Hey, I'm gonna try to plug in all my crap and see what I come up with.
Thanks a lot Steffen
Hello
You may know the Lennon rodgers excel sheet which you can use to predict the range and top speed for your electric motorcycle build.
Well, that is what I consider version the elmoto sheet version 1.0, or stricly speaking 1.5.
The elmoto sheet as made by Lennon Rodgers features feature for:
- Calculating your electric motorcycles;
Weight based on the weight of the rider, components and rolling chassis.
Range based on your batteries specifications.
Top speed based on your motors RPM.
And power required based on aerodynamic requirements.
I've been working on improving the look, feel and workings of Lennon Rodgers sheet as well as bring new features to its capabilities in form of the Elmoto excel sheet V2.0, and here it is.
We are currently up to version 2.18
Version 2.0 Has a number of added features and improvements over the Elmoto 1.0 sheet.
- The user interface has been boiled down for easier viewing
- Full support for and all readouts now in Metric form as well as Imperial.
- Added support for incremental motor readouts, dynomometer readouts.
This feature supports:
Any known motor types and strengths.
Motor output up to 8000 RPM.
- Added graphical interpretaion of motor readout.
- Added a more accurate method of determening top speed.
Graphical readout off motor power up against aerodynamic and rolling resistances.
And if this method doesn't pinpoint your motorcycles topspeed then this sheet also features RPM limited top speed.
Changelog - All the changes and additions made since version 2.0
Version 2.1
- Improved the interface slightly.
- Improved calculations regarding motor readout.
- Added graphical interpretations of Range, Acceleration and Costs.
- Added calculations for determinating the 0-60, 0-100, 1/4 mile times and time to top speed.
- Now factors Aerodynamic drag and Chain resistances in all calculations where these are relevant.
Version 2.15
- Added note stating origin of the sheet.
- Minor fixes of spelling mistakes or bugs.
- Some small tweaks to the graphs to prevent them from going out of control.
- Added support for limited motor opperation.
The motor output is now scaled according to battery limit in the form of rated continuous discharge.
- Battery life and costs now also factor battery rated continuous discharge.
Version 2.16
- Now factors both Max and continuous battery discharge.
- Limited motor operation is now based on Maximum battery discharge and not continuous (how foolish of me)
- Amps at City, Country road and Highway speeds added under the Range tap.
Version 2.18
- Added a "controller specifications" box.
- Controller efficiency now factors in range calculations.
- Thanks to DaveAK motor output is now regulated as a function of controller and battery rating.
- Voltage Sag now factors in motor performance, range, top speed and acceleration calculations.
To view this sheet you need either Microsoft Excel 97 or newer, or any program which is combatible with the .xls format.
You are welcome to post any problems you find with this sheet or any suggestions you might have.
Enjoy
Last edited by Coninsan; 27 March 2012 at 1249.
"I reject your reality and substitute my own." Adam Savage
Hey, I'm gonna try to plug in all my crap and see what I come up with.
Thanks a lot Steffen
Nice work
Couple things I noticed
-You should make frontal area a user inputed parameter
-You should have HP be automatically calculated from RPM and torque (RPM*torque(ftlbs)/5252=HP)
-Your max Amps of the motor can be very misleading because it doesnt take into account voltage sag and for AC it doesnt take into account difference between V Supply and V Motor
-I dont really think continuous power is appropriate to calculate because it is thermally depended
Some more in depth additions.
-You could make a graph that plots range at different speeds, just use 2 or 5 mph increments
-Any easy way to take into account voltage sag at different limits
-You may be able to create a crude 0-60 acceleration using the max torque values at each motor speed (i have an excel sheet at home that does this, ill upload later)
Not trying to complain, just trying to help. I love the layout and it works much simpler than the Lennon Spreadsheet
Thanks!
This is very good input, keep it up. To make this much more user friendly than the Lennon Rodgers sheet was also one of my major goals, so many of the parameters which were just used for calculations have been moved to a seperate sheet.
It already is, I just forgot to mark it as such.-You should make frontal area a user inputed parameter
From trying it out on my own data, it seems pretty spot on, but is this accurate enough for all motor types?-You should have HP be automatically calculated from RPM and torque (RPM*torque(ftlbs)/5252=HP)
I hear you on these, the data you've mentioned is useless anyway, not used in any calculations, so if it's in the way it'll be removed in the next version.-Your max Amps of the motor can be very misleading because it doesnt take into account voltage sag and for AC it doesnt take into account difference between V Supply and V Motor
-I dont really think continuous power is appropriate to calculate because it is thermally depended
Functionality for this feature is already built into the sheet, though it is not in such small increments since it is based on motor RPM. My focus has mainly been to get the major and most common speeds integrated. But a graph might sneak inn in the future, should be simple enough.Some more in depth additions.
-You could make a graph that plots range at different speeds, just use 2 or 5 mph increments
I am sorry but that is beyond my skill, yet if you can find a way to take it into account please do tell.-Any easy way to take into account voltage sag at different limits
Thanks, lets see if we can get that into a future version.-You may be able to create a crude 0-60 acceleration using the max torque values at each motor speed (i have an excel sheet at home that does this, ill upload later)
Last edited by Coninsan; 28 February 2011 at 1522.
"I reject your reality and substitute my own." Adam Savage
No excel sheet yet what gives?-You may be able to create a crude 0-60 acceleration using the max torque values at each motor speed (i have an excel sheet at home that does this, ill upload later)
But basicly, I've just finished a fomula based on the info given here
Which gives the specific time it takes to reach a given speed based on the motors HP. This leans on the fact that 1 HP = 550 ft-lbs/sec.
Basicly:
Time-to-speedX=(HP*550)/(Weight/32,2*SpeedX-in-ft/sec^2)
And when the Elmoto sheet already contains data for speeds given at different motor RPM's this fomula would give a crude curve for acceleration based on motor HP.
I guess I'll be working late tonight
"I reject your reality and substitute my own." Adam Savage
Shoot man. I completely forgot, i even wrote it down to do it. Ill send myself an email to remind me to upload it tonight. Basically the sheet factors in gearing and weight but ignores aero drag. It calculates the constant torque range of the motor then the constant power state of the motor in 5mph increments. It then calculates the time inbetween each step.
Hopefully I get my act together tonight
Ahh no problem.
Basicly what I've worked out just now plots out the acceleration curve in a graph
With time in seconds on the Y-axis and speed on the X-axis
It's based on speed at increments of 500 in motor RPM, the motors HP at said RPM and the motrocycles weight.
I'm figuring that aerodynamic resistance wouldn't matter much as long as the power at said speed is more than required by aerodynamic and rolling resistances. And these figures are accounted for in the top speed graph.
"I reject your reality and substitute my own." Adam Savage
Thats exactly what the one I have does but it just asks for max torque and base speed. You're a smart man sir! If I can remember I may try to implement a formula/model to take into account aero, it gets tricky with the v^2 term.
I have always wanted to update this spreadsheet, but excel has always frustrated me and i donta have enough matlab experience. Keep up the great work and ill try to keep helping
Last edited by Nuts & Volts; 01 March 2011 at 1105.
"I reject your reality and substitute my own." Adam Savage
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