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Discussion Starter #1
>http://money.cnn.com/2011/01/03/~electric_~ commuter_diary.fortune/ =

>Diary of an electric commuter? By Sue Callaway? Jan 4 2011? ... =

>I finally realized I had taken my assignment seriously -- in the wrong =

>direction. Stop and start traffic is what the Leaf eats for breakfast. =

>That is where "hypermiling," the practice of range-preserving driving, =

>kicks in. The slower you go, the less you brake, and the more you =

>coast, the more range you not only preserve but regenerate. There's =

>even an "Eco" mode option that further counteracts battery drain by =

>increasing engine breaking and retarding acceleration. =


That's not "Eco" mode, thats the "ICE Emulate Mode".

Contrary to marketing hype and misconceptions foisted on the public,
coasting to a stop is "Eco" mode.

EV drivers know that Regenerative braking CAcan not increase range.. if it
could a generator on the wheel would do a better job.

Is this a case of ignorance on the part of the Engineer or Marketing?

"The only thing that will increase range is a 180 degree tailwind greater
than 45 Mph.." Its called reducing your parasitic drag.


--
Use what talent you possess: The woods would be very silent
if no birds sang except those that sang best. -- Henry VanDyke
--
Jim - in the valley of the Sun
www.evalbum.com/425
www.evalbum.com/804
www.evalbum.com/1703


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Discussion Starter #2
For that matter - *any* tailwind increases range
for equal driving speed, because it reduces the
power needed to overcome the (lower) air drag...
Just this morning I reviewed the power required
for my S10 truck to drive a certain speed.
With just a light breeze aft/front the current to
drive on a 50 MPH road changed from 40 to 45 Amps
(312V nominal pack voltage)
Increasing the drive speed to max (adding about 17
MPH and achieving 68 MPH on the freeway) caused
the current to spike up to 105 Amps and the pack
to sag slightly to about 300V, so it takes more
than 2x the power to overcome mainly the added
wind drag to increase speed 1/3 (going to 133%)

If you punch 1.33 into a calculator and take the
powers, you see that at the 3rd power, you get a
factor 2.35 so it seems from this simple measurement
that power requirement follows a 3-rd order relation
to the drive speed, which matches well with theory.
(The air drag increases with the square of the speed
and therefor the power which is drag times speed will
increase with the cube of the speed)
http://en.wikipedia.org/wiki/Drag_%28physics%29


Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Wednesday, January 05, 2011 8:12 AM
To: [email protected]
Subject: [EVDL] Subject: EVnews: EVr Diary,BYD,Trabant,T3,Fuji,

>http://money.cnn.com/2011/01/03/~electric_~ commuter_diary.fortune/
>Diary of an electric commuter? By Sue Callaway? Jan 4 2011? ...
>I finally realized I had taken my assignment seriously -- in the wrong
>direction. Stop and start traffic is what the Leaf eats for breakfast.
>That is where "hypermiling," the practice of range-preserving driving,
>kicks in. The slower you go, the less you brake, and the more you
>coast, the more range you not only preserve but regenerate. There's
>even an "Eco" mode option that further counteracts battery drain by
>increasing engine breaking and retarding acceleration.

That's not "Eco" mode, thats the "ICE Emulate Mode".

Contrary to marketing hype and misconceptions foisted on the public,
coasting to a stop is "Eco" mode.

EV drivers know that Regenerative braking CAcan not increase range.. if
it could a generator on the wheel would do a better job.

Is this a case of ignorance on the part of the Engineer or Marketing?

"The only thing that will increase range is a 180 degree tailwind
greater than 45 Mph.." Its called reducing your parasitic drag.


--
Use what talent you possess: The woods would be very silent if no birds
sang except those that sang best. -- Henry VanDyke
--
Jim - in the valley of the Sun
www.evalbum.com/425
www.evalbum.com/804
www.evalbum.com/1703


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Discussion Starter #3
Don't forget you are more enlightened than the average driver. Yeah, most drivers know in the back of their mind coasting to a stop and accelerating slowly saves energy. Most stilll drag race away from lights, wait until the last moment, and brake hard. For the average driver it well could be this "eco" mode gives them more range.

With oil going up in price maybe we'll see more interest in range contests and techniques.




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Discussion Starter #4
On 4 Jan 2011 at 21:41, [email protected] wrote:

> EV drivers know that Regenerative braking CAcan not increase range..

Of course it can! How much, and whether it's worth the incremental cost to
you, depends largely on the terrain where you live, and how you drive.

Here's an example of regen at its best :

http://www.brusa.li/index.php?id=43&L=1

David Roden
EVDL Administrator
http://www.evdl.org/


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Discussion Starter #5
"EV drivers know that Regenerative braking CAcan not increase range.."

Do this test: Start off at zero speed and kinetic energy with the vehicle
stopped. Then convert electrical potential energy from the batteries to
mechanical energy to do work and accelerate the car to some velocity and
kinetic energy. Then coast until you are about to run through a stop sign,
red light or hit the car in front of you which is slowing for a turn, a stop
sign or a light. Then apply the brakes to slow or stop, converting some or
all of the remaining vehicle kinetic energy to heat via friction in the
brakes. Now repeat exactly the same, except instead of applying the brakes,
ease off on the accelerator pedal to slow or stop as needed, converting some
of the vehicle kinetic energy to electrical potential energy in the battery
pack. You have regained some of the energy that would have been lost to
friction in the brakes. So yes, regen can and does increase range. I've
done the test while datalogging battery current, voltage, and Ah used from a
TBS ExpertPro gauge, as well as vehicle velocity and distance with a
datalogging gps. Regen gave me a bit under 10% increase in range for the
about 50 mile course I drove with hills, highway, secondary roads, and stop
signs.
--
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Subject-EVnews-EVr-Diary-BYD-Trabant-T3-Fuji-tp3175218p3176873.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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Discussion Starter #6
If you have to touch the brakes in the non-regen case, then you are correct.
However, if you can work everything out so that the cars in front of you are
just starting to move and match your speed as you arrive, then the non-regen
case will win. This is because it is better to keep the energy as kinetic
energy than suffer the conversion losses to go back to electricity. Of
course, even with losses, this is WAY better than converting to heat in the
brakes.

I know this sounds silly and/or impossible, but a commuter that cares about
this and drives the same route every day can come very close to this ideal
on most days if traffic is not really heavy. I have people pile up
sometimes behind me, but they eventually notice that we arrive at the light
just as it changes to green. (The fact that this area of congestion has a
center turn lane usually keeps them from passing me.) By not having to
stop, we're actually helping to keep traffic flowing smoothly.

I look at this as analogous to the Reduce, Reuse, Recycle paradigm for
trash.

Best of all is to Reduce - Never take the energy out of the battery if you
can.
Next best is to Reuse - Keep the kinetic energy as vehicle speed if
possible.
Next, recycle (convert back to electric energy if possible)
Finally, throw it away (use the brakes) if you have to.

Since my conversion doesn't have regen capability, I obviously try to focus
on the Reduce and Reuse more 8^).

Mike

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of tomw
Sent: Wednesday, January 05, 2011 9:22 PM
To: [email protected]
Subject: Re: [EVDL] Subject: EVnews: EVr Diary,BYD,Trabant,T3,Fuji,


"EV drivers know that Regenerative braking CAcan not increase range.."

Do this test: Start off at zero speed and kinetic energy with the vehicle
stopped. Then convert electrical potential energy from the batteries to
mechanical energy to do work and accelerate the car to some velocity and
kinetic energy. Then coast until you are about to run through a stop sign,
red light or hit the car in front of you which is slowing for a turn, a stop
sign or a light. Then apply the brakes to slow or stop, converting some or
all of the remaining vehicle kinetic energy to heat via friction in the
brakes. Now repeat exactly the same, except instead of applying the brakes,
ease off on the accelerator pedal to slow or stop as needed, converting some
of the vehicle kinetic energy to electrical potential energy in the battery
pack. You have regained some of the energy that would have been lost to
friction in the brakes. So yes, regen can and does increase range. I've
done the test while datalogging battery current, voltage, and Ah used from a
TBS ExpertPro gauge, as well as vehicle velocity and distance with a
datalogging gps. Regen gave me a bit under 10% increase in range for the
about 50 mile course I drove with hills, highway, secondary roads, and stop
signs.
--
View this message in context:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/Subject-EVnews-
EVr-Diary-BYD-Trabant-T3-Fuji-tp3175218p3176873.html
Sent from the Electric Vehicle Discussion List mailing list archive at
Nabble.com.

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Discussion Starter #7
Your statement can only be true if you never need to use your brakes. If you
use your brakes then you are dumping energy as heat, which could have been
recovered with regen. Certainly it's better to coast and conserve where
possible, but a long steep hill where coasting means exceeding speed limits
by a large margin is a good opportunity for regen, as is a stop sign at the
bottom of a hill, or keeping up with stop and go traffic and not becoming a
road hazard. Anyone who thinks regen can't increase range probably doesn't
drive in an area with a lot of steep hills.


[email protected] wrote:
>
>
>
> EV drivers know that Regenerative braking CAcan not increase range..
>
>

--
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Subject-EVnews-EVr-Diary-BYD-Trabant-T3-Fuji-tp3175218p3177438.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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