Well not eMTB I have 2 hybrids

Saracen

Esteemed Pedelecer
Aug 24, 2023
497
51
Basic question please

If the motor is rated at 80Nm (Bafang BS01) (ant motor really), is it ALWAYS 80-90 70-65Nm, if so what does the +- adjustments on the controller actually do, does going from say 1-2-3-4-5-6-7-8-9 increase/decrease the "voltage" to the motor, does it adjust the Nm, or what.

Many thanks
 

Attachments

guerney

Esteemed Pedelecer
Sep 7, 2021
10,697
3,079
We can't know what assistance your levels 1 to 9 have been programmed to provide, without looking at the firmware parameters of your controller's firmware. We also don't know what your controller's amperage limit is. Read all this:



Volts X Amps = Watts

...therefore, the firmware parameters of the motor controller below, have been set to provide a percentage of the controller amperage limit for each level, for up to 100% of the speed limit for each level:





How much of that power is maintained after the short initial part of the pedal assistance has happened, is called "Keep current", which you can also set, if you buy a programming cable, and install the free Windows program or Android app. In this example, "Keep current" is 80%





This motor's amperage limit has been set to 18A, therefore in this example at level 1, 10% of 18A = 1.8A

18A X 36V = 64.8W is provided initially, after which assistance lowered to 80% of 1.8A.

((1.8/100) X 80) X 36 = 51.84W
 
Last edited:

Voltsnamps

Pedelecer
Aug 27, 2023
54
7
Basic question please

If the motor is rated at 80Nm (Bafang BS01) (ant motor really), is it ALWAYS 80-90 70-65Nm, if so what does the +- adjustments on the controller actually do, does going from say 1-2-3-4-5-6-7-8-9 increase/decrease the "voltage" to the motor, does it adjust the Nm, or what.

Many thanks
Not a basic question at all
Short answer, no, 80nm is 59lb/ft in English, about what you’d get from a 1970’s 1000cc twin cylinder motorcycle engine.
Your buttons control input current and therefore input watts as explained above, with the proviso that your 10S (36v nominal) battery almost never IS 36v. Fully charged at 42 , will start to miss at low voltage cutout, perhaps 30v. Simple maths 18 x 30 = 540 watts, 18x42 = 756, big difference.
All my Bafang displays (speedo thing) show input watts, if yours doesn’t it may be worth buying one that does, it is a true energy consumption reading, , the less watts you use, the further you can go on your battery.
Output torque is another story altogether, read up on Tesla tech or High Voltage ebike tuning, so many variables, from motor design and /or condition to gearing and power losses.
It could be another Volkswagongate, the 250watt thing was meant to be output (about a third of one horsepower), actually still is in some parts of the world.
But nobody said where to measure it, at motor, pedal crank, wheel ?
It has since morphed into “nominal” or “ continuous”, or better yet, “rated by manufacturer “
Obviously the big manufacturers have cottoned on to this, Bosch motors have made massive gains in torque whilst still claiming 250 output watts rated.Mathematically difficult to explain.
Worse still, loads of stuff on the net about how to make the most powerful “legal” ebike !
Make of this what you will but don’t expect to put your bbs01 on a motorcycle dyno and make 80 NM, ever
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
5,170
2,501
Telford
Basic question please

If the motor is rated at 80Nm (Bafang BS01) (ant motor really), is it ALWAYS 80-90 70-65Nm, if so what does the +- adjustments on the controller actually do, does going from say 1-2-3-4-5-6-7-8-9 increase/decrease the "voltage" to the motor, does it adjust the Nm, or what.

Many thanks
Any torque figures given are fictitious. The torque changes with your gearing, and they have no idea what gearing you have. The value is based on an arbitrary value estimated about 12 years ago.

The reason they give a torque figure is because they dare not give the power because people would go nuts when they see how much power the motor gives above 250w.

With a crank motor, the only thing that counts is the power, which is a result of the volts and amps going into it. It has an efficiency of about 70%, so the power you get is 0.7 x volts x amps. You control the amps with the throttle or LCD setting.

Torque = power ÷ turning speed (radians per second) to convert from rpm to rads/sec, you multiply by 0.10472. So whatever power you give the motor, you can figure out how much torque you have at the back wheel, provided the motor is turning in its efficient range of about 90 rpm +/- 20 rpm.

As an example. You have a half-charged 36v battery and a 15 amp controller set to maximum assist. The power given by the motor would be 0.7 ×36×15 = 378w. A 26" back wheel turns at 201 rpm at 15 mph, so the torque would be 378÷(201 x .10472) = 17.96 nm.
When climbing a steep hill at 7.5 mph in a low gear, you'd get double the torque - 35.92nm, and if you had really low gearing to keep the cranks turning at 70 rpm, while climbing at 3.75 mph, you'd get 72nm of torque.

If you have a 29" back wheel you need lower gearing to pedal at the above speeds, the torque would be 11% higher, which sounds a bit weird. You don't get more torque by using a bigger wheel, it's the lower gearing that gives it. The driving force up the hill is the same whatever sized wheel you have, provided the gearing is appropriate to the wheel size.

In summary, if you want more torque with a crank motor, one way is to increase the volts, another is to increase the amps, and the third is to use lower gearing. You choose the motor according to how durable it is to handle the volts and amps you want to give it. Any torque figures they give are meaningless, except that they might be a clue to how much power the motor should be able to handle.
 
Last edited:

saneagle

Esteemed Pedelecer
Oct 10, 2010
5,170
2,501
Telford
Another way of looking at it is the torque at the chainwheel. If your motor has a half-charged 36v battery and controller set to 15A max, the power output would be about 0.7 x 15x36= 378w. The rotation speed would be around 70 rpm when climbing, so output torque would be 378÷70÷.10742=51nm. if you were to increase the current to 18A, the torque would be 61nm.

The problem is that the motor can't run at those maximums for long. Maybe when the manufacturers give a torque figure, it's a torque that the motor can sustain without overheating, so a 30nm motor would be 8.8 amps at 36v, 40nm would be 11.7A, and 60Nm would be 17.6A.

The other way round, when Bosch says their motor is 90nm, we can calculate that it needs 26.5A. I can't seeing it doing that current continuously, so either the torque figure is a made up number or converted with some standard for gearing or it's a peak torque that can't be sustained.
 

Voltsnamps

Pedelecer
Aug 27, 2023
54
7
Another way of looking at it is

The other way round, when Bosch says their motor is 90nm, we can calculate that it needs 26.5A. I can't seeing it doing that current continuously, so either the torque figure is a made up number or converted with some standard for gearing or it's a peak torque that can't be sustained.
Or, they are rightfully bragging
Ebikegate, anyone?
 

Az.

Esteemed Pedelecer
Apr 27, 2022
1,587
702
Plymouth
Touche’ mon ami
What I find interesting is that certain manufacturers are ready to play the game and will basically put on motor any label you want while some manufacturers stick to rules of common sense and are at disadvantage.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
5,170
2,501
Telford
What I find interesting is that certain manufacturers are ready to play the game and will basically put on motor any label you want while some manufacturers stick to rules of common sense and are at disadvantage.
Can you give examples of a common sense one at a disadvantage and one that puts any label on?

Remember the 24v 12 Amp E-bike Plus folder is 250w and so is the 85nm Bosch, and so was the 40nm Bosch, and what about the Woosh TSDZ8 with 110nm? All those motors comply with EN15194, so are completely legal.

I think you're still misunderstanding what the law is despite being told many times. Maybe we can clarify it for you when you give examples.
 

Az.

Esteemed Pedelecer
Apr 27, 2022
1,587
702
Plymouth
Can you give examples of a common sense one at a disadvantage and one that puts any label on?
Tongsheng is willing to put legal 250W labels on their 500W and 750W motors.
Grin Technologies will even engrave required number on motor if you ask them and pay for it.

I don't think Bafang or Toseven are doing that with their mid drives, which puts them (and us) at disadvantage, because many of their motors are sold as illegal in EU an UK. At least I haven't seen any relabeled Bafang mid drive motors for sale. Have you?

and what about the Woosh TSDZ8 with 110nm? All those motors comply with EN15194, so are completely legal.
What about it? It is the same motor which PSW sells for £240, only label is different.
 
Last edited:

saneagle

Esteemed Pedelecer
Oct 10, 2010
5,170
2,501
Telford
Tongsheng is willing to put legal 250W labels on their 500W and 750W motors.
Grin Technologies will even engrave required number on motor if you ask them and pay for it.

I don't think Bafang or Toseven are doing that with their mid drives, which puts them (and us) at disadvantage, because many of their motors are sold as illegal in EU an UK. At least I haven't seen any relabeled Bafang mid drive motors for sale. Have you?



What about it? It is the same motor which PSW sells for £240, only label is different.
To be legal, the motor only has to pass the 250w rating test. That's what's written in EN15194. Whatever you think should be written in that standard is irrelevant. Nobody has an advantage or disadvantage. The same EN15194 applies to all of them. If someone can't understand the requirements, that's their own fault. It's very clear what the requirements are when you read it.

The motor is legal if the manufacturer puts a 250w label on it to show that it passes the 250w rating test. When they sell in other markets, they might want to make it look more by putting a 500w label on it The only thing important about the motor is how much power it can actually handle. A motor that's rated as 1000w passes the test for 500w and 250w, but a motor that's rated at 250w wouldn't necessarily pass the 1000w test.

Motors don't need to be relabeled when the manufacturer puts a 250w label on it in the first place. If you want a 250w legal motor, buy one with a 250w label on it that gives the power you want. I don't see what the problem is. You can buy motors from Bafang, Tongsheng, Bosch, Grin and many more that have 250w labels on them and they provide all the power you need.
 

Az.

Esteemed Pedelecer
Apr 27, 2022
1,587
702
Plymouth
To be legal, the motor only has to pass the 250w rating test. That's what's written in EN15194. Whatever you think should be written in that standard is irrelevant. Nobody has an advantage or disadvantage. The same EN15194 applies to all of them. If someone can't understand the requirements, that's their own fault. It's very clear what the requirements are when you read it.
Thank you for explaining it once again, but I think it is you who don't understand why people are coming back to this subject.

Ordinary people are finding it hard to understand why motor with 750W label in one shop costs £230 and is illegal while in another shop the same motor has 250W label, is legal and costs £380.

Motors don't need to be relabeled when the manufacturer puts a 250w label on it in the first place. If you want a 250w legal motor, buy one with a 250w label on it that gives the power you want. I don't see what the problem is. You can buy motors from Bafang, Tongsheng, Bosch, Grin and many more that have 250w labels on them and they provide all the power you need.
and that is the reason why I bought legal TSDZ8 from Woosh.

As a millionaire you don't see the problem, but people quite rightfully are asking why they have to pay £150 extra for label only or £300 extra for bike with approved throttle. That is what Voltsanamps meant by ebikegate... IMHO.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
5,170
2,501
Telford
Thank you for explaining it once again, but I think it is you who don't understand why people are coming back to this subject.

Ordinary people are finding it hard to understand why motor with 750W label in one shop costs £230 and is illegal while in another shop the same motor has 250W label, is legal and costs £380.



and that is the reason why I bought legal TSDZ8 from Woosh.

As a millionaire you don't see the problem, but people quite rightfully are asking why they have to pay £150 extra for label only or £300 extra for bike with approved throttle. That is what Voltsanamps meant by ebikegate... IMHO.
All throttles are completely legal and nobody charges extra, except for the few quid to supply the throttle. The £300 extra is to get approval for the bike when you want to use the throttle for what they call " twist and go" function, which means operation without pedalling up to 15.5 mph.

If Woosh want to charge extra and make more profit because they've ordered something that other suppliers are too lazy to organise, that's up to them. If you don't like it, tell Woosh not to make so much profit from you.
 

Voltsnamps

Pedelecer
Aug 27, 2023
54
7
Thank you for explaining it once again, but I think it is you who don't understand why people are coming back to this subject.

Ordinary people are finding it hard to understand why motor with 750W label in one shop costs £230 and is illegal while in another shop the same motor has 250W label, is legal and costs £380.



and that is the reason why I bought legal TSDZ8 from Woosh.

As a millionaire you don't see the problem, but people quite rightfully are asking why they have to pay £150 extra for label only or £300 extra for bike with approved throttle. That is what Voltsanamps meant by ebikegate... IMHO.
 

Voltsnamps

Pedelecer
Aug 27, 2023
54
7
Au contraire
I have no issue with Woosh charging for a sticker, actually I’d do the same, you are paying for his back up (both as sales receipt to prove your innocence and his advice and aftersales service), no-one can work for free.
More importantly, consumers have the choice, I’ll admit to buying (all but my first) motors and batteries direct from China but I’d have no hesitation in suggesting Woosh Tong Shen to my friends in UK. No waiting AND a man on the phone.
My beef is with the Bosch
I just got this from their website, it carefully explains that if you pay more for a higher spec (torque rated) motor, you don’t have to peddle as fast. So the higher rated motor gives you more assistance at normal cadence, whodathunk it?
Not a mention of more watts, so there can’t be, totally legal, but how far can they push it ? Next year’s model will be better, ad infinitum, 200 NM legal 250 watt ebikes by 2030 ?
Active Line



Back
How are torque and cadence related to power?
Torque, together with cadence, is a component of power. If you compare two drive units with the same maximum power and different maximum torque, you will see that maximum power is achieved with the motor with the higher torque at a lower cadence. Conversely, this means that to achieve the maximum power of the motor with the lower torque, you need to pedal faster.
 

Az.

Esteemed Pedelecer
Apr 27, 2022
1,587
702
Plymouth
Not a mention of more watts, so there can’t be, totally legal, but how far can they push it ?
Why can't be legal? Bosh is a manufacturer, so they can put the right sticker on any of their motors.

Higher torque can be achieved only by extra volts or amps.
 

Voltsnamps

Pedelecer
Aug 27, 2023
54
7
So
Why can't be legal? Bosh is a manufacturer, so they can put the right sticker on any of their motors.

Higher torque can be achieved only by extra volts or amps.
So perhaps Mr Edison said, cunning technology seems to have moved the goalposts. Even the formaluae and theories.
 

Related Articles

Advertisers