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Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 8:44 am
by TomT
Yes, I saw that. He should be ecstatic then when he losses his second bar and still has full range! :lol:
TonyWilliams wrote:The same clueless clown also wrote this:
The good news? I finally lost my first capacity bar the morning after the Vacaville DC charge, at ~20,700 miles.
And still my LEAF still shows no significant loss of range, but I'll post more on that on an appropriate thread.

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 8:51 am
by TomT
People should also be aware that testing at 45C (the constant internal battery temperature during the test, by the way) does not mean that there is NO degradation at that temperature, simply reduced degradation compared to the old chemistry... Keeping a battery cooler will still decrease degradation; the curve has simply been moved higher with the new "hot battery" chemistry. One note: Craig did indicate that they use QC as one of the 45C testing mechanisms...
TonyWilliams wrote:If they are indeed testing the battery at 45C, we already know that Phoenix can be at that temperature, or higher on an asphalt parking lot.

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 8:54 am
by JPWhite
RegGuheert wrote:
drees wrote:Reg, I think we are in violent agreement here. :)
Cool! :)

I'm just concerned because some of the comments about the meeting have made me think that Nissan feels that only hot climates will need the battery with the improved heat resistance. That is simply not true. Nissan needs to consider than the range-limited LEAF can be a very good fit for those of us with minimal driving needs. But this is true IF AND ONLY IF the battery can last for many years just sitting around.

Nissan, please put the heat-tolerant battery in ALL LEAFs!
I'm OK with it not being standard as long as it is offered as an option in all markets. It could be the new chemistry is more expensive to manufacturer. Maybe, maybe not.

To save themselves from future complaints, I agree that they should look to put the new chemistry in all LEAF's.

However we don't know what they know; so they may have reasons to be picky. The chemistry chosen has to balance, heat tolerance, safety and cycle losses. You can't increase all three at the same time (at least not without a totally new battery tech). They may sacrifice battery cycles for heat tolerance. I doubt they would sacrifice safety.

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 9:01 am
by TomT
We were told that the new chemistry is "slightly more expensive." I was also told separately that the new battery would in fact be used in all cars ultimately due to economies of scale and inventory considerations...
JPWhite wrote:I'm OK with it not being standard as long as it is offered as an option in all markets. It could be the new chemistry is more expensive to manufacturer. Maybe, maybe not.

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 9:04 am
by DNAinaGoodWay
Will SW sales lag while people wait for the new chemistry, maybe creating better deals on existing stock, or freeing up inventory for the rest of us?

What about future used car sales?

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 9:06 am
by surfingslovak
JPWhite wrote:The chemistry chosen has to balance, heat tolerance, safety and cycle losses. You can't increase all three at the same time (at least not without a totally new battery tech). They may sacrifice battery cycles for heat tolerance. I doubt they would sacrifice safety.
Image

JP, I believe that should be possible. The NEC R&D report Stoaty linked upthread added some sulphur into the electrolyte for increased heat tolerance. Nothing was said about cycle life, if I recall correctly. Although there could be a change in that characteristic because of this addition, I wouldn't expect anything dramatic. To go back to the somewhat inadequate metaphor upthread: if a preservative is added to a food item, the consumer may or may not taste or appreciate the difference or notice a change in composition. To me, electrolyte and other changes to the battery chemistry should be on the same playing level, and it should be possible to improve the thermal characteristics without impacting some of the other desirable features of the battery.
TomT wrote:People should also be aware that testing at 45C does not mean that there is NO degradation at that temperature, simply reduced degradation compared to the old chemistry... Keeping a battery cooler will still decrease degradation; the curve has simply been moved higher with the new "hot battery" chemistry. One note: Craig did indicate that they use QC as one of the 45C testing mechanisms...
Thank you for making that point, this is very important to realize and perhaps it's an unfamiliar concept to some readers.

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 9:13 am
by TonyWilliams
TomT wrote: One note: Craig did indicate that they use QC as one of the 45C testing mechanisms..
One of the guys from Nissan at Casa Grande, Arizona told us we didn't know what we were talking about last summer with hot battery degradation, and that they had already tested Nissan LEAFs "up to 30 days each" in hot temperatures, so "all was well".

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 9:22 am
by BBrockman
TonyWilliams wrote: If they are indeed testing the battery at 45C, we already know that Phoenix can be at that temperature, or higher on an asphalt parking lot.

Then, any quick charge of 1C or 2C will heat up just about ANY battery. What happens to a "hot battery" when I drive the West Coast Electric Highway on a 100F day? It gets really, really HOT, just like the current one.

The "hot battery" is just an improvement over the existing product; that doesn't make it a "capable" battery that is anything like what Tesla is providing with ROBUST temperature control.
Tony: One thing worth noting is that 45C isn't the ambient temperature for testing. That is the constant, internal battery temperature during the testing, which is more severe than temperature cycles that heat up and cool down.

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 9:27 am
by TonyWilliams
BBrockman wrote: Tony: One thing worth noting is that 45C isn't the ambient temperature for testing. That is the constant, internal battery temperature during the testing, which is more severe than temperature cycles that heat up and cool down.
Yes, we all agree about the 45C battery temp... hopefully, you also understand that a 45C battery can be in a 35C ambient temperature parking lot in Phoenix. At 45C ambient, that same battery can be at 55C.

What happens when we charge it? It heats up further.

One tidbit from my aviation background... testing tended to max out at 50C, and therefore performance data ended there. I have been stopped from operating in the USA by that temperature threshold; can you guess what city?

Folks driving their LEAF aren't going to be constrained by FAR Part 121, and will drive regardless of the temperature.

Re: Update on Battery Warranty Enhancement for 2011 & 2012 L

Posted: Tue Aug 27, 2013 9:32 am
by Weatherman
I'm going to need a couple of years of real-world, independently-verified data before I believe there's any significant improvement in heat-tolerance.

I'm still bugged by the official statements that refer to the current problem as "isolated", or "only affecting a very small number of users", or "only shows up in batteries exposed to extreme heat". We're already having Florida LEAF owners with two capacity bars lost after only 18 months of use. We're on the opposite side of the country from Phoenix and it looks like we're headed down the same path they are.