Common rider inflicted motor failures

[wrayb]

If I am riding my restricted 2019 Comp Carbon Levo at 100% power 100% assist setting...when I am pedaling the Levo the controller is drawing the maximum voltage from the battery...say 200W...regardless of whether my speed is 5mph, 10mph, etc. until I am able to pedal to 20mph...at 20mph the controller switches off all current to the motor. The only difference for a de-restricted bike is this switch isn't activated. If the de-restricted bike is at 25mph or faster the controller is still drawing the same 200W from the battery. De-restricting doesn't increase the draw over 200W...it just allows it to continue past 20mph. My point or question is how is de-restricting changing anything? If the trail conditions don't allow me to go over 20mph I am continously drawing the same 200W from the battery so the output of the motor is still the same as a de-restricted bike going over 20mph. How is pedaling at 50mph for 2 hours on a de-restricted bike different from pedaling up a steep incline for 2 hours on a restricted bike? Or...why would drawing 200W at 50mph be any different from drawing 200W at 10mph?

And...why would anyone ride a Levo that fast for very long anyway? It is an off-road bike. Designed for riding rough, challenging terrain not a nice paved highway.

 

[wrayb]

The motor and rider are however working a gainst gravity and rider/bike weight so revs at the crank will still be relatively slow and not sustained at a high rate unless of course the rider is a super human! Under those circumstances the motor may be working hard but revolutions still quite low.

The rider can still maintain a high cadence as long as he can shift to a big enough cog on the cassette. Spinning.

And at high speeds isn't the aero drag limiting the rider from going any faster affecting the rider the same as gravity on the rider climbing?

 

[beutelfuchs]

I am now seeing a few older Levos coming through for repairs that are out of warranty.
These are the three biggest causes of motor failures that could have been prevented.

Thanks for all the warnings!

One thing regarding Blevo: I used it once to try the smart power feature (regulates motor assistance level according to your current pedal input). I didn't tamper with any speed or circumference settings.
Could you also detect that to void my warranty? Or does it only say if the speed limit was increased? WHat can you read out exactly? Thank you!

 

[GrahamPaul]

It does.
Power is torque × velocity.
Imagine you tune your bike to allow it to have assistance at 32km/h rather than 25km/h (by using something to fool the stock speed sensor). Comparing the 2 configurations, the motor will put out the same torque at both speed. But the deristrected bike will have a 50% greater velocity, and by the formula above, it put out more power.

You've lost me here. I did my 3-phase electric motor theory courses a half century ago and happily forgot just about everything straight away. That imaginary "i" was just too much for my poor brain.

However, some things relating to single phase motors did stick. Isn't the quoted power of an electric motor defined by its current draw multiplied by its voltage? Then the torque of the motor is defined by that power value divided by the quoted rotational velocity of the motor? The velocity of the final driven item is defined by the gearbox. (I've spent my life designing foundations and structures restraining motors and generators, so I'd better not have misunderstood this!)

The motor is not putting out more power. That is an impossibility.

(That said, the start-up phase of an electric motor often has a higher current draw and a higher torque than the quoted figures. But that would mean that a motor would be expected to wear/break quicker with more frequent stop/starts than with running at maximum velocity. But that's not your thesis).

 

[wrayb]

Isn't the quoted power of an electric motor defined by its current draw multiplied by its voltage? Then the torque of the motor is defined by that power value divided by the quoted rotational velocity of the motor? The velocity of the final driven item is defined by the gearbox. (I've spent my life designing foundations and structures restraining motors and generators, so I'd better not have misunderstood this!)

The motor is not putting out more power. That is an impossibility.

I have not studied mechanical engineering (I do have many graduate classes in industrial engineering however)...but what GrahamPaul posted seems spot on to me.

Maybe the issue is with the word "power". The power I was trying to ask about is the output of ONLY the motor (horsepower). GrandesRoues, when you refer to the "power" are you looking at a measure of final power of the system? I can certainly see drawing 200W from the motor with the bike's velocity at 50mph is more total or "system power" than drawing 200W at 5mph. However in both cases the horsepower of the motor is still the same. And...if de-restricting does not increase the horsepower of the motor I am back to my original question...how is de-restricting causing motor failures?

 

[Spagnol]

Isn't the quoted power of an electric motor defined by its current draw multiplied by its voltage? Then the torque of the motor is defined by that power value divided by the quoted rotational velocity of the motor? The velocity of the final driven item is defined by the gearbox. (I've spent my life designing foundations and structures restraining motors and generators, so I'd better not have misunderstood this!)

The motor is not putting out more power. That is an impossibility.

I have not studied mechanical engineering (I do have many graduate classes in industrial engineering however)...but what GrahamPaul posted seems spot on to me.

Maybe the issue is with the word "power". The power I was trying to ask about is the output of ONLY the motor (horsepower). GrandesRoues, when you refer to the "power" are you looking at a measure of final power of the system? I can certainly see drawing 200W from the motor with the bike's velocity at 50mph is more total or "system power" than drawing 200W at 5mph. However in both cases the horsepower of the motor is still the same. And...if de-restricting does not increase the horsepower of the motor I am back to my original question...how is de-restricting causing motor failures?

Speed have nothing to do with power ... RPM ( cadence in our case ) does ... "power" is the result of torque x RPM ...

Derestricting the motor can not cause failure by itself , but can accelerate it ... that's it.

 

[GrahamPaul]

Speed have nothing to do with power ... RPM ( cadence in our case ) does ... "power" is the result of torque x RPM ...

Derestricting the motor can not cause failure by itself , but can accelerate it ... that's it.

Not mathematically correct. RPM is a measure of rotations per minute. Power is not torque multiplied by RPM. The dimensional units of measurement would be all fucked up. That's why I did not refer to RPM or cadence.

 

[wrayb]

Derestricting the motor can not cause failure by itself , but can accelerate it

That's my question...how does it "accelerate" motor failure?

 

[Spagnol]

Speed have nothing to do with power ... RPM ( cadence in our case ) does ... "power" is the result of torque x RPM ...

Derestricting the motor can not cause failure by itself , but can accelerate it ... that's it.

Not mathematically correct. RPM is a measure of rotations per minute. Power is not torque multiplied by RPM. The dimensional units of measurement would be all fucked up. That's why I did not refer to RPM or cadence.

This is how horsepower are measured in any engine I know .... an engine produces power by providing a rotating shaft, which can exert a given amount of torque on a load, at a given RPM . I do believe the internal RPM are related to the cadence of the rider , the cadence of the rider and the internal RPM are independent of bikes speed .

Am I losing something ?

 

[Spagnol]

Derestricting the motor can not cause failure by itself , but can accelerate it

That's my question...how does it "accelerate" motor failure?

The engine will be in use more time , this is theoretically as maybe you do not pedal on downhill , or you do not pedal over 25 ... but if you don't do it ... why derestrict the engine ?

 

[GrahamPaul]

This is how horsepower are measured in any engine I know .... an engine produces power by providing a rotating shaft, which can exert a given amount of torque on a load, at a given RPM . I do believe the internal RPM are related to the cadence of the rider , the cadence of the rider and the internal RPM are independent of bikes speed .

Am I losing something ?

You are used to seeing graphs of rpm versus motor torque - especially for internal combustion engines. Torque is related to rpm, and is how you get to find the power band on your motorbike or your performance car.

However, power is not defined as torque multiplied by RPM. Easily proved by 70Nm torque on, for example, a Bosch motor, multiplied by a cadence of 80 rpm, which would give you a power of 5600W. At 5 rpm your power output would be 350W.

Obvious nonsense!

Electric motor performance curves are totally different to ICE motors. I'll leave that to any passing electrical engineer to explain. Beyond the basic maths that's way outside my competence.

 

[wrayb]

The engine will be in use more time , this is theoretically as maybe you do not pedal on downhill , or you do not pedal over 25 ... but if you don't do it ... why derestrict the engine ?

How is the motor used more when a bike is de-restricted? If I am riding my non-restricted bike on difficult trails (what the Levo is designed to do) at < 20mph on 100% 100% I am using my motor just as much.

 

[Spagnol]

This is how horsepower are measured in any engine I know .... an engine produces power by providing a rotating shaft, which can exert a given amount of torque on a load, at a given RPM . I do believe the internal RPM are related to the cadence of the rider , the cadence of the rider and the internal RPM are independent of bikes speed .

Am I losing something ?

You are used to seeing graphs of rpm versus motor torque - especially for internal combustion engines. Torque is related to rpm, and is how you get to find the power band on your motorbike or your performance car.

However, power is not defined as torque multiplied by RPM. Easily proved by 70Nm torque on, for example, a Bosch motor, multiplied by a cadence of 80 rpm, which would give you a power of 5600W. At 5 rpm your power output would be 350W.

Obvious nonsense!

Electric motor performance curves are totally different to ICE motors. I'll leave that to any passing electrical engineer to explain. Beyond the basic maths that's way outside my competence.

Yeap, I do believe though that internal RPM is really different from cadence , I know they are related ( the internal RPM decrease or increase due to rider input ) but for sure different .

I will take a look on how the power / torque is related on electrical engines for curiosity

 

[GrahamPaul]

How is the motor used more when a bike is de-restricted? If I am riding my non-restricted bike on difficult trails (what the Levo is designed to do) at < 20mph on 100% 100% I am using my motor just as much.

Why is it believed that speed derestriction damages the motor?

 

[Spagnol]

The engine will be in use more time , this is theoretically as maybe you do not pedal on downhill , or you do not pedal over 25 ... but if you don't do it ... why derestrict the engine ?

How is the motor used more when a bike is de-restricted? If I am riding my non-restricted bike on difficult trails (what the Levo is designed to do) at < 20mph on 100% 100% I am using my motor just as much.

Then you should have no problems , but I don't see the sense on derestrict the motor and possibile have a problem with warranty, if you don't use it .

As said before , the only variable I see is the "time use" ... as jerry says , glass is glass , and glass breaks ... I believe any engine that broke unrestricted was already mean to break , it just happened before ( all the buddies I have that derestrict the engine , use it to get more speed on downhill after curves , and speed up on easy terrain ... )

 

[Mikerb]

The question will become irrelevant soon as each manufacturer implements EU regulations to prevent tuning. That is already the case with the Bosch gen 4 motor. Those with no new motor planned will probably implement with firmware updates although I would think an additional chip is also required....so in the case of a Levo replacement motors and/or TCUs may ìnclude the anti tuning circuit.

 

[GrahamPaul]

The question will become irrelevant soon as each manufacturer implements EU regulations to prevent tuning. That is already the case with the Bosch gen 4 motor. Those with no new motor planned will probably implement with firmware updates although I would think an additional chip is also required....so in the case of a Levo replacement motors and/or TCUs may ìnclude the anti tuning circuit.

I guess you are referring to European Standard EN 15194. This is a standard rather than a regulation or law. However, Part 12 does have anti-tampering measures included. Bosch have quite a good argument for this here.

I can fully understand anyone's desire to be able to derestrict their motors. But then just put up with the requirement for helmets, lights, brake lights, registration plates and compulsory insurance. Because, let's face it, what does "derestricted" mean? Surely the "no speed restriction". There are already e-bikes capable of speeds of over 100kph. Why should they be exempt from normal traffic regulations inflicted on the rider of a 50cc moped?

If you want the restriction level raised, that's another matter. But a different conversation.

(Not sure about other countries, but the maximum allowed speed for any bicycle on a public highway here in Spain is 40km/hr).

 

[Slowroller]

Chinese motors seem exempt from any anti tampering measures, just an fyi

 

[wrayb]

I am in this thread for a few reasons:

1) I have had 2 motors go bad on my 2019 Levo and replaced under warranty. I am trying to get info on what is causing these motors to fail. I do not de-restrict my bike but I do ride at 100% 100% for extended time periods (as much as 1 hour). It seems the guys de-restricting are replacing motors too. Is there a problem with going 100% 100% for extended periods? Anyone have an answer for me? Edit: Also...both motors had just over 300 miles when they had problems (km?)...anyone else seeing problems at this mileage?

2) Because I am racing I don't want to be at a horsepower disadvantage if another rider has de-restricted his Levo. I want to be sure what I understand is true, namely de-restricting does not increase the motor's horsepower or torque. I believe most on this forum agree this is true. I do understand the un-restricted bike has an unfair advantage at speeds over 20mph of course.

3) Again because I am racing other Emtbs I am always looking for a legal method of gaining some competitive advantage with the motor. I cannot legally de-restrict (which would be a big advantage on super fast sections) but maybe I can find something else in this forum I can use to increase horsepower and/or torque. Any suggestions? Ideas?

 

[GrahamPaul]

Chinese motors seem exempt from any anti tampering measures, just an fyi

That's because Chinese motors are not sold as bicycles complying with EN 15194. (My point was that there is a misunderstanding between a Regulation and a Standard - and how they fit in with an EU Directive.)

 

[Mikerb]

I guess you are referring to European Standard EN 15194. This is a standard rather than a regulation or law. However, Part 12 does have anti-tampering measures included. Bosch have quite a good argument for this here.

I can fully understand anyone's desire to be able to derestrict their motors. But then just put up with the requirement for helmets, lights, brake lights, registration plates and compulsory insurance. Because, let's face it, what does "derestricted" mean? Surely the "no speed restriction". There are already e-bikes capable of speeds of over 100kph. Why should they be exempt from normal traffic regulations inflicted on the rider of a 50cc moped?

If you want the restriction level raised, that's another matter. But a different conversation.

(Not sure about other countries, but the maximum allowed speed for any bicycle on a public highway here in Spain is 40km/hr).

...yes but conformance with that standard is what enables bike manufacturers to a void going through very expensive type approval processes and is required if the manufacturer wants to legally import/export/sell as pedelecs. They run a risk of being found liable in any court case resulting from consequencial injury or damage if the bike does not conform to the standard ( and therefore the Machinery Directive). The German Cycle industry has taken a particularly strong line on the anti tuning element of that standard which is perhaps why Bosch are the first to implement pro active anti tampering measures in their motors. If the Bosch Gen 4 detects tuning it will put the bike into a "safe mode" ( bit like a car that detects an emissions problem). That is recoverable but 3 strikes and only a LBS can put it right.

 

[Slowroller]

That's because Chinese motors are not sold as bicycles complying with EN 15194. (My point was that there is a misunderstanding between a Regulation and a Standard - and how they fit in with an EU Directive.)

Thankfully, none of that matters outside the EU.

 

[Supratad]

Pulled my battery out last night, just to check if there was any water ingress after mild jet-washing. There wasn't but there was a small amount of mud inside the plastic "bash guard" part at the bottom, the bit with hexagonal plastic thickening bars. Should I be trying to seal this up so wet mud can't get in or is it designed that way to drain out?

 

[Mikerb]

Thats normal and no problem but worth cleaning occasionally. The only feasible way to better protect it...and the battery connection is some form of cover shaped to wrap around the bash guard and fixed with straps or velcro over the top of the motor housing.

 

[Zimmerframe]

Thats normal and no problem but worth cleaning occasionally. The only feasible way to better protect it...and the battery connection is some form of cover shaped to wrap around the bash guard and fixed with straps or velcro over the top of the motor housing.

Or the @Doomanic cling film wrap technique ..

 

[Doomanic]

Shhhh! The patent application is still pending!

 

[KennyB]

I find it a real mud trap and I just take it off lots and clean it all out. Take care with the mounting bolt, it's just 2Nm, screwdriver tight. Specialized warn that over tightening is the most common cause of a cracked bash guard. And be careful not to lose the wee washer. I wouldn't be too keen on any sort of cover, Murphy's Law is clear on this point, if you make it hard for water and mud to get in, it's hard for them to get out. I find that a smear of silicone grease round the battery connector seal keeps it dry.

 

[Supratad]

Hmmm, what wee washer?

 

[KennyB]

Hmmm, what wee washer?

It's under the bolt head and usually comes off with the bolt. It's such a good colour and size match I didn't know it was there until it slid part way down the bolt.

 

[Mikerb]

I find it a real mud trap and I just take it off lots and clean it all out. Take care with the mounting bolt, it's just 2Nm, screwdriver tight. Specialized warn that over tightening is the most common cause of a cracked bash guard. And be careful not to lose the wee washer. I wouldn't be too keen on any sort of cover, Murphy's Law is clear on this point, if you make it hard for water and mud to get in, it's hard for them to get out. I find that a smear of silicone grease round the battery connector seal keeps it dry.

Yep I do the same and also lube the o ring with liquid silicone. It is also worth pushing some grease into the hollow battery fixing brass screw. It prevents dust and grit migrating via the hole to the threads.
I would think an airtight seal like clingfilm could cause sweating. Something like neoprene would be better.