Full charge or not?

valem said:

So tell me why do I need to charge every day... from what I am learning so far, it appears that the only way to preserve this Leaf battery, is to charge it to somewhere around 50% and leave it in a climate control garage, and never use it... Anything else you do, will cause degradation.

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What you are mostly hearing on this thread is everyone's pet theory about how to have the lowest rate of degradation on your battery pack. The trouble is that they are mostly theories (though certainly based on some understanding of Li batteries. For every "never charge it above 60%" owner, you have several others who say they always charge to 100%, have 40k miles on their Leaf, and still have 12 bars. Understandable that you feel frustrated at the range of opinions out there, and the range of experiences. Seems to me you are better off not worrying about it too much.

valem wrote:
So tell me why do I need to charge every day... from what I am learning so far, it appears that the only way to preserve this Leaf battery, is to charge it to somewhere around 50% and leave it in a climate control garage, and never use it... Anything else you do, will cause degradation.

Click to expand...

Ha! I had the same thought a while back. Courageous of you to put it so plainly (and in my view, with a very dry wit.)

What you are mostly hearing on this thread is everyone's pet theory about how to have the lowest rate of degradation on your battery pack. The trouble is that they are mostly theories (though certainly based on some understanding of Li batteries. For every "never charge it above 60%" owner, you have several others who say they always charge to 100%, have 40k miles on their Leaf, and still have 12 bars. Understandable that you feel frustrated at the range of opinions out there, and the range of experiences. Seems to me you are better off not worrying about it too much.

Click to expand...

Indeed. I try not to worry about it, and then some new pet theory comes to my attention. This "charging every day is better than not charging every day" is new to me. I don't like it. It threatens my plan.

"More range than you need" is a bit of a slippery concept when the Leaf is your only car. You could need maximum range and maximum charge at any time. You may reckon that you usually do not, and instead try to calculate what the minimum range you can live with is. If home charging involves getting out the EVSE, plugging it in, unplugging, coiling it up and putting it away again, all outdoors in any weather, you may wish to have some days off from this chore. I am currently on a system of charging overnight only when I fall below 60%. That will never take me to 100%, and on this system I am very unlikely to be at work with less than 50% of charge, either. I rather like it, though I would never put it forth as something optimal for battery life, about which I know nothing. The SOC would dwell mostly between 50% and 80% with random fluctuations, and days with no charging would also fall kind of randomly. If there is a serious and proven benefit to charging every single day instead, I'd like to know what it is.

I used to think that an everyday replenishment charge would be the best approach. Make it a routine so that you don't have to think about it and decide all the time. But I have seen that will I get more juice out of one 10-hour charge than two 5-hour charges, an example being 50% to 81% once rather than 67% to 81% twice. I'd like charging only once every 3 days even better, but sooner or later I think I would regret the risk of being at work with 30% or just getting home with 20%.

NoReleaf said:

valem wrote:
So tell me why do I need to charge every day... from what I am learning so far, it appears that the only way to preserve this Leaf battery, is to charge it to somewhere around 50% and leave it in a climate control garage, and never use it... Anything else you do, will cause degradation.

Click to expand...

Ha! I had the same thought a while back. Courageous of you to put it so plainly (and in my view, with a very dry wit.)

What you are mostly hearing on this thread is everyone's pet theory about how to have the lowest rate of degradation on your battery pack. The trouble is that they are mostly theories (though certainly based on some understanding of Li batteries. For every "never charge it above 60%" owner, you have several others who say they always charge to 100%, have 40k miles on their Leaf, and still have 12 bars. Understandable that you feel frustrated at the range of opinions out there, and the range of experiences. Seems to me you are better off not worrying about it too much.

Click to expand...

Indeed. I try not to worry about it, and then some new pet theory comes to my attention. This "charging every day is better than not charging every day" is new to me. I don't like it. It threatens my plan.

"More range than you need" is a bit of a slippery concept when the Leaf is your only car. You could need maximum range and maximum charge at any time. You may reckon that you usually do not, and instead try to calculate what the minimum range you can live with is. If home charging involves getting out the EVSE, plugging it in, unplugging, coiling it up and putting it away again, all outdoors in any weather, you may wish to have some days off from this chore. I am currently on a system of charging overnight only when I fall below 60%. That will never take me to 100%, and on this system I am very unlikely to be at work with less than 50% of charge, either. I rather like it, though I would never put it forth as something optimal for battery life, about which I know nothing. The SOC would dwell mostly between 50% and 80% with random fluctuations, and days with no charging would also fall kind of randomly. If there is a serious and proven benefit to charging every single day instead, I'd like to know what it is.

I used to think that an everyday replenishment charge would be the best approach. Make it a routine so that you don't have to think about it and decide all the time. But I have seen that will I get more juice out of one 10-hour charge than two 5-hour charges, an example being 50% to 81% once rather than 67% to 81% twice. I'd like charging only once every 3 days even better, but sooner or later I think I would regret the risk of being at work with 30% or just getting home with 20%.

Click to expand...

All are very interesting points.

I was doing some thinking, and I am once again back to the "you should charge everyday" comment, and my "why?" reply.

The best answer I got was, "If you are only charging once every 3 days regularly, then you are charging 3X more than you need."

Still not an answer to my question.

You think going down to 20% is too low (I thought 20-80 was the golden range) so if 20 is too low, is 30 ok? what about 35%? or 40%?

Let's assume I drive 20 mi/day and 1%/mi. I could charge up to 40 ... but 20 is too low ... I could charge up to 60, is 40-60% ok or too high?
So in my 20mi/day that I do 40-60% hypotheses ... I get a day off... so I don't charge. But I have to go to the store, it's 2.5 mi away so 5% use
I'm at 40% ... do I charge to 45% (to meet the charge every day?) or do I come back with 35% 20% is too low, but 35% is okay?

I again get another day off, and I have to go to the store again... now I'm at 35% (omg didn't charge yesterday) ... do I charge to 40% (to meet the charge every day?)
Or do I go and come back with 30% ? 20% is too low, but is 30% is okay?

So now I charged only once for 3 days... oh gosh, did I charge too much 3 days ago? But I was doing 40-60 ... should I have been doing 25-45? 30-50? What do I do ...

I'm not trying to argue, only trying to understand... when you say "If you are only charging once every 3 days regularly, then you are charging 3X more than you need." I ask, from where? Obviously not 20% ... but 25? or 30?

I think that there is no answer ...
If I only drive 5mi/day what do I charge up to? 30? 40? Or is it ok to do 45% to 50% everyday as long as I charge every day?
But if I let it go to 30% and charge every 4 days (30-50) I am charging 4x more than I need?

The more I think about it, the more the "charge every day comment" makes no sense to me ... it's not about it being a hassle, it's because there's no baseline. What is the minimum ... makes no sense to me

Charge to keep the SOC within the range of 25% to 70% and you will be doing the best that can be reasonably expected.

"If you are only charging once every 3 days regularly, then you are charging 3X more than you need."

Click to expand...

I think you are posing the questions to Dave, a Leaf owner far longer than I have been who might well have a valid point, but...

For me, an overnight L1 charge when I fall below x%, in my case 60%, works. Without being religious about it or worrying about it or splitting hairs about whether charging at 61% is "allowed." Nothing but a guideline to make life a bit simpler. If I should happen to fall to 40% or lower, then I can plug in earlier. I can always plug in earlier. Dooglas above probably said it best. Although Dave also pointed out that you could do "whatever" if his advice didn't work for you.

Oh wait - here are some statements from Dave we may have glossed over:

"There is a lot of data that suggests the shallower the cycle, the better the longevity."
"But the predominance of [12V] battery issues happened with people who didn't charge every day."

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OK.

My L1 charges are by definition part of a pretty shallow cycle. No problem there. Skipping a 7 hour charge one day doesn't force me to charge 14 hours the next. You have L2, right? That seems even easier to control. No amount of off-duty charging is out of reach for you. Whenever I have fallen unusually low, I've needed to head for a public L2 charging station to supplement the home charge.

Don't know about the 12V battery thing, but correlation is not cause. People who don't charge every day could be people who charge once a week or do whatever else not related to charging frequency.

Oh, and I just noticed that you have a 2013 Leaf with a replacement battery, whereas I have a 2018 with a new battery, so I should just shut up.

There is no connection between not charging every single day and 12 volt battery failures in earlier Leafs. That is more related to either leaving the car plugged in but not charging, or taking lots of short trips, with heavy accessory use.

Final response to the thread;

Cherry picking ifs and and buts do not lend to the discussion. Nothing but a dodge, waste of time, excessive filler which increases the likelihood of missing something that could be important.

If you think your charging plan is ok, then do it. This thread has already provided information and you have been directed to places like Battery U and you have decided that that is not proof enough. So be it.

But remember; I told you from day one and you were reminded several times that the #1 criteria for charging is maintaining "your" comfort level. Why is that so hard to understand.

I've spoken to other M3 owners, and a number of them limit their charge using their app (or car settings) to 70 / 80 pct. Any reason why Nissan won't allow this again?

Would a third party developer enable a feature in their app be able to stop the car charging at a certain percentage?

jdcbomb said:

I've spoken to other M3 owners, and a number of them limit their charge using their app (or car settings) to 70 / 80 pct. Any reason why Nissan won't allow this again? Would a third party developer enable a feature in their app be able to stop the car charging at a certain percentage?

Click to expand...

I've wondered if someone could make an OpenEVSE which talks to an ODB2 adapter via bluetooth (similar to LeafSpy); and ends the charge cycle when the battery is at 80%. I'm not sure if it's possible to read ODB2 while charging. J1772 will someday include P1901.2 HomePlug/PowerLine Internet communication, which would solve this.

A simple method could be if the EVSE stops charging when the charge current starts to taper.
My charge from last night looks like this:

- starting at 48% (about 13.3 kw-hrs per Tony Williams' chart)
- bulk charge for 90 minutes at 6.6kw (+ 9.9kwhrs to about 23.2 kw-hrs total, or 83% SOC)
- a taper of 67 watts per minute for 90 minutes (+ 5.1 kw-hrs to 28.3 kw-hrs total, or "101%" SOC ).

If charging had stopped after charge current dropped under 6kw, then that would have been around 86% SOC. I suspect that there would be a high day-to-day variability in the end-of-charge SOC%, but this would probably sort-of work some of the time

** UPDATE ** was charging from 20% SOC at 6.6kw today, and saw the charging current draw drop. I went outside 10 minutes later and turned on the dash, and saw 94% SOC. That would mean that the taper had probably started around 91% (higher than the 86% guess above). Not ideal, but still well shy of 100%. I'll try to do some more tests.

Opinions on wether charging to 90 or 95 percent in winter is easier on the battery than the same in summer? Minus 12 Celsius outside. Car charging at 8 amps. I kinda time it so that in winter it’s around lie 90 ‘s when I get in and leave. Couple percent an hour.

Pre warm not so effective at that rate. .

webeleafowners said:

Opinions on wether charging to 90 or 95 percent in winter is easier on the battery than the same in summer? .

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I'm not a battery expert, but other posts here have said that degradation is caused (roughly) by Very-High/Low SOC X Duration X (pack temperature squared). The combination of very high or very low SOC for a period of time causes degradation, in a somewhat linear fashion. But high pack temp has a bigger impact (more like exponential). Across the board, summer temperature is the biggest factor in Leaf battery longevity. The most-babied battery in Pheonix probably degrades faster than the most-abused battery in Portland.

I decided that when it's below freezing, I need the range of 100% charge due to cabin heat; and also, the 100% charge probably doesn't do much damage at those temps. In summer, I don't need 100% to drive the same range, so I try to charge to only 80%. So that actually balances-out pretty well.

Appreciate the reply. I was thinking along the same lines.

John.

I'd avoid letting it sit for days at 100% indicated SOC, but aside from that I agree. Although I don't do that with my 2018, which I try to keep below 90% SOC.

LeftieBiker said:

I'd avoid letting it sit for days at 100% indicated SOC, but aside from that I agree. Although I don't do that with my 2018, which I try to keep below 90% SOC.

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Thanks Leftie. Hoping you would chime in. We got back from a couple hours of running around this morning. Brrrrr. And lots of fresh snow. Came home at 68 percent and plugged it in. Selected 8 amps and will let it percolate till tonight and then unplug it. That will put it back around 80 percent. But depending on start charge we’ll let it percolate till the morning when we leave at which point it ends up in low 90’s which is our comfort zone for winter travel.

Thanks again.

John.

If you know that you'll be taking the car out within a day, go ahead and charge it to 100% in Winter. Enjoy that heater!

LeftieBiker said:

If you know that you'll be taking the car out within a day, go ahead and charge it to 100% in Winter. Enjoy that heater!

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Completely pissed off my passengers today. I had used the app to turn on pre-heat about 10 minutes before we came out of a meeting. Car was nice and warm and seat was warm. Dropped him off at his frozen solid Buick a little while later. Gave him my Nissan contacts info. Way fun.

I don't understand why heated seats and steering wheel are so rare in all cars - ICE and EV. The difference between having a warm seat and wheel that you can preheat remotely, and ice cold everything in most cars, that kind of erases the advantages of having an expensive luxury or sports luxury car. And not bothering with the heated wheel is one of the dumbest things Tesla has done - it's right up there with gull wing doors and a car you can't get into unless the driver's window is lowered first.

LeftieBiker said:

I don't understand why heated seats and steering wheel are so rare in all cars - ICE and EV. The difference between having a warm seat and wheel that you can preheat remotely, and ice cold everything in most cars, that kind of erases the advantages of having an expensive luxury or sports luxury car. And not bothering with the heated wheel is one of the dumbest things Tesla has done - it's right up there with gull wing doors and a car you can't get into unless the driver's window is lowered first.

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Agreed especially when you consider the cost to implement.