Who has the lowest wh/mile bike?

[Jozzer]

The most efficient I know of is Cedric Lynch's "Thing'a'mobile" - he gets around 20wh/m at 50mph steady and can travel over 200 miles on a charge.
http://www.bikeweb.com/node/2601

It might look weird, but if everyone was driving one of these the world would be a nicer place!

That kind of machine is a worthwhile goal for any electric bike project. Combining speed with low power consumption is soooo much better than just brute force speed.!!!

Other than the tiny bit extra you give up to the wind due to the slightly higher average speed, it requires the same energy to accelerate to the same cruising speed. Efficiency at cruise is great, but brute force acceleration is top of the list, and it promotes the cause better than anything else.

John

"Tiny bit"?? "slightly higher"??
In fact it uses less energy to accellerate to speed since air resistance starts to grow exponentially from a fairly low speed. Consider, if it only takes acouple of hundred watts to propel you at 50mph, then all the rest of the power you produce is making you acellerate. If your vehicle already needs 5KW to travel at 50mph just to overcome wind resistance - well - acelerration will have taken a big hit!

It's fitted with a 30KW peak motor, so it's power to weight ratio is higher than the vast majority of ebikes here..it is NOT a slowboat!
Also, a vehicle with "brute force" power is more likely to travel faster and would save even more energy than a lower power vehicle if it were properly streamlined - making it all the more important.

 

[dogman dan]

My gut feeling, so just a pure guess, would be that an "upright" wind screen will cause as much, or even possibly more drag than your chest does.

The key thing being that it sticks up high, and is close to vertical. Pointy only a bit better, if it still sticks up high, as you see if you ever own a minivan. They don't get 30 mpg much since it's still nearly the size of a pickup truck.

But in cool weather, I'd love a big windscreen if it didn't wreck my wh/mi.

 

[MadRhino]

Yep. Aero resistance is a matter of surface and trail. You want to be low, and the tail faring is just as important as the front. Mounting a windshield to an upright bike is not for efficiency, it is for comfort essentially.

 

[iperov]

lowest wh/mile has geared MAC 6T

 

[amberwolf]

That would entirely depend on how you ride it and under what conditions and on what terrain.

No specific motor can make a bike have the lowest wh/mile of them all.

 

[dogman dan]

Sure, 6t mac and pedal your ass off. Battery? what for, it's got an internal freewheel?

I don't disagree that a fast winding motor can be run in an efficient manner using a battery and no pedaling. But it can be just as easily be run inefficeintly too. LIke any motor can.

A faster winding motor can really shine on long uniterrupted rides that don't climb hills too slow.

 

[SamTexas]

I don't have the test equipment to see inside the hub or the controller. But my measurements on the same bike using two different hubs leave me with the indisputable conclusion:

Cell-man 350W front geared hub/17A controller is 10 to 15% more efficient than a 9C 2807 DD front hub/25A infineon controller. Same speed, same route, ridden by the same person, me. And it's not one of those "I tested/measured once". It was repeated many times and the results were always the same (within a 1 to 2% margin of error).

To say that all motors consume roughly the same power under identical conditions is like saying all motors and all controllers have the same efficiency. Nonsense.

 

[iperov]

so, lowest wh/mile depend on riding style:

1) extremelly hard mountains - 6T mac
2) cross country - 12T mac
3) MTB urban - HT3525
4) recumbent urban - HS3548

 

[amberwolf]

so, lowest wh/mile depend on riding style:

and a bunch of other factors, as various poeple have already stated and shown.

1) extremelly hard mountains - 6T mac
2) cross country - 12T mac
3) MTB urban - HT3525
4) recumbent urban - HS3548

Are those four different setups you have, that you've tested for various efficiencies? If not, then that list means nothing; it's just a list of bike types and motors.

To mean anything in this particular type of discussion, you would need to list the full specs of each one, the rider, how you ride (pedal? lots? none?--any pedalling at all makes any electrical readouts questionable at best, useless at worst, unless you also have an accurate way to measure your pedal input), stop and go or continuous? Where do you stop? top of hill, bottom of hill, lots of stop signs? etc? temperature? and the tested results of power consumption on various terrain (with information about exactly what that terrain is, path length, slopes, etc). Otherwise it cannot be compared to any other bike, even the ones in your own list. The same conditions must be known, in order to be testable to do a comparison.

Without all that in pretty extreme detail, then even with a Wh/mile number for each bike, it's just a list of numbers--at best, it would only be a list comparing the bikes on the list itself to each other, assuming that they are all tested on exactly the same route under exactly the same conditions.


It is very difficult to have a meaningful (data-wise) discussion about "lowest wh/mile" without using exactly the same test conditions for every ride of every bike being compared, and that in itself is difficult at best, even with just one person testing all the bikes in question.

When it is a group of people scattered around the world in different terrains, traffic, ride styles, weather, etc., it's even harder.


If all people want is just to see what power consumption is for a bunch of different bike configurations, it's easy to make a list of those, and it's been done here on ES a few times in various threads. But without exact information on all the conditions, specifications, etc., it's not meaningful to compare them except to get certain basic generalizations that may well not apply to very many people/bikes.

 

[amberwolf]

Cell-man 350W front geared hub/17A controller is 10 to 15% more efficient than a 9C 2807 DD front hub/25A infineon controller. Same speed, same route, ridden by the same person, me.

That's not terribly surprising, given that the controller itself on the DD is going to allow higher currents for longer periods than the one on the geared, during startup or at other high-load times, and that the geared motor will probably reach it's more-efficient (higher BEMF) speed quicker than the DD, all other conditions identical, which itself will help to lower startup currents.

However, it is possible that very different results could be had by using the same setups on the same route but ridden in different ways--hard startups at WOT for the geared motor, vs slow startups taking it easy to get up to speed with the DD motor. I haven't directly experimented with that, but it should make the difference in efficiency much less, possibly even make the geared setup appear less efficient than the DD.


(BTW: I would assume these tests were done without any pedalling? (since there are presently few ways to accurately measure the pedal input power, to subract it from the test results). )

 

[SamTexas]

Yes AW. The tests were done without pedaling.

 

[iperov]

It is very difficult to have a meaningful (data-wise) discussion about "lowest wh/mile" without using exactly the same test conditions for every ride of every bike being compared, and that in itself is difficult at best, even with just one person testing all the bikes in question.

just WHY, enough efficiency data in ebike simulator

yes I have geared hubs, torgue DD, speed DD,
in general, most efficiency is geared hub, less - torque dd,
speed DD good when air resistance low as on recumbent.

 

[amberwolf]

Simulator is just that-- a simulator, not reality. It doesn't include all the things that make each route you take unique, and each time you ride the route it will be a little different. You probably can simulate each tiny little section of a route based on mapped infomration about it, so you can simulate the slope and your throttle setting for that section, but this would be extremely tedious and is unlikley to give the same data that actually riding that configuration on that route would.

Plus, not every battery or every motor or every controller is in the simulator, and if referring to the ebikes.ca simulator, it only simulates hubmotors. No middrives are in there at all, so they can't be compared that way. (if the middrive is powered by an ex-hubmotor using a fixed gearing to the wheel, then you can make an approximation of it, but if not, you can't. And if it uses a variable-gearing transmission, especially one like the automatic NuVinci, you would have to know what gearing ratio the NV chooses for various conditons, for each particular simulation setup you want to make).

Also, since not every bike with every rider in every clothing configuration in every wind condition with every tire type at every possible tire pressure, with every possible wheel size, is listed in the simulator, there are a whole bunch of factors that vary from bike to bike that affect the efficiency, that are not being simulated.

If all you want to know is what one of the *listed* combinations of items in the simulator rates in comparison to oen of the other *listed* combinations, under a single set of conditions, then yes, the simulator can be used to determine that to most likely a reasonably accurate degree. But if you wnat to know what any real bike will be like compared to any other real bike, in real-world conditions, the simulator wont' tell you that.


If you want to gather data for a comparison, you have to do the actual experiments. And if you want to compare them to other people's data, then eveyrone has to have the same data points and factors. Otherwise it is not a really valid comparison--it's just a generalization of trends in the data.


I know that ES is not truly a science forum, but if you want accurate comparisons, the data used in them must be gathered the same way it would for a science experiment. The less accurate and expansive the information, the less accurate the comparison will be. If even a single item in the comparison list doesn't include a piece of data that all the others do, then you can't use that piece of data from any of them, to validly compare them all, unless you completely leave out that entire item's data.

 

[veloman]

The worst wh/mile I ever got was 30wh/mile. That was going into a nasty 20mph headwind, slightly uphill, very little pedaling (just on starts), wearing a motorcycle 3/4 face helmet, in 40 F degree temps, cruising at about 25mph, attempting an aero tuck, with stops every 1/4 mile. I usually get 18-22wh/mile and don't pedal much. My last night, out and back I got 16wh/mile with moderate pedaling.