TSDZ2 problem (display switches off when I start pedalling)

[Torbe]

Hi

I have the TSDZ2 350W version with VLCD5 display.

Bought it this summer for my GF. Has done about 1000 km.

But now we have run in to a problem. The motor will not assist and the display turns off as soon as she starts pedalling.

If the assist is set to lowest (off) on the display, it will not turn off when she starts to pedal. Then it will show speed km/h as it should, but as soon as (+) is pressed and level 1 assit or higher is selected, display will turn off.

Any ideas to what could cause this problem or how to fix it?

 

[Nealh]

It sounds like one of two issues to me;
LCD reading lvc from the battery/controller or a torque sensor /calibration issue.
Does the manual suggest if you can try a system reset ?

 

[Torbe]

It sounds like one of two issues to me;
LCD reading lvc from the battery/controller or a torque sensor /calibration issue.
Does the manual suggest if you can try a system reset ?

Hello
Thanks for sound advice.
What is lvc? Low Voltage?

I have not been able to find anything in manual about system reset, but I will browse ze interweb.
Hopefully I will have time wednesday to work on the bike. Can try to measure the voltage display reads.

 

[anotherkiwi]

Low Voltage Cut-off

 

[Deleted member 4366]

Most likely, it's a battery problem. The LCDs don't normally switch off if they detect a problem. Instead, they give an error code. If the LCD switches off, the battery supply is being interrupted.

Check every battery connection all the way from the cell-pack to the display. Is the battery a decent one?

 

[Torbe]

OK so took me some time before i got it testet, but here are my results:

Without load I measure 41V on the battery (it's a 36V 12.8Ah).

I put a 4 Ohm 150W power resistor on the battery for short period. Voltage on battery only drops to 39V.
My guess would be that this is not a problem, and that the battery is not to blame then?

What would be logical next steps?

 

[Deleted member 4366]

Did you read my post?

 

[Torbe]

Did you read my post?

Hi yeah, thanks!
So i measured voltage from battery to display all the way and i cannot find any problems. I will have to try and measure this also when someone is pedelling the bike, to see if it drops out.

Battery is china, so could be crap. However it passed my ~350W load test with the 4ohm resistor.

It sounds reasonable that the voltage to display is somehow cut off when pedelling starts. Since battery is ok, and connections seems fine, to me it looks like it is inside the motor somehow.
I am just not sure how to approach this.

 

[Deleted member 4366]

Voltage won't give you the answer. You know it's reaching the display when there's no load because the display works. The problem is most likely a bad connection. You have to check solder joints and connectors.

You need to place your load where the controller is, if you want to test it with a voltmeter.

 

[Torbe]

Voltage won't give you the answer. You know it's reaching the display when there's no load because the display works. The problem is most likely a bad connection. You have to check solder joints and connectors.

You need to place your load where the controller is, if you want to test it with a voltmeter.

Ok so just to understand: Thesis is, that when peddling, voltage from battery to display is being interrupted, which causes the display to shut off and motor not to assist?

So if I put battery on bike, have bike lifted off ground, peddle (maybe apply resistance to wheel) and measure voltage to the display, I can test this thesis. If thesis holds, i can look inside motor for bad connection?
I have been looking at all obvious bad connections and cannot find one.

Also as noted the display only cuts out ass soon as assist lever is set higher then 0. So it seems like it cuts out when motor tries to help.
This is why I load testet the battery, to see if it was causing the display to low voltage dropout.

 

[Deleted member 4366]

No, that's not what I mean. The display only goes off for two reasons. It's either been switched off or the battery supply to it has been interrupted. Yours only goes off when the motor takes power, so it's not random switching, like when you get water in it. That leaves the supply to it as the most likely cause.

Why would the power only be interrupted when you start to pedal? That's when the motor takes maximum current, so that leads us to two logical causes. Firstly, the battery can't supply the current, so the voltage collapses and its BMS shuts it down, or secondly, a connection, like a solder joint, is bad. A dry joint or dirty connector can provide the miliamps to power the LCD, but as soon as the motor takes current, the voltage collapses. That's very common on key-switches, where there's often bad solder joints. Also fuses often have bad connections.

Your battery test with a 4 ohm resistor, would take 12 amps from the battery, but the voltage only went down to 36v. That's lower than I'd expect, but not low enough to cause problems, so that seems to rule out the cell-pack, therefore I would concentrate on connections all the way from the battery terminals to the controller. The LCD takes a branch off the controller's supply and uses very little power, so you don't need to worry about anything between the controller and LCD.

 

[Torbe]

No, that's not what I mean. The display only goes off for two reasons. It's either been switched off or the battery supply to it has been interrupted. Yours only goes off when the motor takes power, so it's not random switching, like when you get water in it. That leaves the supply to it as the most likely cause.

Why would the power only be interrupted when you start to pedal? That's when the motor takes maximum current, so that leads us to two logical causes. Firstly, the battery can't supply the current, so the voltage collapses and its BMS shuts it down, or secondly, a connection, like a solder joint, is bad. A dry joint or dirty connector can provide the miliamps to power the LCD, but as soon as the motor takes current, the voltage collapses. That's very common on key-switches, where there's often bad solder joints. Also fuses often have bad connections.

Your battery test with a 4 ohm resistor, would take 12 amps from the battery, but the voltage only went down to 36v. That's lower than I'd expect, but not low enough to cause problems, so that seems to rule out the cell-pack, therefore I would concentrate on connections all the way from the battery terminals to the controller. The LCD takes a branch off the controller's supply and uses very little power, so you don't need to worry about anything between the controller and LCD.

Hello d8veh
Thanks for your patience and thorough explanation .
I get your point. I will check solder joints, connections and fuses and make sure they are proper for large currents

 

[Torbe]

Ok so found a bad connector. The wire to it was almost corroded away.
So I cut the wires, found some new connectors (had some high voltage DC outdoor solar panel connectors lying around), soldered etc.

Now the bike runs like a charm again.
Thanks for the help and patience

 

[Eno]

Hi guys
I have a similar problem , when i run and motor have all regular , fully charge battery , after 20min run the motor turn off by itself ....I turn on it again without problem and run, after other 20min it turn off again.
I happens 2 or 3 times and after that i run until the battery is completely discharged without other problems.
Now the seller send me a new display and I will try with it.
What else could it be the issue ?
I really appreciate your advices.
E

 

[Bikes4two]

• Hi Eno and welcome to the forum.
• To help people answer your query, could you provide more information please
  1. I presume you are talking about a TSDZ2 system?
  2. What power is the motor (250w,350w,500w,750w?)
  3. What battery have you got (voltage and amp/hr)?
  4. What display are you using?
  5. How long have you had the system installed on your bike?
  6. If you've had this system for a while, has it worked properly before now?
  7. What are the temperatures where you live (I thinking an overheat situation)?

 

[Eno]

Hi B4
I talking about a TSDZ2 250W 36V motor kit with a battery 36V 13.5A and the VLCD6 display
I have installed this kit 2 months ago and 700km done and it has worked weel for about 600km.
When it turn off itself I run on a plane road at moderate speed, not with hard load.
I have tested it on hill about 12% gradient 6km long at power 4 and 8°C without any problem, in this situation it is very exciting and it pushes me up very well.
I fell to exclude overheating because the temperature of my country in this season is around 5°C..now it is snowing...and climbing hill I have not issue.
It turn off itself every 20minutes with a full charged battery , when the battery is under 50% the problem dissappear.
The only think I have is water inside the display because in this season I ran in the fog, after this I saw some spot of water into the display.
The seller send me a new display, from China...I will try with it asap...nex year...
Many thank for your interesting.

 

[Nealh]

Moisture can cause issues if it enters the display not just mid drive systems but any system, it can cause shorting on the pcb.

 

[Bikes4two]

Thanks for the info and hopefully someone with more knowledge than myself will be along shortly.

It turn off itself every 20minutes with a full charged battery , when the battery is under 50% the problem dissappear.

Now that is an interesting observation. Can you measure the voltage when it is fully charged? for a 36v battery, it should be around 41.5v and also what is the voltage at the point the motor operates correctly.

And finally, is the motor on stock firmware or Open Source Firmware?

 

[Bikes4two]

Moisture can cause issues if it enters the display not just mid drive systems but any system, it can cause shorting on the pcb.

A good point - @Nealh - this post HERE shows a method of bypassing a suspect KT-LCD3 display - is there something similar that @Eno could do for the VLCD6 and then he could do a 20+ min ride to see if things are better?

 

[Bikes4two]

And somewhere along the line I picked up this little nugget of info - might it be relevant?