TSDZ2 problem (display switches off when I start pedalling)

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?

Battery's BMS is probably shutting down as soon as any load is applied.

That usually happens when either the battery is not charged or a cell (group) is defective.

I'd recommend looking up the many battery testing/repair threads and going thru the steps to check it out.

Hi amberwolf.
Thanks alot for the advice. I will check it out asap, think that will be wednesday. I will comeback with result.

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?

Connections would be my next check--anything that has a connector, anywhere, unplug it, then plug it back in, and retest.

Do this *one connector at a time*, not all of htem at once, or you'll never know which it was so you can recheck the connector for problems to permanently eliminate teh issue.


I suppose it's also possible the resistive load isn't enough to trigger the BMS shutdown, and it's still a problem with the pack itself.

The resistive load doesn't have the same surge peak that the motor might, even at a low assist level--the motor could spike high enough to trigger where the resistive load doesn't.

But it's not that likely.

Thanks, will go for connectors, solder joints etc. next, to see if they can handle large current

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