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Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 12:33 pm
by klapauzius
OrientExpress wrote:
Volusiano wrote:
OrientExpress wrote:17 cars out of a population of 25000 is .00068. That is more than 3 standard deviations from the mean, or in layman's terms, an edge case.
You need to compare apple to apple here.

It shouldn't be 17/25000, nor should it be 17/500 because I'm sure there are more capacity losses not reported than the 17 reported.

The only meaningful sampling ratio at all should be

# of reported loss / (# of reported loss + # of reported NO loss) in Phoenix.

So far I've only heard of maybe a few from Phoenix who reported that they haven't lost a bar yet. Some of them who said they hadn't lost a bar have come back later and said they finally lost a bar.

The real ratio that's meaningful to me is more like 17/20 at this point. If you're going to sample, you have to pick samples from the same pool.

I have it right. The comparison are the know outliers vs. the total universe. Cherry picking the total universe from just Phoenix or even the southwest is not valid because one cannot say with certainly that similar condition do not exist outside of your suggested sample universe. Also we cannot say for certain what the total number nor location of all of the outliers are, so by default the entire universe must be considered in the sample.
No you are wrong, because "hot climate" and "cold climate" constitute definitely different distributions and you cannot apply statistics from one distribution to another.

The battery fail statistic in Phoenix is definitely not going to be the same as e.g. in Seattle.
And we dont even need statistics to tell us the difference, battery physics and the known climate stats for different geographical regions make it quite clear why we cant compare across the whole universe.

Now, I wonder what the solution to the conundrum would be:

Suppose Nissan would play extremely nice and replace all those batteries with new ones. Wouldn't they start to lose capacity a year later again? The cant possibly replace them every year?

Installing a thermal management system posthoc would probably be impossible too and would not help much either.

And they cannot pull a new heat resistant battery chemistry out of the hat...

In the end it might turn out that current battery technology is simply not suited for hot climates :(

Maybe they should offer a refund for the whole car?

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:07 pm
by JPWhite
klapauzius wrote:
Installing a thermal management system posthoc would probably be impossible too and would not help much either.

Maybe they should offer a refund for the whole car?
Yeah a thermal management system would only be useful while the car is running or plugged in. If the battery doesn't do well in hot climates, it doesn't do well, tough to change that fact in the short term.

I'm sure Nissan will let the problem show its true nature over time and act accordingly. IMHO they should replace batteries for customers who complain to preserve the vehicles reputation. If the worst case scenario ensues then they can always withdraw the vehicle from hot climates and offer customers an alternative, they aren't likely to do that until they have enough data and have considered their options, they won't act hastily. Nissan do need to shore up customer relations to prevent a Toyota type ding on their reputation. Nissan have stuck their necks out by bringing this vehicle to market in decent numbers, and we should commend them for doing so; now it's time for them to stand by their product, even if it is a hard pill to swallow.

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:12 pm
by Volusiano
klapauzius wrote:Now, I wonder what the solution to the conundrum would be:
Suppose Nissan would play extremely nice and replace all those batteries with new ones. Wouldn't they start to lose capacity a year later again? They cant possibly replace them every year?
I agree that replacing the current battery with the same battery technology is not a viable solution. I think that a more viable solution would be a pledge to affected owners to offer some kind of a pro-rated discount toward a newer/more advanced battery pack that will be available in the future that can be swapped with the old battery pack. Of course it's not going to be easy if nobody knows what/when a new battery pack is available and how much it'll cost yet. But at this point, anything is better than silence and dismissal by Nissan.

Acknowledgement that this is an issue and a statement that they will do right by affected customers would be a good start to restore the trust they lost. If it's truly an outlier situation like they claim, then doing right by a few customers shouldn't put a ding on their pocket book and will go a long way to restore trust. If it's a real issue for hot climate areas, then they will need to address the issue anyway and explain why they chose to sell in hot climate areas and what they're going to do to fix it.

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:20 pm
by shrink
JPWhite wrote: Yeah a thermal management system would only be useful while the car is running or plugged in.
That's not entirely true. Unplugged at a SOC above 75%, the Volt's TMS will run and engage if necessary. Also, the insulation itself helps with heat conduction, although it is not clear to what extent.

Regardless, I would imagine an insulated battery back that has been thermally managed to acceptable temperatures overnight would have a better chance of resisting heat conduction in hot ambient temperatures as compared to the LEAF.

You can also just remote start the Volt in the heat and let it run. You'd run down the battery, but you can still get home on the ICE. That's far from ideal, but at least you can provide battery protection if you decide to do so.

Finally, I don't think it's possible to retrofit a TMS. That's a lot of engineering - space constraints, power management reprogramming, etc.

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:24 pm
by shrink
+1

This is an excellent post! Well said.
klapauzius wrote: No you are wrong, because "hot climate" and "cold climate" constitute definitely different distributions and you cannot apply statistics from one distribution to another.

The battery fail statistic in Phoenix is definitely not going to be the same as e.g. in Seattle.
And we dont even need statistics to tell us the difference, battery physics and the known climate stats for different geographical regions make it quite clear why we cant compare across the whole universe.

Now, I wonder what the solution to the conundrum would be:

Suppose Nissan would play extremely nice and replace all those batteries with new ones. Wouldn't they start to lose capacity a year later again? The cant possibly replace them every year?

Installing a thermal management system posthoc would probably be impossible too and would not help much either.

And they cannot pull a new heat resistant battery chemistry out of the hat...

In the end it might turn out that current battery technology is simply not suited for hot climates :(

Maybe they should offer a refund for the whole car?

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:26 pm
by OrientExpress
6.

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:29 pm
by JPWhite
Volusiano wrote: If it's truly an outlier situation like they claim, then doing right by a few customers shouldn't put a ding on their pocket book and will go a long way to restore trust. If it's a real issue for hot climate areas, then they will need to address the issue anyway and explain why they chose to sell in hot climate areas and what they're going to do to fix it.
Ain't that the truth !!

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:44 pm
by TickTock
OrientExpress wrote:
If it's truly an outlier situation like they claim, then doing right by a few customers shouldn't put a ding on their pocket book and will go a long way to restore trust. If it's a real issue for hot climate areas, then they will need to address the issue anyway and explain why they chose to sell in hot climate areas and what they're going to do to fix it.
This is what will happen, if there is an actual issue with a customers battery, then it will be a simple routine warranty repair.

In the long run, as experience from the fleet grows, I expect that the solid gains in cost reduction, capacity, reliability, etc. of vehicle propulsion batteries will continue.

Even the biggest cynic here has to admit that for a V1.0 product, the LEAF has been exceptional.
OrientExpress has it right on these two points. There is no universe where Nissan will not address the problem - explicit warrenty or not. The cost will be cheap compared to the market share loss (across product lines) and marketing budget required to fix loss of public image. Not to mention the Japanese have this honor thing going on. They are just responding very slowly because they are still evaluating the situation, perhaps waiting for more data. Right now noone who lost a bar is unable to go to work and do their daily activities so really they have some time to figure out what is really going on and decide *the best way* (as opposed the whether or not) to deal with it. Despite the couple articles published on the subject this is still a fringe discussion. As soon as Nissan speaks publicly, it will become much more widely discussed. I can't blame Nissan for wanting to keep this on the fringes as long as possible to buy time to figure it out.

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 1:47 pm
by Stoaty
OrientExpress wrote:Even the biggest cynic here has to admit that for a V1.0 product, the LEAF has been exceptional.
I think you are reading these responses wrong. I don't see anyone here being a cynic:

"a person who believes that only selfishness motivates human actions and who disbelieves in or minimizes selfless acts or disinterested points of view"

The Leaf is a GREAT car, no one doubts that. Our concern is over the Leafs accelerated battery capacity loss in very hot climates.

Re: Lost a "high-voltage battery status" bar, down to 11

Posted: Wed Jun 20, 2012 2:01 pm
by JPWhite
The politically opposed have picked up on the battery capacity loss situation.
http://nlpc.org/stories/2012/06/20/niss ... ctric-cars

Expect Rush Limbaugh et al to comment soon. Not long before it becomes mainstream, especially in election year.

Lutz attacked the media for the fire debacle, I wonder if Goshen will do the same for the AZ battery issues?

Come to think of it let's compare GM's approach to the fire debacle, which was truly an outlier situation, they offered to take vehicles back for a full refund (almost no one took them up on the offer). GM acted swiftly, probably because the main media got hold of it. Nissan are taking a different tack, things may change if Rush gets hold of it.