Tongxin Kit 'where And How'

[daddyboy]

hI there

im new to the forum and would like to turn my claude butler pinelake with quick release wheels into a electric bike, ive heard about this kit but dont have a clue of where to get one or put it together, can anyone help?

ill be doing about 15 miles with a big hill, im looking for duration and speed.

initially i was thinking about a currie kit, BTW my forks are just about 100mm

theresalot of talk about the tongxin so i figured this might be a good kit

id appreciate a few pms to help me out

thanks

 

[Jeremy]

There are a couple of threads here with most of the details you need, I believe. This one: http://www.pedelecs.co.uk/forum/electric-bicycles/1494-my-tongxin-kit-bike.html started by Frank and this one: http://www.pedelecs.co.uk/forum/electric-bicycles/1193-tongxin-k-nano-motor-project.html describing my own project.

This forum has a search function, if you search using "tongxin" as the term it will throw up every thread where this motor has been discussed.

Jeremy

 

[john]

daddyboy,

100 mm forks will be no problem. I did have to file my original suspension forks a little way up as they cut in quickly. However, most modern suspension forks seem to be designed for disc brakes and have a lot more space.

John

 

[frank9755]

If you do go for a Tongxin, I would recommend the version with the hall sensors.

The sensorless motors are fine but the controllers that go with them do not seem to be vey reliable. Mine broke and a poor chap on the endless-sphere forum has had two go in about 20 miles of riding.

I don't know if the sensor version controller is better (although Grizzly-bear on this forum is happily using one), but there are many alternatives available.

Frank

 

[Jeremy]

Frank,

Have you had your motor apart by any chance?

I was wondering if it would be possible to convert a sensorless motor to one with sensors. The Hall sensors are relatively cheap and easy to hook up, the only snag I can see is finding the exact location for them.

I could probably work this out after stripping my motor, but it might be easier to look at a photo first.

I can remember seeing a series of photos of a stripped Tongxin motor somewhere, but can't for the life of me remember where!

Mine is still running OK at the moment, but I have a spare 35A Crystalyte controller, which would most probably work fine if my motor had sensors fitted.

Jeremy

 

[flecc]

I can remember seeing a series of photos of a stripped Tongxin motor somewhere, but can't for the life of me remember where!

One of Tony Castles sites, I think the electrodrive.co.uk one, had some of these stripped Nano photos for a while, but they disappeared later when I looked for them again.
.

 

[john]

Jeremy,

Here are some pictures of the sensors in my old motor.

However, I much prefer the sensorless motor, mainly as there are less wires to break and the connectors I have not found to be reliably enough. I guesss I might not think that if the controller broke down.

I did think of buying a spare. Must be quite cheap if bought direct. Let me know if you think of getting one and perhaps we could share shipping costs.

John

 

[Jeremy]

Many thanks for those pictures John, very useful. I may well be interested in sharing shipping on a spare motor, as I'm guessing that it might well be possible to just swap the motor innards over without going to the trouble of rebuilding the wheel.

At the moment my motor and controller seem to be working OK, but with so many tales of sensorless unit failing I'm thinking ahead a bit. If I don't get a spare motor, I may well invest in a spare controller. I've emailed Diana Lin at Tongxin about this at least a week ago, but not had a reply yet.

If I get a spare controller (or perhaps two, as they are quite cheap) I'd be tempted to take one apart and beef up some of the critical components, like the FETs. I'm inclined to think that just removing the potting compound and mounting the controller components in a way that ensured better heat conduction might improve reliability, too. The thread on the Endless Sphere showing the controller with the burnt out current limit shunt made me think about the internal heat build up problem.

Jeremy

PS: That motor looks a bit the worse for wear, John. What on earth happened to it? Did it get flooded with water?

 

[john]

You're welcome Jeremy.

My controller has done over 2000 miles so far without a problem (touch wood). The other difference I noticed was that the sensor controller I had originally would cut in and out very rapidly with a low battery. This one is slower and more friendly (about 500ms rather than 10ms). What do you find with yours?

I did hear of someone removing the potting and heat sink, and mounting the MOSFET's onto the bike frame to save (even more) space.

I would have thought that both types of controller had the same power components. Is this not the case?

I checked my controller on the way to work (heavy going into a headwind) and it was only a little warm. I suppose a hot summer day would be a better time to check.

The motor was used last winter and does seem to have suffered from water leakage. Just rain and the odd spray with the hosepipe. I think it must have leaked at the bearings. I am told that the new motors are sealed better and my current one seems to be holding up better.

John

 

[Jeremy]

Thanks for that, John. When I was running my bike for a very short time on the 36V SLA pack, I found that it would cut out completely when the voltage dropped below about 32V and the throttle would need to be set back to off to allow the motor to start again. If I just held the throttle on, then the controller wouldn't restart.

I've not had any cut outs at all on the new LiFePO4 pack, although so far (due to the weather) I've not been able to give it a really good test. As soon as I've given it a good run I'll post an update on the project thread.

It may well be that the power stage is similar on both controllers, but it does seem (from the limited data on the Endless Sphere thread) that the FETs blow on the sensorless controllers. I have a few nice IRFB4110 FETs, which in addition to having a very low Rdson (so low losses and controller heating), are rated at 100V, 180A each, so are a bit more robust than those fitted as standard.

I have a suspicion that the problem with some of these controllers might just be a quality issue. I'm not convinced that the heat generating components can conduct heat to the metal case very well, from looking at the pictures on the other forum. The case of the burned out current shunt seems a good illustration of this potential problem. A careful strip and rebuild might well enable me to make a nice, tough, controller, particularly if I took the opportunity to re-house it in a way that made sure nothing could get too warm and uprate some of the parts to make it more bomb-proof.

Jeremy

 

[frank9755]

I've not had mine to bits, and would probably not try to push my technical competence that far!

I've not given much thought to what to do with my Tongxin. Partly because I've been a bit busy but mainly because I've got a new (non-electric) touring bike which I am very much enjoying riding, so haven't used an electric bike for the last month.

My suspicion is that the tongxin controllers are less reliable if you push them hard. Mine failed towards the end of a 12-mile ride, on full throttle much of the way. Jeremy, I seem to remember you are planning shorter trips and more gentle useage, so you may be ok. If I do get another sensorless controller, I'll try to rig it up as a pedelec, which would be a bit gentler on it (and I would prefer to use it that way in any case). However I have found it hard to drum up the enthusiasm to spend the time soldering and tinkering, given the patchy reliability record!

Frank

 

[flecc]

My suspicion is that the tongxin controllers are less reliable if you push them hard. Mine failed towards the end of a 12-mile ride, on full throttle much of the way.

This was what David Henshaw of A to B magazine found in the Nano equipped Scwinn bike review Frank. He didn't fully cover this in the review since he was giving quite a thumbs down already on that bike and didn't want to do a "hatchet job" on the new small Yorkshire business importing it.

He had two controllers fail in similar circumstances, half an hour into rides and when loaded uphill.
.

 

[john]

My suspicion is that the tongxin controllers are less reliable if you push them hard. Mine failed towards the end of a 12-mile ride, on full throttle much of the way.

Frank,
Did you decide that it was the controller in the end or is that a guess at this stage?

I'm told that when a controller goes you can usually see some overheating damage, but I've not actually seen it myself. I'm just keen to help you get it going again.

John

 

[frank9755]

No, I'm not really sure.

I haven't got round to doing any more tests on it, so I'm only basing it on what I think was your suggestion, John, that if it was the motor I'd probably hear something but, as it is completely dead, its probably electrical.

However there's no visible damage to the controller so I am a bit stumped. When I get some free time I'll investigate further.

Interesting to hear David Henshaw's experience. I had thought the Schwinn bikes used their own controller rather than Tongxin, but that may not be right. I have to say it is regrettable when people censor their reviews for tactical reasons as, in the long run, it is better for things to get out so people can act with best information. However David is running a business, not providing a service, so must do what he has to do!

Frank

 

[john]

Frank,

I looked back at your posts and you mentioned two throttles. Have you tried the other one?

If you are really stuck and don't mind paying the return postage I would be happy to try any/all of your components on my set-up to check them out.

John

 

[frank9755]

John that's very kind of you. I may well take you up on that. Slight complication is that I've changed all the connectors so it could be a bit touch fiddly - but I could probably put the Tongxin ones back on

I've not tried the other throttle yet. I think what I might do is try that, then if still dead, send you my controller to see if it works on your set-up. If it does I could be pretty certain the motor had died!

Frank

 

[john]

sounds like a good plan

 

[john]

TongXin motor failures

After four mechanical motor failures in a little over a year's use I think it may be time to throw in the towel .

I've still been able to put together a working motor but I think that the fifth failure will put an end to my use of TongXin kit.

It is a shame, because when it is working it is exactly what I want. It looks like the nearest alternative is an eZee or Suzhou Bafang motor if I can get hold of one. These seem to be a little heavier, more drag and more expensive but a little more powerful and they don't keep breaking! I've not spotted any other options.

Jeremy, I don't think I will bother with a spare TongXin controller unless you have already ordered one for me.

 

[frank9755]

Bad luck John!
I've done nothing with mine yet, and given your news, in addition to all the other bad feedback, i think I will write off the Tongxin. As you say it is a shame as when it works it really is the business - but its just not reliable enough!
Frank

 

[flecc]

Oh dear. Some months back I was warning about them, but was variously opposed, including by one owner who furiously attacked me, saying I had no evidence and was just biased.

I think the record here now speaks for itself as it did in the USA from where I'd gleaned information previously on it's unreliability.

A lifetime of engineering instinct tells me the drive system is a rotten design anyway, but doubtless someone will tell me how wrong I am again.
.