GCC: INL study suggests fast charging can take longer in cold temperatures

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GRA

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http://www.greencarcongress.com/2018/08/20180802-inl.html

New research from Idaho National Laboratory suggests that electric vehicle drivers could face longer fast charging times when temperatures drop. The reason: cold temperatures impact the electrochemical reactions within the cell, and onboard battery management systems limit the charging rate to avoid damage to the battery.

The study, published in the journal Energy Policy, presents an empirical analysis of the effects of temperature on Direct Current Fast Charger (DCFC) charging rate and discusses the impact of such effects on wider adoptions of electric vehicles (EVs).

The authors conducted statistical analysis on the effects of temperature and constructed an electric vehicle charging model that can show the dynamics of DCFC charging process under different temperatures. The results indicate that DCFC charging rate can deteriorate considerably in cold temperatures. . . .

Motoaki and his colleagues analyzed data from a fleet of Nissan LEAFs operated as taxis over roughly 500 Direct Current Fast Charge (DCFC) events. Temperatures for the charging events ranged from 15 to 103 degrees Fahrenheit.

The researchers found that charging times increased significantly when the weather got cold. When an EV battery was charged at 77 degrees, a DCFC charger might charge a battery to 80 percent capacity in 30 minutes. But at 32 degrees, the battery’s state of charge was 36 percent less after the same amount of time.

The more the temperature dropped, the longer it took to charge the battery. Under the coldest conditions, the rate of charging was roughly three times slower than at warmer temperatures.

It‘s important to note that cold weather would only impact EV drivers under specific circumstances, Motoaki said. For instance, people who charge their EVs in a warm garage and use their EVs for commuting within the range of their battery might not experience much inconvenience. Decreased fuel economy in cold weather is also a well-known phenomenon with gasoline and diesel-powered vehicles. . . .
 
LOL, they could have saved themselves a lot of effort if they'd simply asked a few LEAF owners living in colder climates :lol:
 
alozzy said:
LOL, they could have saved themselves a lot of effort if they'd simply asked a few LEAF owners living in colder climates :lol:
Which would have given them anecdotal info of widely varying accuracy and precision, not statistically valid data. Everyone knows that batteries can accept less charge rate when cold; this study quantifies that in a scientifically valid way, rather than asking owners what they 'think' is happening.
 
I shouldn't have bothered commenting, I just can't excited about this kind of stuff - charging takes as long as it takes, there's not really anything one can do to speed it up...

To each his/her own though, more power to you.
 
alozzy said:
I shouldn't have bothered commenting, I just can't excited about this kind of stuff - charging takes as long as it takes, there's not really anything one can do to speed it up...

To each his/her own though, more power to you.

In cold temperatures, you can speed up charging by first warming the battery. Anecdotally, people have had luck with "driving it like they stole it" right before hitting the charger.
 
GetOffYourGas said:
alozzy said:
I shouldn't have bothered commenting, I just can't excited about this kind of stuff - charging takes as long as it takes, there's not really anything one can do to speed it up...

To each his/her own though, more power to you.

In cold temperatures, you can speed up charging by first warming the battery. Anecdotally, people have had luck with "driving it like they stole it" right before hitting the charger.
Uh huh, and vehicles with battery heaters also speed things up (at a cost in energy).
 
GRA said:
GetOffYourGas said:
alozzy said:
I shouldn't have bothered commenting, I just can't excited about this kind of stuff - charging takes as long as it takes, there's not really anything one can do to speed it up...

To each his/her own though, more power to you.

In cold temperatures, you can speed up charging by first warming the battery. Anecdotally, people have had luck with "driving it like they stole it" right before hitting the charger.
Uh huh, and vehicles with battery heaters also speed things up (at a cost in energy).

Exactly. Although to my knowledge, the Leaf doesn't do this. I was responding to alozzy's claim that "there's not really anything one can do to speed it up" in cold weather. That's just not true.
 
Just putting this out there

In my 2018 LEAF, I charged at 25º and the knee started 56%.

I also charged at 81º and knee started at 62%.

During the somewhat "cold" charges (batt temps 59º or less) knee started at 56-60%

During the warm charges (batt temps under 90º) knee happened between 60-65%
 
Sigh :roll: Obviously, it's possible to warm the battery up a bit but what I meant is that the DCFC charging rate is going to be relatively slower in winter months than during summer, which should be self evident. Someone funded that study and it wouldn't surprise me if tax payer money was involved. That's what had me comment to this thread in the first place...

Good luck trying to get your battery more than a few degrees above ambient during winter, unless you are driving around a lot. When it's cold out, DCFC charging is going to be SSSSLLLLOOOOWWW unless you're lucky enough to find an L3 EVSE in a heated parkade.
 
alozzy said:
Good luck trying to get your battery more than a few degrees above ambient during winter, unless you are driving around a lot. When it's cold out, DCFC charging is going to be SSSSLLLLOOOOWWW unless you're lucky enough to find an L3 EVSE in a heated parkade.

I took a long trip in winter from near Seattle to Vancouver area. The first QC was slow. The second, third and fourth QCs were fairly fast.
 
WetEV said:
alozzy said:
Good luck trying to get your battery more than a few degrees above ambient during winter, unless you are driving around a lot. When it's cold out, DCFC charging is going to be SSSSLLLLOOOOWWW unless you're lucky enough to find an L3 EVSE in a heated parkade.

I took a long trip in winter from near Seattle to Vancouver area. The first QC was slow. The second, third and fourth QCs were fairly fast.

Or you can plug in for 5 minutes, heat the pack, unplug and restart the charge.
 
:roll:

NCfC.gif
 
Leaf always limits DC charging according to temperature reading in the pack AND highest voltage reading.
AFAIK, maximum voltage allowed is 4.13V for Leaf.
With warm pack, my Leaf starts to throttle at around 63%. This is the moment when Leaf actually charges at 396*120=47kW.
With cold pack, voltage limit arrives way way sooner. And there is also another limitation with very cold pack even without voltage
limitation.

Difference is around 50%. Best case scenario 24kWh Leaf gets 6-6.5kWh within 10 minutes, bad (not worst) case 3.6kWh within 10 minutes.
Both at low state of charge (less than 20%).

Charging rate can increase during charging session as pack warms up while charging. No need to unplug and try again.

Tesla is even worse. It will NOT CHARGE at all when chemistry is below freezing (literally, 0*C). I mean 0kW. This includes regen.
 
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