watts per mile

[dmcgoldrick]

it would be interesting to see how watts per mile vary from different bikes and riders and also over different terrain.
for instance my (18kg bike + 75 kg rider) storck raddar on full assist is averaging 11.5 watt per mile on rides of about 25 mile including 2000 ft ascent and 2000 ft descent. average speed 12mph......

my (27kg bike + 75kg rider ) wisper alpino averaged approx 15 watts per mile over the same journey and average speed lower at 10mph....

my understanding of battery capacity is ah x volts, minus 10% to make sure there just enough juice to get home...!!!!! this seems to work well when planning a ride out.
as i dont live in a flat area, i dont know what numbers would apply to long flat rides, but assume watt per mile would be lower ?

equally where the power is off, or if riding for long periods above assist level then this is not relevant and should not be included if you have any data, as of course it then looks like the battery is lasting for much longer than it actually is......


anyone got any accurate information for their bikes ?????


regards

 

[mountainsport]

Hi dmcgoldrick,

Your asking too much from me,ask d8veh he can tell you.

Mountainsport.

 

[Artstu]

Rider Wattage must vary greatly, and it's easy to ride at half the effort you would on a normal bike.

These guys give wattage readouts on their rides, not entirely sure how it works though

Strava | Running and Cycling GPS Tracker, Performance Analytics, Maps, Clubs and Competition

 

[dmcgoldrick]

Rider Wattage must vary greatly, and it's easy to ride at half the effort you would on a normal bike.

These guys give wattage readouts on their rides, not entirely sure how it works though

Strava | Running and Cycling GPS Tracker, Performance Analytics, Maps, Clubs and Competition

its the battery usage i was interested in........i dont think the link gives info on ebikes......looks more like data from the 'lycra' clad road racers... ?
regards

 

[50 Hertz]

anyone got any accurate information for their bikes ?????


regards

Kalkhoff Pro Connect. Average pace of 16 MPH, 300 metres of climbing, rider 75 Kg, Bike 24KG. Between 5 and 10 Wh per mile.

There are many many factors which influence this figure, but probably the two biggest are drive type and rider input.


FPO

 

[Artstu]

its the battery usage i was interested in........i dont think the link gives info on ebikes......looks more like data from the 'lycra' clad road racers... ?
regards

You're quite right, no ebikes. I just thought it was a good place to start to look into the relationship between gradients, speed and rider watt output, their ride data gives a wattage they use based on those figures.

I imagine the only way for them to establish their own wattage output is on a static test rig. Although crank force measuring devices are available.

 

[dmcgoldrick]

Kalkhoff Pro Connect. Average pace of 16 MPH, 300 metres of climbing, rider 75 Kg, Bike 24KG. Between 5 and 10 Wh per mile.

There are many many factors which influence this figure, but probably the two biggest are drive type and rider input.


FPO

this is where it gets very interesting 5 watt per mile on a 24 kg bike seems extremely low to me....is this on the flat using minimum assist level.......? 10 watt per mile average looks reasonable with a good level of rider input.....does your bike assist over 15.5mph........? to do average 16 mph then you must be riding long periods not using assist ? or if assisting over that level does the watt per mile usage not actually increase to obtain the higher speed ?

regards

 

[flecc]

11.5 watt/hours per mile is lower than average, so quite good. About 12 W/h per mile is the average for the majority of legal e-bikes.

Riders using their systems lightly for some assist only in difficult conditions can get down to around 5 W/h per mile, but with usage below that it has to be questioned whether it's worth a rider having the extra weight of an e-bike.

At the other extreme, the worst frequently recorded for one particular model of legal e-bike (no longer current) is 24 W/h per mile.

But of course there is no absolute, too much depends on the rider's ability and the terrain to give accurate forecasts.

 

[jazper53]

As said above its a individual computation with many variables to make it almost nonsensical to try and formulate a measure IMHO

 

[Deleted member 4366]

I've said it before. It's a totally meaningless characteristic because everybody rides their bikes in different ways and in different circumstances. The battery has a finite amount of energy that it's prepared to give up. Most bikes have some sort of power level control, so you can get the energy out of the battery fast or slowly. You can travel fast or slowly, and you can pedal as hard or easily as you want. The slower you go, the higher the proportion of energy that you supply. Some bikes have power systems that encourage you to go slowly and some have systems that encourage you to pedal harder, which results in lower wH/m. All ebike systems are approximately as efficient as each other in terms of the way the motor converts battery energy into motive energy, so if you could equalise external factors, speed and pedal effort, most bikes would give approximately the same wH per mile. I don't believe that crank-drives or hub-motors have any advantage over the other, except when you have a bike poorly matched to your needs. If your system was badly designed (rare these days), so that you had a motor wound for a much higher speed than you actually go, you would suffer efficiency losses.

So, to summarise: You can use up you battery energy slowly, go slower and/or pedal harder, or you can use it up faster, have an easier time pedalling and/or go faster. How much energy you have to start with depends on battery size (wH). The bigger the battery, the further you go.

Most people, who travel in the range 12 to 15 mph with steady pedalling will get somewhere between 8 and 15 wH/mile.

 

[50 Hertz]

this is where it gets very interesting 5 watt per mile on a 24 kg bike seems extremely low to me....is this on the flat using minimum assist level.......? 10 watt per mile average looks reasonable with a good level of rider input.....does your bike assist over 15.5mph........? to do average 16 mph then you must be riding long periods not using assist ? or if assisting over that level does the watt per mile usage not actually increase to obtain the higher speed ?

regards

I have to work very hard to get down to the 5 Wh consumption level and its the exception to the rule that I can achieve this. I am quite a strong rider and compete (against myself) in the occasional triathlon, so it's useful to be able to work hard on the Ebike when commuting to help with the training.

My bike assists to about 16 MPH ish, so when working hard and above that speed, the battery energy will remain untapped. I always run the bike on the lowest power setting as well. For general pottering around, the consumption is around the 10 Wh per mile mark. I am basing these figures on a constant in terms of cycling route.


FPO

 

[dmcgoldrick]

I've said it before. It's a totally meaningless characteristic because everybody rides their bikes in different ways and in different circumstances. The battery has a finite amount of energy that it's prepared to give up. Most bikes have some sort of power level control, so you can get the energy out of the battery fast or slowly. You can travel fast or slowly, and you can pedal as hard or easily as you want. The slower you go, the higher the proportion of energy that you supply. Some bikes have power systems that encourage you to go slowly and some have systems that encourage you to pedal harder, which results in lower wH/m. All ebike systems are approximately as efficient as each other in terms of the way the motor converts battery energy into motive energy, so if you could equalise external factors, speed and pedal effort, most bikes would give approximately the same wH per mile. I don't believe that crank-drives or hub-motors have any advantage over the other, except when you have a bike poorly matched to your needs. If your system was badly designed (rare these days), so that you had a motor wound for a much higher speed than you actually go, you would suffer efficiency losses.

So, to summarise: You can use up you battery energy slowly, go slower and/or pedal harder, or you can use it up faster, have an easier time pedalling and/or go faster. How much energy you have to start with depends on battery size (wH). The bigger the battery, the further you go.

Most people, who travel in the range 12 to 15 mph with steady pedalling will get somewhere between 8 and 15 wH/mile.

dont disagree with your general comments......however the question was meant to be very specific as to how an individual on their bike uses the watts available. this may well give a clue as to how different combinations of factors come together to give a more accurate battery usage/performance criteria. a variation of between 8 and 15 does not satisfy my scientific enquiring mind.......
regards

 

[dmcgoldrick]

As said above its a individual computation with many variables to make it almost nonsensical to try and formulate a measure IMHO

sorry if the question is not clear....the question is meant to be very specific to an individual and their bike and the route , not a general 'how long is a piece of string'.
regards

 

[Artstu]

sorry if the question is not clear....the question is meant to be very specific to an individual and their bike and the route , not a general 'how long is a piece of string'.
regards

That may well take you back to the type of route plotting devices Strava users use. If you know the power of yourself and your motor I believe they'll predict wattage. Having said all that this is pretty damn good

Electric bike range

 

[Artstu]

sorry if the question is not clear....the question is meant to be very specific to an individual and their bike and the route , not a general 'how long is a piece of string'.
regards

You weren't very clear

it would be interesting to see how watts per mile vary from different bikes and riders and also over different terrain.

 

[Marctwo]

Can't quite get my head around what watt-hours per mile is supposed to mean??? Wouldn't watts per mile be more appropriate?

<edit> Sorry, just woke up and wrote that backwards. Switch it around and you have my meaning... </edit>

 

[Deleted member 4366]

dont disagree with your general comments......however the question was meant to be very specific as to how an individual on their bike uses the watts available. this may well give a clue as to how different combinations of factors come together to give a more accurate battery usage/performance criteria. a variation of between 8 and 15 does not satisfy my scientific enquiring mind.......
regards

Thats easier then:
1. Standard Chinese 250w Bafang hub-motor on 30 mile commute wit one 2 mile moderately steep hill, I averaged 8wH/mile - mainly by pedalling faster than the maximum power speed of the motor. With a hub-motor, the power decreases once the speed's above about 12 mph, so pedalling at 15mph consumes virtually nothing.

2. Woosh Sirocco sport - medium hilly journey, similar motor,mainly on level one: 9.5wH/mile

3. Woosh Siroccoo CD - fairly hilly journey with several steep hills 14wH/mile

4 Oxydrive kit on same journey as (1) mainly on level one 9.5 wH/mile (Jeoff9 with same kit gets 6.5 wH/M on his trike because he's much lighter)

5 Bafang 500w BPM - same journeys as (1) 10wH/mile increases to 15wH/m when hilly

6 Bafang CST - same as (5)

7 GNG 350w crank drive 36v 22A - same journey as (3) 15wH/M

 

[hech]

On the tonaro pre-mod about 10wh/mile I think. Supered up at 44v more like 16wh/mile.
Rather oddly the old urban mover uses 26wh/mile. We fitted a 36v battery in place of the old 24v NMH battery. Can't understand where all that power is going as it is not being run more than about 15mph, nor does the motor appear to be heating up that much? Turnigy peaks at 17amps or 700watts - too much for the 1C battery.

 

[50 Hertz]

Can't quite get my head around what watt-hours per mile is supposed to mean??? Wouldn't watts per mile be more appropriate?

<edit> Sorry, just woke up and wrote that backwards. Switch it around and you have my meaning... </edit>

Watts is a measure of the rate of energy usage or work done per unit of time. 1 Watt is to expend 1 Joule of energy every second. To say Watts per mile would be like saying that you do an amount of work, per second per mile, which doesn't tell you anything useful in these circumstances. So to quantify the amount of energy used to travel a mile, we need to multiply everything by time, hence a Watt-hour or Wh. A Wh is a measure of the quantity of energy expended rather than the rate at which energy is being used (Watts). So a Watt-hour per mile tells is how much energy is used to travel one mile and this is a much more useful tool for comparrison purposes.

Watts would be useful to know when travelling at a known speed. It would tell you how hard you have to work (Joules per second output) in order to make the bike travel at a certain speed.

FPO

 

[Marctwo]

Watts is a measure of the rate of energy usage or work done per unit of time. 1 Watt is to expend 1 Joule of energy every second. To say Watts per mile would be like saying that you do an amount of work, per second per mile, which doesn't tell you anything useful. So to quantify the amount of energy used to travel a mile, we need to multiply everything by time. Hence a Watt-hour or Wh is a measure of the quantity of energy expended rather than the rate at which energy is being used (Watts). So a Watt-hour per mile tells is how much energy is used to travel one mile and this is a much more useful tool for comparrison purposes.

You did see my edit, right?