Idaho National Laboratory: DC Quick Charging a Nissan LEAF Doesn’t Kill The Battery – High Temps Do

MAR 25 2014 BY MARK KANE 32

Women Now Buying More LEAFs

To quick charge or not to quick charge?

Idaho National Laboratory (INL) is doing an excellent job these days in evaluating electric vehicles.

One of the labs projects is “Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study,” which was presented at the SAE Hybrid and Electric Vehicle Technologies Symposium last month.

INL is testing Nissan LEAFs (2012 model year) and battery packs in the lab.

The vehicles are being tested in tough environment for the LEAF – in Phoenix, AZ where temperatures diminish the LEAF’s pack capacity more quickly than in milder areas.

Two LEAFs are charged slowly – 3.3 kW, the others are quick charged with power up to 50 kW. All the other criteria is basically the same:

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – On Road Cycling Design

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – On Road Cycling Design

Here is some data and performance after initial tests:

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Vehicle Performance Testing

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Vehicle Performance Testing

Now, every LEAF exceeds 40,000 miles and are on the way to the 50,000-mile, when test will come to an end.

Gathered data indicates major effect from mileage on capacity in such conditions.  The impact of quick charging is negligible.

Two LEAFs, which were quick charged at 15-times higher power every day have no more than ~3% lower capacity after 40,000 miles. This is basically 0%, especially when you consider that typical drivers will use QC maybe once a week, so what will be the difference – like 1% maybe?

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

However, capacity drop itself is high in LEAFs in Phoenix and this is not good. 20-25% after just 40,000 miles in tests.

We are interested to see how such results would look in Washington state or a similar mild climate environment – AC vs. DC charging.  Hopefully, the DOE will throw some additional grant money to Idaho National Laboratory for this sort of testing, too.

Interesting is the range graph with identification of the seasons in the table:

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance Study – Results to Date

Soon, INL plans to finish the tests and present a full report. Battery tests in the lab have one more year of testing to go.


Categories: Charging, Nissan


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32 Comments on "Idaho National Laboratory: DC Quick Charging a Nissan LEAF Doesn’t Kill The Battery – High Temps Do"

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Glad to hear this. There are a lot of CHAdeMO chargers in my neck of the woods, and if I someday end up with a Leaf I will defiantly get one with a quick charge option.

Occasionally, spelling errors just make the comment better.

BUUUUT… If you fast charge then it heats up the battery. Not a problem if the battery is already cold. But a hot battery getting fast charged will make it hotter. And since the Leaf has no active thermal management, then the heat can be an issue. So fast charging my not directly hurt the battery, but indirectly it makes it hotter and can..

It’s time spent at temperature that does it. So, spiking our battery for a couple hours is nothing compared to it being outside all day, every day, in Phoenix.

I’ll stick around in the mild climate with it. If there is little or no concern about fast charging temp spikes, I’m glad to hear it.

The fact that the ambient air temperature is hotter means radiation from the battery will be less. So fast-charging when it’s cold should have less effect, since any excess heat will radiate away from the battery, more quickly.
Why don’t they have actively managed thermal control, like Tesla? Was it the expense?
Seems like an error.

For 2013 Phoenix temperatures were not too extreme.

Based on the National Weather service:

“The city’s average temperature, combining night and day year-round, was 75.9. The average high of 87.6 was the 10th-warmest, while the average low (64.2) was the sixth-warmest low temperature.”

There were a few hot single days:

“A year that started with an unusual cold spell for Phoenix, including a 29-degree reading on Jan. 15, was broiling by June. At 94.8 degrees, an average of 4 degrees above normal, it was hotter than any previous June. At 119 degrees, June 29 was the fourth-hottest day in recorded Phoenix history.”

But A 2 kWh drop at 20k miles and a 6kWh drop at 40k miles is not good.

At a max range of 104 miles(at 45mph) for the 24kWh pack. Each kWh = 4.33 miles and a 26 mile drop in max range.

Which puts the real world EPA at 49 miles.

So what did we learn?

Always lease a Leaf new, never buy and enjoy the ride.

Hey Bloggin,

What about this, from summer 2013?

I remember mid-summer last year, reports of a record or near-record heatwave with temps up to 129 degrees in Death Valley, CA, and 119 in Phoenix.

I know many parts of the U.S. can suffer from heatwave. All the more reason Nissan needs to put a thermal-control system on LEAF like most other EV-makers do.

Here is a bit more…

“In Phoenix in 2013, there were 115 days that exceeded 100 degrees and 25 days above 110 degrees — both measures outpacing the average since 1981.”

And you are right James, a thermal management system will add a bit more cost, but add more battery longevity.

Nearly from the beginning, Nissan engineers pointed to economic factors in LEAF possessing a non-temperature-controlled battery pack. They also said years back that LEAF gen 2 would have a thermally-conditioned pack. Let’s hope that’s the case.

I live in Western Washington State, not far from where the massive landslide disaster happened this week. Apart from the sogginess of our rain, the temperatures here are perfect for an EV like LEAF because our temps are moderate, never having extreme highs or lows. Much of North America cannot say this – from the extreme cold of most of Canada, and the northern/northeastern United States to muggy hotness in Central and South America.

LEAF has to up it’s temp control on it’s BEVs and PHEVs or limit it’s sales to Central and Southern Europe and climates like we have here.

Oddly, Washington State has probably the largest variance in average temperatures in North America. We have the Cascade Mountain Range, with 14,400+ ft Mt. Rainier being the tallest peak, and east of there we have desert/dry climes. Eastern WA is where BMW’s composite plant is located, and annual rainfall there is very low. I have friends that moved to W. Washington from Phoenix due to health issues. They literally could not take the heat. I know most people in the hot zones of AZ live a life of spending a great deal of the year inside with A/C avoiding the dreadful heat. I couldn’t live like that – but I must add that we here spend a great deal of our lives ducking in out of the rain – so…

Yep, Oregon is the same way. As a state there is a wide range of temperature zones. I think the mountains in the NE part of the state get colder than the Cascades peaks despite the elevation difference though.

While there is a wide variety of zones, the zones in the western part have a very narrow range of temperature variation. Our winter low temps are higher than places much farther south like Dallas or Atlanta, and in terms of cold hardiness we are in a warmer climate zone than those regions.

Of course, on a typical day even in winter may not seem like a warmer place because the temp doesn’t get that high and we have less daylight and sunshine. Also, if a plant needs thrives in summer heat it will be a slow grower here.

Washington ranks #16 in temperature range (166 deg. +118/-48), Oregon #11 (173 deg. +119/-54). The top five:

#5, California (179 degrees, +134*/-45); #4, Alaska (180 deg. +100/-80**); #3 (tie), North Dakota (181 deg. +121/-60); #2 (tie), Wyoming (181 deg. +115/-66); #1, Montana (187 deg., +117/-70***).

*Death Valley, July 10, 1913 U.S. High
**Prospect Creek, January 23rd, 1971 U.S. Low
***Rogers Pass, January 20, 1954 U.S. Contiguous 48 Low

Yea! Montana is number 1 and it isn’t the obesity rate or amount of beer consumed per year!
I am so proud!
Montana Hi-Liner

What you fail to take into account is that although we do spend a good portion of our summers indoors, we spend most of our winter, spring, and falls outdoors!

Then if we do out in the summer it is to the pools we go; and we have a LOT of pools!

Nissan has stated unequivocally that they will not go to an active TMS, but will rely on improved battery chemistry to handle heat. They announced last year that they had a ‘hot’ battery undergoing tests, and that it might be available this spring assuming no problems. Given their past inaccurate claims re the original battery’s heat tolerance, anyone who believes anything they say without a cast-iron capacity warranty is a very trusting soul.

Great facts, GRA. I wasn’t aware that so many states had such a wide temperature variance!

We look at that data and it only reinforces that TMS is completely necessary nearly everywhere.

I’m not a trusting soul…haha. I looked long and hard at the robust battery mgmt. of the Volt before I bought. I still think leasing is a safer bet in regards to that ever-questionable resale value.

While GM’s extremely waning attitude towards anything that gets great gas mileage, esp. anything with a battery involved, I still give them credit for the larger-than-necessary buffers they placed in their T-pack. After EV-1, if they got it wrong it could’ve sunk the company.

I believe Nissan is taking the cheap route and it just may bite them in the arse after all is said and done.

I think GM is just being quiet about their next EV. No need to broadcast your plans.

L3 charging aside, it also means at the 3-year or 36,000 mile mark, my 2013 Leaf will have about 60 mile range. That is my current max around-town trip. It might be worse when it gets really cold.

So buying my Leaf (at end of lease) is definitely not viable. That’s the downside of electric cars – their “gas tanks” shrink over time.

Hmmm…this would make an interesting article. How many Leafs are leased? How are the leasing companies treating the battery capacity at turn-in? Will they charge for excess wear if they can only deliver less than 17kwh after 3 years or will they go after Nissan? Will they be regulated to state current charging capacity in resale listings? If the EPA range of off lease Leafs varies from 45-65 miles, who will buy and at what prices?

Seems like there is an impending dark stain coming for Nissan. Hopefully it doesn’t infect the entire EV industry.

Looks to me the capacity loss is roughly 22% for AC charge and 25% for fast charge. That is a 13.6% higher capacity loss rate for DC charging and is not negligible. The 3% is a difference in total capacity but not in loss rate. Still, it may result in only a negligible difference if fast charging is used sporadically instead of on a daily basis. The seasonal aspect of the testing explains why the depreciation rate is so much higher in the 20-40K periods. Typical Li is expected to slow the depreciation rate after an initial fast period.

Just get a Chevy Volt. It’s active thermal management system keeps the battery cooled (or warmed) as needed, and no range anxiety. Another study showed that Volt driver more electric miles than Leaf owner. Why? No range anxiety, use up the battery without worrying about getting back home.

Doesn’t really make sense since the LEAF electric range dwarfs the Volt range.

So where is the battery temperature data?

with a drop in range of 25% at 40,000 miles do these vehicles fall under warranty.

Hey George,

While the car is still “under warranty” (Nissan gives 60 months on minimum battery thresholds), this vehicle would not yet qualify for rehabilitation.

The depth of discharge warranty does not kick in until the loss of the 9th bar…which (as a rule) is the last one lit between 66.25%-72.5%. The specific ‘data point’ number for Nissan to do the battery rehab is below 70%

Thx Jay,
30% in 5 years is the warranty then.
I’ll have to commit that to memory.

I agree that a fast DC charge will not harm the battery as long as the temperature is controlled. BTW, that woman is not charging with DC. The DC port on the Leaf shown is still covered (orange cap is on).

She IS using the DC port. The orange port is the AC port – J1772 standard.

From the early data gathering on to the recent decision by Nissan to remove the 80% “long-life mode” from the 2014 LEAF, all the evidence points to the idea that the main factors in reducing battery life are, in order of importance: 1) Extreme heat – roughly speaking, amount of time with battery over 80F, with negative impact of the heat growing exponentially with increase in temperature above that. 2) Miles driven 3) Age of battery After that, there are a number of other factors which were concerns at the outset (2010) but have been demonstrated to have relatively little impact. This includes quick charging – the 2011 LEAF manuals strongly recommended minimizing QCing and that text was dropped in 2012. It also included concerns about charging to 100%, driving to turtle mode, and long periods in storage without being used. While all of those practices probably do have some impact relative to an ideal situation (which is probably keeping the charge between 30% – 50% in moderate temperatures with a single trip daily) the difference in battery life is almost negligible compared to the other factors. This is all part of the technology learning that goes on in… Read more »

Or, they could have just used better thermal management, LIKE EVERYONE ELSE.

I was referring to understanding the relative impacts of things like charging to 100%, quick charging etc. Those were things that couldn’t be known until a sufficient amount of real world data was available.

Certainly the issues with heat and the batteries used by Nissan were known in advance, as there were plenty of warnings given.