Speed and range on a climb

[pagheca]

In your opinion, if on a steep climb one pedals faster or slower, does the range change or does it stay about the same? Obviously with the same setting.

My reasoning is this: I have noticed that if I pedal harder uphill (i.e., when much of the energy is spent against gravity, not to overcome friction, especially aerodynamic friction, which has little effect on energy consumption in low-speed ebikes), the motor puts more power into it, but it takes you less to travel the same distance. In the end, the result is more or less the same.

It seems to me that at low, constant speeds, the percentage of power the bike adds to mine is always the same, so in the end the range remains the same. For those good at Physics:

Energy [kWh] = Power [kw] x time [h]= (k x speed) x (distance / speed) = k [kWh / km] x distance [km]

It's a discussion I've had a myriad of times with my ebike mate that may seem academic, but it isn't because from the anwer depends on whether to increase the range on large gradients it is worth pushing more or not.

 

[JerryB]

85%of people in America don't know basic math.​

Thanks God I'm from the other 25%

 

[James340]

My DD hub motor uses 150 watts to go 15 mph& uses 500 watts to go 25 mph.

 

[pagheca]

thanks but this doesn't apply to this context.

 

[James340]

I was bringing attention to how speed/load increases power/battery consumption

 

[pagheca]

I was bringing attention to how speed/load increases power/battery consumption

Is interesting that according to the thumb rule:

Theory: (15/25)^2 = 36%
Practice: 150/500 = 30%

in quite good agreement.

 

[munirider]

I couldn't say, I haven't ridden enough to notice something like that. I would think someone with the same daily commute would be a better judge, riding the same route day after day then making changes to how hard you pedal and compare the difference in range.

Definitely what James 340 said. it's so much less efficient to go fast. I have a small battery on my full suspension e-bike 52V 10Ah I can burn through it in a very short time if I'm riding fast especially uphill. When I go slow which is most of the time with Biscuit along for the ride, I can go three or four days and 30+ mi on a charge.

Obviously when going up a hill your pedal input is less by percentage than when riding at a slower speed on the flats. If on the flats your motor is using 50W and you are pedaling the equivalent of 50W you are providing half the power. But if you are going up a steep hill and your motor is using 500W and you are still only putting out 50W now you are only adding 10%. If you were to pedal harder than that say 75W adding another 25W isn't going to make that much difference on your total range.

 

[James340]

I have a MTB that I use maximum assists and it has 2 batteries because of the battery drain.I have a Hybrid that I only use the motor to escape dogs and trucks and in 6 months have only charged the battery twice.It is a DD hub motor so it makes .1 volt per 4 miles

 

[pagheca]

as soon as I will be able to ride again (I am currently recovering from a simple surgery but the doctor told me to avoid riding until a control visit in January) I will try a well designed road drive to test my theory...

 

[ronaldsauve]

In your opinion, if on a steep climb one pedals faster or slower, does the range change or does it stay about the same? Obviously with the same setting.

My reasoning is this: I have noticed that if I pedal harder uphill (i.e., when much of the energy is spent against gravity, not to overcome friction, especially aerodynamic friction, which has little effect on energy consumption in low-speed ebikes), the motor puts more power into it, but it takes you less to travel the same distance. In the end, the result is more or less the same.

It seems to me that at low, constant speeds, the percentage of power the bike adds to mine is always the same, so in the end the range remains the same. For those good at Physics:

Energy [kWh] = Power [kw] x time [h]= (k x speed) x (distance / speed) = k [kWh / km] x distance [km]

It's a discussion I've had a myriad of times with my ebike mate that may seem academic, but it isn't because from the anwer depends on whether to increase the range on large gradients it is worth pushing more or not.

It depends on whether you have a cadence sensor or a torque sensor. The cadence sensor is either on or off, so if you pedal harder it shouldn’t make any difference. if you have a torque sensor the amount of work it does for you varies depending on how much effort you’re putting into it, so while pushing harder on a hill you will likely use more range. However, because a torque sensor isn’t on or off, and is only giving you assistance based on the effort you are putting in, overall you will likely use less range overall. So torque sensors are much more economical overall in their use of battery, and thus range. On top of that they are give a more natural feeling bike, like an acoustic bike.

 

[pagheca]

Thank you. Very interesting!

Based on what you wrote, I would say that the Trek Powerfly 7 I own has a torque sensor because the power is continuously modulated as I pedal (I can see this on my Kiox monitor).

However, I do not understand why the cadence sensor should only be on or off. It just counts the pedal turns per time unit, am I wrong? So it should be easy to use the information to modulate the power.

I have searched the internet to find out more details, but companies are very secretive about the technology they use...

 

[munirider]

You are right about that, cadence sensors aren't either on or off, cadence sensing increases power if you pedal faster, where as torque sensing increases power when you pedal harder.

 

[ronaldsauve]

Thank you. Very interesting!

Based on what you wrote, I would say that the Trek Powerfly 7 I own has a torque sensor because the power is continuously modulated as I pedal (I can see this on my Kiox monitor).

However, I do not understand why the cadence sensor should only be on or off. It just counts the pedal turns per time unit, am I wrong? So it should be easy to use the information to modulate the power.

I have searched the internet to find out more details, but companies are very secretive about the technology they use...

What I mean by cadence sensor being on or off, is that as soon as you start pedaling, (actually typically within a rotation or two), it applies power. But that only changes according to how fast your cadence, or rotational rpm is, not according to the power you personally input onto your pedals, so the actual power you receive is constant, until it cuts off when you reach the speed in each PAS level where the power stops being applied. The speed in each PAS level where power stops with a cadence sensor often is set by the supplier of the system. So, for example, a cadence sensor bike might stop supplying power in PAS 1 at 7 mph, in PAS 2 at 10 mph, in PAS 3 at 13 mph, in PAS 4 at 17 mph, and PAS 5 at 20 mph. Of course, this will be different with each bike and manufacturer according to how they have set their system up, so this is just an example, and for this example, for a class 1 or 2 bike that is limited to 20 mph. However, it does not work like a torque sensor, which increases the applied power received from your battery and motor according to how much power you personally input onto your pedals. So, in theory only, you could hypothetically keep applying power in PAS 1 and your lowest gear indefinitely up to the bike’s maximum speed, although this would not be practical in a real world sense, because in your lowest gear you might be spinning your pedals at an unreasonable speed. Your legs would not be able to spin that fast, and you would have to be able to put out a few hundred watts of power with your legs, which no one can do. Bottom line though, is that a torque sensor is a more efficient means of applying power according to how much effort you yourself are applying. And that is why it is preferred by many bikers, in addition to the fact that a bike feels more natural, like an acoustic or analog bike. .

 

[ronaldsauve]

What I mean by cadence sensor being on or off, is that as soon as you start pedaling, (actually typically within a rotation or two), it applies power. But that only changes according to how fast your cadence, or rotational rpm is, not according to the power you personally input onto your pedals, so the actual power you receive is constant, until it cuts off when you reach the speed in each PAS level where the power stops being applied. The speed in each PAS level where power stops with a cadence sensor often is set by the supplier of the system. So, for example, a cadence sensor bike might stop supplying power in PAS 1 at 7 mph, in PAS 2 at 10 mph, in PAS 3 at 13 mph, in PAS 4 at 17 mph, and PAS 5 at 20 mph. Of course, this will be different with each bike and manufacturer according to how they have set their system up, so this is just an example, and for this example, for a class 1 or 2 bike that is limited to 20 mph. However, it does not work like a torque sensor, which increases the applied power received from your battery and motor according to how much power you personally input onto your pedals. So, in theory only, you could hypothetically keep applying power in PAS 1 and your lowest gear indefinitely up to the bike’s maximum speed, although this would not be practical in a real world sense, because in your lowest gear you might be spinning your pedals at an unreasonable speed. Your legs would not be able to spin that fast, and you would have to be able to put out a few hundred watts of power with your legs, which no one can do. Bottom line though, is that a torque sensor is a more efficient means of applying power according to how much effort you yourself are applying. And that is why it is preferred by many bikers, in addition to the fact that a bike feels more natural, like an acoustic or analog bike. .

An addded thought: Yes, I believe your Trek Powerfly 7 does have a torque sensor. Nice bike!

 

[NWA Cycling]

In your opinion, if on a steep climb one pedals faster or slower, does the range change or does it stay about the same? Obviously with the same setting.

My reasoning is this: I have noticed that if I pedal harder uphill (i.e., when much of the energy is spent against gravity, not to overcome friction, especially aerodynamic friction, which has little effect on energy consumption in low-speed ebikes), the motor puts more power into it, but it takes you less to travel the same distance. In the end, the result is more or less the same.

It seems to me that at low, constant speeds, the percentage of power the bike adds to mine is always the same, so in the end the range remains the same. For those good at Physics:

Energy [kWh] = Power [kw] x time [h]= (k x speed) x (distance / speed) = k [kWh / km] x distance [km]

It's a discussion I've had a myriad of times with my ebike mate that may seem academic, but it isn't because from the anwer depends on whether to increase the range on large gradients it is worth pushing more or not.

Range will constantly change with the assist level and torque.

 

[NWA Cycling]

What I mean by cadence sensor being on or off, is that as soon as you start pedaling, (actually typically within a rotation or two), it applies power. But that only changes according to how fast your cadence, or rotational rpm is, not according to the power you personally input onto your pedals, so the actual power you receive is constant, until it cuts off when you reach the speed in each PAS level where the power stops being applied. The speed in each PAS level where power stops with a cadence sensor often is set by the supplier of the system. So, for example, a cadence sensor bike might stop supplying power in PAS 1 at 7 mph, in PAS 2 at 10 mph, in PAS 3 at 13 mph, in PAS 4 at 17 mph, and PAS 5 at 20 mph. Of course, this will be different with each bike and manufacturer according to how they have set their system up, so this is just an example, and for this example, for a class 1 or 2 bike that is limited to 20 mph. However, it does not work like a torque sensor, which increases the applied power received from your battery and motor according to how much power you personally input onto your pedals. So, in theory only, you could hypothetically keep applying power in PAS 1 and your lowest gear indefinitely up to the bike’s maximum speed, although this would not be practical in a real world sense, because in your lowest gear you might be spinning your pedals at an unreasonable speed. Your legs would not be able to spin that fast, and you would have to be able to put out a few hundred watts of power with your legs, which no one can do. Bottom line though, is that a torque sensor is a more efficient means of applying power according to how much effort you yourself are applying. And that is why it is preferred by many bikers, in addition to the fact that a bike feels more natural, like an acoustic or analog bike. .

I prefer torque sensor or cadence.

 

[pagheca]

Range will constantly candle with the assist level and torgue.

It depends. My original question was:

if on a steep climb one pedals faster or slower, does the range change or does it stay about the same? Obviously with the same setting.

I assume at low speed ( <- steep climb, at least for me this is = to low speed )