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Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 10:10 am
by mwalsh
tps wrote:This backs up what I've thought and what Nissan has been saying all along. The lack of an active thermal management system in the LEAF's traction pack does not make it an infereor vehicle. Instead, this shows that the LEAF is traction pack is superior because it does not need active thermal management.
+1! :)

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 10:35 am
by EricH
nader wrote:Here is a sample clip to hold you guys over until the full clips finish uploading.

http://www.youtube.com/watch?v=IcVx4BoNzEM
Excellent... I grew up driving up to CanAm races with my folks, but never got to drive the course. Had to stop from fast-forwarding to the Corkscrew :lol: Very nicely done, and thanks for sharing!

PS: Do you know when the next Refuel is scheduled?

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 11:20 am
by mwalsh

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 11:38 am
by Herm
Its interesting that the Tesla Roadster is still having heat issues, a perfect example why racing improves the breed.

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 11:51 am
by DaveEV
tps wrote:This backs up what I've thought and what Nissan has been saying all along. The lack of an active thermal management system in the LEAF's traction pack does not make it an infereor vehicle. Instead, this shows that the LEAF is traction pack is superior because it does not need active thermal management.
Of course, it doesn't hurt that the LEAF's motor only pulls a max 80 kW from a 24 kWh pack (3.3C) while the Volt pulls 111 kW from a 16 kWh pack (7C) and the Telsa pulls 185 kW from a 53 kWh pack made up of laptop cells (3.5C). I think the main issue with the Tesla is that the motor overheats, though, not the battery pack. Which shouldn't be that tough a nut to crack - after all, ICE engines with similar output have to deal with 20 times the waste heat! (I do have to wonder if the cooling issues in the Tesla are why we haven't seen one race up Pikes Peak yet?)

Let's strap a bigger motor onto the LEAF and then we'll see how the battery does with passive thermal management. I'm sure that Nissan limited power draw to make sure that the battery lasts as long as possible at the expense of performance.

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 12:46 pm
by nader
gasmiser1 wrote:Nice :-) Looks like you guys had fun 8-)

Did the Leaf beat the Volt's time on the track?
Nope. Whoever was driving was pretty good behind the wheel. The Volt is a much sportier ride too.

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 12:50 pm
by nader
awallis wrote:Awsome job. I'm so jealous!

Are you pointing at Tesla's that are dropping off the track because they are overheating?
Pointing out the window to the left or right gives the driver behind you the right to pass. Pointing straight up let's others know you are exiting the track.

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 12:59 pm
by DaveEV
nader wrote:Nope. Whoever was driving was pretty good behind the wheel. The Volt is a much sportier ride too.
What kind of lap times were the Volts posting? Were they disqualified if the range extender came on? :)

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 1:42 pm
by TEG
EricH wrote:PS: Do you know when the next Refuel is scheduled?
It has been an annual event. So, in about a year...

Re: ReFuel 2011 at Laguna Seca in the Leaf (w/ pics)

Posted: Tue Jun 28, 2011 1:52 pm
by TEG
drees wrote:...I think the main issue with the Tesla is that the motor overheats, though, not the battery pack. Which shouldn't be that tough a nut to crack - after all, ICE engines with similar output have to deal with 20 times the waste heat!...
I have seen Tesla Roadsters overheat the motor, the battery pack, and the PEM (Power Electronics Module.)
The motor and PEM are air cooled, so that is why the Leaf (with a liquid cooled motor and inverter) has some advantage there.
Even with liquid cooling, the Roadster battery can sometimes overheat because it is outputting more power, and they also have to be more careful with those laptop cells which can have catastrophic problems if overheated too much.
Note, all of these overheat conditions are monitored and managed. When a Roadster decides to stop racing due to an overheat alert it is because the system is starting to limit power because it detects that things are getting risky. So they aren't having a serious problem, but rather an intentional safety measure kicked in.


By the way, they are opposites in this way:
Roadster has liquid cooled battery, but air cooled motor and inverter.
Leaf has liquid cooled motor and inverter, but (passive) air cooled battery.


The Leaf claims to get away with no active battery cooling by having a more inherently stable and robust battery chemistry.
In a few years we can test these claims to see how well they are holding up.

By the way, newer Tesla Roadsters added another cooling fan for the PEM, and a better air-conditioner (which can cool the batteries), and better ducting for the motor cooling, so they have been making some improvements, but they are somewhat incremental. I recall hearing Tesla folks saying that the Roadster isn't sold as a track car, and it isn't a great top speed car (on the Autobahn for instance.)

Their next model (Model S) will have a liquid cooled motor and inverter which should take care of that sort of concern.