Who has the lowest wh/mile bike?

Mine does 5.9 Wh/km (or 9.5 Wh/mile). 1.7Ah from 20s for 23 km (I don't have a what-cha-ma-call-it but this
is what my iCharger reports for Ah to charge it back to full) . Limited to 25kmh for legal reasons,
1 kW to 20kmh and 250W between 20 and 25. About 110m height difference (going down in the
morning, back up in the afternoon). And I pedal (lazily) of course...

Home-made motor and home-made controller.
 
I think it's important to note the speed when thinking about efficiency. If i designed a bike that would only do 5mph at top speed, i'd automatically win this contest.

If i was running 60mph at 98% efficiency, i'd still lose this contest even though i had a more efficient setup than anyone on this entire forum.

Watt consumption per mile gains the faster you go.
 
There are a number of threads discussing this sort of thing already. You should look around for them to get the info they already contain, as they probably answer your first question as well as it is possible to do so.

The second question could only be answered by a single person owning (or borrowing) all of the available production ebikes, and riding them the same way on the same paths, under the same wind/weather conditions.
 
Totally depends on how well your bike rolls, how fast you go, and how much you pedal.

Here is an example of the efficiency stats for my bike on a group ride with other ebikes. During the group ride portion the pace was so leisurely that I hardly used the electrics at all, just show boating occasionally with a burst of speed past people, resulting in 1.18wh/km for a 10km stretch averaging 20kph. But on the way home, in stop start traffic, hills etc., averaging 28kph I was doing 11wh/km.
http://www.endless-sphere.com/forums/viewtopic.php?f=25&t=33806&hilit=melbourne+group&start=45#p502325

file.php


- Adrian
 
This is a meaningless debate. The only reason a bike has low wh/m is because it's not helping you enough. I have a couple of bikes that use zero wh/m, so I claim the prize.
 
d8veh said:
.... The only reason a bike has low wh/m is because it's not helping you enough. .....

Or that the bike doesn't need as much help.
 
d8veh said:
This is a meaningless debate. The only reason a bike has low wh/m is because it's not helping you enough. I have a couple of bikes that use zero wh/m, so I claim the prize.

No way!

All bikes use Wh/m, either from leg power or from another power source. "There is no such thing as a free lunch". Since the power required to overcome aerodynamic drag increases as the cube of speed, high speed riders can waste power at prodigious rates while moderate speeders can claim much more efficiency. I have only built a few different ebikes, but in all cases so far speed seems to have such a large influence on power consumption that other factors just fade into the background noise.
 
What testing I've done, using a few different hubmotors on similar bikes showed very little difference between brushless hubmotors ridden a set speed on mild street terrain.

My standard test route was about 10 miles long, and rode 5 miles each direction in a large square so the wind direction was both head, tail, and crosswind from both sides. A very mild grade hill along the way, climbing about 400' vertical, then back down.

At the time, I used the time to recharge to compare, and found very similar recharge times for a fairly fast dd hubmotor, a medium speed dd, and a smaller gearmotor. In the test, speed was limited to 20 mph, the fastest the little gearmotor would go. Slower of course on the uphill, but limiting to 20 on the downhill.

Whatever difference there was could be made up easily by pedaling with the motor off for a half mile or so. Later on having a CA, the same thing was seen. On bikes with similar weight and drag, It took about the same 400w average to go 20 mph.

I didn't test every motor or every bike. Tests on a brushed motor did show a difference, about 20% more power used to go the same distance. So I'd say avoid brushed to get best efficiency. Weight matters, as does worse aero. Adding panniers costs you. The longtail bike, with double panniers an over 100 pound weight takes at least 600w to go 20 mph. That's a whopping 200w decrease in efficiency. I gotta ride that thing at a crawl to get less than 40 wh/mi.

To summarize, keep it light, keep it slick, ride it slow, and pedal hard to get the most possible wh/mi. Weight matters, but ride speed and it's effect on drag matters most.

Every time you raise the handlebars for comfort, add bags to carry stuff, pack those bags with heavy stuff, ride fast, or pedal less it costs you. But it is possible to get a reasonable 30 wh/mi on a commuter bike where you can fit a few grocerys in panniers, and ride 20-25 mph.
 
I want the highest possible wh/mile pushing as little load as possible and creating the least amount of waste heat.

For efficiency the full faring guys win. One guy reported low teens wh/mi, or was it lower :?:, at 30mph with no pedaling.
 
The best overall average no-pedal efficiency I've gotten was 11wh/mi. But I've done that on several different bikes with different motors and aerodynamics. At the extreme low end of speed, riding style becomes more important than the differences in bikes.
And I would rather eat my ex GF's cooking than try to ride that way every day. Its boring as hell, and almost at the point of not worth converting the bike. I could have pedaled a normal bike at those speeds, and while I would be more tired, I would have been much less bored.


A better question might be who gets the best efficiency at a given average speed. Say, 20mph.
 
Yep, I bet even Madrhino gets outstanding wh/mi when going down the hills. Gotta get rid of every variable but one to do science. I tried with my standard test route, even down to the weather.

If there is a general type of "normal" bike with potential for good efficiency, it's one you mostly pedal. Typically a light road frame, freewheeling gearmotor, and the lightest battery possible. Then riden by a guy who really doesn't need a motor. In other words, in a 20 mile ride the motor gets used for 5 miles or less, just to get up the hills.

Bents can be low enough to smoke any upright road bikes aero drag, so you tend to see great wh/mi numbers come from recumbents.

But even my lead sled of a longtail cargo bike will go a huge distance if I just watch the CA and keep it under 100w. I won't be getting there soon, but only 100w of assist gives me 7 hours of riding time on a 700 wh battery. I could ride it that way if I must.
 
John in CR said:
I want the highest possible wh/mile pushing as little load as possible and creating the least amount of waste heat.

For efficiency the full faring guys win. One guy reported low teens wh/mi, or was it lower :?:, at 30mph with no pedaling.

Thank you everyone for your replies.

This is what I'm most interested in. Pedaling varies, so I'd like to know the efficiency for motor-only, maybe at a set speed, such as 20mph. I think that this figure is just as important as top speed.
 
To give you a ceiling value on bike efficiency/range, I drained 2kWh of nano-tech's in 3 laps of laguna seca road racing with speeds >90mph on most straights. Laguna is 2.23miles/lap. I covered ~7miles (counting entering and exiting track) on ~1,800Wh used.

That's 257Wh/mile with a very efficient motor/controller setup.
 
The Pterovelo velomobile at 30 mph has virtually no aerodynamic drag and on flat ground on a calm day gets 6 Wh/Mi without pedalling. Its a Carbon Fiber wind tunnel designed velomobile and has about 8 lbs. of metal in it. There aren't even mirrors on it to create drag. Wish my Catrike could get anything near that kind of performance. Best it can do is 12 - 16 Wh/Mi at 20-22 mph on flat ground and a calm day. I could do better if I changed the fairing from a Windrap XT to a Windrap GS, made wheel covers to stop the spokes from pumping air and that sort of thing. The wheel covers are a plan for this Winter. Changing the fairing isn't going to happen though. Harvey is always going to get better mileage out of a battery with his Catrike then me anyway.
 
One thing you guys haven't mentioned, is, do you obey the laws when getting those Wh's.

I could be getting more miles per watt if I rode like most of the bike riders I see around here. Thing is, I use the electrical power to my advantage. Well really, for self-preservation. I slow down to a crawl at stop signs and stop at lights. If I had a pedal bike, I would be more inclined to run the stop signs and lights.

Better to arrive in one piece and use more wattage, then to try to be super efficient.
 
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!
 
d8veh said:
This is a meaningless debate. The only reason a bike has low wh/m is because it's not helping you enough. I have a couple of bikes that use zero wh/m, so I claim the prize.

Yes, another huge variable along with many others. It only becomes meaningful if data is derived from quantitative testing using a reasonable test regimen that shows repeatable results. Big variables like bike/rider weight, speed, inclines, drive efficiency, drag coeff, and rider assistance level need to be tamed for this to have any meaning.
 
Jozzer said:
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.!!! :D
 
Anybody have an idea what sort of Whpm % savings could be achieved at 20mph or 30 mph on a relatively tall mtb using a windscreen like the attached? (23" tall & 18" wide at the base mounted at a slant with the bottom forward)

windscreen.jpg
 
Based on the little I can remember of the much that I read a few years ago on velos, a tailbox will generally help a lot more than a windshield, if you only have one or the other. A full front fairing might help almost as much as a tailbox, depending on the shape of the rest of things, and the fairing shape.

(I keep intending to make a very simple detachable tailbox for Crazybike2 to help fix what those boxes on the back do to my aero, but I have yet to actually do it and test the results).
 
Dave_S said:
Jozzer said:
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.!!! :D

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. :mrgreen:

John
 
I agree with amberwolf
It would have to be one person owning several ebike
From my experience of production ebikes
Eplus is more efficient than TForce
Throttle application /not throttle itself/ can make difference a lot
Why
On TF I often overshoots throttle back up again and on and on
On Eplus throttle application is very linear, the best of all bikes I tried
On/off throttles waste Wattshours of energy
 
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