LuvNLeaf
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Sun Jan 13, 2013 10:07 pm

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
It runs close to two hours in length (1:53:17 to be exact), but it's posted in its entirety start to finish.


Enjoy.
Jim

RWatkins
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 12:20 am

dhanson865 wrote:
TomT wrote: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...

jlsoaz wrote: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.


depends on the source of air and the definition of ambient.

If you put a fan on the bottom of the battery pack near the heat from the pavement then blowing it around might be worthless but if you are blowing cabin air to the top of the battery pack then you might have cooler air in the cabin than the air above the pavement.

Perhaps using the venturi effect would help here, like cold air from a can of compressed air.

The cooling effect of expansion is due to the fact that 1) energy is required to break the bonds (vaporization), 2) the gas has to fill a much larger volume and 3) there is a finite amount of energy available.

cwerdna
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 2:41 am

LuvNLeaf, thank you for posting. I finished watching it. I don't know your affiliation, so I kinda wonder if it'll stay up...

I thought it interesting and insightful but can also understand the continued frustrations by the Phoenicians. From the 1st half or so, it sounds like some people are further confused/frustrated by what the GOM is telling them. I was a bit dismayed to hear that one person not know how many bars he lost. I doubt he's alone though, amongst those in high climate areas.

I don't know what talks went on offline, but I suspect that some people are seeing a greater perceived/actual range of loss than suggested by the lost capacity bars by needing to run the heater now and/or also inadvertently running the heater (w/o knowing it) due to the HVAC's quirks/goofiness.

Regarding a battery fan and using the solar panel, that unfortunately won't help SV owners, unless Nissan installs a solar panel for them.

Most (all?) hybrids have at least battery fan cooling, even all the way back to the 1st gen Prius the US got (NHW11) and the 1st gen Honda Insight. At least w/Toyota hybrids and the Nissan Altima Hybrid, the battery fan intake is in the passenger compartment so that it at least gets the benefit of the cooler cabin when the car's being operated. The Gen 3 Prius (ZVW30 aka 2010+ model year) has an available solar roof that can run the ventilation fan when parked outside to keep the cabin cooler (similar to outside temps) for comfort reasons (so that you can return to a car that's not so hot inside).

It seems clear there needs to be a better communication channel for various issues, ranging from Carwings bugs/reliability problems to suggestions (e.g. Jim Stack's pre-cooling and not charging to 100%). Should people call the 800 #? Tell the dealer (and possibly be blown off and not have the message make up the chain)? Web site? Post here (and have it buried on very long threads :))?

I don't know if it was suggested, but I wonder what kind of telemetry the Carwings smartphone apps have built in that gets sent to the mothership in terms of errors, login failures, or the other problems that happen? If that already is going on, I wonder how much effort there is to attempt to repro the top bugs and fix them?

I know Andy Palmer talked about transparency, but it seems Nissan really needs to give folks (esp. hot climate folks) a graph, numbers, etc. saying what they expect in terms of capacity loss for x years, y miles in _____ major city, along the lines of the battery aging model folks here came up with (wiki/index.php?title=Battery_Capacity_Loss#Battery_Aging_Model). The broad statements (e.g. 70% at 10 years, 80% after 5 years) prior to purchase clearly don't cut it for hot climate folks.

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TonyWilliams
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 10:28 am

cwerdna wrote:I know Andy Palmer talked about transparency, but it seems Nissan really needs to give folks (esp. hot climate folks) a graph, numbers, etc. saying what they expect in terms of capacity loss for x years, y miles in _____ major city, along the lines of the battery aging model folks here came up with (wiki/index.php?title=Battery_Capacity_Loss#Battery_Aging_Model). The broad statements (e.g. 70% at 10 years, 80% after 5 years) prior to purchase clearly don't cut it for hot climate folks.


Nissan is never (intentionally) going to give ammo to the enemy, and that's you!!! Any statements with hard "facts" that they make will likely get read back to them in deposition or court in the form of a question.
Last edited by TonyWilliams on Mon Jan 14, 2013 10:36 am, edited 1 time in total.

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TomT
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 10:34 am

To create any significant temperature differential via the Bernoulli principle would require substantial energy thereby negating any advantage...

By the way, the cold you get from a can comes from a different principle: Inside of the can, there is a chemical which can be used as a refrigerant. It's a chemical with a low vapor pressure. When you press the button on top of the can, you open a valve and release some of the pressure from the can. Because this chemical has a high vapor pressure, it evaporates when the pressure drops. The process of evaporation requires intermolecular bonds in the liquid to be broken. In order to break the bonds, energy must be expended. The energy that goes into breaking bonds comes from the ambient thermal energy. As the amount of available thermal energy decreases, the liquid refrigerant becomes cold (its temperature decreases). If you hold the trigger down long enough, the can will become very cold and the evaporation process will slow down, and you will notice that not much air is coming out. If you add thermal energy to the refrigerant by running hot water over the cold can, you will HEAR and feel the refrigerant boiling inside of the can....the pressure inside of the can increases again to a point where evaporation stops and then you are ready to use the air can again.

RWatkins wrote:Perhaps using the venturi effect would help here, like cold air from a can of compressed air.
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
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gbarry42
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 2:12 pm

What Tom just explained was the principle behind most refrigeration schemes. If you find you are reading about "phase change materials", that's also the same thing. To build the familiar refrigerator (or air conditioner) you need only collect all that escaped gas, compress it down to a liquid again, and stick it back into the can. It also gets hot at that point, so it goes through a "condenser", which is the "radiator that gets hot" side of the unit. Yes, you can use that heat--that's called a heat pump.

Just as we're about to depart completely from the subject matter, I'll reel it back in by saying that the Prius is counting on your running the A/C when you're in the car, and providing some cool air it can steal for the battery. To remove heat from a LEAF battery when it's 100 outside, you'd have to take advantage of the A/C in some way. The Volt already does this. Whether theirs is a separate A/C unit or the same, I don't know. But it's really hard to cool things using hot air.
And there goes the first capacity bar! At 24,000 mi on 9/9/2013.
Second bar at 30,500 mi on 2/7/2015.

jlsoaz
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 8:45 pm

dhanson865 wrote:
TomT wrote:
jlsoaz wrote: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.

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...


depends on the source of air and the definition of ambient.

If you put a fan on the bottom of the battery pack near the heat from the pavement then blowing it around might be worthless but if you are blowing cabin air to the top of the battery pack then you might have cooler air in the cabin than the air above the pavement.


I also am skeptical of a simple air cooling fan, though perhaps something interesting could be done in extreme ambient air temperature situations, such as Phoenix at peak temperatures, such as directing air conditioned air at the battery. I don't know. The goal isn't to save energy, the goal is to save the battery from degradation.

In any event, what struck me was the importance of any Nissan executive entertaining or discussing or noting any suggestions for any attempt at active battery cooling. Up to this point, has there been such a thing? I don't know. Sure, it's hard to gauge the extent to which they were genuinely into the idea, but I thought it was at the least worth noting. Perhaps we can build on that a bit. Even if there's only a moderate chance of active air (ambient or chilled) cooling helping reduce range degradation, why not look into it, given the amount of difficulty it might save?

PS: Wasn't there an issue with the EV1 (the NiMH version only?) where there was added a protocol during charging that the air conditioner would run at some point to help with cooling. Something to do with the last bit of NiMH charging? It all seemed so inefficient and strange to hear this, but I thought there was such a thing that came up circa 2002.
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LuvNLeaf
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 9:25 pm

cwerdna:
No professional association to the EV nor car industry (though I did work for GM back in the late 80s/early 90s.)
I'm driving a 2011 orphaned LEAF the kids have named "EVE" from Wall-E fame. White, futuristic, clean.
My day job is in marketing so I'm taking notes regarding how not to treat and engage customers.

When Bob Stack brought up the "Why can't we run the AC timer and not charge to 100%?" issue I about fell out of my chair. I literally spent 6 weeks with the 800NOGASEV folks telling them about it. They stopped short of calling me a liar, but wouldn't investigate the issue until I took my LEAF to the dealer (which I HATE!) and had them verify and document it. Of course I had to explain to the service writer what the battery saving feature was for and how to use it. Then after numerous "Oh, it's your Blink charger...oh, it's how your have the timer programmed..." they finally said "That's just the way it is, and no, you can't do that." I'll translate: "Sure being able to run the AC while plugged in AND not overcharge the battery past 80% sounds like a great idea for all you nobs who live in ridiculously hot places that bake your battery and brains. But we didn't think of that first (see wikipedia entry "NIH"), and it would take time away from our engineers who are busy working on yet-another air cooled battery system for the 2014 LEAF."

Life goes on, in the ironically sub-freezing temperatures of Phoenix right now. Now about that pathetic LEAF heater...

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Nubo
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 9:26 pm

TomT wrote: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...

jlsoaz wrote: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.
I noticed you're still working with polymers.

cwerdna
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Re: Meeting with Nissan, Phoenix, Jan 8, 2013, 6pm, drinks p

Mon Jan 14, 2013 9:30 pm

LuvNLeaf wrote:cwerdna:
No professional association to the EV nor car industry (though I did work for GM back in the late 80s/early 90s.)
I'm driving a 2011 orphaned LEAF the kids have named "EVE" from Wall-E fame. White, futuristic, clean.
My day job is in marketing so I'm taking notes regarding how not to treat and engage customers.

Ahh. Ok. I was just wondering if you worked for Nissan and whether it was an official post from Nissan that might get yanked, if Nissan might send you a cease and desist, whether they'd post an edited version, etc.

I had similar concerns as expressed at viewtopic.php?f=4&t=11057&p=257494&#p257494.

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