Conditioning Your Battery / Keeping as Healthy as Possible

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fromAtoB said:
Hi. I’ve spent about two hours this morning reading about Leaf charging and Li ion batteries. A lot of posts and information out there is years old and technologies improve.

My Leaf Plus manual had no recommendations about SOC range.

We bought our Leaf+ in April or May of 2019 when the 62 KWHr (?) batteries were still new but I’m not clear whether the technology changes much. And the last post in this thread is from May 2019.

So...my understanding is that the common wisdom from informed knowledge is that, as driving needs allow, it is better to keep SOC between roughly 20% and 80% and not fully discharge or charge to 100%.

And .... that applies also to the Leaf Plus 62 KWHr battery...is that right?

Thanks.
Click to expand...

Better; yes. Best; no

Technologies improve sure but don't change physics. ATM, technology is only minimizing the damage we cause. EVERY EV manufacturer has custom charge settings some as low as 40% and there is a reason for that.

A few things to consider;
There is no need to fully cycle the pack
There is no need to top end balance the pack
Lead Acid wants to be topped off, NiCad has charge memory issues. Li has none of that.

One thing the Plus provides is more options for battery management. Not all of us can spend 20 seconds wandering out to the garage to start a charge on our car. If you can, then you should charge every day. If you aren't that means you are charging to a higher level than you need needlessly.

If you can't charge at home or work, then you have a challenge as long as you aren't driving 100 miles a day that is "doable" I did it with 24 and 30 kwh packs. (Had charging at home but drove WAY over 100 miles several times a week) so 62 kwh is a breeze.

So, live in the middle. MANY studies show that more frequent shallower charging sessions are better than less frequent deeper charging sessions. So 30-50% if you don't drive much. 20-70% if you do. But its all relative. 20% seems "risky" and I have to laugh at that. Even in winter, that is a 40 mile buffer AFTER pulling into my garage. I spent years pulling into my garage with less than 10 GIDs left (realize the last 4-5 are very hard to access)
 
To put it more succinctly: 25% is better than 20% as a 'floor' for SOC. 20% gets suggested mainly as a compromise for 24kwh Leaf drivers so they have a decent range available. If you go down to 20% or less, recharge immediately back to 25% or more when the trip ends. That way there is no noticeable damage to the pack.
 
I am not aware of ANY studies that can be used to quantify longevity differences between these cycle schedules
20 - 80
20 - 70
25 - 70
25 - 80
30 - 70
30 - 80

Take dogmatic assertions with a gain of salt unless they have links to source references to back them up.

The best I am aware came from Prof Jeff Dahn, given as an answer to a twitter question asking how to fully optimize battery longevity in a Tesla battery. His answer was to cycle around 50%, meaning
Always at 50% is best; if not then
45 - 55; if not then
40 - 60; if not then
35 - 65, ....
https://insideevs.com/news/334778/tesla-battery-experts-recommendation-for-maximum-battery-life-video/

HOWEVER, Dahn did not quantify how much longevity is lost as the cycling window increases. Mainstream opinion seems to be that cycling out to as far as 20 - 80 has minimal effect, and becomes noticeable with frequent wider swings. Which is fine and dandy so far as it goes, but you HAVE to keep in mind the underlying assumption all else kept equal. Which never is true ! The other key variables are battery temperature and time spent at SoC > ~ 80%. If you do a Dahn best job at cycling and ignore time at high SoC and battery temperature your battery will age poorly.

Nissan has screwed you in two ways:
1. By not having thermal control, your ability to mitigate temperature effects is limited
2. By not giving owners an easy way to charge to less than 100% SoC, most owners do not mitigate that effect.
 
SageBrush said:
I am not aware of ANY studies that can be used to quantify longevity differences between these cycle schedules
20 - 80
20 - 70
25 - 70
25 - 80
30 - 70
30 - 80
Click to expand...

Check here for insight of what's been discussed prior on MNL; https://mynissanleaf.com/viewtopic.php?f=30&t=23606&p=525629&hilit=battery+cycle#p525452

The link to the source can be found on MNL.
 
SageBrush said:
Nissan has screwed you in two ways:
1. By not having thermal control, your ability to mitigate temperature effects is limited
2. By not giving owners an easy way to charge to less than 100% SoC, most owners do not mitigate that effect.
Click to expand...

The first one I guess you are talking about liquid cooling not air cooling and/or other functions, although I’ve not looked into this so far. Fortunately we live in the Seattle area so our temperatures are moderate.


About this second, yes I seem to be finding that out after sitting, reading, and experimenting in my Leaf for a while last night.

- The Leaf has a timer but it’s simply for start and stop times, is meant for a standard daily cycle, and is based simply on time not charge.
- I downloaded the Nissan Connect app. It gets lots of one star reviews at the App Store and I could not connect to my vehicle in ten minutes of trying. But looking at the demo mode it seems to not support remote stopping of charging.
- The Leaf Spy app hasn’t been updated in two years so I’m hesitant to get it, but the description doesn’t seem to suggest you can start/stop charging with it.

So if I want to charge to some target not 100% then I’ll need to do a little mental math, plug it in, and then remember to walk out to my garage and unplug it at the right time.

Have I got that right?

And now I’m curious, do other EVs allow simple SOC management?
 
fromAtoB said:
So if I want to charge to some target not 100% then I’ll need to do a little mental math, plug it in, and then remember to walk out to my garage and unplug it at the right time.

Have I got that right?
Click to expand...
Some people talk about doing just that.
Others use an EVSE that has a timer;
Others add a timer to the EVSE (uncommon in the US)
Others set the time to end charging *later* (~ an hour for L2) than their planned departure time. I think this is the most elegant and simple, but people appear to have trouble with the implementation and it requires a reasonably consistent leave time. One way or another, Nissan did not make it straightforward. As I said above, the time spent at high SoC is important. I I think most people agree that it is considerably more important than the absolute SoC per se, so I suggest focusing on that parameter rather than agonizing over the occasional charge using L2 up to 100% SoC.

The forum is chock full of discussion that is LEAF specific
And now I’m curious, do other EVs allow simple SOC management?
Click to expand...
Other EVs vary. Tesla is flexible and easy, and I've read that GM is too. I don't know other EVs to say.

---
LEAF has a reasonable reputation in the Seattle/PNW climate. You are fortunate
 
fromAtoB said:
SageBrush said:
Nissan has screwed you in two ways:
Click to expand...
The first one I guess you are talking about liquid cooling not air cooling and/or other functions, although I’ve not looked into this so far. Fortunately we live in the Seattle area so our temperatures are moderate.
Click to expand...

Sage is a Tesla Fanbouy. Expect hate for any other EV.

There are both advantages and disadvantages to liquid cooling. If your car is a daily driver and you live in a moderate or cool place (Seattle is cool), then you will very likely be happy with passive cooling.

Sport driving, long distances with frequent recharging and very hot places you would probably want liquid cooling. Tesla cars only come with liquid cooling, so expect Sage to foam about this.


fromAtoB said:
About this second, yes I seem to be finding that out after sitting, reading, and experimenting in my Leaf for a while last night.

- The Leaf has a timer but it’s simply for start and stop times, is meant for a standard daily cycle, and is based simply on time not charge.
- I downloaded the Nissan Connect app. It gets lots of one star reviews at the App Store and I could not connect to my vehicle in ten minutes of trying. But looking at the demo mode it seems to not support remote stopping of charging.
- The Leaf Spy app hasn’t been updated in two years so I’m hesitant to get it, but the description doesn’t seem to suggest you can start/stop charging with it.
Click to expand...
You can start but not stop charging with the Nissan app. LeafSpy is more instrumentation and tweeking.

fromAtoB said:
So if I want to charge to some target not 100% then I’ll need to do a little mental math, plug it in, and then remember to walk out to my garage and unplug it at the right time.

Have I got that right?

And now I’m curious, do other EVs allow simple SOC management?
Click to expand...

What fraction of the battery do you use every day? Example: If it was around 15%, you might set the timer to charge overnight by 20%. If above 60%, don't plug in. Should stay mostly between 45% and 80%, and while slightly better results would be possible, is still fairly good. One quick look, no math, plug in or not plug in, done.

About every other EV allows better simple SOC management. The eTron has a charge target from 50% to 100% by 10% steps, and I can set different targets at different locations. At home, is currently set for 70%, away from home is set to 100%. Bolt as well, other than older Bolts that had only "hill top mode" or a 90% limit. Even early Leafs allowed for 80% SOC limit...
 
WetEV said:
fromAtoB said:
SageBrush said:
Nissan has screwed you in two ways:
Click to expand...

What fraction of the battery do you use every day? Example: If it was around 15%, you might set the timer to charge overnight by 20%. If above 60%, don't plug in. Should stay mostly between 45% and 80%,
Click to expand...


That’s a good idea. That might work for us on weekends.

During weekdays - when the governor here isn’t closing the economy down - we need to make three round trips of about 55 miles each day totaling 165 mi The last one we arrive home nearly 9 pm. The joys of parenthood! That might change next Summer or Fall but such is our sentence for now. For that I love love love the range of our Plus. We couldn’t have done this with our nice 2015 Leaf, and gas would cost us a fortune.

For those busy days, I might try to start the morning at 80%, and then put in one charging session during the day plus one at night.

The easier strategy could be to estimate a timer for 165 miles and then plug it in at 9 pm arrival and then let it go for maybe 6 hours. 165 miles would be about 75% of our vehicles GOM range as we drive. Now I’m not sure whether high SOC or low SOC is more harmful. I could time it to 100% right before we leave and have about 25% left when the day is done, or shoot for 90% and have 15% left when the day is done.
Click to expand...
 
fromAtoB said:
That’s a good idea. That might work for us on weekends.

During weekdays - when the governor here isn’t closing the economy down - we need to make three round trips of about 55 miles each day totaling 165 mi The last one we arrive home nearly 9 pm. The joys of parenthood! That might change next Summer or Fall but such is our sentence for now. For that I love love love the range of our Plus. We couldn’t have done this with our nice 2015 Leaf, and gas would cost us a fortune.

For those busy days, I might try to start the morning at 80%, and then put in one charging session during the day plus one at night.

The easier strategy could be to estimate a timer for 165 miles and then plug it in at 9 pm arrival and then let it go for maybe 6 hours. 165 miles would be about 75% of our vehicles GOM range as we drive. Now I’m not sure whether high SOC or low SOC is more harmful. I could time it to 100% right before we leave and have about 25% left when the day is done, or shoot for 90% and have 15% left when the day is done.
Click to expand...

High SOC increases calendar loss and cycling loss. Low SOC increases cycling loss.

Don't leave the battery at high SOCs for long periods of time, and make cycles as narrow as possible for best battery life...

So your daily trips are about 25% of the battery. If you only charge overnight, and your schedule is predictable, charge to 100% at departure time. This avoids time at high SOCs as you don't leave the car for long at high SOC, and avoids low SOCs. 100% to 75% is much better for the battery than 80% to 5%. A single charge overnight would likely not work in winter, as efficiency reduces at lower temperatures, more energy is used for climate control, etc.

Depending on the time between trips and where the car is parked, you might plug in multiple times during the day. Hard to analyze.
 
fromAtoB said:
So if I want to charge to some target not 100% then I’ll need to do a little mental math, plug it in, and then remember to walk out to my garage and unplug it at the right time.

Have I got that right?
Click to expand...

That is one option. Another is simply determine a charging duration, add a buffer and set the charge timer. Currently I do what you suggested.

I start my work week out between 45-60% SOC. I get up in the morning, plug in on day 2. Unplug 75 mins later when I leave for work. On my day off, I get up and still plug in but unplug when I have determined I have had enough to get what I need done. Lately it hasn't been much but earlier in Summer, I was setting a timer to start anywhere from 1 to 4 am depending on my plans for that day.

FYI; I have enough every day to go to work and back twice. I have never had to do this but with this much available range, it would be foolish to not be prepared for the first time this comes up.
 
We’ve started changing our charging routine. Last night I unplugged after about four hours instead of letting it fill up. And we don’t let it discharge as low before adding some juice. Thanks everyone for the helpful info and suggestions.
 

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