Re: Range/Driver

[Eric Jelinski <jelinski@idirect.com>]

At 08:55 PM 30/06/98 +0000, Canadian EV wrote:
>
>
>Range is the number one weekness people think an EV has.
>Our 192V Geo has a range of 30-40km AS I DRIVE, and thats what I quote
>when people ask. Today my wife went into town, a trip which usually
>takes 35-40ah out of the pack when I drive.
>She got home and I checked the E-Meter, it was at -22ah!
>I know from experiance that I could not do that trip on less than 30ah.
>I guess its time to find lighter shoes.
>This just points out that range has alot to do with who is driveing and
>shows how hard it is to quote range figures.
>BFN
>Randy

Over and above keeping the lead in the battery, (and not in your foot)
:-).... there are other factors that influence your range such as:
- do your brakes drag, just the slightest drag can make a major difference.
Ensure your brakes work freely by taking them apart and removing any rust
off the sliders.  Make sure the pistons are not corroded and will return
normally. Ensure the rubber boots are in good condition.  Ensure the
parking brake returns freely.   Every ev needs a parking brake in good
condition.  In automatics you have the locking pin, but you should not rely
on that.  Brakes sticking is highly variable and can depend on how hard
they were applied and how much road vibration it takes to rattle them loose.
- the driver ability to anticipate traffic conditions and lights. Figuring
that a green light will turn red by the time you get there and slowing down
 long before you get to the light so when it is green again you have not
lost as much kinetic energy that must be replaced from the battery to get
you up to speed again.   This kind of driving will drive all the
lead-footers nuts, but we can take a leaf from the driving skills of a
transport truck driver whose power to weight ratio is much lower than a car
and who may be aiming for highest fuel economy and still get the job done.  
One test I have done with an e-meter is drive a long flat section of
highway at a certain speed where there are no stops required, and note the
energy in KWh per mile.  Then to back to the same stretch of level road,
and read off the KWh to go from a standing start to your road speed.  Note
also the distance covered to get up to speed. Subtract these two on the
basis of KWh per mile and the result is the KWh to accelerate from any of
these situations, a stop sign or a light.  Therefore this is what you save
everytime you can synchronize with the traffic lights.  You can save even
more if you can synchronize with a traffic light at the bottom of an upgrade.
- recognize that if on a down grade, even slightly, take your foot right
off the accelerator pedal.  Forward emf applied to a motor that is turning
results in back emf also.  You could be needlessly drawing 50 amps, 100
amps what ever the position of your foot going down hill even though if you
took your foot off, you could coast for a bit.  Our bad habit with a gas
car is keep the foot on the accelerator unless you have to brake because of
the effect of engine braking.
- recognize the Peukert's effect of the battery on the range with
especially numerous high ampere draws for acceleration, so keeping the amps
down multiplies out in more distance.
It's in the basic physics,  1/2 mv^2 , mgh, mv, etc....  Conservation of
energy and momentuum.  Whoever suggested somebody should turn in their ev
due to short range should think again..... if we worked on the efficiency
and aerodynamics of gas vehicles, tires, transmissions and driving skills
etc, we could get more mpg out of our gas cars.
regards,   Eric Jelinski
Durham Electric Wheels

www.durhammall.com/electric wheels
Electric Vehicle Products and Services 
Bowmanville, Ontarion Canada