From: cn0gr8af@hydra.unm.edu (Student Class Account)
Subject: Re: Electric Cars Energy Usage: Summary  NEW DATA
Date: Sat, 11 Apr 92 03:31:18 GMT
Organization: University of New Mexico, Albuquerque

In article <1992Apr10.002417.27077@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>In article <43520143@hpindda.cup.hp.com> gph@hpindda.cup.hp.com (Paul Houtz) writes:
>>A great deal is made of the following calculations, which basically try
>>to indicate how many kilowatt hours per mile my car should use, vs
>>my own evidence.

>>>>>I. Power requirement of electric car:
>>>>> 
>>>>>Paul Houtz says his converted Ford Tempo goes 50 miles on an 8 KWH charge.
>>>>>This figures to   ** 0.16 ** kwh/mile
>>>>>John DeArmond quotes Kornhaus as saying Houtz uses
>>>>>                ** 1.5 ** kwh/mile
>>
>>   Okay, let's take this figure.  1.5 kwh/mile.   This is what the 
>>   anti-electric crowd would like you to believe as "reasonable".
>
>No, it's the number *published* as the result of long term tests by
>Southern California Edison, an outfit that *wants* electric vehicles
>so they can increase their sales of electricity. Here's the citation:
>
> 
>                GM Gas  Electric        Chrysler        Electric
>                Van     G-Van           Gas mini Van    TE Van
>                ------  --------        ----------      --------
> 
>wheelbase   :   125"    125"            112"            112"
>gross weight:   8600lb  8600lb          3975lb          5548lb
>Cargo volume:   256cuft 256cuft         133cuft         133cuft
>Payload     :           1800lb                          1200lb
>range       :           60mi*                           120mi**
>top speed   :           52mph                           65mph**
>0-30mph     :           13sec                           7.5sec**
>0-50mph     :                                           14 sec**
>fuel efficiency: 10mpg  1mi/kWh         16mpg           2mi/kWh
PLEASE NOTE *******************************************__________
>energy consump : 14,400  10,800 Btu/mi   9000Btu/mi      5400Btu/mi
> 
>*simulated urban driving
>**projected  
>     
>The above efficiency figures do not include losses of the charging 
>system; another figure based on real operational data by SCE (Southern
>California Edison), the G-Van, "During a seven-month demonstration 
>period, each vehicle was driven an average of 1945 miles, and 
>used 1.5 kWh of electricity per mile for charging".(p.6, Research 
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>Newsletter, SCE, Vol 20, no. 1; 1st quarter 1991)  
> 
>-------------------------------------------------------    

First of all, I would like to thank Gary for the work he has done in
calculating energy usage for electric vehicles.  It is obvious that he 
is trying to elucidate what is often misunderstood.
I drive an electric car, not
because I thought it would solve immediate environmental problems, but
because I am a graduate student in plasma physics who is interested
in alternative energy.  I figured a little bit of experimentation would
give me some new ideas about alternate transportation modes.

The car I put back together last fall has the following characteristics:
1.  Body and frame: Modified VW Rabbit (welded reinforcements around battery
compartment.
2.  Gross Vehicle Weight (Including Batteries, but without driver):3640 lbs.
3.  4 p155/70 tires inflated to about 36psi
4.  Motor: Seimens Compound Wound 120 Volt DC motor (Compound wound for
regenerative braking capability; Magnetic field coils excited separately
from armature)  Rated Output: 33 Horsepower Continuous (Short Spurts Higher)
5.  Controller: Square wave with varying duty cycle
6.  Batteries: Exide GC-5 Electric Vehicle Batteries (18 installed for 
main set).  Also, (1) 12 Volt deep cycle marine installed for accessories
This gives the car a range of about 50 to 55 Miles between charges.
These batteries are rated at 135 Min @ 75 Amp draw = 168.75 AmpHrs to
5.25 Volts across the terminals.
7.  Charger:  Lester Electric Automatic Charger with computer interface
	220 Volt.  

And Most Relevant to this discussion, a Kilowatt-Hour meter installed solely
for monitoring power usage of the car.

I just went downstairs and took the latest readings off the odometer and the
KWh meter and have the following to add to this discussion:
		A.  I have driven a total of 1475.8 Miles since last
		November.
		B.  I have used 758 KWh of energy in that time.  This
		is measured right where the car is plugged in.
		C.  This comes to an energy usage of 1.95 Miles/KWh 

This figure seems to agree rather well with the figure of 2 M/KWh from Southern
California Edison above.  

One other thought I might add concerns comparisons between horsepower
of electric and gasoline powered vehicles.  The horsepower rating of an
electric motor is usually flat (or linearly decreasing, depending on how
the motor is wound, starting at its maximum rating) throughout its entire
RPM range.  That is, the maximum rated horsepower is available from a dead
start.  This is not the case for a piston engine (unless there is a lot of
slipping at the engine-clutch interface during take-off).  Having driven this
car for a few months, and comparing it to my wife's car, I find the electric
car has acceptable acceleration for most city driving conditions.  It 
accelerates well at speeds up to about 40 MPH, and gradually decreases in
performance until it reaches its top speed of about 70 MPH (I haven't tried 
to get it to go any faster).  

I hope this data helps!

Rusty