Long term EV storage procedure

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The last time I drove my Leaf was March 14. I charged it to 100% that day and then unplugged it. This thread got me to thinking that I should go take a look at the charge level. I was very surprised/impressed to see that the battery charge is now at 99%.
 
jlv said:
I personally don't know about the trickle charger. I never had 12V battery issues with my LEAF, while other people have reported lots of issues. I had an 2013 SL with the silly PV panel to top off the 12V; I'm not sure if that is why.
I heard from the current owner of my 2013 SL. He told me the 12V was low after the car sat unused (outside) for 3 weeks. But then again, it's still on the original 12V battery, presumably put into service when the car was mfg'd in December 2013.
 
LeftieBiker said:
Ok, so:

- leaving the main battery charged at 60-80%
- with the car unplugged and
- with the 12V battery remaining connected

should technically be ok for 3 months during the summer (in Southern California)

Yes. I would suggest, though, that it be left closer to 60% than to 80%. 40-50% would be optimum, if you won't need to take it on a long trip right out of storage.

Thanks for all your help. Feeling much better about storing it now!
 
SanCarlosJeff said:
The last time I drove my Leaf was March 14. I charged it to 100% that day and then unplugged it. This thread got me to thinking that I should go take a look at the charge level. I was very surprised/impressed to see that the battery charge is now at 99%.

That's the point: the longer your battery sits near 100%, the the more its long-term health deteriorates.
Lithium batteries are designed to "hold their charge" (that's why they work so well in our cars), but don't like to be stored at/near 100% (especially in warm environments).
 
Stanton said:
SanCarlosJeff said:
The last time I drove my Leaf was March 14. I charged it to 100% that day and then unplugged it. This thread got me to thinking that I should go take a look at the charge level. I was very surprised/impressed to see that the battery charge is now at 99%.

That's the point: the longer your battery sits near 100%, the the more its long-term health deteriorates.
Lithium batteries are designed to "hold their charge" (that's why they work so well in our cars), but don't like to be stored at/near 100% (especially in warm environments).
TLDR: Correct.

This source is behind a paywall. Sorry.
Also is for a different chemistry, one that might had a use for a product I might have designed. Things are strange now. Remember that different chemistries have different properties, but generally similar behavior. These results are not directly usable for a LEAF, or for any other EV. This is not an automotive battery being tested.

http://dx.doi.org/10.1016/j.jpowsour.2013.09.143

The Leaf doesn't allow for an actual 100% charge, but only about 95%. The LEAF SOC gauge reports 100% at about 95% actual capacity, to say this another way.

For the cell tested in the above source, life at storage at 50C at 100% SOC was 107 days to 80% of initial capacity.
Life at 95% true SOC (or LEAF reported 100%) was a bit less than a year. Storage lifetime increased with decreasing SOC, exceeding 4 years at 50C at low SOC. Much longer calendar life at lower temperatures for all SOCs, see Arrhenius. However directly testing them becomes a challenge.

Now how does that apply to the LEAF? This isn't an automotive battery, but the same general principal does apply. Longer life at lower SOC.
Very bad things also happen at low SOC, below about 30%, but not due to calendar losses, but rather due to cycling losses and probable Li plating.

So store the traction battery at about 40% SOC, unless you might need to do a significant drive without charging. Avoid storage above about 70%, if you can help it. Avoid discharge below 30% SOC, if you can help it. 20% SOC isn't so bad, but 10% SOC and 5% are worse.
 
WetEV said:
Stanton said:
SanCarlosJeff said:
The last time I drove my Leaf was March 14. I charged it to 100% that day and then unplugged it. This thread got me to thinking that I should go take a look at the charge level. I was very surprised/impressed to see that the battery charge is now at 99%.

That's the point: the longer your battery sits near 100%, the the more its long-term health deteriorates.
Lithium batteries are designed to "hold their charge" (that's why they work so well in our cars), but don't like to be stored at/near 100% (especially in warm environments).
The Leaf doesn't allow for an actual 100% charge, but only about 95%. The LEAF SOC gauge reports 100% at about 95% actual capacity, to say this another way.

[snip] store the traction battery at about 40% SOC, unless you might need to do a significant drive without charging. Avoid storage above about 70%, if you can help it. Avoid discharge below 30%, if you can help it.

This would seem to imply that unless new battery technologies get markedly better with respect to degradation, we will eventually end up in a world where we drive around with vastly larger batteries than nominally necessary in order to preserve battery life, as costs come down. Batteries with 15-20% reserve would seem to be one solution - that's what you're effectively suggesting isn't it? Drive your car between 30 and 70% charge, i.e. use 40% of available range unless otherwise needed. We've been doing 25-75% more recently, as we've gained experience.

Looking farther forward, manufacturing economies of scale will kick in enough, and we'll just replace a worn out battery every 80k miles or something. It will be interesting to see how things shake out. But for now, it would seem that battery manufacturing capacity is lagging demand.
 
frontrangeleaf said:
WetEV said:
[snip] store the traction battery at about 40% SOC, unless you might need to do a significant drive without charging. Avoid storage above about 70%, if you can help it. Avoid discharge below 30%, if you can help it.

This would seem to imply that unless new battery technologies get markedly better with respect to degradation, we will eventually end up in a world where we drive around with vastly larger batteries than nominally necessary in order to preserve battery life, as costs come down. Batteries with 15-20% reserve would seem to be one solution - that's what you're effectively suggesting isn't it? Drive your car between 30 and 70% charge, i.e. use 40% of available range unless otherwise needed. We've been doing 25-75% more recently, as we've gained experience.

Looking farther forward, manufacturing economies of scale will kick in enough, and we'll just replace a worn out battery every 80k miles or something. It will be interesting to see how things shake out. But for now, it would seem that battery manufacturing capacity is lagging demand.
Batteries have gotten markedly better, and are likely to continue to become better with respect to degradation.

25% to 75% is better than deeper cycles. Mostly you should be trying to do this or a shallower cycle for the regular driving you do to get better battery life. This was true for the early Li-ion batteries and is still true for current batteries. The shallower the cycle the better in the center of the battery capacity.

Battery manufacturing capacity is and needs to be ramping up to keep up with demand.
 
jlv said:
I'd leave the battery with more SOC than that; more like 60-80% (as stated above).

Li-ion battery calendar loss is dependant on SOC. The higher the SOC, the faster the loss. Yes, even down to 10%, the lowest tested.

M. Ecker et al. / Journal of Power Sources 248 (2014)
 
WetEV said:
jlv said:
I'd leave the battery with more SOC than that; more like 60-80% (as stated above).

Li-ion battery calendar loss is dependant on SOC. The higher the SOC, the faster the loss. Yes, even down to 10%, the lowest tested.

M. Ecker et al. / Journal of Power Sources 248 (2014)

This doesn't seem to apply well to the post 3/2013 Leaf packs. The Wolf and Lizard packs have little calendar loss unless charged to near 100%, and the post-Lizard 30 and 40kwh packs seem to have other issues that don't have much if anything to do with storage SOC, again as long as it isn't very high.
 
WetEV said:
jlv said:
I'd leave the battery with more SOC than that; more like 60-80% (as stated above).

Li-ion battery calendar loss is dependant on SOC. The higher the SOC, the faster the loss. Yes, even down to 10%, the lowest tested.

M. Ecker et al. / Journal of Power Sources 248 (2014)
If you leave the car at 80% SOC, it isn't going to reach 10% SOC faster then if you initially left the car at 60% SOC.
 
jlv said:
WetEV said:
jlv said:
I'd leave the battery with more SOC than that; more like 60-80% (as stated above).

Li-ion battery calendar loss is dependant on SOC. The higher the SOC, the faster the loss. Yes, even down to 10%, the lowest tested.

M. Ecker et al. / Journal of Power Sources 248 (2014)
If you leave the car at 80% SOC, it isn't going to reach 10% SOC faster then if you initially left the car at 60% SOC.
???
Unless there is substantial vampire loss due to very low temperatures, a LEAF doesn't lose SOC very fast. SOH is lost faster at high SOC.

So only looking at calendar life, lower SOC is better, all the way down to 10%.

There isn't much reason to leave at 80%, again unless the temperature is low enough for the battery heater to activate. And if it is that cold, you might just want to leave at 100%, as calendar loss is very slow at subfreezing temperatures.
 
WetEV said:
There isn't much reason to leave at 80%, again unless the temperature is low enough for the battery heater to activate. And if it is that cold, you might just want to leave at 100%, as calendar loss is very slow at subfreezing temperatures.

I can't believe I'm reading this...on this site...from an experienced member...after all we know.
Never, ever, ever leave an EV charged to 100% more than a day or so...no matter what the temperature.
I still can't believe Nissan never re-instated the 80% charge option post MY2012 (I use it all the time).
 
Stanton said:
WetEV said:
There isn't much reason to leave at 80%, again unless the temperature is low enough for the battery heater to activate. And if it is that cold, you might just want to leave at 100%, as calendar loss is very slow at subfreezing temperatures.

I can't believe I'm reading this...on this site...from an experienced member...after all we know.
Never, ever, ever leave an EV charged to 100% more than a day or so...no matter what the temperature.
I still can't believe Nissan never re-instated the 80% charge option post MY2012 (I use it all the time).
If the temperature is low enough for the battery heater to activate the EV will not be at 100% for long. If you want the car drive-able when you return, perhaps you might want more charge in the battery.

"100%" on the dash is more like 95% actual. 95% actual is about 3 times less calendar loss than 100% actual. 40% is about half the calendar loss of 95% actual. The LEAF, other than some early prototypes, will not allow charging to 100% actual.

At 0C, the loss will be roughly 1/4 the rate of at 20C. So keeping the charge level higher has an effect, but it is smaller because the temperature is lower. Keeping the battery at 95% actual at 0C is better than keeping the battery at 40% at 20C.

BTW, removing the charge option is close to top of my list of criticisms of the newer LEAFs. The etron allows any 10% from 50% to 100%. As my driving is close to home, I'm now using 60% charge limit and plugging in at 50% on the etron. My son with an essential job is driving the LEAF, and charges to 100% before departure, and comes home with 20% on the worst days in winter (wind, snow inland and cold), and over 50% on nice summer days.
 
Sticking my nose where it doesn't belong, because my OCD issues, finally, are not with my cars!! HAHA!!

Dallas/Fort Worth region. I have charged to 100% virtually every single day that I've owned my 2015 LeafS, now at 37k miles, 11 bars on the GOM. Most days, it is driven to 45% capacity, rarely below 30%. We like 100% charge to allow us a spontaneous lengthy errand w/o range anxiety. Lifetime average 4.1 m/kWh, GOM shows 80-83m every single start-up.

It infrequently sits at 100% w/o being driven, with the exception of my FIRST year, when I left it plugged in for 5 straight weeks (July, garaged, no A/C...HOT!) .

I did lose my OEM battery after 4 years.

EDIT: I lost my OEM 12V battery after 4 years!!!!! I'm still on my OEM Lizard battery, with 11 bars.

...just muddying the water here with my single data point! ;) :p
 
gncndad said:
It infrequently sits at 100% w/o being driven, with the exception of my FIRST year, when I left it plugged in for 5 straight weeks (July, garaged, no A/C...HOT!) .

I did lose my OEM battery after 4 years.

...just muddying the water here with my single data point! ;) :p

In this case, your single data point is important: you lost a Lizard battery in 4 years (probably in large part to that 5 weeks it sat @100% in the Texas summer) where my (replacement) Lizard battery is now beyond 4 years @2BL (I lost my original battery after 4 years in Texas).
 
Stanton said:
Never, ever, ever leave an EV charged to 100% more than a day or so...no matter what the temperature.

"no matter what the temperature" is not well defined by somebody who lives in TX.
If you have no experience with sub-zero Fahrenheit temperatures and batteries,
please don't say "no matter what temperature". Nothing really happens at -15*C with Li-ion,
no matter what temperature and what voltage. Calendar life...stops.

Also please keep the topic clean of endless fight over literally stupid never-ending topic :|
"Long term EV storage procedure" is not about that one thing that has overtaken 10+% of this forum.

Long term is about weeks and months... not days. Battery heater plays no role here.
 
OOOPS!!!! Major typo in my post.

I lost my OEM 12V battery after 4 years, NOT THE LIZARD BATTERY. I'm still on my OEM Lizard battery.

Sorry for the confusion....
 
My story - I bought a 2012 Nissan Leaf SL in 2017 with a replaced main traction battery (24kW) - I presume a Lizard kind - in Los Angeles.

Original 12V battery was getting drained if the car was sitting unused for more than 3 days, since I have replaced it with a newer one it can sit for a 5 days but beyond that I am risking on finding a dead car. Now I use C-tec battery charger when I have to leave the car unused for more than a week. I thought solar panel would trickle charge the 12V battery, but it doesn't seem to help much (if any).

When I bough my Leaf, SOH was 120%, after 3 years of use it is now down to 82%. I am thinking on sending this vehicle to my family summer house in Central Europe, where it would be stored in a shed when not used over winter(s). I do go and spend time over there every 1-2 years in summer when I plan on using the vehicle.

Would charging traction battery to 60% and disconnecting 12V battery is a best strategy or it would be better to have it on a 12V battery tender and connected? There will be no one interacting with the car while I am not there. Easiest would be not to have a charger for 12V battery as if there is some electrical issue and the charger is reset/turned off it might be years before I could get to the car.

Suggestions welcome.
 
How cold does it get where the car would be stored? Because if the pack temp (not the air temp) drops into the mid to high single digits Fahrenheit, the battery warmer will run and consume the charge eventually. Disconnecting the 12 volt battery should prevent that, but then the battery could possibly be damaged...
 
Li-ion battery will not be damaged if temperature drops to extreme cold.
Battery will not be able to discharge at extremely low temperatures, making vehicle undriveable until temperature rises above -15*C.
This is why some smaller devices stop working (phone, flashlight ....) that have Li-ion battery. And are totally fine later on.

Traction battery should be left to around 30-50% and 12V battery should be a) charged and b) disconnected from vehicle.

12V battery should be recharged after 6 months if stored for longer.
Leaf should be stored at temperatures not higher than 20*C.
 
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