Any memory effect or loss from large charge?

[ve2maa]

A) Is there any problem to recharge the Leaf's battery when it's not empty...Let's say I used it from all bars to 6 bars left... Is there any memory effect if I recharge it while it's still 70% full ?

B) Despite the "possible" memory effect, will my battery life be more shortened by large recharge (lets say from 10% to 80%) than small recharge (let's say from 50% to 80%) ? That could habppen if you work near from home and recharge every day.

That might be weird questions but people ask me those question all the time and I'm not sure enough to answer !

 

[EdmondLeaf]

A) Is there any problem to recharge the Leaf's battery when it's not empty...Let's say I used it from all bars to 6 bars left... Is there any memory effect if I recharge it while it's still 70% full ?

I am not expert, and hopefully we will have expert answer, but my understanding is Li battery have no memory effect

B) Despite the "possible" memory effect, will my battery life be more shortened by large recharge (lets say from 10% to 80%) than small recharge (let's say from 50% to 80%) ? That could habppen if you work near from home and recharge every day.

regen create a lot of small charges that go back to battery while you driving. I will want someone to tell me what is better to get more battery cycles small charges or continuous big charge covering most of battery capacity

 

[adric22]

A) Is there any problem to recharge the Leaf's battery when it's not empty...Let's say I used it from all bars to 6 bars left... Is there any memory effect if I recharge it while it's still 70% full ?

Definitely not. Lithium batteries do not suffer from this, nor has most any battery used in a consumer application (laptop, cell phone, etc) for the last 15 years or so.

B) Despite the "possible" memory effect, will my battery life be more shortened by large recharge (lets say from 10% to 80%) than small recharge (let's say from 50% to 80%) ? That could habppen if you work near from home and recharge every day.

That might be weird questions but people ask me those question all the time and I'm not sure enough to answer !

Most batteries are measured in "cycles" as far as their lifespan goes. A smaller recharge would be a fraction of a cycle. Now, the real question is not so much how big or small the charges are, rather how much use it the battery actually getting. The best way to measure that is in miles driven per year, just like any other car.

 

[DaveEV]

Most batteries are measured in "cycles" as far as their lifespan goes. A smaller recharge would be a fraction of a cycle. Now, the real question is not so much how big or small the charges are, rather how much use it the battery actually getting. The best way to measure that is in miles driven per year, just like any other car.

Not true - let's look at 2 different scenarios.

Let's say you drive 50 miles every day and can drive 100 miles on a 100% charge.

So you have 2 options here:

1. You can charge to 100% every other day, fully cycling the battery.
2. You can charge to 80% every day.

While you will put the exact same number of miles on the battery, scenario #1 is much harder on the battery than scenario #2.

Here's some data on how this can affect battery life: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries" onclick="window.open(this.href);return false;

In the example, the battery will last 500 cycles with 100% DoD. But with 50% DoD, you will get 1500 cycles out of the pack - or 50% more miles! This is pretty typical of Lithium (and NiMH) batteries.

Kind of interesting is that the amount of life you get out of the cell drops at 25% and 10% DoD - I suspect that this is because they are not using the middle of the pack's SoC but charging to 100% each time and then discharging 25-10% - would be nice if they noted this. This would support Nissan's warning of waiting until the battery SoC is below 80% before charging it up to 100%.

 

[GaslessInSeattle]

no memory effect, any fraction of charge is fine, 30 seconds or 6 hours. if the li-ion battery in the Leaf is like other Li-ion batteries I've seen large scale tests done on, it prefers charging in the middle of it's capacity. the battery management system already limits the depth of discharge to a more optimal point and prevents over charging, so it's a pretty good system even with regular full charging and discharging. using the 80% charging timer helps to target the bulk of charging closer to the middle of the batteries capacity, the sweet spot. charging in the middle, based on studies of other batteries may improve the cycle life from thousands of total cycles to tens of thousands. I set the 80% timer and plug in every chance I get and don't think much about it. we'll know a lot more once we get a lot more miles on these packs. so far, they are holding up remarkably well!

 

[ve2maa]

That might be weird questions but people ask me those question all the time and I'm not sure enough to answer Most batteries are measured in "cycles" as far as their lifespan goes. A smaller recharge would be a fraction of a cycle. Now, the real question is not so much how big or small the charges are, rather how much use it the battery actually getting. The best way to measure that is in miles driven per year, just like any other car.

![/quote]

According to that... let say I use 1 third of my battery every day...
It would be the same for the battery life to recharge 1/3 of the capacity every day than a full charge every 3 days !

 

[davewill]

According to that... let say I use 1 third of my battery every day...
It would be the same for the battery life to recharge 1/3 of the capacity every day than a full charge every 3 days !

In general that would be correct, but avoiding 100% and 0% is also good for battery longevity, so in that scenario I'd charge to 80% every day.

 

[planet4ever]

Tip to ve2maa: Try to make your post subjects more meaningful. This one, for example, might have been something like:
Any memory effect or loss from large charge?
Since you started the thread, you can go back to your first post and edit it, changing the subject line. If you do that it will help future visitors who try to search, for example, on information about a memory effect.

One more tip about the battery itself: Others have said that lithium batteries do best in the middle of their charge range, and I take that to mean it's best if you don't have to go above 80% or below 20%. The surprising tip is that when you drop from 2 bars to 1 bar showing out of the 12 bars, you still have about 1/4 of your battery charge remaining! Some people are afraid of using the "red bars". There are no red bars on the available charge gauge; they are all blue and white. The red bars are on a separate battery capacity gauge (12 short bars at the far right). If you ever got down to the red bars there your battery would be almost totally worn out.

 

[SteveInSeattle]

In the example, the battery will last 500 cycles with 100% DoD. But with 50% DoD, you will get 1500 cycles out of the pack - or 50% more miles! This is pretty typical of Lithium (and NiMH) batteries.

Kind of interesting is that the amount of life you get out of the cell drops at 25% and 10% DoD - I suspect that this is because they are not using the middle of the pack's SoC but charging to 100% each time and then discharging 25-10% - would be nice if they noted this. This would support Nissan's warning of waiting until the battery SoC is below 80% before charging it up to 100%.

If the number of cycles noted here were true someone driving the full range of the Leaf and charging every night will have a useless battery in 1.4 years, Given those who have already put significant miles on their cars and had their annual battery check (showing little or no degrading) this cannot be true of Nissan's design and chemisty.

The point about the daily vs. every-other-day may be valid, but the life cannot be. We would have owners with no capacity ALREADY

 

[smkettner]

No issues. Charge when you can and go when needed.

Nissan seems to caution only when charging to 100% when already at a high state of charge such as over 80%.
Also cautions about leaving the car 100% charged for an extended period.

Otherwise just enjoy

 

[GRA]

In the example, the battery will last 500 cycles with 100% DoD. But with 50% DoD, you will get 1500 cycles out of the pack - or 50% more miles! This is pretty typical of Lithium (and NiMH) batteries.

Kind of interesting is that the amount of life you get out of the cell drops at 25% and 10% DoD - I suspect that this is because they are not using the middle of the pack's SoC but charging to 100% each time and then discharging 25-10% - would be nice if they noted this. This would support Nissan's warning of waiting until the battery SoC is below 80% before charging it up to 100%.

If the number of cycles noted here were true someone driving the full range of the Leaf and charging every night will have a useless battery in 1.4 years, Given those who have already put significant miles on their cars and had their annual battery check (showing little or no degrading) this cannot be true of Nissan's design and chemisty.

The point about the daily vs. every-other-day may be valid, but the life cannot be. We would have owners with no capacity ALREADY

Note that the batteries in question were discharged at a C/1 rate, far higher than a Leaf undergoes, also that they were a different chemistry. The study is a useful indicator of the effects of different types of cycles on _all_ batteries, but extrapolating from that particular test to the Leaf's pack and conditions is not useful.

Shallow cycling is better than deep cycling for longevity, and that's about all you can say without getting into specifics. Many EV batteries are artificially limited by the battery controls to 50-80% of their maximum cycling range, say from 30-80%, to make sure they last the warranty period. Others, like Nissan with the Leaf, recommend that you normally charge to 80%, but allow you to charge to '100%' if you wish. In some cases, it isn't 100% of the battery capacity, it's 100% of what they'll let you charge to.

 

[DaveEV]

Some people are afraid of using the "red bars". There are no red bars on the available charge gauge; they are all blue and white. The red bars are on a separate battery capacity gauge (12 short bars at the far right).

The red bars apply to both gauges. See the 2011 owners manual page EV-25, you can clearly see that the red bars are dual-purpose.

 

[planet4ever]

Some people are afraid of using the "red bars". There are no red bars on the available charge gauge; they are all blue and white. The red bars are on a separate battery capacity gauge (12 short bars at the far right).

The red bars apply to both gauges. See the 2011 owners manual page EV-25, you can clearly see that the red bars are dual-purpose.

Oops, you are certainly right about that one picture. However I am going to stick with my statement. For those of us who have been around a year or more, I contend that picture refers to "old bars", i.e. the bar to state of charge mapping that existed before the March 2011 firmware update. I didn't have my car before that but, for the few who did, they were apparently treading on thin ice when they got down to the last two bars. That is no longer true, and there should be no concern in using those last two bars. If you don't, you are throwing away nearly a third of your battery's capacity. It is literally almost as bad, in terms of capacity, as refusing to charge more than 7 bars.

Ray

 

[Luft]

Some people are afraid of using the "red bars". There are no red bars on the available charge gauge; they are all blue and white. The red bars are on a separate battery capacity gauge (12 short bars at the far right).

The red bars apply to both gauges. See the 2011 owners manual page EV-25, you can clearly see that the red bars are dual-purpose.

Oops, you are certainly right about that one picture. However I am going to stick with my statement. For those of us who have been around a year or more, I contend that picture refers to "old bars", i.e. the bar to state of charge mapping that existed before the March 2011 firmware update. I didn't have my car before that but, for the few who did, they were apparently treading on thin ice when they got down to the last two bars. That is no longer true, and there should be no concern in using those last two bars. If you don't, you are throwing away nearly a third of your battery's capacity. It is literally almost as bad, in terms of capacity, as refusing to charge more than 7 bars.

Ray

I must admit that I avoid those last two bars. I'm just too much of a chicken I guess. I don't like walking away from a perfectly good car.

 

[planet4ever]

I must admit that I avoid those last two bars. I'm just too much of a chicken I guess. I don't like walking away from a perfectly good car.

Some time when you are not in a rush you really should try running the battery down closer to empty. It will make you a lot more comfortable with the car. A while after you drop to one bar you will get an audio and visual indication that your battery is low. The estimated range remaining (the "guessometer)) will start flashing. Don't stop yet; you can easily get another 10 miles out of the car and still have plenty of power left to get home. Eventually, some time after the last bar disappears you will get a "battery is very low" audio and visual indication, and the range will change to just show 3 flashing dashes. You still have several miles left, but this is a good time to get to a charging station, preferably at home.

Ray

 

[Lopton]

I must admit that I avoid those last two bars. I'm just too much of a chicken I guess. I don't like walking away from a perfectly good car.

Some time when you are not in a rush you really should try running the battery down closer to empty. It will make you a lot more comfortable with the car. A while after you drop to one bar you will get an audio and visual indication that your battery is low. The estimated range remaining (the "guessometer)) will start flashing. Don't stop yet; you can easily get another 10 miles out of the car and still have plenty of power left to get home. Eventually, some time after the last bar disappears you will get a "battery is very low" audio and visual indication, and the range will change to just show 3 flashing dashes. You still have several miles left, but this is a good time to get to a charging station, preferably at home.

Ray

I second this, with the new software you have 10 miles after the car says you have nothing. That is a lot of range and you shouldn't be afraid to get there every now and then in my opinion. I have no problem running to zero bars now, just involves changing your mindset a bit and knowing the car.

-Matt

 

[TomT]

Yep, I had the "old" bars on my car and when the last one extinguished, you were basically dead. Now you have about 1 1/2 bars under the last bar...

Oops, you are certainly right about that one picture. However I am going to stick with my statement. For those of us who have been around a year or more, I contend that picture refers to "old bars", i.e. the bar to state of charge mapping that existed before the March 2011 firmware update. I didn't have my car before that but, for the few who did, they were apparently treading on thin ice when they got down to the last two bars. That is no longer true, and there should be no concern in using those last two bars. If you don't, you are throwing away nearly a third of your battery's capacity. It is literally almost as bad, in terms of capacity, as refusing to charge more than 7 bars.