Offroad use of Tongsheng TSDZ2B 36V 350W

[rcaridade]

Hi guys,
I'm new here but have some experience with motor assisted bikes.
In my case I use Bafang BBS01B 36V 250W for commuting to work and Bafang BBS02B 36V 500W on a Cannondale full suspension for XC.
Both bikes are ok, but for off road, I miss the torque sensor that BBS02B does not have, creating somes problems when trying to go technical climbs, if you have to changer gears when climbing, etc.
So, my question is, does anyone has any experience using the new Tongsheng TSDZ2B 36V 350W in off road conditions? How reliable is it? Does it climb good and smooth?
What is your opinion in replacing the BBS02B 36V 500W for the TSDZ2B 36V 350W to use on the conditions described?
Thanks

 

[scianiac]

I've ridden the TSDZ2 (the B version has some improvements but none related to most of what I'm about to say at least that I'm aware of) extensively on trails, including fairly technical trails, although mine is running the OSF at 52V but I do often use it as much lower power levels around 350W. With the OSF at least it's very responsive and easy to ride off road, the biggest issue is the limited RPM range and limited peak torque and that's with the 52V battery. With the lower voltage battery the issue will be worse.

The issue is that at low RPM the torque is limited due to the low current limit so you have to be in the right gear to let the motor spin up and provide good assistance but then since the max RPM is so low, lower than your max pedaling cadence probably and power tapers off before that point you run out of motor RPM so you have to shift accordingly. If you generally ride at a slow even pace like I sometimes do it's really not an issue but if you want to pick up some speed on flat sections and climb hills gear selection is a thing.

It's not a huge issue but considering now there are more options available on the market that are less limited, generally by having higher power ratings and many of those options potentially are more reliable considering the TSDZ2 has a not great track record. I would say I like my bike and am pretty happy with it from a pedal assist bike but probably wouldn't choose the TSDZ2 again over the newer offerings.

And what I mean about higher power drives being nicer to use in this way is you have to think of the peak wattage rating as only one part of the puzzle, what you really want is the ability for the motor to output a known amount of power or torque depending on how you want it to feel at a wide RPM range matching your cadence, which will often vary a lot more than when riding on road. So 350 watts may be plenty but if if only gives you that in a narrow RPM range and you get far less above and below that it feels awkward and you end up shifting a lot. While a motor that can provide 1500w peak but is limited to 350w in the settings will be able to provide that 350 much more of the time.

On the reliability point I've had no serious issues and many have had great results, however many have also had numerous failures and it seems that questionable QC means it's kind of a game of chance unfortunately. The one perhaps most serious issue is the axles snapping which will be at a higher risk when riding off road, I think so far my light weight has kept me safe but if you weigh more it's a concern. Perhaps the advantage the TSDZ2 (which the B version has made some improvements but only some) is the problems and solutions are well documented while some of the other options are too new for us to really know longer term their reliability, but they certianly seem better engineered than some of the frankly stupid shit in the TSDZ2 (circlip slot that makes the axles break, thermally isolated motor, sloppy axle spacing tolerances).

 

[rcaridade]

I've ridden the TSDZ2 (the B version has some improvements but none related to most of what I'm about to say at least that I'm aware of) extensively on trails, including fairly technical trails, although mine is running the OSF at 52V but I do often use it as much lower power levels around 350W. With the OSF at least it's very responsive and easy to ride off road, the biggest issue is the limited RPM range and limited peak torque and that's with the 52V battery. With the lower voltage battery the issue will be worse.

The issue is that at low RPM the torque is limited due to the low current limit so you have to be in the right gear to let the motor spin up and provide good assistance but then since the max RPM is so low, lower than your max pedaling cadence probably and power tapers off before that point you run out of motor RPM so you have to shift accordingly. If you generally ride at a slow even pace like I sometimes do it's really not an issue but if you want to pick up some speed on flat sections and climb hills gear selection is a thing.

It's not a huge issue but considering now there are more options available on the market that are less limited, generally by having higher power ratings and many of those options potentially are more reliable considering the TSDZ2 has a not great track record. I would say I like my bike and am pretty happy with it from a pedal assist bike but probably wouldn't choose the TSDZ2 again over the newer offerings.

And what I mean about higher power drives being nicer to use in this way is you have to think of the peak wattage rating as only one part of the puzzle, what you really want is the ability for the motor to output a known amount of power or torque depending on how you want it to feel at a wide RPM range matching your cadence, which will often vary a lot more than when riding on road. So 350 watts may be plenty but if if only gives you that in a narrow RPM range and you get far less above and below that it feels awkward and you end up shifting a lot. While a motor that can provide 1500w peak but is limited to 350w in the settings will be able to provide that 350 much more of the time.

On the reliability point I've had no serious issues and many have had great results, however many have also had numerous failures and it seems that questionable QC means it's kind of a game of chance unfortunately. The one perhaps most serious issue is the axles snapping which will be at a higher risk when riding off road, I think so far my light weight has kept me safe but if you weigh more it's a concern. Perhaps the advantage the TSDZ2 (which the B version has made some improvements but only some) is the problems and solutions are well documented while some of the other options are too new for us to really know longer term their reliability, but they certianly seem better engineered than some of the frankly stupid shit in the TSDZ2 (circlip slot that makes the axles break, thermally isolated motor, sloppy axle spacing tolerances).

Thanks for this precious description that helps me a lot to understand this motor.

 

[Joakim]

I ride tsdz2b offroad since a couple of weeks, 36V 350W and so far I love it. I can only compare to a shimano steps 8000 and I think that motor is slightly better but not by far. The only thing I really dont like is the max cadence being so low, so I’m going to flash OSF to improve that. Its not always possible to change gears offroad so sometimes you need high cadence to speed up before a hill and similar, and thats really limited right now

For reliability I cant say yet, fingers crossed my axle doesnt snap jesus

I have not ridden a bafang with pas so cant compare

 

[rcaridade]

I'm worried, I didn't know the the axel was braking so many times. I'm not complaining about my Bafang BBS02B 36V 500W, it is an excellent and powerful motor, you only need to understand the way it works, to be on the right gear and assist mode when facing a climb. I was eager to test a torque sensor that would be more natural to ride.
I don't understand why Tongsheng don't fix this issue, they are selling a new variant the TSDZ2B that was a good opportunity to solve this problem.

 

[Joakim]

Looking at google search it seems the axle breaking is very rare, almost only find the fatbike axle thread from this forum.

 

[rcaridade]

Does anybody knows If there is a 250W/350W/500W system with TSDZ2B, when I look for spare parts, only see the 36V motor and 36V controller, seems that the W is only by software limitation, is this right? Even the prices are the same all 36V cost the same and 48V also.
So does it mean that I can buy a 36V 350W and the using the community OpenSource firmware to specify the amount of Watts that I want regardless the system bought?

 

[Elinx]

....
So does it mean that I can buy a 36V 350W and the using the community OpenSource firmware to specify the amount of Watts that I want regardless the system bought?

Mechanical and electronical all Tsdz2(b) systems are exactly the same.
Only difference is the bare motor, that could be 36V-4000RPM or 48V-4000RPM
Because of these 2 motors the firmware of the controller is different too.
With OSF you can choose which motor you have and a lot of other settings.

Breaking the axle has to do with the weak circlip grooves on both sides of the axle.
Adding extra bearings, instead of the rubber dustseals, will support these grooves on both sides.
This could help to prevent early breaking.

 

[rcaridade]

Mechanical and electronical all Tsdz2(b) systems are exactly the same.
Only difference is the bare motor, that could be 36V-4000RPM or 48V-4000RPM
Because of these 2 motors the firmware of the controller is different too.
With OSF you can choose which motor you have.

Breaking the axle has to do with the weak circlip grooves on both sides of the axle.
Adding extra bearings, instead of the rubber dustseals, will support these grooves on both sides.
This could help to prevent early breaking.

So, do you think that buying a TSDZ2B 350W flashing on it the new open source firmware is going to make this motor powerful enough to use it on an XC Cannondale RZ120 and climb stepe hills and mountain XC trails with a more natural feeling that on a Bafang 36V 500W with only a cadence sensor? Is it a good motor to spend €245?

 

[scianiac]

The axle issue is partially one of use, if you weight 250lbs and are going off drops probably not a good idea, if you weight 130lbs and don't do drops or jumps is much more reasonable. Same with use on a hard tail or FS bike.

So, do you think that buying a TSDZ2B 350W flashing on it the new open source firmware is going to make this motor powerful enough to use it on an XC Cannondale RZ120 and climb stepe hills and mountain XC trails with a more natural feeling that on a Bafang 36V 500W with only a cadence sensor? Is it a good motor to spend €245?

Climbing super steep hills is one of my favorite things and so far after the proper setup my TSDZ2 has been great but there are some things to consider. My setup is OSF max current settings 52V battery 48V motor with heatsink plate, bike has 29in wheels with a 30T chain ring and a 46T cassette. With that setup I can climb extremely steep climbs basically at the limits of rear wheel traction (rear tire is pretty aggressive with low tire pressure and reversed direction) and even pedal in a very controllable way while doing so (at least to the limits of my skill in balancing). That being said that super low gearing is important to do so due to power and torque limitations.

I would say if you want a natural assist feeling and are going to be pedaling the TSDZ2B with OSF (make sure you drive you get can be flashed to OSF as I think there are some from one source that cannot) is not a bad option especially on a tight budget (although a photon or tosevens should be better performance wise but we just don't know much about them, they are just too new). The other option would be a higher power controller for your BBS and a better throttle setup so you can pedal and control the power with the throttle at the same time, this solution would be more powerful, probably a little cheaper but worse for pedaling. Honestly it wouldn't hurt to try a better throttle setup and see how you like it, can always install it on the TSDZ2B later.

 

[rcaridade]

The axle issue is partially one of use, if you weight 250lbs and are going off drops probably not a good idea, if you weight 130lbs and don't do drops or jumps is much more reasonable. Same with use on a hard tail or FS bike.


Climbing super steep hills is one of my favorite things and so far after the proper setup my TSDZ2 has been great but there are some things to consider. My setup is OSF max current settings 52V battery 48V motor with heatsink plate, bike has 29in wheels with a 30T chain ring and a 46T cassette. With that setup I can climb extremely steep climbs basically at the limits of rear wheel traction (rear tire is pretty aggressive with low tire pressure and reversed direction) and even pedal in a very controllable way while doing so (at least to the limits of my skill in balancing). That being said that super low gearing is important to do so due to power and torque limitations.

I would say if you want a natural assist feeling and are going to be pedaling the TSDZ2B with OSF (make sure you drive you get can be flashed to OSF as I think there are some from one source that cannot) is not a bad option especially on a tight budget (although a photon or tosevens should be better performance wise but we just don't know much about them, they are just too new). The other option would be a higher power controller for your BBS and a better throttle setup so you can pedal and control the power with the throttle at the same time, this solution would be more powerful, probably a little cheaper but worse for pedaling. Honestly it wouldn't hurt to try a better throttle setup and see how you like it, can always install it on the TSDZ2B later.

Just one note, 52V or 36V doesn't matter, in the end, what matters is the wattage, if for your build as:

• Motor rated 52V 750W and battery with a battery 52V 14,4A +-750Wh, number of cells = 14S x 5P = 70, more weight
• Motor rated 36V 750W and battery with a battery 36V 20,8A +-750Wh, number of cells = 10S x 6P = 60, less weight

Both systems provide the same power and capacity.

 

[Elinx]

Just one note, 52V or 36V doesn't matter, in the end, what matters is the wattage, ....

Yes, but I would prefer a higher Voltage and lower current, because that could benefit the distribution of energy to motion and (lesser) heat.

Also that way you stay under the current limit of the controller. (ca.20A)

 

[rcaridade]

Yes, but I would prefer a higher Voltage and lower current, because that could benefit the distribution of energy to motion and (lesser) heat.

Also that way you stay under the current limit of the controller. (ca.20A)

Agree, but the diference from 36V to 48V is minimal, only 5A in diference. I personally prefer 36V because the battery is cheeper, lighter and I have several . But I understand that most of all main manufactures of eBikes use at least 48V.

 

[scianiac]

The battery voltage and motor wind does very much matter, the TSDZ2 has a hard coded battery current limit of 18A so the same current at a higher voltage will mean more peak power (when battery current limited). And perhaps more importantly a higher voltage with the same motor wind will have a higher RPM which is important for cadence match but also means you can pull more power at a given RPM. (when phase current limited and it shifts the RPM curve over)

 

[rcaridade]

The battery voltage and motor wind does very much matter, the TSDZ2 has a hard coded battery current limit of 18A so the same current at a higher voltage will mean more peak power (when battery current limited). And perhaps more importantly a higher voltage with the same motor wind will have a higher RPM which is important for cadence match but also means you can pull more power at a given RPM. (when phase current limited and it shifts the RPM curve over)

In the case of the TSDZ2 both 36V and 48V according to you are both limited to 18A, so, from that limitation you get on a 36V nominal - 648W (42V full charge - 756W) and on a 48V nominal - 864W (54,6V full charge - 983W).
Then I don't understand why are they rating their motors 36V 250W/350W and 48V 500W/750W if the limitation on the controller/motor for both voltages is 18A and with that a much higher wattage.
And if both are rated 80 Nm and 4000 RPM, what is the advantage of having 36V 648W and 48V 864W to get the same torque and RPM?
I'm confused with all this values that don't make any sense, something is not clear on the specs of something.

 

[Elinx]

.... are both limited to 18A, ....
Then I don't understand why are they rating their motors 36V 250W/350W and 48V 500W/750W if the limitation on the controller/motor for both voltages is 18A and with that a much higher wattage.
...

The given motor power is always a nominal value.
Meaning the temperature rise is minimal for more than an hour with that power and battery Voltage.
This value you can't calculate that easy, because this has to do with the characteristics from the coils and rotor of the motor.
You only does calculate the max. power which is possible with 18A limit for the given battery Voltage.

 

[scianiac]

And that max power is only possible under some conditions, at higher RPMs the back EMF will be too high to draw at much current, which is why higher voltage and a faster wind motor (the 36V is a faster wind than the 48V) allows more power to be drawn at higher RPMs by countering the back EMF. Similarly at low RPM the motor will be phase current limited an not battery current limited.

This relates to what I was saying before about how in reality to get a good consistent power feeling one aspect is to have the motor, controller, and battery be able to provide that power across a wide RPM range which often means it will be capable of a lot more max power too. Put simply, the TSDZ2 feels like it has consistent power when operated at lower power levels but at higher power levels the power band is rather narrow and requires careful gear selection.

Maybe a good estimate would be if you want to use less power as the BBS in pedal assist the TSDZ2 is not a bad choice but if you want any more power it won't be. The best feeling control is having more power than you need more of the time but that depends on how much you need/want to be using.