SageBrush
Posts: 4747
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Effect of SoC and Temperature on Battery Life

Sun Apr 21, 2019 11:00 am

joeriv wrote:If you read the study, the conclusion:

"The final conclusion from this study is that there is a huge potential for prolonging the battery lifetime by avoiding high SOC values. Additional prolonging of the lifetime can also be reached by only charging the battery with the needed energy, using a small DOD, and to do this just before the driving. This strategic planning of the charging will limit the impact from the calendar ageing."

For those of us who use a BEV for local driving, keeping the battery at something like 30-60% SOC and charging only as much is needed to maintain this range will significantly increase battery life. It also suggests, all things being equal, the larger the battery the better.
Right.

The suggestion to charge before driving is another way of saying that letting the battery stew at a high SoC is best to avoid. This is particularly true as ambient temps increase, as the data shows.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

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TomT
Posts: 10640
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: Effect of SoC and Temperature on Battery Life

Sun Apr 21, 2019 1:23 pm

Which is why I expect the 75Kwh battery in my Tesla Model 3 to last longer than I do! <G>
I normally charge to 80% and use a very shallow DoD...
joeriv wrote:If you read the study, the conclusion:
"The final conclusion from this study is that there is a huge potential for prolonging the battery lifetime by avoiding high SOC values. Additional prolonging of the lifetime can also be reached by only charging the battery with the needed energy, using a small DOD, and to do this just before the driving. This strategic planning of the charging will limit the impact from the calendar ageing."
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

johnlocke
Posts: 393
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: Effect of SoC and Temperature on Battery Life

Sun Apr 21, 2019 5:09 pm

So having a large battery, charging less often, limiting DOD, and charging to less than 100% are all good things. So is keeping the battery's internal temp in a moderate range (active cooling and heating). Too bad my 30KWH leaf has too small a battery and a lack of internal cooling. Since I drive 55-75 miles daily limiting DOD doesn't work very well and I don't really have any way to reliably charge to only 90%. It would have been nice of Nissan to tell me this instead of telling me to "just charge it up every night"! Of course I might have then not bought a Leaf.
2016 SV, New battery at 45K mi.
Jamul, CA
San Diego East County

baustin
Posts: 711
Joined: Tue Feb 24, 2015 1:23 pm
Delivery Date: 09 Mar 2015
Leaf Number: 402162
Location: North Las Vegas, NV

Re: Effect of SoC and Temperature on Battery Life

Mon Apr 22, 2019 4:09 am

Charging to 100% is not a problem. It is required, periodically, to keep the cells balanced. It is leaving it at 100% charge for extended periods of time, especially in high temperatures, that is the problem. For those without the ability to limit charging, use a timer so that charging completes just prior to the intended departure time.

I am one of the fortunate ones with a 2013 Leaf. I use the charge timer to start at 2:10am every day and charge to 80%. I can override this at anytime by hitting the Charging Start button in the EV App and get it up to 100% whenever the range is needed. The car is always plugged in when not being driven, which allows remote Climate Control or Charging to be activated whenever desired.
2013 Leaf SV - Cayenne Red - QC Port - LED Headlights

SageBrush
Posts: 4747
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Effect of SoC and Temperature on Battery Life

Mon Apr 22, 2019 5:33 am

baustin wrote:Charging to 100% is not a problem. It is required, periodically, to keep the cells balanced. It is leaving it at 100% charge for extended periods of time, especially in high temperatures, that is the problem. For those without the ability to limit charging, use a timer so that charging completes just prior to the intended departure time.

I am one of the fortunate ones with a 2013 Leaf. I use the charge timer to start at 2:10am every day and charge to 80%. I can override this at anytime by hitting the Charging Start button in the EV App and get it up to 100% whenever the range is needed. The car is always plugged in when not being driven, which allows remote Climate Control or Charging to be activated whenever desired.
Agreed. Setting the charging end timer to about ~ one hour after the time the car is to be used may also work pretty well.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

goldbrick
Posts: 572
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: Effect of SoC and Temperature on Battery Life

Mon Apr 22, 2019 10:20 am

Thanks SageBrush (and cwerda) for exposing this. It's not really anything new although it does add a lot of credence to what used to be mostly anecdotal speculation.

FWIW, my strategy going forward is to charge the car every night just enough to get through the next day's driving. My use is almost entirely small trips and commuting. So far I've kept the car between 30% and 80% SOC as much as possible but sometimes I'm stuck in a meeting or forget to check it and it goes outside this range. I charge for free at work and usually charge about 2x or 3x a week.

I just bought an OpenEVSE since it appears to allow great scheduling or charging either by time or even amount of power. So.....once the weather gets hot this summer, I will charge X minutes or X kWh every night at 3AM or something to get through the next day. That should allow the battery to cool after my drive home and before my drive to work and will also charge when the inside of the garage is coolest. Plus it's a low usage time although I don't have to worry about TOS rates now.

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