Power calculator

[Miles]

This spreadsheet calculator was posted on the Power Assist list sometime ago. Credit for the program to Dave Everett. I've corrected one of the slope conversion formulas, that's all.

[Miles]

Just tidied this up a bit.

[Miles]

Version 3 attached.

The expressions used for the formula in cell G7 were revised to enable the spreadsheet to function correctly on Google Spreadsheets.

You can now use this calculator without the need for Microsoft Excel.

Create an account with Google and upload the file to http://docs.google.com/

Please post any bugs/suggestions here.

Miles

P.S. I'm intending to append a table of "typical values" to the spreadsheet, so that people will be able to enter the value that most closely corresponds to their specific case.

[Miles]

If you don't have spreadsheet software, you can also upload this program to: http://www.editgrid.com/site and use it online. Editgrid seems to be better than Google Docs.

[PJD]

As far as power calculations for climbing various grades, a while back I set up a spreadsheet so I could use the various slope hills in my area, along with a drag force calculation as a sort of poor-boy dynamometer test.

The spreadsheet is attached. It provided actual motor performance graphs for a hub-motored bike, or it could be modified easily for a chain or reduction gear.

It gives the calculation results and both metric and US units, but the raw data has to be in US units, sorry.

The numbers entered on it representing the actual performance on my e-max.

[fechter]

Whoa.. almost 5kw. That's a pretty spunky scooter.

[deardancer3]

I like this power calculator; thought I would share.

(It lets you easily swap out different bike frames with default setting)

http://www.kreuzotter.de/english/espeed.htm


Dick in colorado

[paultrafalgar]

As far as power calculations for climbing various grades, a while back I set up a spreadsheet so I could use the various slope hills in my area, along with a drag force calculation as a sort of poor-boy dynamometer test.

The spreadsheet is attached. It provided actual motor performance graphs for a hub-motored bike, or it could be modified easily for a chain or reduction gear.

It gives the calculation results and both metric and US units, but the raw data has to be in US units, sorry.

The numbers entered on it representing the actual performance on my e-max.

That's a fascinating spreadsheet, PJD. What I find interesting is comparing Row 12 with Row 16.
You have halved (approx) the speed and EVEN though it's doubled the slope, you use 60% of the power!!!
SLOWING DOWN ON THE CLIMB is the way to go.

[Miles]

SLOWING DOWN ON THE CLIMB is the way to go.

Slowing down makes very little difference to the total energy consumed to climb hills.....

[paultrafalgar]

Not according to PJD's spreadsheet.

[paultrafalgar]

If you don't have spreadsheet software, you can also upload this program to: http://www.editgrid.com/site and use it online. Editgrid seems to be better than Google Docs.

Just a little plug for OpenOffice. You don't need to be without a spreadsheet! OpenOffice is FREE for both Windows and Linux (probably Mac as well, I don't know).
IMHO better than Microsoft Excel by far.

[Miles]

If you halve your speed you take twice as long to climb the hill.....

Sure, we know the power required to overcome air resistance goes up with the cube of the speed but if the power required to climb goes up linearly then slowing down on hills will have less effect on the total energy consumed than it would on the flat.

[Miles]

If you don't have spreadsheet software, you can also upload this program to: http://www.editgrid.com/site and use it online. Editgrid seems to be better than Google Docs.

Just a little plug for OpenOffice. You don't need to be without a spreadsheet! OpenOffice is FREE for both Windows and Linux (probably Mac as well, I don't know).
IMHO better than Microsoft Excel by far.

I certainly wouldn't disagree with this

I moved from Excel '98 to Open Office Calc after trying Microsofts' latest.......

[Miles]

Latest version, in ODS format:

[Eric]

Am I the only one who cannot open this due to its password protection? It probably works fine in other spreadsheets, but Xcel is having issues.
Eric

[paultrafalgar]

Am I the only one who cannot open this due to its password protection? It probably works fine in other spreadsheets, but Xcel is having issues.
Eric

It's an open-source format that OpenOffice uses, I'm not sure if Microsoft recognises/tolerates importation of .ods, but if you ask Miles nicely, he will convert it using Openoffice to Microsoft .xls format! BTW IMHO Openoffice calc is vastly superior to Excel and it's a free download, so why not get a copy that runs on Winders (if you must use a c**p operating system. )

[Miles]

Hi Eric,

Here's an older version in Excel format and a conversion of the latest from .ods to .xls:

[Miles]

Revision 5.

- Added breakdown of torque at the wheel.

- Altered background colours of cells.

[Miles]

Revision 6. Simplified version.

- Removed battery characteristics; motor efficiency and torque inputs.

- Removed distance and amps outputs

- Added motor torque output.

OpenOffice format (for Excel format see 2 posts down).

[Miles]

Reference for aerodynamic data: http://books.google.co.uk/books?id=0JJo ... on&f=false

[Miles]

Revision 6 as an Excel file:

[Miles]

Good reference for rim/tyre sizes:

http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3802