Keeping battery at 20% to 80%?

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

ElectriCute

Well-known member
Joined
Oct 29, 2021
Messages
72
As some of you know, I'm new to the Leaf, and EV in general. My main concern about my car is "battery degradation." This, of course, is something that happens to the battery over time. The idea is to keep that degradation as low as possible. I hear this 20 to 80% theory a lot. A range to keep your battery at in order to lengthen it's life. Why is this? Isn't charging it to 100% a good idea to take advantage of the car's max range? A Nissan customer service rep mentioned to me that charging it to 100% is fine, and as soon as you reach 100%, charging stops. So no trickle charging. Is, what he told me, correct in regards to newer Leafs, or all Leaf cars in general? Like all of us Leaf owners, we want to maintain the battery as best we can so that we get the longest life out of it. To be honest, all of this is rather confusing. What are your thoughts on this subject, please?

Thank you.
 
Others more knowledgeable will weigh in soon, but to begin with 80% charge is plenty of miles for most people's runabout uses and for us in particular it lasts us several days depending on use. It turns out to be stress-free to charge to 80% or so, and then not worry till it gets down to 30% or so. No real need to charge it full unless planning a trip in which case, go for it and don't worry. Main thing? Not to worry, you are gonna love the way it functions!
 
There's about a hundred threads on this topic...but since you are new to EV's (and the newer Leafs only charge to 100%), here's some simple advice:
  • set a charging timer to finish in the morning before you leave for work (which also lets the battery cool in the late evening)
  • plug in (that evening) when you go below 50% SoC

And some tips:
  • don't let any EV sit @100% SoC for long periods of time (e.g. more than a day)
  • don't let any EV sit <20% SoC (or VLB) for long periods of time

heat accelerates all forms of battery degradation, so try to avoid charging during the hottest parts of the day/year (for example, I avoid charging when my Gen1 Leaf shows >6 temperature bars).

Other than that, enjoy driving electric!
 
The physics are well known and the batteries do lose capacity over time. Like with almost any chemical phenomenon, heat accelerates the process. Very high or very low SOC states are also accelerating factors. The worst case seems to be high SOC (eg 100%) and high heat. Thus the advice to not leave the car at fully charged for days at a time while it's hot outside.

Many of the studies that show all this can be found online but they are usually several years old. From what I've read here, it appears that the manufacturers are making better batteries every year and the ones you buy today perform much better than the ones available 5 years ago.

I like to think of it like exposure to UV rays. You can 'go crazy' and never leave the house without 100+ SPF on. That is probably sound advice and many dermatologists might recommend that. Or you can just be careful not to get sunburned and wear a hat and long sleeves or SPF 30 in the summer when you are going to be outside for a long time. If you can get 90% of the benefit for 10% of the trouble that seems like a reasonable path. I found that after accepting the fact that the battery degrades with time, I could worry about it less and enjoy it more.
 
Stanton said:
There's about a hundred threads on this topic...but since you are new to EV's (and the newer Leafs only charge to 100%), here's some simple advice:
  • set a charging timer to finish in the morning before you leave for work (which also lets the battery cool in the late evening)
  • plug in (that evening) when you go below 50% SoC

Make the charging timer start so that about 40% of the battery is filled in one night. Or a bit more or less, depending on details.

Plug in below 50%. Will charge to between 80% and 90%. Adjust as desired.
 
Nissan salescritters will say just about anything to sell a Leaf - as will most other salescritters and, of course, the Dreaded Salesvermin. They told customers that the original 75 mile range Leaf had 100 miles of range or more. So take what they say with a grain of salt.
 
Make the charging timer start so that about 40% of the battery is filled in one night. Or a bit more or less, depending on details.

Plug in below 50%. Will charge to between 80% and 90%. Adjust as desired.


We use 5 hours of level 2 at our particular station. Timer on at midnight, off at 5 AM, all off-peak and adds about 35%. As stated above, plug in below about 40%.
 
It is not too surprising that new to LEAF owners are confused by people who say charging to below 100% SoC is advisable, yet Nissan does not give the owner that option, implying that routine charging to 100% SoC is fine.

Answer: Nissan is wrong if the goal is to mitigate battery degradation. How wrong depends on the circumstances. The longer the car sits at 100% SoC, and in particular the longer the car sits at 100% SoC when the battery is hot, the worse the Nissan approach becomes.

OP: you will find that EVERY single owner in this forum who wants to slow down battery degradation takes steps of one form or another to do two things: reduce the time the pack sits at 100% SoC; and second, tries to charge after the pack has had a chance to cool down some in the hot months of the year. The actual implementation details vary from person to person because each person uses their car differently, and each person has their own inconvenience:benefit threshold.

Read the different approaches and adapt one to fit you. Follows is my personal advice to you:

Don't let perfect stop you from doing good enough
A battery stewing for an hour or two is a whole lot better than overnight
A battery stewing at 95% SoC or less is a whole lot better than stewing at 100%
A battery stewing at 80F is a whole lot better than stewing at 90F+

Make an effort, and get on with life. The car will thank you. You can probably gain 70 - 80% of the possible benefit by doing 15 - 25% of the optimal.
 
dmacarthur said:
Make the charging timer start so that about 40% of the battery is filled in one night. Or a bit more or less, depending on details.

Plug in below 50%. Will charge to between 80% and 90%. Adjust as desired.


We use 5 hours of level 2 at our particular station. Timer on at midnight, off at 5 AM, all off-peak and adds about 35%. As stated above, plug in below about 40%.

I can charge during the time when it's off peak hours. I don't have the power source on a timer, but I can keep an eye on it through the phone app. During the high temps of the summer, I'll use the onboard timer on the car so it can charge during the night when the battery itself is cooler. I do have one other question about charging. Is it detrimental to the life of the battery if say I charge in small amounts, 30% to 60%, for example, when I don't have enough time to give a fuller charge, but a little bit extra for when I need more range? Just small charges when I get a chance to add a little juice, so to speak?
 
Charging in small increments is fine. The only exception is that you should avoid plugging in to charge when the state of charge is already well above 80%. You have the right idea about nighttime charging, but because of the mass of the pack and the slowness with which it heats up and cools off, the best time to charge is as close to morning as is possible to get the charge you need. Midnight is the earliest I plug in when the weather is Hot.
 
ElectriCute said:
During the high temps of the summer, I'll use the onboard timer on the car so it can charge during the night when the battery itself is cooler.
Do what I bolded above. Don't worry about putting the EVSE on a timer or any of that other complicated stuff: just set the onboard timer to end before you need it in the morning. This isn't supposed to be a PITA; it doesn't hurt to leave the pack @100% for a couple hours.
ElectriCute said:
Just small charges when I get a chance to add a little juice, so to speak?
That's fine: just try to avoid "topping off" when the pack is already at or near 80%
 
Stanton said:
ElectriCute said:
During the high temps of the summer, I'll use the onboard timer on the car so it can charge during the night when the battery itself is cooler.
Do what I bolded above. Don't worry about putting the EVSE on a timer or any of that other complicated stuff: just set the onboard timer to end before you need it in the morning. This isn't supposed to be a PITA; it doesn't hurt to leave the pack @100% for a couple hours.
ElectriCute said:
Just small charges when I get a chance to add a little juice, so to speak?
That's fine: just try to avoid "topping off" when the pack is already at or near 80%

Not unless I’m going out shortly after. It’s a shame you can’t check the batter temp from the Nissan Connect mobile app.
 
Stanton said:
just set the onboard timer to end before you need it in the morning.

If the end timer is set to ~ one hour after departure time, the car is charged up to around 90% SoC when it is unplugged. This varies by LEAF and EVSE but it is an elegant solution for people who have predictable schedules
 
ElectriCute said:
It’s a shame you can’t check the batter temp from the Nissan Connect mobile app.
Just look at the temperature bars in the dash when you park at night: if it's > 6 bars, then you know you should wait.
I used to monitor the exact temp with LeafSpy, but that was back when I was trying to manage a Gen1 battery pack with (known) degradation issues.
 
ElectriCute said:
As some of you know, I'm new to the Leaf, and EV in general. My main concern about my car is "battery degradation." This, of course, is something that happens to the battery over time. The idea is to keep that degradation as low as possible. I hear this 20 to 80% theory a lot. A range to keep your battery at in order to lengthen it's life. Why is this? Isn't charging it to 100% a good idea to take advantage of the car's max range? A Nissan customer service rep mentioned to me that charging it to 100% is fine, and as soon as you reach 100%, charging stops. So no trickle charging. Is, what he told me, correct in regards to newer Leafs, or all Leaf cars in general? Like all of us Leaf owners, we want to maintain the battery as best we can so that we get the longest life out of it. To be honest, all of this is rather confusing. What are your thoughts on this subject, please?

Thank you.

Why are you attacking one truth with another? Is there no such thing as many "right" things depending on the ever changing need? Or are you simply determined to find a single process and defend it to the death?

You want the "best" process? That is an easy one rule answer

Charge up to what you need.

Now, your needs will change frequently...or not but they will change so some planning is required. Not much really. Its no more than the mental inventory you take every day when getting dressed, setting your alarm, or whatever.

So we have the best case. Now we also have to look at convenience. Best case means nothing if its too much work or causes an avoidable disruption in your life.

I hear this 20 to 80% theory a lot.

Its based in truth but realize it is a generalization that does not take into account YOUR needs. Adjust as necessary. If you use 60% of your range most of the time, this is a good place to start although I would move away from the idealized centered SOC and go 40 to 100 or even 30-90. Your decision.


Isn't charging it to 100% a good idea to take advantage of the car's max range?

No, actually its the ONLY WAY you can take advantage of the max range but how you plan to use it? It ain't a gasser and yeah, it takes "time" to plug in but its not a special trip away from home (if you have home charging can't recommend that enough) so charging to 100% like every 3 days or something is an incredibly bad idea. Get the "gasser analogies and nonexistent parallels out of your head ASAP!


Anyway, back to "need" Remember, its YOUR definition and EVERYONE's will be different and they will come here passing it off as some sort of no brainer right way and that might be true for them but it is not true for you.

Remember; its your need so NOTHING is off the table. You have already expressed the desire for best battery longevity. That is a great start. Remember; like the Christmas budget (for everyone but my ex) the need is sometimes tempered by the ability so the adherence to the ultimate or best case goal will fluctuate.

So now you have the basics.

My need is 100 miles during the work week; my 3 days off, I have no set formula cause its always changing.

Need;

28 mile RT commute
winter penalty
Unexpected transpo need. After MANY years of tracking my driving (since TG weekend 2003 so not quite a few decades) I found the only one that pops up with any regularity is Seatac airport. That is 53 miles. Other things pop up but are shorter sooo...

This is how I get my 100 miles. Close enough for me so my target SOC in the morning is 50 to 65% using the charge timer. I don't care about being off on my target and have hit nearly 80% a few times and have been under 30% a few times. Its all good. I have no experience whatsoever in pushing the car. ;)
 
SageBrush said:
It is not too surprising that new to LEAF owners are confused by people who say charging to below 100% SoC is advisable, yet Nissan does not give the owner that option, implying that routine charging to 100% SoC is fine.

Answer: Nissan is wrong if the goal is to mitigate battery degradation. How wrong depends on the circumstances. The longer the car sits at 100% SoC, and in particular the longer the car sits at 100% SoC when the battery is hot, the worse the Nissan approach becomes.

OP: you will find that EVERY single owner in this forum who wants to slow down battery degradation takes steps of one form or another to do two things: reduce the time the pack sits at 100% SoC; and second, tries to charge after the pack has had a chance to cool down some in the hot months of the year. The actual implementation details vary from person to person because each person uses their car differently, and each person has their own inconvenience:benefit threshold.

Read the different approaches and adapt one to fit you. Follows is my personal advice to you:

Don't let perfect stop you from doing good enough
A battery stewing for an hour or two is a whole lot better than overnight
A battery stewing at 95% SoC or less is a whole lot better than stewing at 100%
A battery stewing at 80F is a whole lot better than stewing at 90F+

Make an effort, and get on with life. The car will thank you. You can probably gain 70 - 80% of the possible benefit by doing 15 - 25% of the optimal.

Very good generalized one size fits all advice. I thought about trying that as well but no sense in two of us providing the same advice. :lol:
 
Dave, you seem determined to argue vehemently against something (twice, in fact: would you like the duplicate post removed?), but I'm not entirely sure what it is. We are just trying to answer the OP's questions, not brainwash her or force her to do what we do. As for "attacking one truth with another", well, I'm not entirely sure what that means.
 
LeftieBiker said:
Dave, you seem determined to argue vehemently against something (twice, in fact: would you like the duplicate post removed?), but I'm not entirely sure what it is. We are just trying to answer the OP's questions, not brainwash her or force her to do what we do. As for "attacking one truth with another", well, I'm not entirely sure what that means.

I have to laugh when members think I’m a her. I’m a him. 😂😂

I wonder if it’s an assumption based on the name ElectriCute, as in electrocute. I selected that name, but realized some time after that I spelled the name wrong. I should have spelled it, ElectroCute. 😬.
 
I may not have been clear in my earlier post. I baby my LEAF battery to an unusual degree even by this forum's standards, but I think quite a bit less can be done and still reap a good share of the benefits. I am suggesting that battery degradation can be improved by a useful amount if a thoughtful and reasonable approach is used. Nothing crazy is needed. OCD is not needed. The car does not have to turn into the center of one's life.

Here is the proverbial LEAF abuser example. Try to not act this way:
I quick-charge every day up to 100% because it is free, and then I stick the car in my closed and hot garage until the next day. When I drive, it is pedal to the metal, ALL THE TIME !
 
Back
Top