What is the best way to cool your battery.

[dgpcolorado]

Though that image doesn't give very good resolution, and you use dash m/kWh rather than the more accurate CarWings kWh use reports, it appears you may be observing one or both of the same kWh use report errors I believe I have observed in my LEAF, both a seasonal error variation in your LEAFs kWh use reports (What appears to be a lesser distance between the two trend lines during warmer months) and much less distinctly in your case, an increasing error over time (as shown as the distance between the two lines on your graph, perhaps, tending to increase with time).

Would you please post these results in more useful detail?

I believe both of these effects may well have been more apparent in MY LEAF, due to the warmer climate it has experienced (as compared to yours) and similar reports from truly "hot" climate LEAFs might show one or both of these kWh use report errors to a greater degree.

My graph was intended to show seasonal differences in electricity use and mileage efficiency, averaged a month at a time to compensate for trip variations, and has nothing whatever to do with battery capacity. As for the suggestion of a "a seasonal error variation in your LEAFs kWh use reports" I will point out that no such conclusion can be drawn because my driving conditions and trips are highly variable. That's why I average them together over a month to smooth out the variations somewhat. You are looking for precision where none is possible. There is an increasing gap between the "wall" and "dash" numbers in Winter but that's due to preheating, so it is of no significance whatever.

I have noticed that my range was down quite noticeably this Winter versus last Winter based on my long (~65 mile, 2300 feet elevation change) grocery shopping trips. While obvious to me, it isn't practical to try to make precise measurements because my driving environment is too complex. I suppose it would be nice to be able to drive over a consistent course at a given temperature, but that isn't the world I live in here in these mountains.

I am certainly aware that you will dismiss such a casual observation out-of-hand but that doesn't change the plain fact that I am having to work harder to make long trips that were easy last Winter. And that, actual useable range, is the whole point of all this fuss over battery capacity.

 

[surfingslovak]

And that, actual useable range, is the whole point of all this fuss over battery capacity.

Absolutely, agreed 100%. Your post and similar reports from other drivers was the reason why I suggested to Tom Saxton to include a question about the perceived range in his Plug In America LEAF battery survey last October. I'm glad that he agreed, and later eloquently explained the reasoning behind it, when it was questioned by someone here or on some other public forum. Customer satisfaction matters, and is quite important, even when it comes to new technology, such as mass-produced EVs.

 

[Feng]

I'm fortunate to have an underground car park in our strata complex which keeps a fairly cool and consistent temperature. However I might go on long drive (over 130 miles) to visit a friend in summer where temperatures here can exceed 40C (100F). I'm worried that staying outdoors for a couple of days in the summer heat will be bad for the battery.

Has anyone tried to cool down their battery by hosing down the underside or using a garden sprinkler and measured the effects on battery temperature? My latest hairbrained idea is to strap a plastic tarp to the underside and creating a makeshift ice bath with a few bags of ice and a hose when I arrive to quickly cool the car down. Will the sudden temperature change from hot to cold be bad for the batteries? Am I going overboard?

I read about people losing four bars here in such a short time and it's scary! We haven't got as many leasing options with the car or batteries here in Australia, I'm in it for the long haul and need to do everything I can to look after my battery!

 

[surfingslovak]

I read about people losing four bars here in such a short time and it's scary! We haven't got as many leasing options with the car or batteries here in Australia, I'm in it for the long haul and need to do everything I can to look after my battery!

Where in Australia are you approximately? Did you get LeafSpy for your car yet? That might be a good initial and less dramatic step. Also, would you know if Nissan is offering the new capacity warranty for LEAFs purchased in Australia?

 

[Feng]

I'm in Sydney. I've used the LEAF Battery App but haven't upgraded to LEAF Spy yet. Haven't exceeded 30C yet but I haven't had the car past a summer before. My battery reads 98.5% and it was built in April 2012. I only bought it in June this year. As you can tell by the delay, LEAF uptake in Australia is very slow and our 2013 model is in fact the older pre-updated model. The charging infrastructure here is insignificant here too with only 7 publicly accessible Charge Points in Sydney, most at Nissan dealerships and half of them available only during business hours. Nissan Australia is only making a minimal effort in selling the LEAF here and had has no leasing options. There's not even the eight year warranty on the battery, just the standard three year car warranty!

 

[Den]

Battery is very well isolated (at least ours with winter package) so you need to keep car in cold for quite long period (couple of days I guess).

I never saw more that 5 bars whole summer (even when day temperature was more that 25C). Only QC can rise it to 6 bars for some time, then it goes back to 5 quite quickly.

And now we have 0C at nights and I'm still with 5 bars. if I remember right last winter it will be on 4 bars when it will be continuously around 0C (days and nights).

When temperature drops more it always takes couple of days that battery temp. become equal to outside temp. E.g. if it will be almost -10C it still takes time to drop to 3 bars, but if it will stay continuously it drops and stays here even temperature rises for some periods.

When it goes under -10C (2 or less bars) then battery heater starts working (at least if temp. reaches -20C) and changes in bars are not taking so much time, I so 1 and 2 bars and even zero bars, but they are reacting quite quick to changes in temperature as heater helps then.

 

[ksnogas2112]

I'm fortunate to have an underground car park in our strata complex which keeps a fairly cool and consistent temperature. However I might go on long drive (over 130 miles) to visit a friend in summer where temperatures here can exceed 40C (100F). I'm worried that staying outdoors for a couple of days in the summer heat will be bad for the battery.

Has anyone tried to cool down their battery by hosing down the underside or using a garden sprinkler and measured the effects on battery temperature? My latest hairbrained idea is to strap a plastic tarp to the underside and creating a makeshift ice bath with a few bags of ice and a hose when I arrive to quickly cool the car down. Will the sudden temperature change from hot to cold be bad for the batteries? Am I going overboard?

I read about people losing four bars here in such a short time and it's scary! We haven't got as many leasing options with the car or batteries here in Australia, I'm in it for the long haul and need to do everything I can to look after my battery!

Feng,
Don't worry about a few days at 40*C. While it would do a little extra degradation it wouldn't be much. I have a 2012 that I got in June of '12 (built Apr '12). Summer of '12 was one of the worst summers we've had in a long time. 30-40 days running where high temp was between 32-42*C. I had the car outside during the day and garaged at night. I was at 6 battery temp bars all summer June-middle September with a couple spikes at 7 bars when it was 110+*F. I still have all 12 capacity bars and I think I'm running around 93% capacity after 17,000 miles in 16 months.

For degradation it's really about the high temp, high miles, and frequent cycles. If you're normally at 5 battery temp bars and then travel and spike to high 6 or even 7 for 3-4 days, you're ok. If you're at 6 bars month after month or worse, 7 month after month then you'll see the types of degradation they had in Phoenix.

If you have a full season, cold, warm, hot, warm, cold then you'll probably be good.

 

[KJD]

Feng,
Don't worry about a few days at 40*C. While it would do a little extra degradation it wouldn't be much. I have a 2012 that I got in June of '12 (built Apr '12). Summer of '12 was one of the worst summers we've had in a long time. 30-40 days running where high temp was between 32-42*C. I had the car outside during the day and garaged at night. I was at 6 battery temp bars all summer June-middle September with a couple spikes at 7 bars when it was 110+*F. I still have all 12 capacity bars and I think I'm running around 93% capacity after 17,000 miles in 16 months.

How did you measure the 93% number ?

 

[TomT]

The easiest way is with something like Leaf Spy or LeafDD. You will find threads for both of them on here...

How did you measure the 93% number ?

 

[stjohnh]

I've read the whole thread and there is not really much info on cooling the battery. As far as I can tell, there is actually no way that is practical to cool the battery. The battery is well insulated and the bottom of the car is covered, so fans and sprinklers under the car have minimal effect. Putting the car in an air conditioned garage may work over the long run, but is very expensive.

Does that about sum it up?

 

[stjohnh]

Of course, I could move to Alaska

 

[surfingslovak]

I still have all 12 capacity bars and I think I'm running around 93% capacity after 17,000 miles in 16 months.

Yes, that's what the degradation model predicts approximately for Kansas City.

For degradation it's really about the high temp, high miles, and frequent cycles. If you're normally at 5 battery temp bars and then travel and spike to high 6 or even 7 for 3-4 days, you're ok. If you're at 6 bars month after month or worse, 7 month after month then you'll see the types of degradation they had in Phoenix.

If you have a full season, cold, warm, hot, warm, cold then you'll probably be good.

Sydney models similarly to LA, Nashville or Kansas City, so this advice is sound. One thing to consider is that if you live in a moderately warm climate without a pronounced winter, such as Florida or Hawaii, you could still experience faster than average degradation. This is because the chemical reactions aging the battery never slow down, and the overall speed of that process is faster than in many other locales. Florida ranked very similar to Phoenix on the aging scale based on the Arrhenius equation last year.

 

[donald]

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!

Ah! So that means you'd consider every other EV on the market, globally, except the Leaf!

The battery is well insulated and the bottom of the car is covered, so fans and sprinklers under the car have minimal effect.

I can't see why hosing the underside of the car off mid-day could hurt. It may be insulated, but you still want to reduce the thermal flux into the battery. Cooling the underside of the car would therefore still help.

Park it over one of those fountains that shoot out at pavement height. I imagine that would help, no?

 

[stjohnh]

The battery is well insulated and the bottom of the car is covered, so fans and sprinklers under the car have minimal effect.

I can't see why hosing the underside of the car off mid-day could hurt. It may be insulated, but you still want to reduce the thermal flux into the battery. Cooling the underside of the car would therefore still help.

Park it over one of those fountains that shoot out at pavement height. I imagine that would help, no?

Well, my 2013 has an undercarriage covering that would keep the water from actually hitting the battery case.

 

[surfingslovak]

Well, my 2013 has an undercarriage covering that would keep the water from actually hitting the battery case.

Yes, you might want to look at this. Note that Donald does not have any direct LEAF ownership experience.

Underneath the Beast; a Tour of the Dark Side

 

[yujungchang]

It might be unrealistic to cool the battery from underneath. Looking at this picture http://en.wikipedia.org/wiki/File:2013_Nissan_Leaf_cutaway_(2).jpg
Wonder if we can cool the battery from the top by ducting the portable AC to the service quick disconnect port, rather cool down whole garage with it. When the car is parked outside, maybe we can leave the quick disconnect cover open and turn on the AC remotely.

 

[LeftieBiker]

Depending on how you define "below" I don't see why the pack can't be cooled with a 'turbo' type fan from the front bottom or rear bottom, using the existing air channel.

 

[TomT]

If, at that time, the Leaf did not have a proven change in battery chemistry to eliminate degradation or a TMS to protect against it, yes, I'd consider every other EV available in the U.S. I have a deposit on a reservation for a Tesla model X, so I'm already hedging my bets for when my lease is up in early 2015... By the way, my second bar is now long gone...

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!

Ah! So that means you'd consider every other EV on the market, globally, except the Leaf!

 

[cwerdna]

Has anyone done any measurements to see if the pack internal temperature is lower or is kept from rising as quickly if the AC left on/triggered via pre-cooling, to cool the cabin above? (No, I’m not talking about the crap temp bars on the left.) Some days at my work, I end up needing to use our EV valets, which means the car stays outside in the sun. I can remotely trigger the AC and set the timer too.

Or, is it made worse due to the AC condenser w/radiator fans throwing off heat?

 

[TomT]

Are you always so obtuse when quoting messages that are more than a year and a half old? :roll:

I'm very close to losing my second (and now-fourth) capacity bar and will not ever again consider any EV that does not provide some form of TMS!

Ah! So that means you'd consider every other EV on the market, globally, except the Leaf!