program the controller like the BionX works?
6. There should be 3 ways to operate (1.Throttle only, 2 Throttle and PAS and PAS with sensor only?) but how and how to change from one to the other? Just plug in and out?

Thanks for your comments and help!

As Flecc says, Jeremy is the undoubted expert in fitting a Tongxin to a recumbent. I can answer only a couple of your questions. Some are ones I tried to clarify with Diana but with no luck!

1. I'm not aware of this being used with disk brakes and imagine you would need to do some basic metalwork to achieve that.

2. No, you can't use a typical freewheel cluster because the rear wheel motor is centered on its spindle. There is only enough room to have a small freewheel - either a single or perhaps a 3 or 5 speed at most. I tried to fit a 7-speed and there isn't room. Perhaps if you shaved of a little excess thread from the motor casing you might just get a 7- but it would be tricky.

Good luck with the others!

Frank