Power calculator

A place to list links to sources for EV related parts and services.
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Miles   100 GW

100 GW
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Joined: Mar 16 2007 4:15pm
Location: London UK

Re: Power calculator

Post by Miles » Jan 16 2014 1:08am


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made_in_the_alps_legacy   10 kW

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Location: the alps - near italy, france, switzerland

Re: Power calculator

Post by made_in_the_alps_legacy » Jan 16 2014 1:15am

From a very good doc
The Aerodynamics of Human-Powered Land Vehicles
Albert Gross Chester Kyle Douglas Malewicki
Image

Read the complete doc HERE
Pay attention to the chart on page 6 :
Image
Last edited by made_in_the_alps_legacy on Jan 16 2014 1:59am, edited 1 time in total.

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Miles   100 GW

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Posts: 11020
Joined: Mar 16 2007 4:15pm
Location: London UK

Re: Power calculator

Post by Miles » Jan 16 2014 1:16am

:) Thanks!


mountain biker   100 W

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Re: Power calculator

Post by mountain biker » May 08 2015 5:00pm

hey appreciate that...wow sounds like you guys are into some serious calculations....but i am still stumped..the question revolves around how can i use this for a mid drive calculator...

i.e....let say you got a gng mid drive...say 20 to 1 is final ratio at crank...the motor is 24 volt...3650 rpm....controll allows 21 amps....

potetially motor could run at 175 rpm at crank maybe..more like 150 rpm is max... then it is driven through the bike gears...

lets say...1.3 to 1 first and then seven others going down from a 38 t crank...to 44 cassete to 18 t....

how could i use this for these calculators.. i would like to know the amount of power transferred to the bike wheels...

wouldn't a 1000 watts of power have different speeds and load capacities if geared differently....i just can't figure out the above charsts..but i would love to...i am thanking you guys in advance..bar none this is some pretty cool techinical stuff...the reason i am asking is i am trying to figure out what gearing i need in order to use a 24 volt motor...i know crazy but hey this is what we do here.

200 pound man 50 pound bike 250 for it all lets say...pounds...different inclines 2 and 4 and 6 and 8 and 10 and 12 percent......final speed would be interesting..i guesse as long as rpm is running around 50 to 90 percent would be cool.

mountain biker   100 W

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Joined: Sep 26 2014 2:21pm

Re: Power calculator

Post by mountain biker » May 08 2015 10:38pm

okay went to the thread and omg i was amazed...you must go to the end to get the updated version and man it is awesome.....you guys are really helpful and really smart.......thank you.

rimrock   1 µW

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Joined: May 17 2017 8:12pm
Location: Monterey, CA

Re: Power calculator

Post by rimrock » Jun 11 2017 4:25pm

Miles wrote:Revision 6 as an Excel file:
I downloaded this and tried to run it. I got the following message:
Screen Shot 2017-06-11 at 2.18.45 PM.png
Screen Shot 2017-06-11 at 2.18.45 PM.png (32.52 KiB) Viewed 1007 times
I'm running
Screen Shot 2017-06-11 at 2.20.34 PM.png
Screen Shot 2017-06-11 at 2.20.34 PM.png (37.04 KiB) Viewed 1007 times
The spreadsheet appears to work fine.

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Miles   100 GW

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Location: London UK

Re: Power calculator

Post by Miles » Jun 12 2017 3:44am

Thanks for the feedback. Do let me know if any errors surface during use.

I saved it as an Excel file using Libre Office.

swbluto   100 GW

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Re: Power calculator

Post by swbluto » Jun 12 2017 12:31pm

Okay, time to interject here.

There's a minimum amount of energy needed to climb a hill.
Then there's the minimum amount of energy to push away air molecules at a given speed.

Energy to climb hill = The sum of both of those.

So, yes, speed matters, but there's going to be a minimum amount of energy necessary to lift weight up a hill, regardless if you're going 0.1 mph. Tall hill+lots weight = the minimum is going to be A LOT of energy.

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