What is the best way to cool your battery.

I am intrigued with the people on this board who say they have experienced no battery degradation after a considerable period of time. Wanting to see I might duplicate that result, I have been experimenting with my new Leaf to see if it would/could go below 5 bars of heat, assuming that 4 would be better than 5 (feel free to tell me it don't matter). Anywho, I drove the car to 30% SOC and parked in the garage, during weather from 50's to high 60's for a couple days. No budge. Then I rolled down all the windows for the next day, still no budge. So, what's the secret?... My best stupid idea: Run A/C for a few hours while parked. Thx, Bob

It would be nice if Nissan would see fit to include a digital readout on the Battery Temp gauge. The bar graph leaves a lot to be desired.

Another crazy idea. ( I did this last summer )
Try parking the car outside the garage and have a small box fan blow the night air under the car to help cool the battery. Let us know if the temp gauge drops from 5 bars to 4 bars.

The 5th Temperature Bar covers 50 to 74 degrees F.

So, your testing, as described, appears to be doing
nothing that would lower the battery temperature
below 50 degrees F.

A possible way to cool a battery in hot (and somewhat
humid) weather, which is when one usually runs the
air conditioner for cooling, which also extracts water
from the air.

Instead of discharging that water onto the ground,
use it for evaporative cooling of the battery box.

Perhaps attach cloth of some sort (or strips of cloth,
maybe glued) to the bottom of the battery box,
where there is some reasonable air flow, and
then dribble the water into the cloth.

The resulting cooling might help, but would it be enough
to be significant?

You might need a reservoir, filled daily at home or at
a filling station?

One LEAF owner in LA has been air conditioning his garage and is still down 10%, he says he uses more kWh for A/C than driving the car.

bobsfreeleaf said:

Wanting to see I might duplicate that result, I have been experimenting with my new Leaf to see if it would/could go below 5 bars of heat, assuming that 4 would be better than 5 (feel free to tell me it don't matter).

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It's my understanding that somewhere around 70 degF is the optimal battery temperature for range, so 5 bars is where you want to be. Here in Seattle, we spend most of the winter with 4 temperature bars, and the range is reduced 10-15% compared to the summer.

bobsfreeleaf said:

I am intrigued with the people on this board who say they have experienced no battery degradation after a considerable period of time. Wanting to see I might duplicate that result, I have been experimenting with my new Leaf to see if it would/could go below 5 bars of heat, assuming that 4 would be better than 5 (feel free to tell me it don't matter). Anywho, I drove the car to 30% SOC and parked in the garage, during weather from 50's to high 60's for a couple days. No budge. Then I rolled down all the windows for the next day, still no budge. So, what's the secret?... My best stupid idea: Run A/C for a few hours while parked. Thx, Bob

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You Live in San Diego and you lease, correct?

"Battery degradation" is virtually a non-issue for you, but if you really want to assuage any anxiety you've developed by reading MNL FUD, just park outside at night during warm weather, to allow ambient temperatures to cool down your battery, after those brutal high daily temperatures in the 80's...

edatoakrun said:

You Live in San Diego and you lease, correct?

"Battery degradation" is virtually a non-issue for you, but if you really want to assuage any anxiety you've developed by reading MNL FUD, just park outside at night during warm weather, to allow ambient temperatures to cool down your battery, after those brutal high daily temperatures in the 80's...

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San Diego is a big city and the temperatures vary considerably depending on how near the coast one is. Inland, 90s or even low 100s are routine in Summer. The temperatures the LEAF will experience depend a lot on where the OP lives or works. For example: Del Mar, La Jolla, and Pacific Beach are mild. Mira Mesa is hot. El Cajon and La Mesa are even hotter.

(Yes, I lived in SD for thirteen years.)

That there is even a topic on cooling the battery is a good indication of how badly Nissan screwed up by not providing a TMS... I'm very close to losing my second capacity bar and will not ever again consider any EV that does not provide some form of TMS!

dgpcolorado said:

edatoakrun said:

You Live in San Diego and you lease, correct?

"Battery degradation" is virtually a non-issue for you, but if you really want to assuage any anxiety you've developed by reading MNL FUD, just park outside at night during warm weather, to allow ambient temperatures to cool down your battery, after those brutal high daily temperatures in the 80's...

Click to expand...

San Diego is a big city and the temperatures vary considerably depending on how near the coast one is. Inland, 90s or even low 100s are routine in Summer. The temperatures the LEAF will experience depend a lot on where the OP lives or works. For example: Del Mar, La Jolla, and Pacific Beach are mild. Mira Mesa is hot. El Cajon and La Mesa are even hotter.

(Yes, I lived in SD for thirteen years.)

Click to expand...

And I've lived in hotter climates, for all but 10 years of my Life.

More to the point, my LEAF has spent two full summers at considerably higher peak daytime temperatures, with no evidence of significant capacity loss.

Looks like overnight lows never exceeded 71 F in El Cajon over the Summer of 2012.

http://www.accuweather.com/en/us/el-cajon-ca/92020/july-weather/342295?monyr=7/1/2012" onclick="window.open(this.href);return false;

As I said previously, if you live anywhere in San Diego, and still suffer from "Battery degradation anxiety", park outside overnight, to let your battery pack cool.

TomT

That there is even a topic on cooling the battery is a good indication of how badly Nissan screwed up by not providing a TMS... I'm very close to losing my second capacity bar and will not ever again consider any EV that does not provide some form of TMS!

_________________
Cayenne Red SL-e w/ 32K miles/10 bars/230Gids...

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So you presently have 11 capacity bars, correct?

What evidence do you have of your present actual capacity loss, from recharge tests, range tests, or other means?

I expect I'll probably lose my 12th capacity bar sometime between this Spring and this Fall.

I also expect to have a very good idea of what my actual capacity loss is at that point, from both range and recharge tests.

And I expect that experience will lead me to conclude I will probably never consider buying a BEV with a battery pack using on-board-air-conditioning-liquid-cooled ATM.

A combination of range and my Lincomatic Gid Meter... Remember you have to lose 15% to lose the first capacity bar but only 6.25% more for the second...

edatoakrun said:

What evidence do you have of your present actual capacity loss, from recharge tests, range tests, or other means?

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edatoakrun said:

And I've lived in hotter climates, for all but 10 years of my Life.

More to the point, my LEAF has spent two full summers at considerably higher peak daytime temperatures, with no evidence of significant capacity loss.

Looks like overnight lows never exceeded 71 F in El Cajon over the Summer of 2012.

http://www.accuweather.com/en/us/el-cajon-ca/92020/july-weather/342295?monyr=7/1/2012" onclick="window.open(this.href);return false;

As I said previously, if you live anywhere in San Diego, and still suffer from "Battery degradation anxiety", park outside overnight, to let your battery pack cool.

Click to expand...

I'm in a considerably cooler climate than SD, or even compared to the PNW, and I have noticeable capacity loss in fifteen months and 9000 miles (I am hoping that Nissan is correct that the rate of loss will flatten out after the initial drop). Whether it might be due to frequent steep* hill climbing and regen descents I couldn't say.

But to dismiss capacity loss concerns in Southern California as "FUD" isn't helpful, given the number of people there who are seeing it.


* My personal definition of "steep" is a hill that requires 18 kW or more to maintain a constant velocity of 25 mph going uphill.

TomT said:

That there is even a topic on cooling the battery is a good indication of how badly Nissan screwed up by not providing a TMS... I'm very close to losing my second capacity bar and will not ever again consider any EV that does not provide some form of TMS!

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Can't help but agree with you there, and this summer hasn't even happened yet! IMHO, it's going to be a blood bath!!

Yep. I calculate I'm at about a 20% loss now and have two more summers in front of me before my four year lease is up...

GaslessInSeattle said:

TomT said:

That there is even a topic on cooling the battery is a good indication of how badly Nissan screwed up by not providing a TMS... I'm very close to losing my second capacity bar and will not ever again consider any EV that does not provide some form of TMS!

Click to expand...

Can't help but agree with you there, and this summer hasn't even happened yet! IMHO, it's going to be a blood bath!!

Click to expand...

TomT said:

Yep. I calculate I'm at about a 20% loss now and have two more summers in front of me before my four year lease is up...

GaslessInSeattle said:

TomT said:

That there is even a topic on cooling the battery is a good indication of how badly Nissan screwed up by not providing a TMS... I'm very close to losing my second capacity bar and will not ever again consider any EV that does not provide some form of TMS!

Click to expand...

Can't help but agree with you there, and this summer hasn't even happened yet! IMHO, it's going to be a blood bath!!

Click to expand...

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Yes, this summer will certainly be interesting. Have Gid counts started to decline already? I believe we saw that in April and May last year.

Do I have this right, to avoid degredation?:
1. Keep the battery at five bars (or four depending on who you talk to). Use ambient temperative or possibly cooling under the car. Avoid parking the car in extreme heat or direct sun on hot days. If your battery heats up, cool it as soon as possible.
2. Do not discharge below 20%; or charge beyond 80%, when convenient.
3. Do not stress your battery with very heavy acceleration, steep mountains, etc.
4. Unplug your battery for an hour before you drive.
5. Avoid quick charging too often
6. If you do experience a hot period of time, try really hard not to exceed 80% SOC.

Even with all these safeguards, we should expect serious SOC loss over time, and certainly by the third year.
Thx.

Yep, I'm down about 8 Gids from the late fall...

surfingslovak said:

Yes, this summer will certainly be interesting. Have Gid counts started to decline already? I believe we saw that in April and May last year.

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bobsfreeleaf said:

Even with all these safeguards, we should expect serious SOC loss over time, and certainly by the third year.

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Bob, I think you have mentioned pretty much everything. Thankfully, for you as a lessee, this is much less of a concern than it might be for others in hotter parts of the country. While the new capacity warranty is great, and it provides a safety net, it might not see much action outside of a few locales.

That said, please have a look at the chart below, if you haven't see it yet. TickTock jotted it down from memory after meeting with a Nissan engineer, and graciously shared it with the rest of us here. It's believed to be the closest we have to an actual disclosure.

Note that in your climate and with some precautions, you should be able to follow the path of the blue curve, which presumably designates the median. As it happens, the trajectory of my LEAF was very similar, at least to the extent that I was able to measure it. The coastal climate here is similar to San Diego based on the temperature modeling we did last year. This excludes solar loading, but if your car is usually not baking in an open parking lot, that should be insignificant.

TomT said:

Yep, I'm down about 8 Gids from the late fall...

surfingslovak said:

Yes, this summer will certainly be interesting. Have Gid counts started to decline already? I believe we saw that in April and May last year.

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Thanks for that, Tom! Summer apparently came early this year. I'm seeing some degradation with the ActiveE as well. I should have a year's worth of data by August (they replaced the battery pack in July 2012).

It's interesting that, based on their graph, I'm doing worse than Phoenix...

TomT said:

It's interesting that, based on their graph, I'm doing worse than Phoenix...

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Yes, that's pretty puzzling. I believe that your battery pack has recorded unusually high energy draw from the wall when we were trying to confirm usable battery capacity a while back. That said, I wonder if your LEAF's mileage played any part in this. Scott's car was pretty much toast after 29K miles and 1 1/2 years. It was down four bars and had 70.8% of usable capacity remaining based on the Phoenix range test (Blue494). Wasn't the green curve in the chart above based on the mythical 7,500 annual miles, which Nissan engineers plugged into their model? I wonder what mileage projections were used for the blue and red curves.

Thanks all for the resonses. Not sure I approve their policy of "DTDT" (don't tell, don't tell) . However I certainly see why their marketing strategy has evolved to the current state of affairs. If they posted that graph on the window of all Leafs, I doubt they would sell even one. Holy Mackeral, these guys need to expand the battery by 20%, and move it off display to avoid the issue of buyers feeling like they bought a bunch of bananas, rather than a car. :roll:

I believe someone said the first bar goes at about 12%. So I am guessing participants that say they have had no battery loss after a year or so are probably "thinking" there is no loss because the screen still says they are at 12 bars, even though they could be down a huge 11%??? That leads me to ask if the GOM (now much more accurate), would reflect an 11% reduction in its calculations, even though the bar has not dropped? I wake up every day and see a shinny 87 miles or so on the GOM, but a year or so from now (all things being constant), with 12 bars showing, will it say about 78? If not, then that could be the essence of the "slop" in the GOM readings. This has been helpful. Thx, Bob