Wattage per mile or kilometre

[Mr. Coffee]

Still, it is hard to talk to someone who mixes pears (Watts) with apples (Watt-hours). Both are fruit, true. Both are engineering units. For different physical quantities.

To be more strict with your analogy, one of them is fruit and the other is the rate at which you throw fruit at someone who doesn't know the difference between the two.

 

[Manu]

If you stored 500 Watts Manu, it probably took 10 seconds to charge the battery, Manu, didn't it. (Joke, in any case).

You do not store "watts" in the battery. You store watt-hours. If you were unloading a 576 Wh battery, you might get electric current of 250 W / 36 V = 6.9 Amperes and this current flows through the motor circuits, disregarding the battery capacity. However, since you are drawing energy from the battery, and you are drawing 250 W, your battery will work for 576 / 250 = 2.304 h or roughly for two hours and eighteen minutes.

Also, the fact Wh (not W!) are measure of energy stored is the charging process. Assuming your charger is 4 A and the voltage is 36 V, you push 36 * 4 = 144 Watts or 144 Joules per every second. Your battery capacity is 576 Wh, so charging would take at least 576 / 144 = 4 hours. It is because you are storing energy (Wh) not power (W).

Still, it is hard to talk to someone who mixes pears (Watts) with apples (Watt-hours). Both are fruit, true. Both are engineering units. For different physical quantities.



Good joke @PaD So I can tell you the tank of my car is good for at least 900 km How many liters per Swedish mile does my car use?

I said it was watts hour = total energy consumption, the capacity is voltage by intensity,

"In a battery the consumption or watts/ hour that can be stored is determined by voltage and intensity"


and another very different charger that has nothing to do with the ability to store electrical energy.



you are next to a high voltage turret with 22000 volts and you receive an electric shock ..... ¿what killed you? ¿the voltage or intensity ?




In the case of the photo you see the voltage is 36 volts and the amps are 13.6 amps, but not instant second amps, amps / hour, that's the total amps it stores and releases in one hour.



in the high-voltage turret, what kills you is not the voltage is the intensity with which that energy is released to your body in a unit of time, be it second / hour or days .....


I can be next to the 22000 volt turret and I receive a discharge but the intensity was 0.000001 ampere and that discharge does not kill me, but I am with an electrical box of 380 volts and 80 amps second and you are dead .

 

[Stefan Mikes]

What is killing you are Joules because it always takes some time (even short) before the electric current (you call it intensity) can kill you. You may grab power cables with both hands and there is a chance you survive if someone else cuts the electricity off fast. For your information, energy units are Joules (J), kJ, MJ, calories, kcal, Watt-hours, BTU (British Thermal Units). All describe energy. Heat, Work, and Energy are equivalent terms. Watts are for Power, which is Energy Rate.

EDIT: You are talking 22 kV electric source to kill a person. It will kill the person fast because the ENERGY flows much faster and you get your killing Joules in milliseconds.

To be more strict with your analogy, one of them is fruit and the other is the rate at which you throw fruit at someone who doesn't know the difference between the two.

Nothing else to say.

 

[Johnny]

On flats, if I use custom modes at %25 I spend 4-6wh/mile at speeds up to 20mph. But this feels like a regular bike.
Eco seems to be between 8-15wh/mile depending on the speed, less than 8wh/mile around and below 17mph.
25+mph it is >15wh/mile.

Rider effort plays a big role so these numbers may not be very informative.


Note: As Stefan explained it is VxAh=Wh , 48V battery having 10Ah of capacity can store 480Wh of energy.

 

[Manu]

What is killing you are Joules because it always takes some time (even short) before the electric current (you call it intensity) can kill you. You may grab power cables with both hands and there is a chance you survive if someone else cuts the electricity off fast. For your information, energy units are Joules (J), kJ, MJ, calories, kcal, Watt-hours, BTU (British Thermal Units). All describe energy. Heat, Work, and Energy are equivalent terms. Watts are for Power, which is Energy Rate.

EDIT: You are talking 22 kV electric source to kill a person. It will kill the person fast because the ENERGY flows much faster and you get your killing Joules in milliseconds.

View attachment 43858


Nothing else to say.

in the high-voltage turret, what kills you is not the voltage is the intensity (amper)with which that energy is released to your body in a unit of time, be it second / hour or days .....


I can be next to the 22000 volt turret and I receive a discharge but the intensity was 0.000001 ampere and that discharge does not kill me, but I am with an electrical box of 380 volts and 80 amps second and you are dead


and that you can take the cables with both hands, I do not recommend it, the electricity will pass through your heart and it will be dead sooner rather than later


understand this the battery is voltage x intensity =¿ watts ok? if a battery of 48 x 10 amps / hour = 480 watts hour = to deliver that energy in 60 minutes
¿Does your ability to store more than 480 watts change by delivering them instantly second zero or within 2 days? NOT change = 480 w!!!!! The energy capacity is the same apply the voltage x amp formula that you apply the voltage x amp / hour formula.

what changes is the time to deliver that stored energy, when it sets / amp hour it is netted that it is to deliver 60 minutes not to the second but its capacity is the same even if it was at 2 hours at 3 days released that energy = 480 watts


the capacity in watts that the battery stores does not change because it has a release energy in seconds, hour or day, its capacity is equal to 480 w.

 

[Stefan Mikes]

It needs time to kill a man with electricity. The higher voltage the higher amperage, meaning watts (energy rate = energy transfer speed). These watts need to accumulate in the body as watt-seconds, or Joules.

Sorry you missed physics lessons at school.

 

[PaD]

The point is that number is meaningless if you are riding in variable terrain, variable temperatures, and variable road surface. It becomes even more challenging when you are riding someplace you never rode before.

I understand that. But the same goes for any ”fuel tank” doesn’t it? Gas, Ah or calories - you use what have in a shorter time or distance if you face e.g. a strong headwind.
The answer to the thread title is - It depends.. but of course those who want to specify Wh/mile for various riding conditions should do that in this thread.

 

[justforfun]

I refuse to talk with someone who says "watts spent".
You do not understand this simple concept Manu. You cannot spend watts. You might as well "spend" volts or amperes (same wrong).



It is the voltage, not the battery capacity. The battery capacity is expressed in Wh.

480 Wh

 

[Balinus]

Really interesting thread. I am in the market for an ebike. I am wondering how much W/km is consumed at speeds around 45km/h (28mph)?

I am looking at my options and battery needs for a commute of 32-34km where I could in theory goes to 45km/h for 12-15km and remaining parts would be around 30km/h.

Thanks for any infos!
Cheers!

 

[steve mercier]

Really interesting thread. I am in the market for an ebike. I am wondering how much W/km is consumed at speeds around 45km/h (28mph)?

I am looking at my options and battery needs for a commute of 32-34km where I could in theory goes to 45km/h for 12-15km and remaining parts would be around 30km/h.

Thanks for any infos!
Cheers!

How long can I play cowbells ? It depends on how fast and loud I play them and what size sticks I use as well as my armstrength. If I play real slow and quiet with a chopstick I can play all day...but if I want to rock the Casbah I need a little help from my group " Boschy and the Extra Powerpacks".

 

[steve mercier]

My wife prefers to play the shaker (-:

 

[Balinus]

How long can I play cowbells ? It depends on how fast and loud I play them and what size sticks I use as well as my armstrength. If I play real slow and quiet with a chopstick I can play all day...but if I want to rock the Casbah I need a little help from my group " Boschy and the Extra Powerpacks".

hehehe! As this is for commuting, I'd like as much assistance as possible but I know that I'm probably gonna need to settle for a "normal" assistance if possible (~200-250% support as opposed to a "maximum" assistanceof > 300%)...

I hope I make sense! Quite new to all of this. Just hoping to get some numbers of W/km for those speed. I kniow they will vary according to the level of assistance, etc.

Cheers!

 

[harryS]

I can play a cowbell too! Let's look at the engineering again.

It's interesting, If you use Steve Gribble's calculator with a frontal area of 5 square feet, it takes 300 watts for 25 mph. This matches other calculators I have found. If you google power meters, many roadies will say they can go 25 mph on less than 300 watts. By the way, weight is not a big factor, but the area is. So is grade. A 2% grade increase the power to 540 watts. Yes, variable terrain and wind is tough.

(Link Removed - No Longer Exists)

But then we have this guy's numbers. 600W to go 25 mph.

Motor Output Watts For MPH

www.twospoke.com

He claims an efficiency loss of 50% is typical for ebikes, and that's what we miss using the aero charts.

So 600Watt at 25 mph computes to 24 wh/mile (on level ground).

 

[justforfun]

Really interesting thread. I am in the market for an ebike. I am wondering how much W/km is consumed at speeds around 45km/h (28mph)?

I am looking at my options and battery needs for a commute of 32-34km where I could in theory goes to 45km/h for 12-15km and remaining parts would be around 30km/h.

Thanks for any infos!
Cheers!

Actually you are in luck! To attain level speeds of 28mph or more, there are fewer vendors, but speed is attainable. Personally, I ride a motorcycle when I feel the need for speed and distance

 

[Balinus]

I can play a cowbell too! Let's look at the engineering again.

It's interesting, If you use Steve Gribble's calculator with a frontal area of 5 square feet, it takes 300 watts for 25 mph. This matches other calculators I have found. If you google power meters, many roadies will say they can go 25 mph on less than 300 watts. By the way, weight is not a big factor, but the area is. So is grade. A 2% grade increase the power to 540 watts. Yes, variable terrain and wind is tough.

(Link Removed - No Longer Exists)

But then we have this guy's numbers. 600W to go 25 mph.

Motor Output Watts For MPH

www.twospoke.com

He claims an efficiency loss of 50% is typical for ebikes, and that's what we miss using the aero charts.

So 600Watt at 25 mph computes to 24 wh/mile (on level ground).

Thanks! That's very informative

Actually you are in luck! To attain level speeds of 28mph or more, there are fewer vendors, but speed is attainable. Personally, I ride a motorcycle when I feel the need for speed and distance

hehehe! Yeah, thought about this option but I'd prefer to use an ebike. From my calculations, it would take the same time for commuting over those 32km (traffic on streets!)

 

[justforfun]

Thanks! That's very informative



hehehe! Yeah, thought about this option but I'd prefer to use an ebike. From my calculations, it would take the same time for commuting over those 32km (traffic on streets!)

But wait: Damon Motorcycles Hypersport electric motorcycle. 200 horsepower, 200 mph top speed, 200 miles of highway range, 300 miles of city range, and a price tag of $24,995 (before EV rebates).

 

[Balinus]

But wait: Damon Motorcycles Hypersport electric motorcycle. 200 horsepower, 200 mph top speed, 200 miles of highway range, 300 miles of city range, and a price tag of $24,995 (before EV rebates).

Tempting!

 

[Mass Deduction]

My bike will go at least 50 miles on a charge. That is as technical as I get.

At what level of assist? Low? Medium? High?

 

[Mass Deduction]

recreational riders: 8-15whr/mile

sport riders: 15-25 whr/mile
[...]

Oof, I'd be disappointed if I used up 10 whr/mile or more. That would suggest I wasn't pedalling nearly hard enough!

Since I've got interested with e-bikes, the battery range has become one of my greatest interest. Now, having read big claims of Bulls about their new "super-range" e-bike, I started thinking in terms of "watts per distance unit". There are several factors affecting the range per battery charge:
[...]

In my experience, Shimano and Yamaha seem to get the best range on a charge on average. Shimano is particularly impressive on the entry level, where both the STePS 5000 and STePS 6100 advertise themselves as getting about 75 km (about 45 miles) on a 418 Wh battery on high assist, and about 150 km (90 miles) on low assist. Shimano comes up with their ratings by riding in relatively still wind, on relatively flat terrain (which favours longer range), but keeping the speed constantly at 32km/h (which favours shorter range), so it's a reasonably fair test.

I've seen bikes with Yamaha motors (the Haibike Radius Tour comes to mind) that advertise 85 km (about 50 miles) range on high assist, and 205 km (125 miles) on low assist, though that's on a 500 Wh battery.

All of the above examples are class 1 bikes, which makes a difference since the faster you go the worse the range will be.

STePS 6100 is rated for using up about 9 Wh/mile on high assist, and about 4.5 Wh/mile on low assist, all at 60 Nm of torque. Now that's what I call range! That Haibike with Yamaha is approximately equal for range, at 9.5 Wh/mile on high assist with its high assist being 70 Nm of torque, and 4 Wh/mile for its lowest level of assist.

It seems to me that most of the rest of the e-bike industry doesn't get anywhere near the kind of range that Shimano and Yamaha do, especially on the entry-level.

 

[linklemming]

Oof, I'd be disappointed if I used up 10 whr/mile or more. That would suggest I wasn't pedalling nearly hard enough!



In my experience, Shimano and Yamaha seem to get the best range on a charge on average. Shimano is particularly impressive on the entry level, where both the STePS 5000 and STePS 6100 advertise themselves as getting about 75 km (about 45 miles) on a 418 Wh battery on high assist, and about 150 km (90 miles) on low assist. Shimano comes up with their ratings by riding in relatively still wind, on relatively flat terrain (which favours longer range), but keeping the speed constantly at 32km/h (which favours shorter range), so it's a reasonably fair test.

I've seen bikes with Yamaha motors (the Haibike Radius Tour comes to mind) that advertise 85 km (about 50 miles) range on high assist, and 205 km (125 miles) on low assist, though that's on a 500 Wh battery.

All of the above examples are class 1 bikes, which makes a difference since the faster you go the worse the range will be.

STePS 6100 is rated for using up about 9 Wh/mile on high assist, and about 4.5 Wh/mile on low assist, all at 60 Nm of torque. Now that's what I call range! That Haibike with Yamaha is approximately equal for range, at 9.5 Wh/mile on high assist with its high assist being 70 Nm of torque, and 4 Wh/mile for its lowest level of assist.

It seems to me that most of the rest of the e-bike industry doesn't get anywhere near the kind of range that Shimano and Yamaha do, especially on the entry-level.

The numbers Ravi posted are inline with my experience and many other peoples posts, I have done rides as low as 4wh/m and as high as 25wh/m. I like it best around 10-15wh/m. You are trying to equate this to actual user effort which just isnt the case. My highest ever 25wh/m on a juiced CCX was an average speed of 21mph with a good 15-20mph headwind/tailwind going up and down 4-6 degree grades for 20 miles (an out and back ride so the tailwind turned into a headwind halfway into the ride). One of the hardest ebike rides I have ever done as verified by my heartrate monitor.

I had a loaner shimano e8000 bulls eMTB(500wh battery) for 2 weeks and rode it a ton. On max assist I could easily run out of juice in less than 20 miles (flatish ride with head/tail wind) maxed out at 20mph for the whole ride. My Bulls Brose ebike (650wh battery) usually comes back with 2/3 bars left out of 5 for the same ride/conditions/assist. I have done this ride twice on the bulls on the same charge although a tad slower on the second ride.

I am by no means a shimano hater(except for the noise), I actually had an e8000 equipped bike on order last year before cancelling.

That being said, my next ebike will probably be yamaha based.