Tongxin stopped, any ideas?

[andyh2]

Well I've had a very enjoyable 400 miles so far, but a couple of days ago the power ceased 8 miles into a ride.

I checked the fuse between battery switch and controller -blown. Replaced fuse there was no life. When I turned battery switch on it made a slight noise so I thought maybe fault is somehow with the switch. Rode home without motor .

Got home checked battery voltage 39V seemed about right as it was an almost fully charged Ping 36V. Found a new (better) battery switch today and replaced the old one in case that had something to do with it.

Connected battery, turned on and fuse blew. Replaced fuse again and nothing. ie no lights on at throttle, but it didn't blow this time.

I haven't checked all the wiring for continuity, but since everything goes through the controller first I'm suspecting something wrong with controller. I've no idea if there's anyway to test the controller.

Is the next step to replace the controller and see if that works or do you have some other ideas.

I can't see as I've particularly stressed the system as it's a 175rpm motor in a 26" wheel and I always pedal up to 5mph + before switching on motor. I do ride with the throttle fully open and use the throttle switch to turn power on and off if that might make any difference to stressing system.

Any ideas gratefully received.

Thanks

Andy

 

[frank9755]

99% sure it will be the controller.

My experience is that they can overheat during extended periods at full throttle or if they don't get full airflow. One of mine behaved as you describe, blowing a fuse when connected.

Change it and I'd expect the bike to work

Good luck!

Frank

 

[andyh2]

I'll try a new controller first then Frank.

I remember you'd said that you take the spring out of the thumb throttle so you don't have to hold it open all the time. Does that mean the throttle stays in whatever position you put it in until you change it. My method of using zip tie to keep throttle open means it's full on continuously. I've noticed when going up steep hills that as the speed reduces the motor does feel laboured and I've wondered if the motor is actually able to use full power at lower speeds say 6-7mph. i had wondered if for battery efficiency it would be best to back off the throttle some when uphill at those lower speeds. Now I wonder if trying to use full throttle when/if the motor can't use it stresses the controller.

The Cytronex bikes first versions had a button for speeds 5-9mph and once up to around 9-10mph a second button for full power to go up to around 15mph. And I understand the newer singlespeed versions have a crank speed sensor which increases power as crank speed increases. ie they are designed not to try and use full power at lower speeds. They don't seem to be suffering controller failures so maybe the power restriction at lower speeds helps with that.

 

[wurly]

Full throttle at low speeds will almost certainly increase current quite a bit especially on hills. It does seems that the controllers do not like to be worked hard.
I would check the wiring first. Mine stopped on one occassion, i feared the worst but it was a connection i had made on the throttle wiring.

 

[frank9755]

It could be wiring and it is therefore worth checking the connections first, but I suspect it will be the controller.

I normally do as you describe - back the throttle off to about half power when the bike is going up steep hills.

With the spring removed I do find it much easier to keep the throttle partially open - I found that with a spring it was quite awkward to do anything other than have it full on.

If you do need another controller, Keywin Ge - aka eCrazyman - can supply ones suitable for sensorless motors but which have some beefed up components which should be less likely to blow. I have a couple and have had no problems, but they've only had light use so far.

Frank

 

[andyh2]

Wiring to check then.

Is this the sort of controller you're using Frank?

36V 350W brushless controller for E - bike & scooter on eBay (end time 28-Aug-09 14:39:22 BST)

 

[frank9755]

No, that one is for motors with Hall sensors.

I don't think the sensorless ones are on eBay but if you send Keywin an email, asking about a sensorless controller for a Tongxin motor, he will know what you need.

I got two from him a few months ago. Can't remember exactly what they cost as I get confused between the $ and £ amounts, but I'm sure it was less than £50 delivered to the UK for the two

 

[andyh2]

Thanks Frank, I'll drop him an email.