SURVEY: Your watts at various speeds

TylerDurden

TylerDurden

100 GW
Joined
Jan 4, 2007
Messages
7,176
Location
Wear the fox hat.
How much power do you use, cruising on the flats?

You don't need to provide figures for all speeds, but more entries are better...

Watts at:
10mph -
15mph -
20mph -
25mph -
30mph -
35mph -
40mph -
45mph -
50mph -
>50mph -

or*
Watts at:
10kph -
15kph -
20kph -
25kph -
30kph -
35kph -
40kph -
45kph -
50kph -
55kph -
60kph -
65kph -
70kph -
>70kph -


Comments regarding your power use on hills (at speeds) are welcome.

A brief description of your system, or a link to your setup would also be helpful. (One post for each vehicle.)

(Having this info in one place could help new folks plan their setups)


*Edit: added for the more advanced civilizations and species. Also, just in case... http://www.sciencemadesimple.net/length.php
 
As I am currently gathering data such as this, I'll post it when I have enough to be useful. Right now all I can say is I use typically 30-35Wh/Mile, at around 15-18MPH, on my 300lb (bike+rider) CrazyBike2, with frequent complete starts and stops (usually at least two per mile, and often four to eight, depending on traffic controls and path taken).

CB2 uses a four-pole powerchair motor that is nominally 24V 650W as designed, along with a gearbox reduction built-in. I run it at 36V, and the gearbox output goes via sprocket/chain reduction to about 100RPM max into the bike's regular 18-speed shiftable drivetrain. Most commonly I use only the largest front ring and the lower four or five of 6 rear cassette sprockets.

There is always at least some pedal assist, but not usually much; occasionally there is a lot, when I feel I need the extra push to accelerate very fast (but I am afraid of breaking the drivetrain again so I don't try to push it too hard--the motor can do that all by itself!).
 
"No hurries, no worries"... as watt-meters become more affordable, more people can submit info. This should be an evergreen topic.

The typical prospective EV owner may start with a post like: "I hope to go 30mph for 15mi.". A simulator could roughly predict the power needed, but actual reports with descriptions will give noobs examples of setups they can use for reference.
 
This is the only data I've noted

20mph - 450W
25mph - 700W
35mph - 1700W (at 80V)

270lb me plus about 70lb bike.
Absolutely flat around here, I only go uphill when coming out of a pot hole.
Crystalyte 406 with Clyte controller 24-72v analog.
Bosch 36v fatpacks at 12Ah.
Forge Sawback 5xx Blue.
 
Tostino posted in a similar thread:

22mph = 374W-440W
45mph = 1575W-2025W*

tostino said:
Well, my bike while i'm going 25mph on my bike, averaging 22mph on flat land with no wind, I am getting about 17-20 wh/mi.... If i'm blasting about going 45mph, my wh/mile can range from 35-45 wh/mi.
Click to expand...


http://endless-sphere.com/forums/viewtopic.php?f=2&t=15455&p=229463#p229463


*Edit: Revised, as per TPA's post below.
 
SoSauty posted...

Bafang:
22mph = 440W

Trek 3700 hardtail MTB
48V Lith-ion 10.5amp hr
25amp C-lyte controller
408 C-lyte
1.5" Schwalabee Marathon tires
cruise control


Clyte:
20mph = 350W

Schwinn 26" MTB
48V Ping 10amp hr
Bafang 8FUN
20amp 36V Shenzen Controller
1.75" Schwalabee tires
spring removed from throttle

SoSauty said:
My Ping 48V 10ahr batt provides 500W and I get close to 25mi with easy pedalling, maybe 400W Bafang. I weigh 180lbs, and cruise 20-22mph on somewhat level terrain. So, around 20W per mile :) My Lith-ion is a slightly stronger performer, 48V 10.5 provides 525W and will run 30 miles at 19-20mph in the hills with easy pedalling, C-lyte 408 maybe 500W; 17.5W per mile for it :p
Click to expand...
http://endless-sphere.com/forums/viewtopic.php?f=2&t=15455&p=229463#p229463
 
Extremely skeptical of <1000W at 45mph

40wh/mi at 45mph is more like 1800W.

40 Wh/mi * 45 m/h = 1800W
 
Come on guys, can we get with the TWENTIETH CENTURY HERE !!!! A LITTLE SI UNITS PLEASE!!!! WTF IS A MPH?????

Make ya guys sound like you were born in a barn!!<---a joke,

Cheers,

Ps: I am collecting data on riding in various snow conditions and temperatures. 20wh/ Km in -25C. Combination of sheer ice and 1-2 inch crusty snow. Big 2.5(6.35cm!) maxxix advantage runing at 30psi(206.7kPa!) 700km so far in the last month!!!!

mike
 
Heck I only used MPH because I couldn't remember the abbreviation for cubits. :p
 
DayGlo Avenger stats:
Fusin 36V hubmotor kit, 800 successful previous owner miles on it.
36V 9Ah D-type NiMH pack (from a Giant suede-e brand bike). I hadn't been able to fully charge it yet at the time I got this data.

Forgot to note the watts at actual specific speeds yet, but if this data is useful, here it is anyway:

2.5 mile trip to work at typical straightway speeds of 12-16MPH, with around a dozen or more full stops and starts for traffic controls:
42V starting rest voltage
40.47V finish rest voltage
34.32V minimum trip voltage
16.35A peak
22.4Wh (about 9Wh/Mile)
578W peak
0.538Ah

2.5 mile trip home from work at typical straightway speeds of 12-16MPH, with around a dozen full stops and starts for traffic controls. The light was also powered during this trip (had to put electrical tape over it to keep *every single light source* from turning it off!), which takes roughly 70mA extra:
40.68V starting rest voltage
38.64V finish rest voltage
32.01V minimum trip voltage
18.64A peak
23.9Wh (about 9.5Wh/Mile)
616W peak
0.652Ah
 
My bike does roughly 1 (0.94) parsec per petasecond, and uses about half a nano-quad/second of power to maintain the speed.

Quickly jumps to a full nano-quad/sec of power in hills.
 
Remind me how many cubits are in a bushel??? Or was that 7 chains to the fathom? :p
 
Hey TD, how about getting the troops to submit a standard format CSV file as an attachment then you can publish a spreadsheet here intermittently. For example,
MemberName, BikeName,SpeedInKph,Whrs,Speed,Whrs,Speed,Whrs,Speed,Whrs...
Just a thought.
 
Here are some fairly typical commute numbers for my set up. WE BL-36 600W front hub on Trek 3700 MTN Bike with total load of rider and bike at 270lbs running on 36V 14Ah SLA pack. Sorry I do not have watts per speed calculations. I hope to get some this week if it stops snowing. Typical ride has 3 or 4 full stops and starts over 8.68 miles so it is wide open most of the time at between 21mph and 25mph.

20 degrees F 8.68 miles 21.7mph avg 40.45V starting 4.293Ah 153.7Wh 23.00A peak 33.76V min 821.3W peak 37.27V stop 19.9Wh/Mi
43 degrees F 8.68 miles 22.6mph avg 40.63V starting 4.095Ah 146.8Wh 22.92A peak 34.21V min 818.2W peak 37.47V stop 18.9Wh/Mi
 
Interesting. An ebike takes double the amount of watts as a road bike at 20mph. At 30mph, it uses 3 times the amount of watts. :roll:
 
I will make a quick post then update it later to keep to the one post per person idea.

I soon will have three complete systems with all interchangeable parts so documenting all the possible combinations is unlikely - although putting some numbers to a 5303 Front/5303 Rear powered by a 120V of series headways/Ping v3 could be fascinating. I will put some numbers to the normal combinations and get more precise as I get some logging in (it's COLD around here yet although I still get 40 miles a week or so). I may try to document temperature variations, as I will surely get them.

Bianci MTB, No Suspension, V-Brakes
26" - 5303 Front
Ping v3 48V20aH
Crystalyte 48V35A Controller
Schwalbe 26x2.3 Big Apple Folding
10 MPH I don't go 10MPH
20 MPH 15 wh-m
30 MPH 30 wh-m
38 MPH 50 wh-m

My editor screws up with text longer than this. I'll edit offline and update: Updated 02-22-2010
 
JEB posted in another thread:
JEB said:
On a 6 mile run, same place every time (to stores) I found that if I used 100% battery power it would take 1amp hour per mile @ 24 volts. or 6amp hours for the run. On a sunny day when I was not in a hurry, peddeling away from every stop, and running 12 to15mpr instead of full throttle (20~mph), only 3 amp hours were used for the same trip. Lots of savings using the same wheel size.
Click to expand...
http://endless-sphere.com/forums/viewtopic.php?f=3&t=16553

12-15mph = 240W (+ some helping)
20mph = 480W (motor only)
 
D-Man said:
Interesting. An ebike takes double the amount of watts as a road bike at 20mph. At 30mph, it uses 3 times the amount of watts. :roll:
Click to expand...

Power is cubed to speed according to aerodynamics. So, (30/20)^3 = 3.375 times as much. So, that sounds about right.

An even more interesting fact, 20 mph can go nearly 2.25 times as far as 30 mph. :shock: A 10 mph difference doesn't sound like much, but a 15 mile difference between 15 miles and 30 miles does!
 
It's amazing how efficient a road cyclist is, especially on good racing equipment in a skinsuit. The pros you see on the Tour de France, most of them can ride 30mph in their time trial gear on 400 watts, on a flat, windless road. It sure helps having a 15-18lb bike and having the aero dynamics of a skinsuit and full aero position on aero bars.

I myself, still feel quite efficient on my road bike, it's nice because I can coast and my speed holds pretty well compared to my ebike, which drags down so much faster. I can't really figure it out, I guess it's just a combination of more drag from casual clothes, and more rolling resistance, especially due to the weight. I can roll around at <15mph on smooth pavement for what seems like forever on the roadie, like in a hilly parking lot, just going back and forth, coasting. So efficient, those 1" 120psi tires.

Here's a website some of you may go crazy over: www.analyticcyling.com

Since you have a CycleAnalyst, compare your input wattage to what you calculate you are putt to the wheels on your ebike, going up a known steady % grade hill.

Is there a cheaper alternative to the CycleAnalyst, maybe with less functions?
 
It is quite interesting to see that the watts may pretty much stay constant at 1,000 to 1,100W. In case of my ebike this is limited by the CA. You could pull more out of the batteries, but I set 25Amps as the max set for the 10Amp/hr 48V LiFePo4s I got from Justin. As a result, I am drawing an almost constant power out of the pack. Close to max efficiency, the wattage seems to drop a little.
(fast windings nine continent in 26 inch wheel, 25 Amps controller, 48V battery pack = low acceleration, but cruise speed of 43km/hr).
 
1700 watts @ 55 kph
1900 watts @ 60 kph

numbers are very rough, unfortunately and averaged by my poor heuristic based algorithm (brain). I am running a M1018z at 50V (~38 amps) with final gear reduction of 12.6 or so.
 
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