Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks prior

[RWatkins]

I fail to see much value to an air cooling fan if the ambient air temperature is high, as it is in phoenix and other areas in the summer. You need something to lower the temperature (liquid cooling, A/C, Peltier, etc.) below ambient...

When Jim Stack at the end suggested using the solar panel to power a fan on the battery, Andy indicated some enthusiasm and was taking notes.

It still could be useful to run a fan, but at night if/when temperature drops sufficiently. Lowering the pack temperature overnight gives it that much more thermal inertia to resist heating during the day. The net effect is still a lowering of the average battery temperature over time, and less time spent at the hottest temps.

While this would require some energy, a simple fan is a lot less energy expense than active refrigeration. Just clearing the boundary layer of air could make a difference in the amount of cooling that takes place overnight. Inside the pack, heat tubes could convey the heat from the center of the pack to the case. All depends on where you're parked, how hot your garage stays (if garaged), etc... But I wouldn't dismiss it out of hand.

+1. Any idea how warm the pack would get in typical Phoenix day from pre-cooled state of 65-70 degrees F ?.
Pre-cool the battery while plugged in, reduce solar gain with shading and/or window treatment, line inside of underbelly cover with radiant barrier to block excess heat when parked over hot pavement and look at other ways of stabilizing battery temp in ideal range. If ambient air temp is too high it obviously can't be used to cool battery without being pre-cooled itself. Using cooled cabin air while driving would help maintain lower temp until next plugin permitted pre-cooling the battery.

 

[surfingslovak]

Any idea how warm the pack would get in typical Phoenix day from pre-cooled state of 65-70 degrees F ?.
Pre-cool the battery while plugged in, reduce solar gain with shading and/or window treatment, line inside of underbelly cover with radiant barrier to block excess heat when parked over hot pavement and look at other ways of stabilizing battery temp in ideal range. If ambient air temp is too high it obviously can't be used to cool battery without being pre-cooled itself. Using cooled cabin air while driving would help maintain lower temp until next plugin permitted pre-cooling the battery.

TickTock posted this last summer:

Click to open

 

[MrIanB]

Sorry it took so long, but I finally managed to get my video of the Jan 8 Nissan LEAF Town Hall talk posted on YouTube: http://www.youtube.com/watch?v=uuPQe23vP0Y" onclick="window.open(this.href);return false;
It runs close to two hours in length (1:53:17 to be exact), but it's posted in its entirety start to finish.
[youtube]http://www.youtube.com/watch?v=uuPQe23vP0Y[/youtube]

Enjoy.
Jim

Thanks for posting the video. Quite a bit of frustrated and disillusioned Az buyers. I can't complain here in Texas after 1 year on y lease, still have 12 bars but my range has decreased some as I can no longer reach 100 miles driving as I did in my first 6 months. Overall very satisfied as still getting between 75-80 miles per charge. No problems and the car going in the next couple of weeks for its first yearly battery test.

I hope Nissan comes through for everyone starting with my compadres in Az.

Ian B

 

[mwalsh]

Sorry it took so long, but I finally managed to get my video of the Jan 8 Nissan LEAF Town Hall talk posted on YouTube: http://www.youtube.com/watch?v=uuPQe23vP0Y" onclick="window.open(this.href);return false;
It runs close to two hours in length (1:53:17 to be exact), but it's posted in its entirety start to finish.
[youtube]http://www.youtube.com/watch?v=uuPQe23vP0Y[/youtube]

Enjoy.
Jim

Well, there's 1:30 I'll never get back, but thanks for posting it. Love the way the group heads for the stage en-masse immediately following the meeting's close. Good job they confiscated torches and pitchforks at the door before hand. :lol:

I guess I could have fast-forwarded to the last 20 minutes or so, because that's when the most important point was made...that the technical loss of battery capacity does not mean an equal loss of vehicle autonomy. Did they get it? Well, Andy Palmer certainly appeared to comprehend what was being said, but disagreeing with it on a "mathematical" basis wasn't completely helpful.

All-in-all, probably better than not having the meeting. But I would have liked to see more after 9 months with the issue.

 

[RegGuheert]

Thanks for posting the video, Jim!

But I would have liked to see more after 9 months with the issue.

We've certainly been discussing the fact that usable range is dropping faster than battery capacity for at least six months now.

 

[JPWhite]

Came across a video with an interesting theory on the LEAF Battery and heat. This analyst blames the battery configuration. First time I've heard that theory!

[youtube]http://www.youtube.com/watch?v=fgcxZl6KELE[/youtube]

 

[surfingslovak]

Came across a video with an interesting theory on the LEAF Battery and heat. This analyst blames the battery configuration. First time I've heard that theory!

Intetresting theory, thanks for posting. Note that the rear stack is vertically oriented, and the front stack is not quite as high, which would indicate that the engineers at Nissan were giving this particular problem some consideration.

 

[Nubo]

Came across a video with an interesting theory on the LEAF Battery and heat. This analyst blames the battery configuration. First time I've heard that theory!

[youtube]http://www.youtube.com/watch?v=fgcxZl6KELE[/youtube]

After the 2nd dismissive "these things [LEAFS]", I'd had enough.

 

[leafwing]

Came across a video with an interesting theory on the LEAF Battery and heat. This analyst blames the battery configuration. First time I've heard that theory!

Intetresting theory, thanks for posting. Note that the rear stack is vertically oriented, and the front stack is not quite as high, which would indicate that the engineers at Nissan were giving this particular problem some consideration.

The guy to the left could not even bring himself to call the LEAF a car; he kept saying that "thing" over and over...

 

[leafwing]

Came across a video with an interesting theory on the LEAF Battery and heat. This analyst blames the battery configuration. First time I've heard that theory!

[youtube]http://www.youtube.com/watch?v=fgcxZl6KELE[/youtube]

After the 2nd dismissive "these things [LEAFS]", I'd had enough.

You beat me to it...

 

[Herm]

Its an interesting theory but not correct.. internal cooling of the battery pack is by conduction from module to module and then to the skin of the battery case, there is very little air convection going on inside that case.. in any case the only time that battery heats up is while fast charging to 100%, a rare event.

The show was well done and interesting, they could have spent a bit more time on the Leaf but it is selling poorly.

 

[Herm]

[
TickTock posted this last summer:

Click to open

Its just amazing how that battery stays at 100 deg (average) all day, no wonder Phoenix has Leaf issues.

 

[Stoaty]

Came across a video with an interesting theory on the LEAF Battery and heat. This analyst blames the battery configuration. First time I've heard that theory!

The available data does not support that theory. All of the heat affected battery packs appear to be aging evenly, with minimal differences in cell voltages from all the reports we have heard. Have any of the "hot" packs been repaired by replacing a module? Not that I know.

 

[TonyWilliams]

Its an interesting theory but not correct.. internal cooling of the battery pack is by conduction from module to module and then to the skin of the battery case, there is very little air convection going on inside that case.. in any case the only time that battery heats up is while fast charging to 100%, a rare event.

I had the battery at 130F with successive quick charges, all below 80%, in 65F ambient air.

 

[Herm]

I stand corrected then, fast charges to 80% will do it also. Did the pack cool off by the time you would get to the next charger?

 

[TonyWilliams]

I stand corrected then, fast charges to 80% will do it also. Did the pack cool off by the time you would get to the next charger?

No, it got successively hotter.

 

[JPWhite]

No, it got successively hotter.

That is consistent with the experiences of a Nashville driver who went from Nashville to Knoxville and back in the same day, fast charging along the way. By the time he got back to Nashville after 8 QC's the battery temp gauge was nudging the red zone.

 

[hill]

and then you have our Leaf's battery gauge which has never ventured to move any more than between the 5th & 6th bars

 

[TonyWilliams]

I want to be clear- many of those quick charge events were well below 80%, since I had one every 25-40 miles. Here ya go:

June 2012, outside temps low 60F's
Springfield, Oregon to...
Halsey, Oregon to...
Portland, Oregon...

Yes, Virginia, that's one hot battery (10 temperature segments at the redline). Go to 3 minutes in this video:


[youtube]http://www.youtube.com/watch?v=mqd9qbvBoME[/youtube]

 

[dgpcolorado]

Its an interesting theory but not correct.. internal cooling of the battery pack is by conduction from module to module and then to the skin of the battery case, there is very little air convection going on inside that case.. in any case the only time that battery heats up is while fast charging to 100%, a rare event...

The battery also heats up with driving, especially at power levels of 20 kW or more, as when climbing hills. And it heats up with significant regen when descending hills. (Not that you have any hills in Florida. )