[ausev] EV Calculator Script

[Charles Birkhead]

I have found Uve's electric vehicle calculator
(http://www.geocities.com/CapeCanaveral/Lab/8679/evcalc.html) to be
useful in estimating EV performance.  It includes the peukert effect.  I
have modified it to include internal wiring resistance and idle current
draw.  It is relatively easy in Uve's calculator to add/modify battery
characteristics.

Suggested modifications to your version include:
O	motor speed/torque/current characteristics
O	drive gear ratio (transmission and rear axle)
O	idle current draw

Each electric motor type has a given speed/torque/current
characteristic.  This needs to be matched to the vehicle requirements.
The motor must develop the required torque at its rpm for the given
vehicle speed.  The needed gear ratio for a given motor will vary
depending upon operating requirements.  Incorrect selection will result
in poor performance and should be reflected in the calculations.

For example, operating an ADC FB-4001 directly coupled to the rear
differential will result in poor acceleration.  Further, operating a
Kostov only in first gear also result in motor overspeed at freeway
speeds.  This should be indicated by the calculator, such as Uve's. 


-----Original Message-----
From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
Behalf Of Nick Viera
Sent: Wednesday, January 03, 2007 9:32 PM
To: ausev at austinev.org; aceaa at aceaa.org
Subject: [ausev] EV Calculator Script

Hi all,

I know that there are a handful of sites already online with scripts 
that attempt to calculate things such as range and top speed for EVs. 
However, I've been under-impressed with all the ones I've seen so far, 
because their user-interfaces tend to be counter-intuitive and all the 
results I've gotten were very to extremely inaccurate/inapplicable to 
what my EV can achieve in real life.

So I've been playing around with writing my own calculator script I call

the Electric Vehicle Range, Acceleration, and Top Speed calculator (aka 
EV-RATS). My main goals for this calculator script is to be easy to use,

yet powerful and as accurate as possible for such a script. For example,

*correctly* calculating Peukert's effect for a given battery pack and 
adjusting range and run time accordingly is too important to ignore.

EV-RATS is here: http://www.driveev.com/tools/evrats/index.php

I'm interested to hear any thoughts, suggestions, etc. about it. I'm 
still working on it, so there may be issues with it that I haven't 
discovered yet. Most importantly I'd be cool to hear how close it comes 
to predicting the real-world results (range, top speed, V sag, power 
consumption, etc..) you all get from your EVs after putting your numbers
in.

Thanks!

-- 
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
http://www.ACEAA.org/
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